Feeling Small in a Big Cosmos 02: Discovery

by Shane L. Larson

Suppose we wanted to imagine some very big numbers, to somehow develop an appreciation for how BIG the Cosmos truly is. Sitting on a the beach somewhere, one might idly wonder “how many grains of sand are there on all the beaches and in all the deserts of Earth?”  Counting is certainly out of the question, so how might you figure that out?

How many grains of sand, on all the beaches and in all the deserts of Earth?

You would do it the same way we “counted” the galaxies in the sky using the Hubble Extreme Deep Field. You count all the grains in some small amount, perhaps a handful of sand picked up off the shores of Lake Michigan. Then you figure out how long and wide all the beaches and deserts are, and how deep the shifting sands run, and figure out how many handfuls of sand would cover them all. Multiplying my the number of grains in my hand, you would find there are some 10 billion billion (10¹⁹) grains of sand on the planet Earth.  That’s a BIG number; a number that is beyond ordinary human understanding, beyond our everyday experience.

The night sky over the Pando Forest in central Utah. Pando is an 80,000 year old aspen grove — it has seen almost 30 million nights like this one, a sky full of stars [Image: Shane L. Larson]

But imagine for a moment comparing it to the total number of stars in all the Cosmos. The Hubble Deep Fields have convinced us there must be something like 100 billion galaxies in the Cosmos. A galaxy like the Milky Way has more than 100 billion stars in it, so multiplying those two numbers together, there are some 10,000 billion billion (10²²) stars in all the Cosmos, more than all the grains of sand on Earth. An even bigger number, well beyond our everyday experience.

When there is so much we don’t understand here on our own small planet, it is easy to be overwhelmed by the immense size, the immense possibilities of what we don’t understand in a Universe far larger than our brains can easily imagine. We could very easily crawl into our shells, hide from the immensity, and turn our vision inward, with nary another glance outward into the deep vastness that doesn’t even notice we are here.

But we don’t do that. We have, for countless generations, stared into the immensity in an ongoing  (and surprisingly successful) camapign to understand and explain all we can about the Universe. But when everything is so impossibly far away, when the Cosmos is full of so many different and unknown things, how is it that we can know anything?  The answer to that question is that we ask questions.

Consider a popular game that most of us have played since we were kids (I have a 9 year old — I get to play this A LOT).  Here is a box (with a question mark on it). You want to figure out what is under this box by asking 20 “Yes-No” questions. Go!

• Is it alive? No.
• Is it something made by humans? Yes.
• Is it small enough to hold in my hand? Yes.
• Is it edible? No.
• Does it have batteries? No.

So there we have asked just 5 questions. The answers are nothing more than a simple yes or no. But the tremendous power of asking questions is clear. Despite the vastness of the Cosmos, despite its immense size and the mind-boggling large number of things it contains, you have eliminated almost ALL of it from consideration with only 5 simple questions. You know it is not something huge (galaxy, star, planet, white dwarf, asteroid, comet, …). You know it is not alive, so every organism on Earth — plant, animal, bacteria, fungus, protozoan — is eliminated.  Your attention is now focused on only things that humans make, and only those things that aren’t powered by batteries.

And you have 15 questions left! With 20 carefully constructed questions, you will be able to figure out almost anything I wanted to hide under that question mark, with a high degree of success! If we went on and I let you ask the rest of your 15 questions, I am confident you would eventually arrive at the fact that hiding in my question mark box is a little Lego version of me and Neil deGrasse Tyson.

We could have done this with anything in the Cosmos. I could have had anything under that box — an elephant, a quasar, a piece of Pluto, the left foreleg of a carpenter ant, a circle of paper from a hole punch, a cough drop wrapper, an oyster shell, that little plastic do-hickey that holds your gas cap on your car, a Calving & Hobbes sketch, a molybdenum atom, Marie Curie’s lab notebook, a lost pawn from a Sorry game, and so on. ANYTHING!

But you can figure out what it is with only a few questions so reliably we’ve made it into a game children can play and enjoy! It’s usually called “20 questions,” but it also goes by the name science. Except when we play science, we don’t limit ourselves to just 20 questions — we ask as many as we want! You can learn a LOT with carefully constructed questions. And we have learned a lot. We have collected and gathered and recorded our knowledge of the Cosmos so effectively that much of it has passed into the communal memory of our species, integrating itself into the fabric of who and what we are so effectively that we often don’t give it a second thought. We’ve forgotten how hard it was to earn that knowledge, the struggle our forbears went through to wrest some secrets from Nature and then understand what they meant.

A 1/2 globe of the Moon, roughly 5 feet in diameter, made before spacecraft had ever flown to the far side. You can see this in the Rainbow Lobby of the Adler Planetarium in Chicago.

To understand this, consider the Moon. What do you know about the Moon? It orbits around the Earth. It is spherical, and is illuminated by the Sun. The near side always faces the Earth. It is covered with lowlands (called maria, lunar “seas”), highlands (called terrae, the brighter areas), mountains, craters, and canyons. All of this is common knowledge, which if you didn’t know it you could have found out using the electronic web that girdles our world. I’m pretty sure almost everyone reading this has not been to the Moon. In all the history of our species, only 24 humans have ever crossed the gulf between the Earth and the Moon; only 12 humans have ever walked on the Moon and seen what we know with their own eyes. The pictures of the Moon, taken by the Apollo astronauts and robotic emissaries have virtually erased from our memory what it was like to not know what the Moon was like.

Consider the globe of the Moon shown here. It is about 5 feet in diameter, and lives up to our expectations of a rugged, desolate landscape covered in mountains and craters. How far away from this globe would I have to stand, for it to look roughly the same as the Moon in the sky?  About 140 feet. The full moon in the sky, is about the size of a US dime, held at arm’s length.

When you see the Moon in the sky, it is quite small, roughly the size of a dime held at arm’s length. The detail your eye can see is minimal — mostly just dark and light shading, with no topography! [Image: Shane L. Larson]

When the Moon is that small, you can’t tell it has any topography at all. It is clearly shaded in some irregular pattern (which allows you to make the famous Moon shadows), but there are no craters or mountains to be seen. Go out and look, but don’t look with your brain plugged in to what you know; just look at what you can see. This is how the Moon has always look to the naked eye; it wasn’t until the  application of the telescope to astronomy that we knew anything different.

Galileo’s early views of the Moon through his telescope revealed previously unknown topography.

In 1609, Galileo Galilei was the first person to plumb the depths of the sky with a telescope, and what he saw shook the foundations of what we thought we knew about the Cosmos. In 1610, he published one of the seminal works in astronomy: Sidereus Nuncius, “The Starry Messenger,” wherein he described all that he had seen during his first excursions in 1609.  He wrote of the Moon

“... the Moon certainly does not possess a smooth and
polished surface, but one rough and uneven, and, just
like the face of the Earth itself, is everywhere full
of vast protuberances, deep chasms, and sinuosities.”

Two things stand out to me about this passage. The first is how he initially describes the Moon: a smooth and polished surface. This is how people thought of the Moon — it is, in a very real sense, what the Moon looks like, and what you would think if you had never been taught that there were craters and mountains on its surface. The second is when he describes what he saw on the Moon: just like the face of the Earth itself. The telescope allowed us to see that the Moon had features and topography that were at once recognizable and intimately familiar, appearing just like the topography we see here on Earth. In a singular moment of discovery, the telescope deprovincialized our view of the Earth. The Moon is, in a very real sense, the first world other than the Earth that we ever discovered, and this is how it happened.

Galileo’s planet sketches, while not showing the detail of his lunar observations, were no less revolutionary.

There were many other startling revelations Galileo had looking through the telescope. In addition, he was the first person to look at the planets through a telescope. And what he found was that the planets were not stars at all, but also were other worlds. Every planet showed size, and round shape. The planet Saturn had odd protrusions; Galileo wrote “Saturn has ears.”  Turning his telescope to Venus, Galileo found that it went through phases, just like the Moon, a fact that was easily explained by the still new Copernican idea that the Sun was at the center of the solar system.  But Jupiter revealed one of the greatest secrets of all — it held in its grasp its own entourage of moons, that orbited the great world much as our own Moon orbits the Earth. Today, they are known as Io, Europa, Ganymede, and Callisto — the Galilean moons.

When I think about these momentous discoveries, my mind always wanders to the following, often overlooked fact: even though Copernicus’ De revolutionibus orbium coelestium had been published more than 60 years before Galileo’s observations, and placed the Earth in orbit around the Sun, Galileo’s observations were the first to reveal the planets were indeed other worlds. To put an even finer point on it, Galileo’s observations were the first to definitively show that the Earth was a planet, possibly not unlike the other planets that orbit the Sun. Galileo’s telescope allowed us to discover the planet Earth.

Galileo’s observations of the Pleiades revealed stars that could not be seen with the naked eye. There was an unseen — an unknown — part of the Cosmos to discover.

Galileo also peered at stars. He found that when he looked at the Pleiades, the Seven Sisters, the telescope revealed stars that could not be seen with the unaided eye. When he peered at the diaphanous glow of the Milky Way, arching horizon to horizon in the dark skies of 17th Century Italy, he found it was comprised of uncountable numbers of individual stars, so far away and so dim that without the telescope their combined light looked no more than an evanescent fog in the dark.  The scale of the Universe was suddenly much larger. The structure of the Universe was suddenly more complex. Larger and more complex than humans had ever imagined. The revelation of the Cosmos had begun.

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This post is the second in a series of three that capture the discussion in a talk I had the great pleasure of giving for Illinois Humanities as part of their Elective Studies series, a program that seeks to mix artists with people far outside their normal community, to stimulate discussion and new ideas for everyone.  The first post can be found here:  http://wp.me/p19G0g-xB

The idea of describing science in the context of 20 Questions is one I was introduced to at a very young age, by Carl Sagan in “Cosmos: A Personal Voyage” (in Episode 11: Persistence of Memory).

Knowing something about everything

by Shane L. Larson

During the early 1970’s, a yellow cab crawled up Park Avenue in New York City. By all accounts, this was an innocuous happenstance, repeated thousands of times a day before and since.  But this cab ride was special, because it gave rise to one of the greatest treaties in human history, the so-called “Park Avenue Treaty.” The signatories were Isaac Asimov and Arthur C. Clarke, who agreed that Asimov was required to insist that Clarke was the best science fiction writer in the world (reserving second best for himself), while Clarke was required to insist that Asimov was the best science writer in the world (reserving second best for himself).  The treaty was famously referred to by Clarke in the dedication to his novel, Report on Planet Three, which read “In accordance with the terms of the Clarke-Asimov treaty, the second-best science writer dedicates this book to the second-best science-fiction writer”.

Arthur C. Clarke (left) and Isaac Asimov (right), the signatories of the Park Avenue Treaty.

The treaty is indicative of one of lost truths of those by-gone days — Asimov was widely regarded as one of the finest communicators of science, though he is most often remembered for his science fiction (if you haven’t read the original Foundation Trilogy, stop reading this now and go find a copy; this blog post will be here when you get back).  He became a proficient and popular science writer in the years after the Soviet Union launched Sputnik, when there was widespread concern about the “science gap” between Americans and the rest of the world (an earlier incarnation of the current growing science gap in our country).  Asimov’s writings were wide ranging, accessible to broad audiences, and enormously popular. Kurt Vonnegut once famously asked Asimov how it felt to know everything.  Asimov replied that he was uneasy with his reputation for omniscience.

Despite his play at modesty, Asimov’s reputation was not ill-deserved.  He was, by all accounts, a polymath — a person whose intellect and expertise span a vast number of areas in the entire body of human knowledge. There have been many polymaths throughout history, many of their names are well known in our popular culture.  Perhaps the most famous, was Leonardo da Vinci, widely regarded as one of the finest mechanical geniuses and artists who has ever lived. Apprenticed as a young boy to the artist Verrocchio in Firenze, Leonardo was immersed and trained in artistic and technical skills of the day: drafting, metalwork, drawing, sculpting, and painting.  Leonardo’s skill manifested itself even at this early age.  Anecdotal stories tell that when he began painting under the tutelage of Verrocchio, the young Leonardo’s skill was so great that Verrocchio swore to never paint again.  In his life, Leonardo produced stunning works of art that have survived and are revered today — the Mona Lisa, The Last Supper, and the Vitruvian Man.  One of my favorites works is the first sketch that we are certain is a work of Leonardo, of the Arno Valley from 1473. It is a simple line sketch that somehow captures the effervescent beauty of that far away Italian countryside, though I have never been there.

“Study of a Tuscan Landscape.” This sketch of the Arno Valley is the oldest known work of art by Leonardo da Vinci.

In my mind’s eye, I imagine the young Leonardo sitting on a grassy hillside, his pen and paper in hand, recording the image of his home in quick lines and shades. As the shape of the Arno Valley emerged and the walls of the Castle Montelupo sprang up on the page, his mind must have wandered in the fertile ground of imagination, exploring new seeds and thoughts planted by the sun and the landscape. Leonardo was not one to let seeds go untended. His genius and creativity are well known, spawning not only some of the most famous works of art in western culture, but also straying to ideas about flight and helicopters, harnessing the Sun’s energy by concentrating it, and the possibility that the Earth’s surface moved (something geologists today call plate-tectonics). No topic was too mundane, nor of little interest to Leonardo. He was a true polymath.

It is a funny fact of human nature that we discourage the behaviour that we so often value.  Polymaths dominate the ranks of the most revered scientists of all time: Leonardo, Galileo, Newton, Huygens, Feynman, Dyson. But in academic circles, polymathism is discouraged. University professors are often encouraged to be narrow minded, to focus their attention and efforts in narrow back-waters of science so they are the world’s single expert in very rigidly defined and narrow boxes of knowledge.  Somewhat surprisingly then, the most awesome applications of human imagination to science are efforts that are highly interdisciplinary, requiring expertise from hundreds of scientists in an astonishing variety of fields.

Approximately a hour to the west of Vinci, on the outskirts of Pisa, one of the greatest miracles of the modern age is taking shape.  Astronomers and physicists, in collaboration with computer scientists and engineers and laser technologists, are constructing an enormous, multi-kilometer long laser interferometer called Virgo (http://goo.gl/maps/CYzrE).  A similar, but smaller observatory called Geo has been constructed in the farmlands outside of Hannover, Germany (http://goo.gl/maps/Ozlco).  The Japanese are constructing another facility called Karga underground at the famed Kamioka Observatory in western Japan.  Two larger observatories have also been built in the United States, called LIGO — one in the high desert of eastern Washington near the Hanford Reservation (http://goo.gl/maps/C1QEj), and one in the verdant cypress forests of Louisiana near Livingston (http://goo.gl/maps/pifQn).

These massive scientific instruments are the cousins of interferometers that have been used in physics laboratories for the past century, simply enlarged by a factor of 4000 and instrumented with state of the art lasers, seismic isolation systems, the world’s largest vacuum system, 30,000 environmental sensors and one of the most powerful linked computer networks ever created for scientific analysis.  The goal is to detect one of the holy grails of physics: gravitational waves.

Gravitational waves are a completely new way of looking at the Universe, not with light, but with gravity.  Virtually everything you know about the Cosmos — everything you’ve ever been taught, everything you’ve ever read in a textbook or seen on the news, has been discovered with light using telescopes.

The Hubble Space Telescope (left) extends our vision deep into the Cosmos, providing views like this one of the Carina Nebula (right), showing us a secret birthplace of stars.

It is a time honored tradition that has passed down to us from another great polymath, Galileo Galilei who built the first telescope in 1609 and wrote about his experiences the following year in the celebrated Sidereus Nuncius (”The Starry Messenger”).  The descendants of that first modest spyglass are simple telescopes you might use in your backyard, as well as the Hubble Space Telescope.  The telescope has taught us much about the Cosmos and our place in it.  But there are new frontiers to be explored by changing our perspective.  The detection of gravitational waves will revolutionize our understanding of compact astrophysical systems. We will be able to directly probe the interior structure of neutron stars (the densest objects known) as they tear themselves apart in titanic collisions; we will watch black holes merge and ringdown, revealing their size and spin; we will see stars plummeting in chaotic spiraling orbits around black holes that will map out the gravitational field to reveal the structure and shape of the hole.  And, if we are lucky, we may even detect the faint echoes of gravitational waves from the Big Bang, whispers across time from an era 400,000 years earlier than any ordinary telescope will ever be able to see.

It was Einstein himself who discovered the idea of gravitational waves in 1916, but he almost immediately discarded the notion of detecting them because the physical effect that has to be measured was, in his estimation, beyond our abilities. Fast-forward to the modern era, and technology has changed.  Not just a single technology, but many technologies.  The instruments we build to detect gravitational waves are a complex synthesis of ideas requiring people of broad mind and discipline.

The enormous arms of these interferometers had to be laid out by our best construction contractors, because the arms are long enough that the curvature of the Earth matters!  The 1 meter diameter vacuum pipes had to be manufactured then spiral welded without any leaks or cracks over the entire 4 kilometers of the instrument arm.  Thermal engineers had to design expansion baffles on the beamtubes that contract and expand with the heating and cooling of the arms with the rising and setting of the Sun. Seismologists and meteorologists and electrical engineers had to create a network of some 30,000 environmental sensors that monitor and report on the health and environment of the observatory.  Exquisite isolation engineers had to build suspension systems capable of filtering out vibrations from everything — people walking down the hall, the echoing tremors of ground motion on the other side of the world, and the rumble of car tires on a highway ten miles away.  Computer scientists and network engineers have designed a computing and data acquisition system that has thousands of individual links, stores and processes data, and delivers that data to a collaboration of nearly 1000 scientists spread around the world.  Master optical engineers and laser physicists have built a laser injection and control system that takes as input a single infrared laser beam, circulates it over 1600 kilometers during 400 trips up and down the vacuum beam line, and brings the laser light all back together to measure minuscule changes in distances that herald the arrival of gravitational wave signals from remote corners of the Cosmos.

LIGO is an awesome machine, whether you are looking down one of the 4 km arms (left), or staring into the guts of the computer system interlinking the instrument and all of its vast sensor network (right).

Standing at the vertex of one of these great instruments, staring down the arm to the distant end stations 4 kilometers away, it is easy to be amazed by the ingenuity of our scientists and engineers — large teams who have butted heads, argued, designed, tested, and ultimately built the most sensitive scientific instruments our species has ever created.  A pool of talented people who had the where-with-all to imagine every possible problem that might be encountered along the way and design a solution.  Talented people who encountered unforeseen problems, ferreted out the cause of the trouble, then built a solution that allowed us to continue down the long road toward discovery.  These great machines, and ultimately the discoveries we make with them, are a testament to their dedication and perseverance, a legacy as great as that of Newton, and Huygens, and Leonardo.  We polymathed our way to these instruments, not through the intellect of a single person, but through the linked abilities of a vast team of people spanning multiple decades of work.  As a result of those efforts, we find ourselves poised on the brink of discovery: breathless with anticipation, and rightfully proud of our accomplishment.

The LIGO-Hanford interferometer, seen from the air.

Standing at the vertex of LIGO, one can’t help but be overwhelmed by two things. The first is the awe-inspiring example of what we can engineer through sheer ingenuity and perseverance. Instruments like LIGO will fundamentally change the way we view the Cosmos, pushing us to look beyond the simple prejudices imposed by the limitations of our physical senses and listen to the grandeur of a Universal symphony we’ve never been able to hear before. The second is that this machine is only the beginning of so much more than just astrophysics. New technology and new insights always flow back to society and are used in startling and unexpected ways, propelling our young species forward. This was true with Apollo, and as many others have pointed out, is true for LIGO.  The LIGO laser technology is already making its way into the carbon composites industry where it is being used to test aircraft parts. Einstein@Home (like it’s big sister, Seti@Home) was one of the first projects to use your home computer to do scientific crowd-computing while your computer was sitting idle during Monday Night Football, turning the world into a vast supercomputer. LIGO’s advanced laser control systems are demonstrating the precise methods needed to shape and control lasers in applications ranging from laser welding, to high precision laser cutting systems, to advanced laser weapon systems.  None of this was intended, but it all sprang from the same fertile ground — the seeds of ideas planted and nurtured from an exquisite mix of ideas stirred together with reckless abandon.  Polymathism in the large.

Standing at the vertex of LIGO, staring down the arm, the joy in our accomplishment is pierced by an unerring certainty that we should be doing more of this.  We need more polymathism in the world, on scales both large and small.  We should unfetter our young scientists, and let their minds stray to the far reaches of wonderfully crazy ideas and fantastic imaginings about what our future could be.  It is hard to imagine that good things can and will result from allowing such freedom, particularly in trying times of economic woe and political discord.  It is even harder for the vanguard of scientific leaders (the “greybeards”, as I call them) to encourage big expansive thinking among our young scientists when the great discoveries could easily overshadow our own seemingly meager contributions to the state of human knowledge; the egos of scientists (despite their outward bravado) are fragile. But that doesn’t change the fact that we need more polymaths, not just to inspire us by charging down the frontiers of discovery, but to address serious problems with new and creative connections and solutions that narrow box thinking will never discover.  The world has serious problems, and we need creative thinking to address those problems.

Standing at the vertex of LIGO, staring down the arm, I wonder what Leonardo would have thought if he was right here with me?  I can imagine him sitting here next to me, with a parchment and a pen in hand, sketching the long lines of LIGO’s arm, the scrub desert of eastern Washington and the distant shadow of Rattlesnake Mountain, and my mind strays into imagination, wondering all the things that could be.