Black Holes 5: Inklings & Obsessions

by Shane L. Larson

There are many exotic phenomena in astrophysics — some pervade the public consciousness, and others do not. Most folks have heard of the “Big Bang” and probably about “dark matter.” Fewer people have heard of the “Cosmic Microwave Background” or “neutron stars.” Perhaps even fewer have heard of “cosmic strings” or “radio jets.” But of all the strange and wonderful things astronomers and physicists have contemplated, the most universally known and recognized are probably “black holes.” Just about everyone has heard of black holes, and just about everyone has some cool science factoid they know about black holes and keep in their pocket — they pull the factoid out anytime the subject of black holes come up because the factoids typically MELT YOUR BRAIN.

On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box. Cygnus X-1 is located near large active regions of star formation in the Milky Way, as seen in this image that spans some 700 light years across. An artist’s illustration on the right depicts what astronomers think is happening within the Cygnus X-1 system. Cygnus X-1 is a so-called stellar-mass black hole, a class of black holes that comes from the collapse of a massive star. New studies with data from Chandra and several other telescopes have determined the black hole’s spin, mass, and distance with unprecedented accuracy.

I find black hole factoids to be a curious mix of some things that are true, some things that are speculative but possibly true, and some things are are outright fiction. Where do all of the exotic facts about black holes come from, how do we all learn them, and why are some right and some wrong? Wondering about this led me to contemplate when I first heard about black holes.

Black holes have long been a passion of mine — my mom will tell you I was always kind of obsessed with them. But when did I first hear about and learn about them? I certainly can’t answer that question definitively, but I do know some things about my early exposure, so I can try to understand what strange and awesome ideas first attracted my attention.

The earliest encounter of which I am certain is during the 1979/1980 timeframe. This was the time that many people saw Disney’s epic space opera The Black Hole, replete with adorable robots, killer robots, really awful bad dialog, and archetypical mad scientists. It has often been derided for its scientific inaccuracies (most notably by Neil deGrasse Tyson [link]). I definitely saw The Black Hole. Multiple times. And I still watch it sometimes. Neil’s right, there is a lot of inaccurate science about black holes in The Black Hole, but there is a lot that I think was okay too (more on that later). There are definitely modern movies that get the science more uniformly correct (Interstellar), but I don’t mind The Black Hole — certainly not as much as Neil. The point here is this is a known anchor point in my love affair with black holes.

So what could a movie like The Black Hole teach me about real black holes? If you ask almost anyone, they know the correct fundamental thing: a black hole is an object whose gravity is so strong, not even light can escape — even The Black Hole got that right. Since nothing can travel faster than light, nothing can escape. If you fall into a black hole, your fate is sealed. It is this idea of being trapped forever, without recourse or hope of rescue, that lies at the heart of our fascination with black holes. They are strange; indubitably. But to be inescapable suggests a kind of absolute and infinite supremacy. 

Me in elementary school. I’m not sure what I’m doing, but I’m pretty sure I’m not getting into trouble! [Image: Pat Larson]

In 1979/1980 I was in fifth grade, and I was gobbling this stuff up left and right. I was a well known fixture in both my school library (Hygiene Elementary School, in Colorado), and in the Longmont Public Library, where my mom had gotten special dispensation for me to have an “adult” library card so I could prowl through all the science books in the grown-up section. My parents also exposed me to a steady diet of books at home, and while they were all nominally “family books,” some of them made it to the bookcase by my bed and never went through anyone else’s hands. In 1980 one such book was Roy Gallant’s lavishly illustrated Our Universe, published by the National Geographic Society.  I was certainly enraptured with outer space by then, steadily fed by the ongoing exploits of Viking and Voyager as they played out on the pages of National Geographic. But this book — this book. Blew. My. Mind.

It is a book filled with great pictures from an exquisite generation of space probes, and from the best telescopes the world knew in the pre-Hubble era. But the art and scientific illustrations are what sucked me in. Paintings of the surface of Venus. Speculations of what weird alien lifeforms evolution could have created. Stupendous cutaways of planetary interiors and atmospheres. All of it was linked together with Gallant’s trademark lucid storytelling.  This ode to the Universe captured my mind and imagination and never let go. That first copy my parents gave me was read cover-to-cover, and carried for miles and years everywhere I went, pulled out of my backpack in moments of wonder and curious indulgence.

Examples of the art and technical imagery in Roy Gallant’s “Our Universe.”

Near the end of the book, Gallant talks about black holes in just 4 short paragraphs, but accompanies the text with a lavish, full-page artist’s idealization of a black hole in space, tugging on a nearby star, bending the shape of spacetime, and absorbing a beam of light that was inexorably caught in its pull.

He asks in the caption of the picture, “Can you imagine a star so massive that its gravitation eventually crushes it out of existence, leaving only a black hole in the sky?” This is classic Gallant, imploring the reader to immerse themselves in the mystery, throw caution to the wind, and employ their imagination — take what little knowledge you have and simply speculate. That is where good ideas come from, and it is the basis for all science.

The artist’s representation of a black hole in “Our Universe.” [Image: Helmut K. Wimmer]

In many ways, the reason you and I are having this little blog conversation is precisely because astronomers know that black holes exist in Nature and are the central players in many astrophysical phenomena. But reading Gallant’s text it is clear that when he wrote Our Universe, the existence of black holes was still a subject of much debate among scientists. Today there are many ways that we have measured the properties of black holes and confirmed their existence, not the least of which are the many that have been detected via gravitational waves. But still, pictures of black holes remain elusive. The best we have so far is the Event Horizon Telescope picture, a silhouette of a black hole against the backdrop of stuff around it.

The picture in Gallant’s book is an attempt to show a black hole as a three dimensional object in real space, but how do you do that?  It was a noble attempt, and it is certainly not what a black hole looks like, but it served its purpose — it got my attention, it fueled my imagination, and it made me ask questions then go see if the answers were known. To this day I keep copies of Our Universe nearby — one in my office and one in my study at home. It is never far from my mind nor my fingertips, and I often pull it down and lose myself in the epic stories it tells.

The other thing I know happened to me in the fall of 1980 was my first exposure to Carl Sagan’s Cosmos. Starting in late September, every Sunday night, I sat rapt on my parents’ living room floor in front of the television, whisked away to worlds and places in the Cosmos I had only previously imagined, transported by the magic of film, the lilting and elegant soundtrack of classical music, and Sagan’s poetic and sonorous narrative. One of the most widely known episodes is Episode 9, “The Lives of the Stars” which famously begins with Sagan declaring, “If you wish to make an apple pie from scratch, you must first invent the Universe.”

Sagan uses his famous declaration about pies to introduce the concept of the chemical elements — the atoms from which all the beautiful and complex structures of Nature are built. Beyond the simplest elements — hydrogen and helium — very little was created when the Cosmos was born. Almost everything on the periodic table is created by stars during their lifetime, and a great deal of it (the heaviest elements) during the catastrophic death throes we call supernovae and gamma ray bursts. In telling us about the death of stars, Sagan uttered the magic words I had heard before — black hole. In his trademark penchant for poetic description, he called it “a star in which light itself has been imprisoned.”

Sagan’s Cosmos was the first place I was introduced to the ideas of black holes in the context of general relativity, beginning with masses curving space and affecting the motion of other masses, and also a discussion of the principles of black holes as tunnels [Images from Ep 9: “The Lives of the Stars”]

He had led us to the existence of the super-strong gravity of black holes through an imagined tea party with Alice and her friends in Wonderland, but then he hung on it all the modern picture of curved spacetime. It was, as far as I know, my first exposure to Einstein’s brilliant realization, and it has ever since dominated my destiny. Today, I have a doctorate in theoretical physics, earned for studying the magical mysteries of that self-same curved spacetime.

Me and J. Craig Wheeler. He’s one of the reasons you’re reading this blog right now!

For many of us, our interest in black holes might be piqued by these kinds of exposures, and then we go back to our lives as dental hygienists or soybean farmers or city managers. But this was all still swirling in my mind when I entered college, and in the true traditions of higher education, my exposures took those latent passions and exploded them into what would become my life. I was an undergrad at Oregon State University and at that time there was a stupendous class on campus called “Rocks & Stars,” run by the indomitable Julius Dasch. This was one of the most popular classes on campus, and had a regular stream of guest speakers who visited and talked to us about cool stuff.  I have strong memories of one visit from J. Craig Wheeler, a supernova expert from the University of Texas at Austin.

Supernovae are one of the pathways for making black holes in the Universe, and Wheeler gave us a spectacular talk that culminated with him reading to us from a science fiction book he wrote, called “The Krone Experiment.” I won’t give it away (go read it!) but what I remember from the talk was Wheeler talking us through what would happen if you were standing on a sidewalk and a micro-black hole came booming up out of the ground next to you. What would you see and experience? It’s the sort of question that just captures your brain and won’t let go. To be honest, it was the perfect question to ask a young scientist in the throes of deciding to commit their career to studying these enigmatic objects.

I think every one of these stories illustrates a key fact in my mind: it didn’t matter what I heard about black holes in my youth, only that I did hear about black holes. Exposure did what it should: it filled my head with all kinds of possibilities, all of them totally brain-melting, and made me pay attention and ask questions later.

This last point is the most important point here: we want people to ask questions. Either because they are confused, or because they are idly curious, or because they want to learn more. To that end, having mind bending movies like The Black Hole is stupendously important, and I don’t care if they get the science perfectly right! I have colleagues who often grouse about bad science in movies, complaining vociferously that the producers should have taken a basic science class, or gotten a good science advisor. They proclaim, “Is it really that hard to get the science right? The right science is just as cool!” 

But people aren’t watching The Black Hole to learn science (I certainly wasn’t) — they are being entertained, itching a part of their brain that wants to be asked “is that even possible or real?” And that serves its purpose, because eventually every one of them ends up in an audience somewhere at a public lecture and raises their hand and asks someone like me “is what happened in the movie real?”  THAT is where we get the science right. The movie’s job was to put a question in someone’s mind, to make them care enough to know what the right answer might be, and then in some other part of their lives have some discussions about science, what is known, what is not known, and what the other mysteries of the Cosmos might be.

————————–

This post is the last in a series about black holes.

Black Holes 01: Imaging the Shadow of Darkness

Black Holes 02: What are black holes made of?

Black Holes 03: Making black holes from ordinary stuff

Black Holes 04: Singularities, Tunnels, and Other Spacetime Weirdness

Black Holes 05: Inklings & Obsessions (this post)

Astronomy as Sherlockian Drama

by Shane L. Larson

The world, and social media in particular, was riveted this past week by the announcement of a strange optical signal from a star 1480 lightyears away in the constellation Cygnus, called KIC 8462852. Part of the suite of targets observed by the Kepler mission, the data shows the brightness of the star going up and down in odd ways, unusual when compared to typical stellar brightness records (what astronomers call a “light curve”) that we’ve ever seen.

The location of KIC 8462852 in the sky, 1480 lightyears from Earth, in the constellation of Cygnus.

In an of itself, the changing of a star’s brightness would not normally garner news around the world. Many stars fluctuate in brightness, and dips in brightness caused by a planet passing in front of a star is a common tool to search for worlds elsewhere (this is, in fact, what Kepler’s primary observational goal was).

No, what caused the stir is the somewhat speculative notion that the weird light curve could be artificial in origin, caused by mega-structures, built by some unimaginably advanced alien civilization, orbiting this star.

For a species that longs to know if we are alone in the universe or not, and for a civilization that is well versed in speculating on the existence of life elsewhere for entertainment purposes, the idea of alien mega-structures immediately conjures well imagined pictures and ideas in our heads, and generates tremendous excitement. Hence, the response of the world-girdling infoweb.

Alien mega-structures might slowly be built up to girdle the parent star, occasionally blocking the light. [Image by Kevin M. Gill]

The idea has been met with tempered and cautious response from scientists (here, here, here, many more!). There are many competing psychological and sociological forces at work. First: we don’t want to squelch people’s enthusiasm for our work (“OMG! The world cares about light curves!”). We also don’t want to give the impression that we put much stock in an (obviously crazy) idea like “alien mega-structures.” But we also want to impress upon people that we entertain any and all ideas.

I’m a practicing scientist myself, and I’d like to take a slightly different view on this matter. We shouldn’t be tempering our response at all! There is nothing wrong with assuming from the get-go that this signal IS alien mega-structures — the analysis and  evolution in our thinking that follows will be the same either way.  So how will it all shake out?

Annual World Energy Demand. Note the constant and steady growth over time. [Wikimedia Commons]

To begin the story, it is useful to go back to the beginning — where did the idea of alien mega-structures come from? It is part of a very old observation that as our civilization grows, and our dependence on technology grows, our need for energy grows as well. Since the Industrial Revolution this growth has, more-or-less, been unchecked. Looking at a graph of the growth in energy use by the human race, we see that there will come a time when we will outgrow our ability to produce the energy we need by “simple” means (such as burning fossil fuels).

This idea of predicting the future is a large part of what science and engineering are all about: take some observations of the world today (“data”), look at what the evolution up to today has been (“historical record”), and using the Laws of Nature calculate what should happen tomorrow (“prediction”). When tomorrow gets here, you make a new observation and ask, “did things turn out like I expected?” If not, you refine your prediction method and try again. Over time, you get very good at predicting the future.

Scientists do it all the time — we know where Mars is will be when we shoot rockets towards it; we know how much water and waste dialysis removes from a kidney patient’s blood and can tell how often they have to dialyze; we know how much friction the cylinders in your car experience, so know how much heat your cooling system has to dissipate; and so on. Science is about predicting the future, and using that power to improve our lives.

Freeman Dyson

So in 1960, physicist Freeman Dyson was thinking about the escalating energy needs of our civilization, and proposed that some day we would reach a point where the best possible source of energy was the Sun, and in order to maximize the use of that energy, we should completely surround the Sun by a solid sphere (now known as a “Dyson sphere”), so that every bit of sunlight was captured and could potentially be used. The idea has originally been proposed in a science fiction novel by Olaf Stapleton (“Star Maker” in 1937), and Dyson suggested one way to look for alien civilizations was to look for such a mega-structure in the Universe.

Find a quiet corner of your couch, grab a bowl of popcorn, and start thinking about building such a structure. You can imagine what an enormous engineering endeavour it would be — the sphere would have a surface area 550 million times larger than the Earth! Obviously it would have to be built by a civilization far more advanced than ours. Perhaps more obviously, it could not be built all at once — it would take generations to design, construct, and maintain! So one might imagine that it could be built up piecemeal, not as an entire sphere, but as a swarm of parts that if connected, would form a Dyson sphere. One famous realization of this is Larry Niven’s “Ringworld”, where a star was girdled by a single continuous ring, with the inhabitants living on the starward side of the ring.

A ringworld is one option for a civilization that does not want to invest in building an entire Dyson Sphere. Perhaps it is just an intermediate stage that will ultimately lead to a full sphere. [Wikimedia Commons]

This all sounds perfectly reasonable, provided you can imagine the construction endeavour needed to construct such an artifact.  So why all the skepticism toward the idea of the signal in KIC 8462852 being alien mega-structures? The simple fact of the matter is we can’t imagine humans building a mega-structure, so we find it hard to imagine any civilization building a mega-structure.

The cautious skepticism of the scientific community can be summarized by Marcello Truzzi’s observation that was popularized by Carl Sagan in Cosmos: “Extraordinary claims require extraordinary evidence.” This is often regarded as a modern restatement of the Principle of Laplace: “The weight of the evidence should be proportioned to the strangeness of the facts.”

[L] Carl Sagan, [M] Marcelo Truzzi, [R] Pierre-Simon Laplace

Laplace was highly cognizant of the fact that our knowledge of the world, and hence our understanding of the world, evolves over time. New discoveries and new observations necessarily make way for new ways of thinking. So what to do when you encounter something strange and unusual?  Laplace wrote in 1814 in his essay Essai philosophique sur les probabilités, “We are so far from knowing all the agents of nature and their diverse modes of action that it would not be philosophical to deny phenomena solely because they are inexplicable in the actual state of our knowledge. But we ought to examine them with an attention all the more scrupulous as it appears more difficult to admit them.”

So, at the outset, intellectual honesty insists that we cannot deny the weird signal from this star may be due to alien mega-structures. But we must examine such claims with extreme skepticism. Because it appears difficult to explain how it might be alien mega-structures.

Or is it? Why is it difficult to explain these as alien mega-structures? Any more-so than some other plausible explanation (many of which astronomers have already discounted)?

Astronomy is a Sherlockian drama, and as the famous detective observed to Watson (in “The Sign of the Four” [1890]), “When you have eliminated the impossible, whatever remains, however improbable, must be the truth.” Astronomers are starting at the top of their list of possible “natural” causes, and eliminating them one by one.  The data at hand is that we see the brightness of the star changing with time, and the pattern of brightness changes looks… weird.  What could it be?

Light curves for KIC 8462852 — the lines plot the brightness of the star, with time across the horizontal direction. If the line is high, the star is bright, and if the line dips, the star gets dimmer by some amount. The deeper the dip, the bigger the change in brightness. The top panel shows the full light curve. [C] Enlarged view of the dip around day 793; very typical shape for “common” dips used to detect planets, but BIG. [d-f] These enlargements of other dips are the mystery — they are BIG, but also show remarkably complex structure. What is causing this? [Figure adapted from Boyajian et al (2015)]

Perhaps it is just a variable star. We know of many different kinds of variable stars in the Cosmos. These stars, due to some process in their innards or due to some interaction with their environment, change in brightness in a steady and regular way. These variations seen in KIC 8462852 are not apparently regular in immediately obvious ways. More to the point, astronomers would not normally expect there to be intrinsic variations in the brightness of this star. Why? We know how big and how old it is, its temperature and composition — all of these bits of information define what astronomers call the “spectral type.” It’s a bit like classifying different breeds of cats — you know one cat is a different type than another based on gross, observational characteristics like fur color and length, tail and ear structure, and so on.

KIC 8462852 is a spectral type F3 V/IV (just in case you ever get that question in a round of Trivial Pursuit) — this means it is about 1.0-1.4 times the mass of our Sun, and has a surface temperature between 5700 and 6700 degrees Celsius. There are lots of F-type stars known to astronomers — they are yellow dwarf stars, in the middle of their lives, stably burning hydrogen on the main-sequence. To see an F-type star show tremendous strange variability would be a serious challenge to our understanding of stellar astrophysics, and the overwhelming data supporting the stable brightness of F-type stars in the galaxy. Astronomers think this is not what is causing the light curves.

Perhaps it is a debris disk of some sort. The Oort Cloud is a bubble of debris that surrounds the outermost fringes of stars like the Sun, the left-over icy detritus from the formation of the Sun and its attendant planets. We know of the Oort Cloud because periodically, it drops an icy rock into the inner solar system, which you and I call a comet. Maybe another star in the galaxy passed very close to KIC  8462852 (a rare, but not impossible occurrence) and disturbed its Oort Cloud. The gravitational tug of this passing star would have churned up the Cloud, and destabilized it so lots of comets dropped in toward the star. That doesn’t sound far fetched until you look at the light curve — fully 22% of the light from the star is blocked during some of the light curve dips. Comets are tiny, only 1/10,000th the diameter of a star. It would take an absurdly large number of comets to make the data look the way it looks.

There are many scenarios we can imagine that will generate vast debris fields around stars [NASA Image, PIA11375].

Maybe there was an enormous collision between planetary sized objects, creating a debris disk or some kind of large asteroid field. This is not unheard of — the Earth’s Moon is thought to have formed by such an impact, early in the history of the solar system.  If there was such an event, there should be a lot of residual dust, which would glow brightly in infrared light. So far, astronomers have not noticed any extra infrared light from KIC  8462852, casting doubt on this idea.

And so on. We just keep working our way down the list of clever and plausible explanations.  But when we get to the bottom of the list, what if the one idea we have left is alien mega-structures? What will we do then?

I maintain that this should not bother us at all. The reason is simple: we have not looked for alien life long enough, nor the signatures of alien civilizations carefully enough, to know what their signatures are! When you’ve been doing zillions of experiments and making zillions of observations, it is easy to discount ideas in the face of overwhelming data, but in the case of alien civilizations, our experience in the search is so profoundly limited that scientific integrity demands we consider the possibility.  We haven’t searched for aliens enough to know whether they are improbable or not.

But science is not a game where you rest on your laurels either.  Everything we believe is subject to constant scrutiny no matter how confident we are in the results. That’s what science is about — not fooling yourself. As Feynman quipped, “The principle is that you must not fool yourself, and you are the easiest person to fool.” (Caltech Commencement Address [1974]).

So over the next many weeks, possibly months, maybe even years, we will observe and scrutinize and ponder KIC  8462852. Eventually someone will have a clever idea that suggests it is not alien mega-structures. When they do, astronomers will look at the idea and say, “if this is true, then this other thing should also be true” and they’ll go check.

If they are right, the idea of alien mega-structures will fade, and we will be no worse for wear. But if they are wrong, we won’t be able to discard the idea, and we’ll live with the notion of alien mega-structures a bit longer. And perhaps longer, and perhaps longer still.

My standard bet: a Dr. Pepper and a Boston Cream Donut. What have you got to lose?

But in the end, the Sherlockian drama will play itself out: whatever remains in the end, must be the truth. Alien mega-structures or not.

PS: In case you haven’t guessed: I don’t see any reason to favor or disfavor alien mega-structures. So I’ll bet you a Dr. Pepper and a Boston Cream donut it’s alien mega-structures… 😉

Equality in the Market of Ideas

by Shane L. Larson

Science is a beautiful and inspiring endeavour that has many facets. It satiates a deep and abiding curiosity about the world around us. It expands the boundaries of knowledge. It resolves powerful mysteries about the machinery of the Cosmos. It provides solutions to daunting problems, both abstract and concrete. It teaches us about cause and effect, about predicting the future from the past and the now. It inspires us to think deeply about our place in the Cosmos, and our role in the future of our small planet.

All of these things that science can do are uplifting, and in the end serve to condition our brains to accept the most important feature of science: that science can help us improve the human condition. Medical imaging allows us to diagnose and prepare treatments for conditions that killed our ancestors. Modern vaccines have almost wiped out diseases like smallpox and polio. Clean drinking water is available to millions of people around the planet. Disaster relief supplies can be flown around the world in less than a day, to any locale on the planet. Massive dikes and levee systems can protect cities from seasonal flooding, and bank water for future agricultural use. There are millions of examples of how science touches our lives, every single day.

Science directed at the human condition. (Top L) Non-invasive medical imaging. (Top C) Iron lungs keeping victims alive during a 1952 polio outbreak. (Top R) Clean water supplies. (Lower L) Dikes and levees to manage water. (Lower R) Transportation technology connects the world, especially in times of need.

Perhaps one of the most recognized ways that science has improved our lives is through the connectivity of the modern world. We live in an age where the world is inter-connected in exquisite and instantaneous ways. Technology has democratized the collection and distribution of information. The internet, the great marvel of the modern age, changed information from a commodity into a pervasive entity that many of us take for granted, in the same way we take electricity and air for granted. Digital communications technology allows us to be instantly in contact with colleagues, family and friends on opposite ends of the planet, and it puts every bit of human knowledge instantly at the fingertips of everyone who has a link to the pulsing network of information exchange that now girdles the Earth.

But the global information network has an unappreciated shadowy side, namely that everyone can post/blog/tweet anytime they want, and can post/blog/tweet anything they want. Gone are the days when produced newspaper and television and radio were the only sources of information. Not everything you see now has been carefully thought out, researched, or vetted. Much of the information we receive today is spat out in the moment, as events are happening, and colored by whatever emotionally charged state we find ourselves in at the moment we post/blog/tweet.  Additionally, information gets compressed into easily digestible soundbites (something that is not always easy to do with difficult concepts!).

The currency of the day is not expertise in a particular area of human knowledge. No, that idea would preclude the central tenet of the information age: the web is an egalitarian medium, where every voice has an equal chance to garner attention. The currency of the day is influence — the number of followers you have, who listen to what you have to say and repeat it to those who listen to them.  And therein lies the hidden seed sown with the idea of equal access to information. In this web of the information age, any opinion is and can be expressed.

This simple fact has one enormous consequence on the world: ideas from the fringe (sometimes dangerous ideas, if dangerous ideas do exist) gain traction in our society.

If you have a lot of social influence in the electronic sphere of information that cradles our society, then it is easy for you to promote ideas that support your agendas and ideals. The global network allows you to connect with like-minded people in a way that was never possible before, and those connections will help amplify your agenda. Soon, your ideas have been repeated so often and seen by so many people, that it gains status as a “fact.”

There is no stronger lobby in this respect than the growing anti-science movement. Science created the web, and as it turns out, is falling victim to it as well. Every day, the long slow gains our species has made against the darkness, the triumphs that have been excruciatingly won from Nature, are roundly challenged in the wild frontiers of the information age. Climate change denialism; anti-vaccination propaganda; moon-landing hoaxers. It is at best, misunderstood ideological differences that could easily be resolved over beers and pizza. It is at worst, willful ignorance being promoted to prop up other ideological, economic, and social agendas. But it is enabled — powered — by the notion that every idea has equal validity and deserves equal voice in the electronic medium of our time.

This willful promotion of ignorance is nothing new. It has always been a weapon used by those with their own agendas to sow discord among the masses. Isaac Asimov famously noted this in a 1980 essay for Newsweek (21 Jan 1980), that is an almost eerily prescient assessment of the world today. He wrote, “There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that ‘my ignorance is just as good as your knowledge.’ ”

At the heart of Asimov’s point is the meaning of the all important commodity of science: knowledge. As scientists, we must accept any ideas as valid points for consideration — science is founded on the equality of ideas. All points of view are deserving of investigation and consideration. However with that open and egalitarian philosophy about ideas comes the hammer of science: scrutiny. There are no aspects of an idea that are off-limits for investigation; no implications are left unconsidered, no question is left unasked, there are no weak spots in ideas that are left unpoked and unprodded. The analysis of all ideas in science is ruthless and unforgiving — as much as possible, it is dispassionate and detached. Sometimes the outcome of our investigations are uncomfortable, but as scientists we must accept that fact courageously and move forward, no matter what the implications might be. In this sense, not all ideas are created equal. Notions about the world that fail to explain or predict what we see going on around us must be abandoned and discarded.

Knowledge is nothing more than our current best understanding of the world, based on everything we see around us. Science is the tool we continually use to cast self-doubt on our knowledge, to ask “Is this right? Are we still sure it is right? Have I seen anything that convinces me this is wrong?”  If we see something new, that conflicts with what we previously believed, then we update our beliefs — we update our knowledge.  Science is not politics — flip-flopping is a required part of the game.

This idea makes people uncomfortable and nervous. If knowledge can evolve, how can we believe anything? The problem with this perception is that most of us have been raised to put knowledge on the highest pedestal of importance. In reality, however, there are two pillars in science: knowledge and data. And they are NOT on equal footing.

Data is what we see around us, observations of the world. Data is immutable; it can be added to, but never changed. By and large, there are not huge shifts in scientific thinking because for the most part we’ve been observing the world for 40,000 generations, and Nature seems pretty well behaved. Gravity on the Earth doesn’t suddenly start pulling upward instead of downward. Cups of coffee don’t sit on your kitchen counter and start spontaneously heating up. Squirrels don’t suddenly develop fangs capable of delivering venom more deadly than a cobra’s. The preponderance of millennia of observations assure us none of these crazy things will happen. But if they did, we would have to explain them!

Knowledge is how we explain the world.  “Knowledge” is malleable, constantly evolving to reflect new data. It seldom changes dramatically, because of the preponderance of data that exists. Any knew observation of the world has little, if any chance, of invalidating the millions and millions of things we’ve seen before. If we see something new — a new particle in Nature, a new kind of cloud, or evidence of water on Mars — we update our knowledge in such a way as fully explain everything that we knew before, but explain the new data as well.

You and I do this every day.  For instance, consider color. You think you know what you mean when you say “green” and when you say “yellow.” So what color is this sign? If you had never seen this sign before, you probably wouldn’t have a name for it. Now go show it to several of your friends, and ask them what color it is — you’ll probably get several different answers. In the end, you have to update your “knowledge” (your list of colors) to accommodate your observations of the world (whacky colored signs). The data (a new colored sign) was more important than your previous knowledge (a limited number of colors).

There are many examples of this kind of “updating” of knowledge that have occurred in the course of history. The transition from Newtonian gravity to general relativity, which is now used in every GPS device on Earth. The mathematical development of quantum mechanics and its subsequent experimental validation, ultimately leading to the development of diodes and transistors in the computer you are reading this blog post on. The discovery of Mendelian inheritance in genetics, and its use in the cross-breeding of agricultural crops to develop foodstocks that are high-yield and resistant to disease and drought. Knowledge evolves, and the consequence of that evolution is the improvement of the human condition.

In the end, the epic battle of our age is a struggle to explain and communicate ideas as subtle and conflated as “data” and “knowledge” because they are central to the scientific underpinning of our modern world. They are notions that every scientist has to be comfortable with. But in the parliament of the the global information network, not everyone has the same background and training and vocabulary as your garden variety scientist — it makes communication difficult at best, and it makes understanding even harder. But the effort must be made, lest we condemn our society and planet to an uncertain, if not bleak, future. The efforts must be ongoing, relentless, understanding, and compassionate. Beliefs about the world are dearly held, and difficult to let go of. It is easy to ignore or dismiss ideas that are difficult to understand. It is uncomfortable to feel confused, it is disconcerting to not know who to trust or what to believe.

Carl Sagan, ever a great humanist, commented on those arrayed against science in his 1995 book, The Demon Haunted World, writing, “In the way that skepticism is sometimes applied to issues of public concern, there is a tendency to belittle, to condescend, to ignore the fact that, deluded or not, supporters of superstition and pseudoscience are human beings with real feelings, who, like the skeptics, are trying to figure out how the world works and what our role in it might be. Their motives are in many cases consonant with science. If their culture has not given them all the tools they need to pursue this great quest, let us temper our criticism with kindness. None of us comes fully equipped.”

None of us comes fully equipped.

——————————————

This post was written as part of Blog Action Day 2014, whose theme this year was #inequality. #bad2014

Cosmos 14: A Personal Voyage

by Shane L. Larson

As I write this, I’m heading home from the PhD defense of a new young mind in Physics, where we argued about how Nature might have created time from gravity. I’m typing this on an iPad, a glossy piece of imagination made of glass and aluminum that instantly connects me to all the collected knowledge of the human race.  I’m sipping a cup of coffee, water infused with flavor and essences of a plant, extracted with one of the oldest human discoveries, fire.  Most impressively, I’m sitting in an airplane as I write this, blazing along at 520 mph.  To quote the comedian, Louis C.K., I’m sitting in a chair in the sky! I’m like a Greek myth right now.

The CRJ700 I flew today; one small bit of a modern Greek myth.

All these things are a result of the human proclivity to know the world around them. Each one is an evocative realization of imagination and creativity. Someone once imagined that we could do what birds do, and fly through the sky — an ancient dream told in the myth of Icarus, unrequited in the notebooks and imaginings of Leonardo da Vinci, realized at last barely more than a century ago. Someone imagined that I should be able to more or less instantly find out when the Slinky was invented, or hear Johann Sebastian Bach’s Brandenburg Concerti  on demand (No. 2 in F major is included on the Voyager Golden Record). Someone imagined that we could understand how Nature created time itself, and suggested ways that we could test those ideas. And perhaps most importantly, someone imagined that you should throw an innocuous bean into the fire, pull it out before it is completely destroyed, mash it up, mix it with boiling water and drink it — a stunning tour de force of imagination, perseverance and creativity!

iPad and coffee — two important and remarkable outcomes of science!

These are the kinds of things I think about every day — the trappings of every day life, which we often take for granted.  We overlook how truly remarkable every one of them is. Everything around you in your life we discovered by studying the world and figuring out how it works. That game of curiosity, exploration, discovery and application is what we mean when we say SCIENCE, and it is one of the most important things humans have figured out how to do.  Not just important because we know how to make smartphones and pharmaceuticals and band saws and rubber duckies, but important because in all the vastness of the Cosmos, we are the only form of life that we know of (with certainty) that has figured out how to do science. The methods of science are a natural and inevitable consequence of applying our curiosity to the world, and with it we can improve our lives.  This was one of the central themes of Cosmos.

The frontpiece to my Ph.D. thesis.

For the past two and a half months, I’ve revisted Cosmos each week, once again walking along the shores of the Cosmic Ocean, turning over interesting shells and poking at bits of cosmic flotsam and jetsam that have washed up on our shores.  I’ve listened to the tales of adventure and discovery; I sailed along side our robotic emissaries once again as they made the first grand voyages to the other planets in our solar system; and I once again learned a little bit of the history of how we came to start thinking about the wonder and mystery of the Cosmos.  And woven throughout it all, I once again soaked in the unshakable belief in our ability to learn, adapt, and make a better tomorrow.

I’ve enjoyed revisiting Cosmos one more time; I’m sure I will do it again, many times in the future.  On this particular visit, I did something I hadn’t done before — I tried to add to the stories, as many of you reading along know (my series started here).  All told, this game produced 31,000 words posted to the blog (not including this post).  I learned some new things along the way, and enjoyed myself immensely. For now, this is the last bit that I’ll write about Cosmos directly, though I’m sure we’ll return to it now and again in the future.

For the moment then, my Personal Voyage has come to a resting point.  In a few short hours, we will all return once again to a broken cliff on the shores of the Pacific Ocean, a place where more than thirty years ago we set off on a journey with Carl Sagan to explore the Cosmos.  Tonight, we’ll start the journey anew, with a new guide.  Like that first personal voyage, this one promises to be full of wonder, mystery, introspection, and discovery.  It’s time to get going again.

Carl Sagan, on the Pacific Coast, where the Cosmos journey began.

————————————

This post is the last in a series celebrating the forthcoming science series, Cosmos: A Spacetime Odyssey by revisiting the themes of Carl Sagan’s classic series, Cosmos: A Personal Voyage.  The introductory post of the series, with links to all other posts may be found here:  http://wp.me/p19G0g-dE

Cosmos 13: Who Speaks for Earth?

by Shane L. Larson

Let me tell you a story about me that many people don’t know. When I was in junior high school, I was a small, exceptionally nerdy child who loved Star Trek, science, games of all sorts (provided they didn’t involve “teams” or “athletics”), and learning. My very best friend of the day was a similarly minded young gentleman, who introduced me to computer gaming (“Colossal Cave”, which we played on the mainframe at Ball Aerospace, where his father worked), World War II aircraft, and car mechanicing. He also had epilepsy. It was frightening when he would have seizures, because he would go blank and suddenly it was like he didn’t know me or anything about the world around him. I don’t recall how long these episodes would last, but what I do remember is his father would swoop in, and sit with him for time, and eventually my friend would be back, and we’d be off to explore the world again.

A scar on the orbit of my left eye; stitches in my 7th grade year. The scar has faded slowly over the years, but is still obviously there if you know to look for it.

Now, as was often the case in the cruel world of middle-school aged children, we were the target of bullies. My locker neighbors reveled in shutting my locker each time I opened it, or knocking all my books on the ground so I was tardy to next period. Once they took my prized possession of the day, the Collected Novels of H.G. Wells; when I decided that day to fight back, I was bodily thrown across the room into a metal chair, gouging myself on the orbit of my left eye, requiring 7 stitches and leaving a scar I still have today. My best friend was a similar target, with more serious consequences because the physical bullying would often trigger a seizure. The school administration took an all too common viewpoint on these matters: no one saw it, so it is your word against theirs. An odd viewpoint in light of the amount of blood streaming down my face (I don’t know what the bully had told them, but to be fair I had bit him when he had me in a headlock).

Me and my family, in my high school years. My mom and dad instilled in all three of us boys a robust sense of justice.

Now my parents are the most moral, upstanding people I know, and taught me a deep personal philosophy about justice. Now, in the wisdom of my adulthood, I like to hang quotes from Gahndi on it, like “It is better to be violent, if there is violence in our hearts, than to put on the cloak of nonviolence to cover impotence.”  But really, what I remember are words from my Pa: “Bullies are really just cowards, so knock them down. And make sure the bastards don’t get back up.”  The matter all came to a head on a late winter day during my 7th grade year. My best friend had his head bashed against a locker, which triggered a bad seizure. No teacher saw it happen, but I resolved it was going to stop.  At the end of lunch period that day, I bought an extra milk, and opened the carton on both sides. I remember one of my other nerdy-friends standing next to me saying, “Aw, how are you going to drink that now?” I didn’t answer; I was standing behind the locker-basher, who was sitting at a table. I upended the carton of milk over his head, and beat the tar out of him. The event instigated one of the largest food fights the junior high school had ever seen, and I was awarded a 2-week suspension, which I took without argument.

One of the most often reproduced Apollo images; Jim Irwin on the plain at Hadley, in front of the Lunar Module Falcon and Lunar Rover. [NASA Image AS15-88-11866]

The aftermath was the most important. My friend and I were never the target of these particular bullies again; nor were we the target of a somewhat wider group of bullies who had always circled on the fringes of our lives. This kind of mayhem was far outside the boundaries of what was expected from me. The event somehow incited some people to ask what really happened, and to pay attention. After a long discussion with the faculty advisor about the event and the reasons behind it, my National Junior Honor Society membership was maintained. My suspension was lifted a week early, so my friend and I both could attend a school assembly featuring Apollo 15 astronaut Jim Irwin, whom we met and talked with! But most importantly, my science teacher docked my term project about the anatomy and life cycles of frogs from a 100% to an 80%, dropping me a letter grade in the class. It blemished an otherwise admirable middle-school academic record. She never said a word, and just kept right on treating me like the scientist she seemed to know I was going to become. She reinforced a lesson my parents had already touted — there are always consequences, even when you are doing the right thing, but it shouldn’t stop you from doing the right thing.

Now, in my adulthood, I still carry that same overbearing, black and white opinion about justice, and an unfailing opinion that people who can stand up should stand up for those who can’t. It is something that I often think about as I push my way blindly forward in my career.  What do I do everyday, when I’m not writing this blog for you to read?  I’m a scientist; an astronomer. What does that have to do with bullies and childhood scraps? Everything in the modern world.

A white dwarf is the skeleton of a star like the Sun, long after it has died. It has about the mass of the Sun, but is the size of the Earth. [Image by STScI]

In my everyday life as a professional scientist, I spend my time thinking about astrophysics, exploring our understanding of how gravity influences the evolution and life of white dwarf stars, the ancient cooling skeletons of stars that lived their lives like the Sun. Some days, I teach intro science classes to young women and men bound for careers in business, medicine, law and management; people who may never take another science class in their lives, nor think all that much about science ever again. Every now and then, one of them asks me, “What is understanding white dwarfs good for?” There are a whole host of reasons related to how stars act as astrophysical laboratories, simulating conditions that are difficult and expensive to replicate on Earth, and how the knowledge has applications to technology, energy, and medicine.  But the real reasons, the important reasons are these:

(1) Astronomy, unlike bench science in a laboratory, in an exercise in looking, thinking, and understanding Nature from afar. The practice of astronomy teaches us how to think deeply about the Cosmos, how to unravel the secrets of Nature, and not fool ourselves into thinking something false. More than any other science, astronomy teaches us to be harshly critical of our reasoning, to be brutally honest about what we know and don’t know, and to be quite certain of our conclusions when we say them out loud.

(2) Every person has a deep seated sense of wonder, waiting to be ignited and tapped. We cannot know who or what will inspire those who see the future for us, but we know it will happen, just as it has happened in the past to people named Steve Jobs, Temple Grandin, Dean Kamen, Rachel Carson, and a thousand others. We explore, learn, and teach the wonder of the Cosmos with the certainty that it can and will inspire someone someday to consider a life in science and technology, a life in service to our species and our planet. The consequences of not teaching people about the wonders of astronomy are almost too awful to contemplate. What if the next Newton never discovers science? What if the cure to cancer is hidden inside someone who is never inspired to continue their education?

(3) Lastly, in a world increasingly dependent on science and technology, science has become a weapon.  Not a a tangible device of destruction (though there are certainly plenty of examples of those), but a psychological bludgeon used to prey on those who have weakness or uncertainty in the realms of science and evidence based reasoning. The Earth faces an uncertain future in terms of its long term evolution, and the survivability and impact of our species on this planet. Special interests, driven by economics, politics, or ideology, have become the bullies of the modern world. Their tactic of choice is the subversion of knowledge and evidence-based wisdom, using modern media to sow uncertainty and discontent, holding the world hostage in a constant state of confusion and embittered debate. The weapon against those with shallow vision and self-serving interests is critical thinking, and common cause.  For the first time in all the history of the Earth, we have both. The practice of science is the human species’ profound realization of the process of critical thinking; it’s only goal, is to seek the truth with unflinching respect for the evidence and facts. Technology has given us the ability to communicate, directly and personally, with every person on the planet.

In a 1990 essay for the Committee for Skeptical Inquiry Carl Sagan wrote, “We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.”  This is a trend that has not changed in the two decades since; if anything, it has become exacerbated as technology and mobile technology has interlinked our world and become enmeshed with our daily lives.

Smartphones and carburetors, two of the great mysteries of the modern world. Making sure everyone can explain their inner workings is not the goal of science literacy.

The danger is not that people don’t understand the workings of a smartphone touchscreen or the purpose of a carburetor.  No, the true danger lies with people being told what they should think about a complex and interconnected world, instead of being able to think critically about how trustworthy the information being passed to them is. The best way for the citizenry of the Earth to protect themselves from charlatans is to know how science works. The second best way is for scientists to put some more skin in the game.

Science cannot be limited to those who practice it; it cannot be an esoteric playground of wonder and imagination for the privilege of a few.  What scientists know must be explained and popularized for the citizens of the world; people must understand that the purpose of science is to improve their lives, and it has.  Modern medicine has erased crippling diseases, satellites girdle the world providing a never-ending stream of data about the weather and evolving state of the planet, and telecommunications technology has deprovincialized knowledge to build a global community. The world-spanning internet has made communications instantaneous and egalitarian, exposing a vast fraction of the world to the wisdom and art of our species, but also connecting all of us instantaneously to the abject horrors our race is capable of, and showing the implacable forces of Nature casually destroying human constructs. Science is all around us.  It is not perfect, but it has repeatedly demonstrated an unfailing ability to change the world.

There are plenty of vocal scientists and active science communicators.  Phil Plait (twitter: @BadAstronomer) is a robust opponent (among many other things) of the anti-vaccination lobby. James Hansen and Michael Mann (twitter: @MichaelEMann) are prominent faces in the battle against climate denialism. Jennifer Ouellette (twitter: @JenLucPiquant) writes and blogs tirelessly about science and mathematics.  But there need to be more — many more. It is estimated that only 5% of the labor force in the United States are practicing scientists or engineers. That is an extraordinarily tiny fraction, so there is a challenge for everyone.

Richard Feynman

On the part of the scientists, the challenge is to talk with your neighbors, talk with your friends, talk with anyone who will listen. There has been a slow and steady decline in the public percpetion of the value of scientists and academics in general.  This has been widely discussed recently in light of an excellent OpEd by Nicholas Kristof. Many academics have taken great affront to this article, but as I tell my 7-year old: how you act is up to you, but how people think you act is up to them. If you want people to change how they think of you, then you have to change how you act (especially when they are watching). In this case, many many decades of unremitting dedication to the urbane life of an academic, steeped in our own traditions and mindsets, have burned bridges that should never have been severed. Scientists are particularly bad at this, and we see the results — charlatans are slowly eroding public confidence in science to the point where despite overwhelming evidence, people don’t know what to think about the future of our planet or species. Richard Feynman always said, “Science is what we do to keep from lying to ourselves.”  Our job is to help people understand that.

George Bernard Shaw.

On the part of everyone else, the challenge is learn to think critically, just as you do with everything else in your lives — you are the ones who are going to decide the future of our civilization, with your money, your actions, and your votes. Talk with your neighbors, talk with your friends, talk with your children.  Honor the wisdom of George Bernard Shaw, who admonished us to “Beware of false knowledge; it is more dangerous than ignorance.” We are being bullied, scarred for life, and we don’t even know it.  Forces within our society think they can play on our fears, for their own benefit, by encouraging us to doubt and deny our hard-fought ability to reason.  It’s time to fight back against these nebulous and callous forces, with the most powerful weapon we have: science. Denial of science is a denial of our birthright, an abandonment of a legacy of 40,000 generations of human beings who have walked before us.

With all the long future days of our planet and our race in front of us, there is but one task before us: preserving the lives of the citizens of the Earth, be they human or not, and ensuring the future habitability of this planet, the only place in the Cosmos we know, with certainty, where any form of life can and does survive.

We speak for Earth, you and I.  Our loyalties are to the species, and the planet. We speak for Earth. Our obligation to survive and fluorish is owed not just to us, but to the Cosmos, ancient and vast, from which we spring.

*******************************

Final Note: This closing quote, is the closing quote from Cosmos as well. Thank you, Carl, for a journey that defines much of what I think, say, and do every day of my life. From the stars we came, and to the stars we shall return, now and for all eternity.

————————————

This post is part of an ongoing series, celebrating the forthcoming science series, Cosmos: A Spacetime Odyssey by revisiting the themes of Carl Sagan’s classic series, Cosmos: A Personal Voyage.  The introductory post of the series, with links to all other posts may be found here:  http://wp.me/p19G0g-dE

Cosmos 8: Journeys in Space and Time

by Shane L. Larson

When I was a kid, I wanted to be one of four things when I grew up: an astronaut, Captain Kirk, Carl Sagan, or Indiana Jones. Now that I am (almost) grown up, it seems my chances of being an astronaut are limited by the slow pace of progress in space tourism, and as far as I know the Enterprise is not being constructed as we speak in some remote cornfield in Iowa. I’m still working on learning to communicate like Carl Sagan. What about Indiana Jones? Well, let’s see: Bullwhip? No (sigh).  Cool hat? Cool enough hat.  Professor?  Check!  Archaeologist, adventure fraught life?  Yep!

Wait, what? I’m an astronomer, not an archaeologist! Archaeology is the study of human activity in the past. In a very similar way, astronomy is the study of the Cosmic past, not entirely limited to the human perspective. (So basically, astronomy and archaeology are the same; that is to say, me and Indiana Jones, we’re the same!)

My childhood ambitions, left to right: (1) astronaut [this is Heidemarie Steefanyshyn-Piper on STS115], (2) Captain Kirk, (3) Carl Sagan, (4) Indiana Jones

Archaeology is often described primarily as being conducted through the study of artifacts. Astronomy also sometimes relies on artifacts (such as meteorites), but more often than not astronomy is about images captured by telescopes. But herein lies a fundamental difference between archaeology and astronomy: archaeology is about the interpretation of artifacts in an attempt to understand the past, whereas astronomy is a direct observation of the past. The light we see from the Cosmos beyond the shores of the Earth takes time to make the journey across the deeps of space.  At the moment we detect the light from some remote shoal of stars, the image we see is a snapshot taken millions of years before, when the light left its point of origin.

Consider this supernova (known as SN 2014g), detected only one week ago on 14 January 2014, in the galaxy NGC 3448, located just under the bowl of the Big Dipper.  Astronomers call this particular type of supernova explosion a “Type II Supernova” — an explosion from a massive star imploding on its core, then bouncing back from the enormous pressure in an explosion that, for a time, will outshine all the other stars in the parent galaxy.  When did this occur?  NGC 3448 is 157.9 million lightyears away, so this explosion occurred 157.9 million years ago!  When this star exploded and the light started travelling toward Earth, there were still dinosaurs on our planet (it was the Jurassic Period!); but we just heard the news of the supernova this week.

(L) NGC 3448 as seen by GALEX and Spitzer [Image, JPL/NASA], (R) Supernova SN2014g.

Even stuff “close” to us is far away.  During the month of January, if you go out shortly after it gets dark, you will see the constellation Orion.  The belt stars point down and to the east toward a brilliant blue-white star called Sirius, the brightest naked eye star in the sky.  Sirius is 8.611 lightyears away.  When the light you see tonight left Sirius, it was June 2005 (assuming you are reading this in January 2014).  What was going on then?  The San Antonio Spurs had beaten the Detroit Pistons 4 games to 3 in the 59th NBA Championship; Batman Begins had just been released; Watergate informer “Deep Throat” was revealed to be former Associate Director of the FBI, Mark Felt; and NASA was less than a month away from Discovery’s STS-114 flight, the first flight of the space shuttle since the loss of Columbia in 2003.

Some of the happenings 8 years ago, in June 2005. Left to Right: (1) Robert Horry’s game winning 3-point jumper during overtime in Game 5 of the NBA Finals; (2) Batman Begins was dominating the box office; (3) former FBI Associate Director Mark Felt was revealed to be the Watergate informant “Deep Throat“; (4) Discovery returned the Space Shuttles to flight, just over 2 years after the Columbia disaster.

Looking across space is looking back in time. The farther away from the Earth you look, the farther back in time you look.  This connection between distance and time may seem a bit esoteric and weird at first sight, but in fact we are used to conflating space and time; you do it every day and don’t even realize it! Just go around the house and ask different members of the family how far it is to the grocery store across town. Some of them will say 10 minutes, and some of them will say 3 miles. There is no difference in the amount of space between you and the store — these are just two different ways of saying the same thing, and you understand them both!

Even Google Maps knows you can understand travelling either in terms of space, or in terms of time, telling you both!

But travelling into space is not the same thing as travelling to the supermarket. The distances are far vaster, so the travel times are far longer. It took Apollo astronauts about 4 days to fly across the gulf of space to the Moon; that’s about the same time it takes to drive from New York to Los Angeles (assuming you aren’t doing some kind of Cannonball Run thing).  It has taken Voyager 36 years to reach the boundary of our solar system, where the interstellar winds from all the stars in the galaxy dominate over the faint, fading stream of wind of our own Sun; light takes 35 hours to make the round trip out to Voyager and back.  Voyager is the fastest object ever built by humans; if we could travel with Voyager, it would take an entire human lifetime to travel to the edge of the solar system and back.  The stars are vastly farther away; travelling by the means we know today would seem to preclude us ever travelling to the far corners of the Cosmos.

Despite the fact that we often conflate time and space, we perceive them to be very different, as evidenced by the tools I use to measure them — we use rulers to measure space, and we use wristwatches (if you’re old enough; otherwise you use a cell phone!) to measure time.  We see space and time as different because we only travel through space when decide to get up and go somewhere, but we are always travelling through time — there seems to be no way to avoid getting to next Tuesday.

Different ways we have devised to measure space or time.

At the start of the 20th Centruy, a young Albert Einstein had a startling realization: time and space are really manifestations of a single, unified fabric that underlies the entire Cosmos, called spacetime. That space and time are inextricably intertwined is hard to see in our slow, everyday lives, but what Einstein realized is the intertwining becomes far more important and obvious when you start travelling fast, at speeds approaching the speed of light. The laws of Nature that describe how we experience and measure the world at high speeds are called “special relativity.”  The laws of special relativity are a generalization of the usual Newtonian laws of mechanics that govern cricket games, the flights of unladen swallows, and car crashes; at the low speeds of these everyday events, special relativity gives exactly the same predictions and results as Newtonian physics.

But suppose you had a fast car, and you could stomp on the accelerator, increasing your speed without difficulty. As you approach the speed of light you would notice that your observations of the world change compared to your friends who are standing still (or driving Yugos). Special relativity accurately predicts the consequences of travelling at high speeds, and foremost among these predictions is an effect known as time dilation — clocks that move at high speeds (mechanical, electronic, or biological — it matters not) tick more slowly than clocks that move slowly or remain at rest.

Free neutrons die, on average, after 881.5 seconds, decaying into a proton, an electron, and an anti-neutrino.

Changing how fast you move through space changes how you move through time. It is an altogether astonishing result, completely counter-intuitive to our everyday experiences here on Earth.  But science is a game where the proof is in the pudding — extraordinary claims require extraordinary evidence, and special relativity has been put through the wringer. The most prominent way in which special relativity has been tested is in particle accelerators.  Many species of atoms and sub-atomic particles have limited lifetimes and eventually die by breaking apart (“decaying”) into smaller, more stable pieces. The time that these particles live is called the “half-life” and it is easy to measure in the laboratory — you plunk a particle down on your bench and you watch it until it dies!  The classic example of this is the neutron, one of the fundamental particles that makes up all the atoms in your body.  If you set a neutron on your workbench, it will live for about 881.5 seconds, just over 14 minutes and 41 seconds. Special relativity tells us that all clocks moving at high speeds run slow; this includes the clock the neutron carries with it that determines when it is going to decay. If we accelerate the neutron to speeds approaching the speed of light, we find that it lives longer than the predicted 881.5 seconds, confirming that its internal clock is running slow.  Special relativity has been tested in this way billions and billions of times in particle accelerators around the world, and never once has it failed to correctly describe the outcome of an experiment.  

While special relativity explains a great many physical phenomena that can be observed in the Cosmos, there is an important realization to be had: special relativity provides a way for us to journey to the stars. If we can construct a rocketship that could travel close to the speed of light (a not implausible idea, even with today’s technology), special relativity tells us that as passengers, our biological clocks will tick slowly enough that we will live to see the journey’s end.

Nuclear powered starship concepts that, in principle, are not outside the boundaries of our technology. (L) Starship Orion; (C) Project Daedalus; (R) Bussard Ramjet. [Images from Cosmos: A Personal Voyage] For many detailed starship concepts, see the book The Starflight Handbook by Eugene Mallove.

What kind of travels could we imagine? Consider a rocket where we hold down the accelerator and never let up. We accelerate just enough that it feels like we have Earth normal gravity (“one gee”) on the ship, allowing us to pass time on our journey in comfort, pursuing ordinary everyday activities like ping-pong and shuffleboard. Our rocketship would increase its speed rapidly, ticking off the decimal places ever closer to, but never reaching, the speed of light.  The table below shows what different trips would look like.  For destinations close to Earth, like the Voyager spacecraft, our rocket travels fast enough to make the trip no more onerous than an extended vacation, but not so fast as to see the relativistic slowing of time.  But over Cosmic distances, time slows dramatically aboard the ship.  Travelling to the center of the Milky Way,to explore the wilderness near the monstrous black hole that lurks there, would take only 10.6 years, less than 22 year around trip.  But on Earth, 52,000 years will have passed, changing our planet and civilizations in unimaginable ways. We don’t even know what human life was like 52,000 years ago, because our written histories only extend back a tenth that long — who knows what 52,000 years in the future will look like!  To those of us on the voyage, scant decades will seem to have passed, but our species will have moved on without us.

Distance an measured times on relativistic rocket trips at acceleration of 1 g.

For most of these journeys, those of us who make the trip will behold firsthand the wonders of the Cosmos, but there will be none of our friends and family to hear the tales when we return home.  I often think  about these journeys, and wonder whether I would do it, given the chance.  Would I leave the Earth behind, never to walk her green meadows again?  I would never be able to Sail the Aegean Sea, or hike down Olduvai Gorge, or howl with coyotes on cool fall evenings in the Sonoran Desert.  But in return I would see the galaxy from the inside out, watch as the Milky Way black hole tears a star apart, and surf along the tendrils of molecular gas and dust that will one day become a new generation of stars.  It may be, perhaps, a fair trade — one set of Nature’s wonders for another.

The black hole at the center of the Milky Way, surrounded by a swarm of stars and the strained tendrils of gas clouds and stars that have been eaten by the black hole. [Image from European Southern Observatory]

But for now, it is only a lovely daydream, enabled and provoked by our growing understanding of the Cosmos, and how it is put together.

————————————

This post is part of an ongoing series, celebrating the forthcoming science series, Cosmos: A Spacetime Odyssey by revisiting the themes of Carl Sagan’s classic series, Cosmos: A Personal Voyage.  The introductory post of the series, with links to all other posts may be found here:  http://wp.me/p19G0g-dE

Cosmos 6: Travellers’ Tales

by Shane L. Larson

Sitting at the gate at Chicago’s O’Hare International Airport, staring at the thousands of other people around me, I am struck by how remarkably connected the modern world is.  I’m not thinking about smartphones and instant personal communication; rather I’m staring out the window at a Boeing 777 and thinking that I can go travelling virtually anywhere on the Earth, in just a day or so, by walking down the jetway.  And we all do it in a blink of an eye.  Sometimes we go for work, to exotic places like Dallas or Albuquerque.  Sometimes we go to visit family, like grandma in Mobile, or Aunt Becky and Uncle Bob in Bemidji.  But sometimes, we jet off across the world, just to go exploring.  We go to see the grand Buddha of Leshan, or the primeval rain forests of the Amazon, or the volcanoes near Reykjavik, or Gaudi’s Sagrada Familia in Barcelona.

(L) The Grand Buddha of Leshan. (R) Sagrada Familia. [Photos by S. Larson]

While on our adventure, we take selfies, we send text messages that say “Guess where I am?”, and we wonder at the marvels of the world. When we return home, we may bring a few trinkets — a silk shirt, a wall hanging, a journal embossed with foreign words and images.  But the things we return to time and again, years after our voyage, either in idle strolls down memory lane or to show family and friends, are our pictures.  Pictures are the single most common and important thing brought back from adventure voyages, as they alone have the magic to transport us  back to those far away lands, with our friends alongside us.

Text messages and selfies, some of the most common travellers’ tales of the modern age.

There was a time when our world was not so easily accessible, when the far corners of the Earth had not yet been discovered, and adventurers didn’t know what they would find on a long voyage of discovery. In the 1700’s, Captain James Cook made three epic voyages around the world, aboard ships whose names have become synonymous with exploration and discovery: HMS Endeavour (a name latter passed onto a United States space shuttle orbiter), and HMS Resolution. Cook’s papers and journals of those voyages were collected and studied for many years after his death, but one of the greatest treasures returned from the voyages were images of far away lands. In those days of exploration, every ship was crewed not just by sailors, but by professionals.  Some were scientists tasked with observing and recording discoveries along the voyage, and others were artists tasked with capturing images of the voyage to record and relay the adventure to those left behind. Without those artists eyes, we would never know what Cook saw on those first, epic voyages.

Images by artist William Hodges, who accompanied James Cook on his second voyage. (L) The HMS Resolution near Antarctica, and (R) HMS Resolution in Matavai Bay, Tahiti.

Today, the world is completely mapped, cultures (for the most part) have been found and documented, and there are precious few places humans have not yet tread.  Voyages of new discovery come more rarely, and people like you and me have adventures that begin with airplane rides and are documented through the lenses of smartphones.  While you and I have set our sights on worldly adventures like visiting Mammoth Cave in Kentucky, or picnicking in the shadow of Moai on Easter Island, our species’ thirst for adventure has grown beyond the Earth.  We have embarked on a new adventure to seek out new horizons and unknown landscapes far out into the Cosmos. The primary commodity of these new adventures are pictures — thousands and thousands of stunning pictures of cosmic vistas that move our spirits in ways we could have never imagined.

I often dream of being able to visit the Moai of Easter Island. [Illustration by S. Larson]

The sky has always compelled us to look up.  Even were we not fascinated with the strange and unearthly things we have found in the sky, the sky presents events that compel us to look up.  Consider the case of eclipses.  The Sun is the most brilliant source of light in the solar system, and every object it shines on casts a shadow, including the Earth. The Moon, on its rounds about the Earth, sometimes fleets through the shadow of the Earth.  As it passes into the shadow, it begins to disappear, an ever growing curve of shadow slowly eating the bright disk of the Moon. When it reaches the center of the shadow, the Moon takes on a deep reddish hue, cast in scarlet tones by the sunlight streaming around the Earth and through its atmosphere — an Earth sunset on our closest neighbor in the Cosmos.  This event is called a lunar eclipse.

(L) The geometry of a lunar eclipse. (R) iPhone image of the total lunar eclipse on 10 Dec 2011. [images by S. Larson]

The Moon also casts a shadow, and sometimes that shadow falls on the surface of the Earth, casting a fleeting moment of darkness wherever it falls.  Seen from the Earth, the Moon creeps across the Sun, an ever growing curve as the Moon blocks the brilliant solar disk.  At the center of the eclipse, the Moon covers the Sun and those standing in the center of the shadow are treated to a rare sight — the blazing corona of the Sun.  This event is called a solar eclipse.  Eclipses in our ancient past were unexpected and likely inspired fear and superstition.  Today, we can predict when they occur and where to stand to see them. People from all over the world step onto airplanes, and fly to stand in the shadow of the Moon.  They take their cameras with them, and capture images of the event to share with friends and family when they return from their travels.

(L) The geometry of a solar eclipse. (C) Image of total solar eclipse taken by Arthur Eddington in 1919. (R) Hydrogen alpha image of the annular solar eclipse on 20 May 2012 in Cedar City, Utah. [by S. Larson]

Another, rare kind of eclipse is called a Transit of Venus, when Venus passes between us and the Sun, appearing as a small black dot traversing the solar disk. Beautiful and inspiring to see, observing a transit of Venus was one of the first ways that people figured out to measure the distance from the Earth to the Sun. Transits can be seen in pairs roughly every 121 or 105 years (a 243 year pattern), when the orbits of Earth and Venus are aligned just right. The most recent pair of transits was in 2004 and 2012. Two scientists, Charles Green and Daniel Solander, accompanied James Cook on his first voyage, tasked with observing a transit of Venus, which they did from Tahiti on 3 June 1769.

Transit of Venus seen from Wasilla, Alaska on 5 June 2012 [iPhone photo, through a solar telescope, by S. Larson]

While one could spend a lifetime standing on the surface of the Earth looking up into the Cosmos, some part of us knows that we could learn so much more if we just go up there.  And so we have.  For the most part, our emissaries beyond the Earth have been robots — machines of human design, supremely instrumented and exquisitely engineered to make interplanetary voyages that we cannot. Our robots have sailed the interplanetary sea and visited every major world in the solar system, providing tantalizing and brief glimpses of alien shores through pictures radioed back to their creators on faint radio links.  Travellers’ tales, recorded through the electronic eyes of semi-intelligent robots, are the principal commodity of the age of space exploration. Tales that paint a tapestry of wonders brilliant and evocative, tempting us with the promise of what we might discover if we were to dig deeper, push farther, and continue the exploration.

Of all the many worlds in the solar system of which we are aware, there are only five on which we have landed and returned images from the surface: the Moon, Venus, Mars, Saturn’s moon Titan, and the asteroid Eros. These are the only worlds beyond the Earth whose surfaces we have tread upon, and only on the Moon and Mars have we ventured away from the landing site (using rovers). At all of the sites, we have tantalizing pictures of alien shores that sing a siren song of adventure when we look out across them. 

(A) Surface of Eros by NEAR-Shoemaker. (B) Surface of Titan by Huygens. (C) Surface of Venus by Venera 14. (D) Apollo 15, station 9 on Hadley Rille. (E) Surface of Mars, near Bonneville Crater by the Spirit Rover.

But most of our probes are not landers — they are semi-intelligent cans of electronics, wires, metal and composites that we have hucked out into the Cosmic sea, leaving them destined to drift forever in the sky.  Most of the images they return are all taken from orbit or on a one chance “flyby.”  The stories they tell are a bit like describing a state by looking out the window of a plane as it passes overhead, but the tales are riveting mysteries of the past, present and future of the worlds in our solar system. 

On Mercury, we’ve found a vast impact basin, just discovered in 2008 by the MESSENGER spacecraft. The basin is more than 700 kilometers across; if it were on Earth it would stretch from San Francisco to Seattle.  A vast circular hollow excavated in the early days of the solar system, the central plains are a vast expanse of ancient lavas criss-crossed with ridges and troughs that have been frozen into the landscape since their formation — there is no weather on Mercury to weather and fade the scars of ancient geologic trauma.  We’ve named it Rembrandt after the famous Dutch painter — a fitting name for such a picturesque place.

(L) Rembrandt, on Mercury. (R) Saturn by Cassini.

At Saturn, Cassini has radioed back exquisite images of the subtle tawny clouds of Saturn, always framed by the brilliant arc of the great rings.  But on its way to Saturn, Cassini did a little sight-seeing, and as it sailed past Jupiter toward Saturn, recorded a mesmerizing movie of that planet’s banded clouds. The clouds swirl and rotate as they are pressed before winds blowing as fast as 500 kilometers per hour, nearly twice as fast as the strongest winds ever seen on Earth.  

Jupiter’s cloud bands, as seen by Cassini (click to animate).

Among all the space probes we have set adrift, five hold a special place of honor.  They are Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, and New Horizons.  These are the only probes we’ve built that are destined for interstellar space after their reconnaissance of the solar system.  Thousands of years from now, their creators long forgotten and returned to dust, these spacecraft will sail on into the interstellar void of the galaxy.

Now fallen silent, their energy reserves exhausted, the Pioneers no longer send tales home to Earth. But each carries a story with it, in the form of a small plaque telling the tale of the probes’ origins, should any intelligent being find it in the distant future.  A bottle cast into the Cosmic Ocean, I often wonder about those who might one day stumble on Pioneer 10 and 11.  Will they be alien intelligences?  Or perhaps will they be some impossibly distant descendant of humans, stumbling on a forgotten remnant of their past? Will they understand the message, and understand what Pioneer was doing in a long forgotten epoch of time?

(L) The Pioneer plaque, amidships on Pioneer 10. (R) The two sides of the Voyager record. You can explore the Voyager record online (at the JPL Voyager site, or at a complete online archive), or in the (now out of print) book Murmurs of Earth.

Both Voyager spacecraft also carry a message in the form of a Golden Record. The record contains instructions for use, a map pointing back toward Voyager’s origin, and its own set of travellers’ tales: a set of 55 greetings in different languages of Earth, 116 images of life on Earth, and 90 minutes of music from around the world ranging from masterpieces by Mozart, to Chuck Berry’s Johnny B. Goode, to a traditional Peruvian wedding song.  The record bears one final message, inscribed on its inner edge, a handwritten message: “To the makers of music — all worlds, all times” (etched by Timothy Ferris, the producer, when the record was completed).

The ADS All Sky Survey, a rotatable interactive map showing where we’ve taken pictures of the sky.

The principal commodity of science, and astronomy in particular, is knowledge. The tangible evidence of that knowledge is pictures.  Images capture both scientific knowledge and cultural aesthetic; they can be appreciated by everyone for the wonder they evoke and the questions they provoke.  At a recent gathering of the American Astronomical Society, some of my colleagues showed a new kind of astronomical map.  It is a map of the entire sky, but instead of showing us the secrets veiled away in the deep Cosmos, the map shows us how often we have looked at or studied — taken a picture of — a particular place in the sky. To the trained eye, you can see the Andromeda Galaxy, the Large and Small Magellanic Clouds, the plane of the Milky Way, the plane of the Solar System, and the area covered by the Sloan Digital Sky Survey.  But what amazes me most about this picture is how LITTLE of the sky we have seen — most of the map is  black, meaning no picture has been taken there.  That is a staggering shame, since as the Hubble Deep Field as shown (and its successors, the Ultra Deep Field, and the Extreme Deep Field), even the most remote, dark and (we thought) empty places in the sky are filled with uncountable mysteries.  The sky is a BIG place, and we are far from having seen it all.

And so we continue to stare, we continue to take pictures, and we continue to spin travellers’ tales about what we’ve seen, what we know, and what we still would like to discover.

The Hubble Ultra Deep Field (UDF), showing what is unseen but can be found if you stare at an empty part of the sky for long enough.

————————————

This post is part of an ongoing series, celebrating the forthcoming science series, Cosmos: A Spacetime Odyssey by revisiting the themes of Carl Sagan’s classic series, Cosmos: A Personal Voyage.  The introductory post of the series, with links to all other posts may be found here:  http://wp.me/p19G0g-dE

Cosmos 5: Blues for a Red Planet

by Shane L. Larson

More than any other world in the solar system, Mars has captured the imagination of the human race (except maybe for Pluto, but it’s not a planet, right?). Mars has dominated our imaginings of other worlds for more than a century, beginning with H.G. Wells’ masterpiece of invasion, The War of the Worlds.  Since The War of the Worlds was first written, many other tales of adventure, danger and horror have been penned or filmed concerning Mars — Kim Stanley Robinson’s epic Mars Trilogy, the classic 1964 film Robinson Crusoe on Mars, Elton John’s sonorous musings that Mars is no place to raise a family in “Rocketman,” and many many more.

Mars in fiction. (L) The frontpage of the first edition of The War of the Worlds. (C) The poster for Robinson Crusoe on Mars. (R) The three volumes of Kim Stanley Robinson’s Mars Trilogy.

Ray Bradbury [Wikimedia Commons.]

I was first exposed to Mars in elementary school, through the reading of Ray Bradbury’s The Martian Chronicles, followed closely by viewing the 1979 screen adaptation of those Chronicles starring Rock Hudson. Bradbury’s Mars was a distant frontier, populated by indigenies resisting the influx of pioneers from Earth. Those pioneers were attempting to create a human civilization on Mars, ignorant of the fading race of natives who lived on the red sands before them. Having grown up in the American West, descended from a long line of ranchers who had homesteaded on the front range in Colorado, it was a familiar tale to me cast on a fantastical tapestry of rocket ships and alien landscapes. Bradbury’s tales of Mars are stories humans have always told about the frontier — tales of discovery, of finding out who we are by looking through the lens of our interaction with (and ignorance of) other lifeforms we have discovered.  In this case, the other lifeforms are the Martians.

The word “Martians” has come to mean more than just beings of Mars; the name has become synonymous with any alien species, vaguely if not outright humanoid.  Tales of Martians are often an allegorical mirror of the best ideals and worst fears we have about our own species.  Sometimes Martians are wise and benevolent; some, like the ghosts in The Martian Chronicles are noble and introspective in the face of extinction. Sometimes Martians are implacable and malevolent conquerers bent on owning the Earth, like the invaders in The War of the Worlds.

It was only natural that Mars become a focal point for our musings about other intelligent species.  Since the invention of the telescope, Mars has sung a siren song to the human race. It is the only planet whose surface can be seen through a telescope, giving us tantalizing glimpses of icy polar caps, vast dark plains that change with the Martian seasons, and long sinuous markings that look for all the world like river channels. It is easy to tempt our imaginations with the idea that Mars could be much like the Earth.

Mars, as seen by the Hubble Space Telescope. (L) The Tharsis Bulge, showing the large shield volcanoes of Mars, and the Valles Marineris in the lower right. (R) The large, dark plain of Syrtis Major, as well as polar ice caps and fleeting clouds. [Images by NASA]

By the 1970s we discovered that Mars was indeed much like the Earth — volcanoes and canyons, ice caps and river valleys. Our landers sent pictures of rocky red deserts, studded with boulders and rolling landscapes that terminate at the foot of mountains on the distant horizon.  But Mars is simultaneously unlike its neighbor, the Earth. The volcanoes are the largest known in the solar system; the largest canyon is a rift valley that is large enough to stretch from New York to Los Angeles; craters stud the surface, worn by the ages but not completely disappeared; and there is not an open body of water to be found anywhere on the planet.  Perhaps most importantly, we have failed to find any sign of life anywhere on the planet.  Unlike our home the Earth, Mars may very well be a dead world, if indeed it was ever alive at all.

Panoramas from the surface of Mars, shot by our rovers. From top to bottom: (1) Ares Vallis from Mars Pathfinder. (2) Lookout Panorama from Spirit, looking up the slope of Husband Hill. (3) Everest Panorama from Spirit, from the summit of Husband Hill, looking out over Gusev Crater. (4) Opportunity’s view of Endurance Crater.

Thus, I was electrified on a summer’s day in 1996 when a stunning announcement was made. Tiny, mineralized structures had been found using high resolution images of a Martian meteorite known as ALH84001 (name decode, from right to left: 001 = first meteorite found, 84 = in 1984, ALH = in the Allan Hills region of Antarctica).  The structures looked very much like microbes one might encounter on Earth, leading to the very real possibility that the mineralized structures may be fossilized infusoria from the planet Mars.

(L) ALH84001 is a chunk of Mars that drifted through space and landed in Antarctica, where it was discovered in 1984. (R) Micrograph images of structures found in ALH84001, highly suggestive shapes like bacteria.

Like all monumental discoveries in science, the announcement generated tremendous debate. The evidence is not completely unambiguous, and there is still much skepticism about what ALH84001 is telling us.  But it opened up the very real possibility that microbial life could have arisen on Mars, suddenly forcing all of our idle speculations and daydreams about Martians into a definite shape and form.  The human brain is fickle, particularly with regard to the kinds of daydreams it finds compelling — a Universe where all the life in the Cosmos consists of Earthlings and a few microbes on Mars just isn’t that exciting!  Microbes, shmicrobes! So it comes as no surprise to me that I have noticed a subtle uptick in the number of adventure stories told not about Mars, but about other worlds in the solar system: Europa near Jupiter, or Saturn’s enigmatic moons, cloud-swathed Titan and cryovolcanic Enceladus.

New worlds where we might search for life. Left to right, (L) Jupiter’s moon Europa, (C) Saturn’s moon Titan, and (R) Saturn’s moon Enceladus.

Why is that?  Why are we, at least sub-conciously, singing blues for the Red Planet? I suspect it is because we have landed on Mars and mapped the planet in exquisite detail from orbit.  Mars is by no means a fully explored world; we have roved only over 49 km of  Mars, but the planet has a total surface area roughly equal to the land area of Earth.  There is no way our 4 little rovers (Sojourner, Spirit, Opportunity, and Curiosity), and a handful of landers have seen every nook and cranny of the vast Martian frontier.

Our robotic explorers on Mars: (L) Sojourner micro-rover, (C) Mars Exploration Rovers, Spirit and Opportunity are identical, (R) Curiosity.

Never-the-less, we have yet to see indications of any large lifeforms.  Our cameras have sent back no pictures of Martian tapirs, no pictures of many-legged thoats, no pictures of giant sandworms. The net result: we have given up on the idea of there being substantial lifeforms. We’ve seen enough to convince ourselves that if there is life on Mars, it will be microbial.

Don’t get me wrong — without a doubt, the discovery of a single Martian micro-organism will transform biology forever, but it is not what we’re really looking for! Microbes are not what we long to discover — we long to find companions in the Cosmos. The discovery of a single large organism, whether it is the Martian equivalent of a squirrel, or stag beetle, or snail, would tremendously boost our hopes of one day finding life we can communicate with. 

A Europa cryobot submarine mission concept from NASA.

And so, our imaginations have moved on to new unexplored worlds that could still hide the greatest discovery we have ever imagined.  Foremost among these, is Jupiter’s icy moon Europa.  Europa is sheeted in ice, a solid blanket covering a sub-surface ocean.  What lies beneath the ice?  With so much water, could it perhaps harbor life? There must be heat sources to keep the sub-surface ocean liquid. Perhaps the constant squeezing by Jupiter’s gravity has produced volcanic thermal vents that provide the heat to keep the ocean liquid. On Earth, deep ocean thermal vents were discovered by  explorers in 1977 aboard the Alvin manned submersible. Much to everyone’s surprise, the area around the vent was thriving with life, despite the intense heat and high acidity of the water.

Examples of extremophile life. (L) The Sully Vent in the Pacific; extremophile bacteria glean energy from the extreme heat and acidic water [NOAA image]. (R) The Grand Prismatic Spring in Yellowstone; different colored algae are tolerant of different water temperatures, giving the spring its banded appearance [National Park Service image].

The discovery of life around the hydrothermal vents startled us, but scientists soon realized they were seeing an example of extremophiles — lifeforms that have evolved to uniquely survive in an environment that would normally be too extreme for fragile beings such as us to survive in.  This epiphany opened our eyes, and we see extremophiles everywhere on Earth. A famous and prominent example are the microbial algae mats around the thermal features in Yellowstone National Park — the colored bands surrounding a feature like the Grand Prismatic Spring are simply different species of algae, each tolerant of different water temperatures. In most extreme environments, the extremophiles are microbes, so even a planet like Mars could harbor life, despite the cold, despite the aridness, and despite the ultraviolet radiation.

Tubeworms around a hydrothermal vent survive because the bacteria break down the acids, providing a way for the worms to chemically synthesize energy [NOAA image].

The discovery of microbial extremophiles has amplified our confidence in the odds that there is life elsewhere in the Cosmos, but it has done little to dampen our enthusiasm for large lifeforms.  In reality, microbial extremophiles should boost our chances of finding more complex organisms, if the conditions are right.  The deep ocean thermal vents are particularly interesting examples when considering life on Europa, not just because there may be similar vents heating the Europan oceans, but because of the ecosystems we see growing around the vents on Earth.  The microbes that thrive in the immediate vicinity of the vents themselves are the base for a very localized ecosystem and food chain. Other, larger, more complex organisms, such as giant tubeworms, also glom onto the thermal vent, feeding farther down the food chain from the microbes who have learned to exploit the extreme environment.  If we could sink a cryogenic robot beneath the Europan ice, maybe we could find a similar, complex ecosystem.

We have yet to explore beneath the ice of Europa. But in the minds eye of our fiction writers the adventure is on, and already we are by-passing microbes in favor of speculation about there being big Europans, complex lifeforms against which we can compare ourselves.  I was first exposed to adventures on Europa by Arthur C. Clarke’s novel, 2010 (and the associated 1984 film starring Roy Scheider), where the Monolith (already a  manifestation of an alien intelligence beyond our own) fosters the growth of big lifeforms on Europa after collapsing Jupiter into a small star.  More recently, we have all been charmed by “Europa Report” which follows an expedition to Europa to discover not only microbial life, but something more.

The depiction of the unambiguous discovery of microbial life is very tell-tale of our desperate desire to not be alone in the Cosmos.  The first discovery of life beyond the Earth will be a monumental event, but the depiction of discovering extraterrestrial microbes in the movies is similar in excitement to the construction of a new frozen yogurt shop down the street.  Discovering alien life should be an Earth shattering event for our culture: we will know for the first time that we are not alone in the Cosmos!  But perhaps our fictional heroes, like us, have become immune to wonder at the discovery of microbes.  They want to discover something more, something bigger.  Microbes, shmicrobes.  Why is Europa a destination in stories now?  Because Mars, at best, will be the home of microbes, so we are searching for new arenas upon which to cast our dreams, fears, and hopes.

I dream of camping on Mars, whether there be Martians or not. [Illustration by S. Larson]

But despite our civilization’s fleeting wonder about life on Mars, I still often dream about adventures on the Red Planet and what might be found there.  It is still a world full of mysteries, and as worthy of exploration as any corner of the Earth, or any other world in the solar system. What a grand adventure it would be to go hiking across Mars with my daughter, camping near the now dead Spirit rover, to toss rocks over the edge of the Valles Marineris,  and take iPhone panoramas of the vast rocky deserts of the Red Planet.  I would love to spend an afternoon chipping open rocks on the shoulders of the Tharsis volcanoes, looking for some sign of ancient microbial life as we watch dust devils spin lazily on the plains below.

It may yet be true that Mars harbors no indigenous life, but we’ll never know until we ourselves go, and turn over every rock we can find. It will be the work of a lifetime, indeed of uncountable lifetimes if the exploration of the Earth is any kind of indicator.  In the end, there will be Martians, but as Carl Sagan so aptly noted (and Rock Hudson discovered at the end of The Martian Chronicles), the Martians will be us.

————————————

This post is part of an ongoing series, celebrating the forthcoming science series, Cosmos: A Spacetime Odyssey by revisiting the themes of Carl Sagan’s classic series, Cosmos: A Personal Voyage.  The introductory post of the series, with links to all other posts may be found here:  http://wp.me/p19G0g-dE

Cosmos 4: Heaven and Hell

by Shane L. Larson

I am writing this on the 45th anniversary of one of the most iconic photographs of the Space Age. As Bill Anders, Frank Borman and Jim Lovell rounded the far side of the Moon, after traveling farther than any humans in history, they beheld a sight that had never been seen before — the distant blue sphere of the Earth rising over the horizon of the Moon. This single image captured an idea which up to that time was a mere abstraction — that the Earth is a single world, without borders and boundaries, interconnected and bound together in ways that are simultaneously obvious and subtle.

(L) The original Earthrise image, shot by Bill Anders on Apollo 8’s 4th lunar orbit in 1968. (R) Recreated Earthrise image by NASA’s Lunar Reconnaissance Orbiter.

This is the nature of great voyages of exploration and discovery — finding the unexpected, and realizing it was the most important thing that happened. The Earthrise image, like image of Buzz Aldrin’s bootprint on the Moon, or the Genesis rock found by Apollo 15 Commander Dave Scott on the delta of Hadley Rille — those are transformative moments from the Age of Space Exploration that changed how we think about who we are. 

(L) The Apollo 15 Genesis Rock, in situ as found on the Moon at Hadley Rille, and in the Lunar Sample Laboratory at Johnson Space Center. (R) Aldrin’s bootprint experiment on the surface of the Moon [Apollo image AS11_40_5880], and the iconic image that symbolizes humanity’s first voyage beyond the Earth [Apollo image AS11_40_5878].

To be connected to the Cosmos, to know why we are here and understand the part we play in the design of the grand machine of Nature — these are the deepest passions of the human psyche, passions that fuel art, exploration, and science, endeavours one and all whose sole purpose is to figure out what it all means.

Human beings are good at figuring things out. Sometimes we do it for recreation — we play tangrams, we play matchstick riddles, we solve Soduku puzzles.  Sometimes we do it because we have to, because our very survival depends on it — we figure how to shore up the banks of a river before it floods a town, we figure how to rescue a family who’s car has skidded off an icy road into a ravine, or we figure how to increase grain yields to feed a million starving people.  Sometimes we do it to improve our lives — we know how to make the human body invincible against the polio virus, we know how to forecast the arrival of a hurricane along our seaboards, and we know how to make the sum total of all the knowledge of the human race available to anyone on a device that fits in your pocket.

Science is a way of thinking about the world specifically geared toward figuring out how things are related. That everything on Earth is deeply interconnected is one of the great realizations of the last two hundred years. Consider the Wave Rock in the Hyden Wildlife Park of Western Australia: 14 meters high, and 110 meters long, Wave Rock has the shape of an enormous cresting wave on the ocean, but the nearest seashore is 300 km away. That Wave Rock is a natural formation is clear. But how did it get there? How did it form?  This formation is an example of weathering and erosion.  Constant and continued exposure to weather, wind and rain have eroded the rockface away, leaving the flared shape of a cresting wave.  It happened slowly, over millions of years, far too slowly for humans to observe, but we figured it out.

Examples of weathering processes on Earth. (L) The Grand Canyon of the Yellowstone. (C) Rub’ al Khali, the “Empty Quarter” on the Arabian Penninsula. (R) The Elephant’s Foot Glacier, in Greenland. [Images from Wikimedia Commons.]

The idea that the weather and climate of the Earth are responsible for some of its physical features is not at all immediately obvious, but part of figuring things out about the Cosmos is connecting the dots.  Rivers run in channels, clearly carved into the skin of the Earth. Wind moves vast dunes of sand as it blasts across the empty quarters of the Earth’s deserts.  Ice, in the areas where it persists, also shapes and molds the land in stunning and pictueresque ways.  At the heart of all of this, is water. The most common substance we encounter everyday, our planet is a veritable water paradise.  We encounter it all of its forms, and all are spectacular eye candy — ice, liquid, and vapor. When we see the Earth from the near reaches of outer space, seen as the Apollo astronauts saw Earth from the Moon, what is immediately noticeable is the water — the blue oceans, the white clouds. Water is the stuff of life, the single most important substance that, to our biology, makes the Earth a paradise without peer.

Water in all three forms found on Earth: liquid, ice, and vapor (clouds). [Image from Wikimedia Commons.]

A hot Jupiter near its parent star. [Image from NASA.]

It is not surprising then that, as we begin to search the Cosmos for other worlds and planets, our prejudice is always skewed toward worlds that remind us of home, worlds that harbor water in some shape or form.  In the last two decades, we have tallied up an impressive catalogue of planets, 1056 as of the time of this writing.  But this number is only the smallest fraction of all the worlds that must exist; these are only those that we have found so far. In their number, we have yet to find any that have the biological friendliness of Earth.  There are many which can only be described as hellish.  Consider the “Hot Jupiters,”  which are sometimes called “roasters.”  These planets orbit closer to their star than any planet we have ever seen. The first hot Jupiter discovered was the first planet found beyond our solar system, called 51 Pegasi b (sometimes known as Bellerophon).  This planet orbits its parent star once every 4.2 days!  By contrast, Mercury, the closest planet to the Sun, orbits once every 88 days!  51 Pegasi is located 50 lightyears from Earth, so we may never know what it is like on that far away world, but we can be quite certain it is nothing like the Earth; I’m willing to bet it is not a water paradise.

(L) Saturn’s moon Titan, seen up close by the Cassini spacecraft in ultraviolet light. (R) Titan’s liquid hydrocarbon lakes, displayed in false color (colored by computer). [Images from Wikimedia Commons.]

Closer to home, we have discovered many worlds that may harbor some water in some form, but none have exactly the perfect balance of energy, water, and air to produce the veritable garden that is the hallmark of Earth.  The only other world in the solar system known to have liquid of any sort on its surface is Saturn’s moon, Titan.  We have sent our spacecraft to reconnoiter Titan, and have even landed on its surface. Our maps are colored in a way that is pleasing to the eye, seductive in its suggestions of land and sea.  But the seas of Titan are unlike any that humans have sailed. They are not water at all; they are liquid methane, roiling under the “oppressive heat” of the distant Sun at Titan’s surface temperature of -180 ºC.  Closer, but still beyond easy reach, is Jupiter’s icy moon Europa. Only slightly smaller than Earth’s Moon, Europa is covered in a thick layer of water ice, laced with vast  enigmatic colored striations known as linae (scientists believe these are fractures where Europa’s icy crust has broken and shifted back and forth). Europa is too far from the Sun for enough radiant energy to keep water liquid on the surface, though there is strong evidence that below the ice may lie a sub-surface ocean.  What might we find, if we could dive below the ice shield, and skim the seas of another world?

What might lie beneath the icy surface of Europa? Future missions may tell us. [Illustration by S. Larson]

Venus, as seen by Mariner 10 in February 1974. [Image by NASA.]

Perhaps the most interesting nearby world is Venus. Nearly the twin of Earth in terms of size and gravity, Venus lies slightly closer to the Sun, on the edge of what astronomers call the “habitable zone” — the distance from a star where the laws of physics make the existence of liquid water “easy.”  Like the Earth, Venus lies just far enough from the Sun that water could remain liquid and not freeze. But unlike the Earth, the atmosphere of Venus is dominated by carbon dioxide, a gas that traps energy on the surface of the planet.  As a result, the temperature has sky-rocketed to 462ºC (863º F) — hot enough to melt lead. Like an oven, the blanket of heat fills every far flung corner of the planet — there are no tropical, temperate or polar zones on Venus. The entire planet is consumed by the pressing heat; the planet is a hellish world without peer.

The knowledge that Venus is a hothouse without equal has passed into the collective knowledge of our civilization, a bit of information that most people know and can use to win a Saturday night game of Trivial Pursuit.  But we have not always known this fact; it was something we figured out.  That Venus was shrouded in an apparently eternal cloud layer was a fact known since the invention of the telescope. Having little experience with clouds other than those on Earth, it was oft assumed that the clouds were water-based, and that Venus was a watery, swampy morass — perhaps not a heavenly paradise, but certainly no less-liveable than the jungles of the Congo or the back-bayous of southern North America.

Approximately true color image from the surface of Venus, taken by the Soviet Venera 14 lander in 1981.

But science is a self-correcting process. When new information is discovered, we revisit old thoughts, old models, old assumptions and view them anew, asking ourselves “how have we fooled ourselves this time?”  We generate new ideas that explain all of the old information and the new information together.  Such is the case with Venus. In the 1950’s, the advent of electronic technology allowed us, for the first time, to detect microwaves being emitted from our nearby sister world.  This was a startling revelation — how could it be that a planet was emitting copious amounts of microwaves?  The puzzle was resolved by a young Carl Sagan in 1960, who in his Ph.D. thesis demonstrated the basic runaway-greenhouse effect model that successfully explains the character of Venus.  The clue to the existence of the greenhouse effect was the microwaves — hot gasses produce copious amounts of microwaves. This was confirmed directly by the Soviet Venera 9 spacecraft, which soft-landed on Venus on 20 October 1975. It was the first human spacecraft to return pictures from the surface of another planet; it survived for 53 minutes.  Today, Venera 9 is slowly eroding away under the oppressive heat, pressure, and acidic rain, a decaying testament to the human penchant for figuring things out.

The Venera landers lived very short lives on the hellish landscape of Venus. Long ago fallen silent, they are now slowly eroding away. [Illustration by S. Larson]

The desire to find a world like Earth is a reflection of our understanding of how fragile and, so far as we know, unique the Earth is. The paucity of Earth-like worlds might be reason for discouragement, but we are still figuring out how to find other planets, and we aren’t giving up yet. But one thing is true — there are no worlds like Earth anywhere close to us; there are no places we can go and exist as easily as we do in the garden of Earth.  The idea that we as a civilization can and are changing our planet in dramatic (and possibly irreversible) ways is something we are just figuring out. The existence of worlds like Venus should serve as gigantic flashing billboards to our civilization screaming “Do not Enter! Wrong way!”  Part of exploration is discovering not just who we are, but what the future may hold.

————————————

This post is part of an ongoing series, celebrating the forthcoming science series, Cosmos: A Spacetime Odyssey by revisiting the themes of Carl Sagan’s classic series, Cosmos: A Personal Voyage.  The introductory post of the series, with links to all other posts may be found here:  http://wp.me/p19G0g-dE

Cosmos 2: One Voice in the Cosmic Fugue

by Shane L. Larson

Humanity is simultaneously blessed and cursed with one of the most ingenious creations of Nature: our imaginations.  Our brains have developed not just to run our bodies, and not just to absorb sensory data from the world. They store all the vast myriad of experiences we have and then, at a later time, recall that data for the express purpose of inventing ideas that may or may not have anything to do with reality.

An excellent example of how your brain works can be found in a simple game my daughter and I play at restaurants while we’re waiting for our food.  We call it “The Napkin Game.”  One person draws a simple line doodle, without lifting the pen, then the other person takes that doodle, looks at it from all angles, then adds more lines to turn it into a picture. When you draw a doodle for your partner, you don’t a priori know what it will be turned into.  That’s the magic of brains! Any random doodle could be Batman’s cowl, or a Wonka Bar, or a turtle. Your brain takes a little bit of visual input, maps it onto one of the trillions of neural connections in your mind, and makes something new!

An example of the Napkin Game. One person draws a simple line doodle, and the other person adds to it to make a picture.

One of the most important things your imagination does, is it extrapolates into the future.  Sometimes it makes up extrapolations out of whole cloth that likely have little bearing on reality (though they may be perfectly entertaining, if not desirable, daydreams).  I count among such extrapolations imagined futures where zombies have taken over the world, Apple Slice has made a comeback, or I am close personal friends with Queen Elsa of Arendelle.  But very often, the extrapolations are really simulations — attempts to divine a realistic future. This is the origin of wonder, of anticipation and excitement, and also of fear (particularly fear of the unknown). Imagination uses both of these extrapolations in the game we call science.

The most remarkable thing about imagination is that it knows no boundaries. T-rex flying a fighter jet? No problem. I’m really Walter Mitty, a member of MI:6 who cleans up after Bond?  Duh. Every kind of particle we have ever seen maybe has an undetected and completely made up “super-symmetric” partner particle?  Sure, that sounds cool to think about! 

Examples of imagination, possibly run amok. (L) Dinosaurs flying fighter jets [Lego model; dino added by S. Larson]. (C) The Standard model of particle physics. (R) The “SuperSymmetric” addition to particle physics, imagined by some physicists.

Unfettered by physical limitations or abstract societal rules, our imaginations can stray from the possible to the impossible, from the real to the unreal, and from the mundane to the extreme. The most powerful aspect of this ability is that it allows us to ask questions about things of which we currently are completely ignorant.

Consider the question of life in the Cosmos.  Is there life elsewhere? Are we a singular instance of life, or is there a vast froth of life-filled worlds filling the deep, deep dark of the Universe?

One lonely dish in the Very Large Array (VLA) near Socorro, NM, staring out into the Cosmos. [image by S. Larson]

It is a deep and through provoking question that has profound implications for our philosophical and cultural identities. We can ponder such questions precisely because our brains can take the question and push it to the extreme boundaries, which are:

(1) The Earth is unique. We are a singular instance of the music we call life, a lone voice shouting vainly into the vast, dark cathedral of the stars.

(2) The Cosmos is teeming with life, a vast ecosystem of atoms that have organized into patterns capable of replicating and contemplating their own existence.

Arthur C. Clarke once famously summarized these extremes, saying “Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.”  The amount we are terrified by this thought is the fault of our imaginations.  We are inherently social creatures — we thrive on contact, discussion, and shared common experience. All of us have, at some point in our lives, experienced profound loneliness — being lost, being trapped, being left out by our peers. When we imagine being alone in the Cosmos, our brain magnifies that sense of loneliness a trillion-fold.  What gets simulated is not the Earth all alone, but ourselves all alone — what if I were alone in the Cosmos, lost in the vast dark? We anthropomorphize the entire human race, mapping our own personal feelings onto 7 billion other souls.

In the opposite case, our imagination proposes a Cosmos completely contrary to the normal hubris that humanity wields.  Despite our proclaimed belief in the fundamental tenets of Copernican astronomy, where the Earth is not the Center of All That Is, we certainly don’t lead our lives that way. Humanity, as a rule, does not pretend to be anything other than the Center of Everything!  But it could be that we inhabit a Cosmos with other intelligences, some perhaps vastly greater than our own, some perhaps implacable and as unaware of us as we might be of ants or bacteria.  Such musings are disquieting because they challenge the central tenet of our perceived existence as the premiere lifeform, on planet Earth or anywhere else.

The question of whether the Cosmos harbors life elsewhere is a compelling one from the perspective of our psychology, but also because there is an apparent conflict between two eminently reasonably scientific viewpoints.  The first of these viewpoints is the so called “Principle of Mediocrity.”  This is the no-holds barred manifestation of the Copernican Principle — there is nothing special about the Earth.  The Cosmos seems to be filled with planets (the latest count, as of today, 9 Dec 2013 is 1051 known planets (visit the Exoplanet Encyclopedia Catalog), with some 3000 candidates from the Kepler mission.  Our deepest probes of the Cosmos (the Hubble Extreme Deep Field) suggests there could be as many as 600 billion galaxies. If each galaxy has 300 billion stars, and every star has at least 1 planet (probably more) then there are a staggering number of possible worlds on which life could have arose. There is nothing special about Earth, so if life arose here, there should be no impediment to life arising on any of the trillions and trillions of other worlds that fill the Cosmos.

The Hubble Extreme Deep Field (XDF). [Credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team]

The opposing viewpoint is something called “The Fermi Paradox.”  It was originally proposed by Enrico Fermi, and can succinctly be summarized as, “Where are they?”  What Fermi wondered was why has the Earth, or any world in the solar system, not been visited by self-replicating robotic explorers of some distant alien race?  His point was that if we really want to explore the galaxy, the most efficient way to do that would be to send a robotic probe out to the nearest star.  It won’t get there in a human lifetime, but it will get there in a time substantially shorter than the age of the galaxy.  When the robot gets to a star system, it pokes around a bit, then builds 10 copies of itself using the natural resources it can find, and sends those copies out to the next 10 closest stars.  If every robot successfully makes 10 copies of itself, it only takes 11 replication cycles before there is 1 robot for every star in the galaxy.  But really, why would they stop there? They would just keep replicating until there are a whole lot of robots in the galaxy.  But we haven’t seen one yet!  Why not? One’s immediate gut reaction might be to think, “Well humans are just the first species to have such a crazy idea. The galaxy is not full of self-replicating robots because we haven’t built them yet!”  But if we apply the Copernican Principle to Earth and humanity in particular, there is no reason to believe we are the first instantiation of intelligent life; some civilization should have preceeded us, and built the fleet of galaxy filling robots.  But there are no robots, and the chance that we are the first civilization in the entire galaxy is vanishingly small.  The fact that there are no robots means that we are alone in the Cosmos. 

Why has our solar system not been visited by alien robots, sailing through to see what the galaxy is full of? This is the central tenet of the Fermi Paradox. [Model by S. Larson]

The space in between these two possibilities is a matter of intense debate among aficionados of the search for extraterrestrial life, as well as professional scientists who spend their careers thinking about this. There are as many facets of the debate as there are persons engaged in the discussion!  In the absence of true, reliable knowledge, our imaginations have free reign. We imagine every idea we can, then argue about whether the idea is plausible or even possible.  One of the most intriguing ideas in this space is that perhaps no civilization ever survives to build a self-replicating army of robots to explore the galaxy. Maybe the Cosmic fugue of life never grows beyond the initial swelling notes of the song.

The dinosaurs haven’t gone (didn’t go?) exploring the galaxy. [Image from Captain Raptor and the Moon Mystery, by O’Malley and O’Brien]

This is not an unreasonable idea. Even if we confine our considerations to the history of life on Earth, we’ve seen “civilizations” that persist for long periods of time. The dinosaurs existed on Earth for 160 Million years, and never developed a single bit of technology (so far as we know), let alone build a self-replicating robot to proclaim their existence to the Cosmos. In the end, the dinosaurs were completely obliterated, wiped off the face of the Earth by an asteroid. Today, their closest living descendants are the birds, but no chicken has reached out to explore the Cosmos either. 

But we don’t even have to think about lifeforms long gone. Even among our own species, entire civilizations have utterly vanished from the world.  Five thousand years ago, the Indus Valley Civilization (IVC) was comprised of 5 million persons, fully 10% of the entire world population at that time. It stretched all along the Indus River valley, in what is today the borderlands between modern India, Afghanistan and Pakistan. The preeminent civilization of the era, the IVC developed the first system of weights and measures; quantitative measure is the foundation of all technology and science.  But they did not colonize the galaxy. The civilization survived for almost two millennia, until the cities were mysteriously abandoned and the civilization collapsed, never having once cast their voice out into the Cosmos. Before they had the ability to build a robot, drought and shifting economics with other, nearby civilizations destroyed the greatest civilization the world had known to that time.

If I were to take these two examples at face value, and use my imagination to extrapolate to other worlds, I might imagine that life is common throughout the Universe, but perhaps it is far too fragile a form of matter to survive. Perhaps it is always obliterated, by the abusive hand of the Cosmos or through ignorance and self-destruction. Obliterated before it can send its seed, robotic messengers, out into the Cosmos.  That would be a depressing thought, with terrifying implications for our future on this world. But it is not inconceivable (even knowing what that word means); even in my lifetime, the spectre of the destruction of our world has constantly loomed, though it has been an evolving chorus of spectres, each sharing the lead.  As a child growing up in the 1980s, the possibility of nuclear annihilation was real and forefront in our minds, even as children. The threat is perhaps no less real today, but the end of the Cold War has reduced the threat in people’s imaginations. Today, the fragility of our climate and environment plays a more prominent role in considerations of what our future may be. Now, as in The Cold War, the conversation is driven by ideology and arguments built around emotional viewpoints rather than scientific considerations. It is not clear we will survive to build a robot army that will explore the galaxy. 

The Earth as seen from Saturn. Can you tell there might be life there from this picture?

Another possibility is that maybe it is just too hard to find other life.  Maybe it is out there, but detecting it is far more difficult than finding the proverbial needle in a haystack.  We are not even sure if there is life elsewhere in the solar system, and we live here! What would an alien robot sailing into the solar system find?  There are almost 100 known worlds in the solar system that are at least large enough to be round (say larger than 200km; list at Wikipedia). Would a robot explore all of them, or simply gaze from afar?  Consider what the Earth looks like from beyond Saturn.  Can you tell there is life here?  Look at the Earth from the Moon.  Can you tell there is life here, especially compared to a picture of Titan from roughly the same distance?  What if the probe never came in this close, landing on the first world it encountered, say Neptune’s enigmatic moon Nereid? 

The Earth (L) and Titan (R), each viewed by a spacecraft from roughly the same distance. Can you tell if either harbors life?

Despite all the difficulties, real and imagined, of searching for life elsewhere, we continue to do it, both by sifting the surfaces of worlds near Earth, as well as plumbing the depths of interstellar space looking for messages from other beings.  The idea of there being life elsewhere is one that is hard to let go of, because the alternative is far too depressing — that we truly are alone. It is a staggering thought, which we are constantly reminded of.

There is a very famous picture of Earth, taken by Michael Collins during the Apollo 11 flight.  As the ascent stage of the Lunar Module Eagle returned to dock with Collins aboard the Columbia in lunar orbit, he snapped a picture showing the Eagle (containing Aldrin and Amrstrong) hanging in front of the magnificent desolation of the Moon, with the partially illuminated Earth in the background.  Collins later remarked,  “I remember most vividly the picture of the lunar horizon and then the LEM ascent stage in the foreground with these two guys in it, and then the Earth popping up at that instant… You’ve got 3 billion people over there, two people here and that’s it.” 

A picture from Apollo 11 of every human being, alive or dead, except for Michael Collins (the photographer). [NASA Image AS11-44-6642]

It is perhaps one of the most poignant images of the lonely Cosmos ever taken — every member of the human race, alive or dead, except the photographer. If indeed we are alone in the Cosmos, then that was everything, captured in a single frame, at a single moment in time.  Every voice in the Cosmic fugue, the chorus of life.

————————————

This post is part of an ongoing series, celebrating the forthcoming science series, Cosmos: A Spacetime Odyssey by revisiting the themes of Carl Sagan’s classic series, Cosmos: A Personal Voyage.  The introductory post of the series, with links to all other posts may be found here:  http://wp.me/p19G0g-dE