#AdlerWall 03: Look for Patterns

by Shane L. Larson

(L) John Trusler (R) William Blake

(L) John Trusler (R) William Blake

In August of 1799, the Reverend John Trusler commissioned a pair of watercolors to illustrate the concept of “malevolence.” As a philosophical construct, we often regard concepts such as malevolence as being aspects of human behaviour that are part of our free will, not as natural phenomena that are able to exist independent of our free thinking. Does malevolence exist outside of humans, in Nature itself? Philosophers may differ, and certainly artists’ interpretations may vary widely. Perhaps not surprisingly, Trusler was not happy with the first painting he received.

Blake's painting of "Malevolence." [From the collection of the Philadelphia Museum of Art]

Blake’s painting of “Malevolence.” [From the collection of the Philadelphia Museum of Art]

The painter commissioned by Tusler was none other than the great English artist, William Blake.  The two shared a contentious exchange in a pair of letters that month about Blake’s depiction. In a letter on August 23, Blake admonished Tusler that we all see the world differently, writing:

The tree which moves some to tears of joy is in the eyes of others only a green thing that stands in the way. Some see Nature all ridicule and deformity…and some scarce see Nature at all. But to the eyes of a man of Imagination, Nature is Imagination itself.

Blake’s exhortations to Trusler dance around an interesting and lovely conundrum — what is Nature and how do we separate what Nature is from what we perceieve or think of it?

Consider clouds. In your high school science class, you may have once been told that clouds are suspensions in the Earth’s atmosphere, huge agglomerations of tiny water droplets and ice crystals. Most of the familiar clouds form in the troposphere, the lowest part of the Earth’s atmosphere where weather happens. Gossamer and diaphanous, they are pushed around by the winds of the world, carrying weather and moisture to the far flung corners of our planet. Meteorologists, partnered with amateur cloud watchers, have categorized a large number of cloud types, though if you restrict your attention to the most common there are only ten or so that you encounter most often (see NOAA’s “Ten Basic Cloud Types”).

The most common types of clouds, only a few of the more than 60 types classified. [Image: Wikimedia Commons]

The most common types of clouds, only a few of the more than 60 types classified. [Image: Wikimedia Commons]

But many of us have, at some point in our lives, wasted away an afternoon staring at clouds in the sky. Part of those lazy gazings is calling out shapes and figures we see in the clouds — bunnies, turtles, ships, books, hands.

There are clearly patterns in the clouds. Nature made the clouds, so Nature made the patterns. After many long years of staring at the sky, we have elucidated some regular, recurring shapes and forms that Nature creates over and over again, and we’ve given them names: cumulonimbus, altostratus, cirrus, and so on. By a similar token, the shapes and figures we recognize as bunnies and sailing ships are also patterns we have elucidated from staring at the sky. What’s the difference between our observations and Nature’s patterns? What’s the difference between afternoon figures and the cloud archetypes?

Some clouds seen from airplanes. What do you see? On the left I see a trilobite, a kid blowing a bubble, and cauliflower. On the right I see a poodle, and a shaking fist.

Some clouds seen from airplanes. What do you see? On the left I see a trilobite, a kid blowing a bubble, and cauliflower. On the right I see a poodle, and a shaking fist.

One of the great realizations we have made about the world is that it is predictable. The world does not evolve randomly, changing each day in unpredictable and unexpected ways. Quite the contrary — when I throw a water balloon up in the air (or, possibly, at someone) it always comes back to the ground. The Moon moves through a steady progression of phases every 29 days, always in the same order, just as it has for all of recorded history. A popsicle always melts when left on the kitchen counter. All of these happenings, and the many others that surround us in the natural world, occur according to precise sets of rules that we call the Laws of Nature. The fact that we can recognize patterns, that we can deduce and use the Laws of Nature to improve our lives, provides the impetus for one of the great endeavours of our species — science.

When we look at the clouds, there are two sets of patterns in play. One set of patterns are the recognizable shapes and forms of the basic cloud types. Each of these different forms is governed by a particular realization of the Laws of Nature. They are predicable and repeatable, appearing anytime the same physical conditions appear in the atmosphere. Consider “Kelvin-Helmholtz clouds.” They can form when layers of wind are sliding across one another, with the upper layer moving faster than the lower layer, creating turbulence at the boundary between them.

A classic example of Kelvin-Helmholtz clouds, created when different layers of wind slide across one another. [Image: Wikimedia commons]

A classic example of Kelvin-Helmholtz clouds, created when different layers of wind slide across one another. [Image: Wikimedia commons]

By contrast, the picture patterns that you can pick out staring up at the sky are unique to your own experiences and interpretations. You can certainly point them out to friends and get them to see what you see. But left to your own devices, you may see a turtle whereas your dearest friend may see a hoagie sandwich.  These are patterns made by your mind; the difference between them and the patterns made by Nature is that the patterns of the natural world are predictable and subject to rules. Our job as scientists and observers of the world is to figure out what those rules are.

wall_patternsThe #AdlerWall this week exhorts us to “Look for patterns,” and that “patterns can be man-made or found in Nature.”

So what kinds of patterns can you find around you? There are clearly patterns that humans make, usually quite deliberately. Our brains crave the regularity and dependability of patterns. One of the most obvious places we encounter patterns is in woven textiles. There are global patterns — stripes, dots, space cats — that you can see standing next to your friend with the loud and colorful shirt. But there are smaller, more subtle patterns you can see if you look closely, notably the interwoven fibers that cross up and over one another to give the fabric its structure. The interlocking up and down, over and under pattern of individual fibers is a human invention, though who thought of it and when is now lost to history; the oldest known woven textile fibers date to about 6000 BCE.

There are many patterns to be seen in textiles, all of them made by humans. The patterns your eye can see, as well as the underlying patterns in the weave of fabric. Patterns occur on all levels. [Images: S. Larson]

There are many patterns to be seen in textiles, all of them made by humans. The patterns your eye can see, as well as the underlying patterns in the weave of fabric. Patterns occur on all levels. [Images: S. Larson]

Carpets are another great place to see human-created patterns. These grace the floors in the Salt Palace Convention Center in Salt Lake City. I want to know whose job it is to make up these patterns!

Carpets are another great place to see human-created patterns. These grace the floors in the Salt Palace Convention Center in Salt Lake City. I want to know whose job it is to make up these patterns!

In a similar way, there are impressive patterns visible in Nature too. On cold winter days, frost ferns can form on your windows. These beautiful displays of symmetry look almost organic in nature, but result from water molecules binding to other water molecules. As a large structure forms, the molecules are forced to remain near the cold surface of the glass, and the structure of the fern emerges. Frost ferns exhbit fractal structure — a repeating pattern that appears on many many different size scales. We see fractal structure in tree branches and clouds as well.

A classic frost fern that formed on my sliding glass door this spring. [Image: S. Larson]

A classic frost fern that formed on my sliding glass door this spring. [Image: S. Larson]

There are other patterns in Nature that you can notice. I just popped outside, and with a few quick sweeps found this rock on the gravel path next to my house. I could have picked up any old rock and found something interesting, but this one has a clear structural pattern. Look closely at the exposed, broken surface. It is comprised of a myriad of interlocking small crystal structures. I’m not a robust rockhound (I just pick up cool rocks and carry them around in my pockets), but this looks like a quartzite of some kind. Quartzite is a metamorphic rock — a rock that has formed by transformation under extreme heat. In the case of quartzite, extreme pressure and heat on sandstone variety rocks causes the glassy minerals in the sand to break down and reform in crystalline arrays, not unlike the one you see on the surface of this rock.

An everyday rock, picked up off a gravel path, shows a jumble of quartz crystals on its surface. [Image: S. Larson]

An everyday rock, picked up off a gravel path, shows a jumble of quartz crystals on its surface. [Image: S. Larson]

You can see much more robust crystal formation in a kind of rock known as a geode. Geodes are roughly spherical rocks with a hollow core, where crystals have slowly grown inside the core. Beautiful (and expensive!) specimens can be bought, but breaking open common geodes will reveal a beautiful little garden of crystals. Crystals are a special pattern of matter that arises from molecules that have regular geometric shapes that are preserved when the molecules are stacked together. The regular geometric shape of the crystal that you can see with your eye is a clue to the microscopic alignment pattern of the molecules that your eye cannot see.  Salt crystals and sugar crystals are other examples.

Geodes are known for their crystal structures. The crystals are macroscopic manifestations of the underlying molecular shapes -- large patterns building from small patterns. [Image: S. Larson]

Geodes are known for their crystal structures. The crystals are macroscopic manifestations of the underlying molecular shapes — large patterns building from small patterns. [Image: S. Larson]

Another example of patterns, where human and Nature’s patterns collide is in the layout of city streets. I grew up in the American west, on the fringes of the Great Plains of North America. There the landscape is vast and flat, and humans could have laid their streets out willy-niIly in any way they wanted.  But a quick glance on satellite shows the roads are usually in a nearly perfect grid, roads running straight north-south or straight east-west. This is not true everywhere. In central Pennsylvania, the rolling landscape of the Appalachian Mountains strikes across the state from the southwest to the northeast. If you look at a town along the rolling, folded ridges you see that the roads and streets are aligned parallel to the mountains — humans patterns have been influenced and shaped by the natural patterns of the world around them.

Human patterns [streets] often follow Nature's patterns [terrain]. (L) Fort Morgan, Colorado is in the Great Plains and streets run N-S and E-W, oriented to the cardinal directions defined by the spin of the Earth. (C) In central Pennsylvania the Appalachians form long ridgelines and valleys. (R) Cities like State College, PA have street grids aligned parallel to the terrain of the mountains in the area. [Images: Google Maps]

Human patterns [streets] often follow Nature’s patterns [terrain]. (L) Fort Morgan, Colorado is in the Great Plains and streets run N-S and E-W, oriented to the cardinal directions defined by the spin of the Earth. (C) In central Pennsylvania the Appalachians form long ridgelines and valleys. (R) Cities like State College, PA have street grids aligned parallel to the terrain of the mountains in the area. Click to enlarge. [Images: Google Maps]

But seeking patterns in everything is a dangerous proposition — while we certainly believe that the laws of Nature govern everything, recognizing repeating and organized patterns is not always so easy. One of the classic examples of this is the tale of wealthy Bostonian Percival Lowell, whose imagination was captured in 1877 by the announcement of Italian astronomer Giovanni Schiaparelli that he had observed canali (Italian, “channel” or “groove”) on Mars. Many people’s inexperience with the Italian language caused them to map the word onto the English word “canal” which has a definite connotation of being an artificial and constructed edifice. (This erroneous mapping of words between one another is a failure to correctly match patterns!).

Lowell was entranced by the idea of canals on Mars, and spent a not inconsiderable amount of money constructing what is now known as the Lowell Observatory in Flagstaff, Arizona. He himself spent many long hours at the eyepiece, staring at Mars and sketching what he saw. Looking at his sketches and records we find Lowell saw what he wanted to see — canals. Lots and lots of canals. Looking at Lowell’s exquisite maps of Mars a century later, after our robotic spacecraft have returned tens of thousands of pictures of Mars, we see none of it. The interwoven pattern of canals which Lowell saw appear to be a dramatic case of scotomathe mind sees what it wants to see.

(L) Percival Lowell observing on the 24-inch Clark Refractor at Lowell Obseratory. (R) Lowell's map of the canals he thought he was seeing on Mars, now a classic example of seeing patterns that are, in fact, not there at all. [Images: Wikimedia commons]

(L) Percival Lowell observing on the 24-inch Clark Refractor at Lowell Obseratory. (R) Lowell’s map of the canals he thought he was seeing on Mars, now a classic example of seeing patterns that are, in fact, not there at all. [Images: Wikimedia commons]

Which carries us back to the tale of Blake and Trusler. We all see the world through our own eyes. The goal of collecting knowledge and one of the purposes of doing science is to capture the world as it really is, and to use that knowledge to improve our lives. No single one of us can do it all on our own; it requires all minds on deck. No single one of us ever gets it right on first glance; we have to look at the world, examine what we have seen, ponder its meaning, and, if necessary, let go of what we once thought in favor of a more real picture of what Nature has laid out before us.

So head out and look for the subtle patterns in the Cosmos; it’s all there for you to see.  See you out in the world — I’m the guy trying to take a picture of the repeating tile pattern on the cafeteria floor!:-)

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This post is part of an ongoing series about the #AdlerWall. I encourage you to follow along with the activities, and post your adventures, questions and discoveries on social media using the hashtag #AdlerWall.  Links to the entire series are here at the first post of the #AdlerWall Series.

#AdlerWall02: See What’s Hidden Under Rocks

by Shane L. Larson

Our senses — our sight, our touch, our smell, our hearing, and our taste — are the detectors we use to interface with the world. They are a biological sensor network of billions of cells, responsible for probing the world, gathering information, and delivering that information continuously to the brain.

The flow of information to your brain is tremendous, and you have adapted to ignoring most of it. Consider your sense of touch. Do you notice exactly how tight your shoes are right now? Did you think carefully about which direction you moved your leg a moment ago to make yourself more comfortable where you are sitting? How does your bracelet or watch feel on your wrist?

Consider your sense of hearing. Where ever you are, close your eyes for 20 seconds and see what you can hear. Do you hear the fans in your computer? Traffic passing by outside? Maybe sound from a TV or radio in another room or your office mate’s headphones?

All of this sensory data is constantly flooding into your neural network, but you are very adept at ignoring it. Scientists call this filtering — taking a huge amount of data, and separating and keeping just the bits you are interested in. In everyday life that means only listening to the person across the table from you, and not the cacophony of sounds that fills our world. It means looking only at the book or ereader in front of you and ignoring all the interesting things happening in your peripheral vision.

Our filtering is a habit, and given the constant demands on our attention from modern life, it is a completely necessary habit for coping with our overly busy and crowded lives. But it’s a habit we freely indulge in, so much so that we never lift the filter and notice all the wonder in the world around us.

Consider the following picture, taken of the trees outside my back door. What do you notice? Look out your window and jot down what you notice about the trees around you (hopefully you can see some trees — if not what else do you see? Just your quick impressions.).

A typical scene you encounter everyday. A yard with "yardy" things -- trees, grass, gardens, bushes. You filter this and, very often, never even consciously register what you are seeing.

A typical scene you encounter every day. A yard with “yardy” things — trees, grass, gardens, bushes. You filter this and, very often, never even consciously register what you are seeing.

My quick list might go like this: big and small trees; no leaves; grey bark; spring, but barely. All that can be gathered from a quick glance and without much thought or consideration, though at any given moment you may only register “trees,” if you even registered that at all. But what happens if I look closely at one? Take that large one in the center.

You know what trees are all about from past experience, and recognize the bark on the trunk. But what is it really like?

You know what trees are all about from past experience, and recognize the bark on the trunk. But what is it really like?

It’s bark is rough, and more or less aligned up and down the trunk. It is clearly ridged or grooved, and very rough to the touch. But careful inspection yields some odd color variations which, when viewed up close, are not bark at all!

If you didn’t look closely, you may never have noticed the off-color grey-green is a wavy sheet-like lifeform known as a lichen. This particular lichen is of the foliose (“leafy”) variety.  Lichens are a symbiotic amalgam of a fungus and an algae existing together to each others mutual benefit. The algae contributes its photosynthetic powers to harvest sunlight and generate carbohydrates that are used by the alga and the fungus both. The fungus provides a matrix around the algae that protects it and collects water. Lichens have existed on Earth for at least 400 million years (the age of the oldest fossil that we are certain is of a lichen). They are extremely robust organisms, thriving in nearly every climate on the planet.

A foiliose ("leafy") lichen, growing on the bark of this very tree. If you look at the tree picture, this lichen is there, but you filtered it! To notice new things, we must concentrate on overcoming our filtering.

A foiliose (“leafy”) lichen, growing on the bark of this very tree. If you look at the tree picture, this lichen is there, but you filtered it! To notice new things, we must concentrate on overcoming our filtering.

If I look around the tree bark a bit more, I encounter another lichen. This one is not grey-green at all, but orange. It is small, and hard to notice unless you are looking carefully. When I first saw it, I thought this particular lichen was of the crustose (“crusty”) variety. But if I look at the picture, it looks like it might still be foliose, just smaller and a different color. There’s nothing wrong with that — scientific knowledge evolves with consideration and reflection, and is driven by the collection of new and better data (in my case, a picture that showed me this lichen up close, way better than my eye could see in the bright afternoon sunlight!).

Another, smaller lichen I noticed when I was up close. I originally thought it was a crustose lichen, but after looking at the picture I think it must be foliose. Careful examination of data makes our thinking evolve -- that is what the process of science is about.

Another, smaller lichen I noticed when I was up close. I originally thought it was a crustose lichen, but after looking at the picture I think it must be foliose. Careful examination of data makes our thinking evolve — that is what the process of science is about.

Lichens are common throughout the world, and you may or may not have encountered them in one of their many forms. But interestingly, lichens are a delicate probe of the environment in which they live — they are one of many types of organisms that are referred to as bio-indicators. Many species of lichen are sensitive to levels of sulfur dioxide (SO2). In the solar system, we find plentiful amounts of sulfur dioxide. On the moons of Jupiter it is found in the ice and frost of Io, as well as mixed in the crust and mantles of the other Galilean satellites, Europa, Ganymede and Callisto. On Venus, sulfur dioxide is one of the most abundant gases in the atmosphere, playing a role in the cloud and “rain” cycle and contributing to the runaway greenhouse effect. On Earth, it is generated naturally from volcanic activity, but vast quantities are created from industrial processes, particularly the burning of coal. Sulfur dioxide in the atmosphere is a precursor step to the production of acid rain which has dramatic impact on lichens as well as other plant communities.

Covering the base of the trunk of our tree is a colony of moss.

Covering the base of the trunk of our tree is a colony of moss.

Farther down the tree, on the shady side of the trunk, we find another organism that is not the tree. Dark green, with feathered spiny leaves but no real branches. This is a moss, a plant that belongs to a larger group of planets called “bryophytes” — plants that do not have branchy structures with a system to move water and nutrients around. Lacking a transport system, these plants stay small and close to the ground. Mosses do not flower; they instead release spores from tall stalks, and looking closely, I can spot a small forest of stalks, getting ready to spread more moss about my yard.

A mosquito, trying to stay warm on the bed of moss. The iridescent colors are amazing!

A mosquito, trying to stay warm on the bed of moss. The iridescent colors are amazing!

It was a cool spring day when I was looking at this tree — definitely not into the hot and humid part of the summer; it was pleasant in the sunshine and a bit chilly in the shade. As a result, much of the animal life is still hunkered down trying to keep warm.  When I was peering close to this moss, I noticed one such denizen of my yard — a mosquito. Mosquitoes have been on Earth far longer than humans — almost 100 million years. There are more than 3500 different species known, though only a hundred or so actually use humans as a food source. Like most insects, they are cold-blooded, and prefer the temperature to be well above what we were experiencing this day. If this one saw me, it ignored the proximity of my phone as I snapped this picture.

seeUnderRocks

All of this is right there in front of us, all the time. I just picked a single tree in my front yard. I could pick any other tree and would have discovered similar interesting things, and probably a handful of other different and interesting organisms.  But let’s return to the #AdlerWall, which exhorts us to “see what’s hidden under rocks.

I picked a rock at random. This one is roughly the size of my fist. I don't carry a ruler with me, but I did have my pocket knife so I put it here for size reference. Improvising with what you have is a perfectly acceptable way to explore the world.

I picked a rock at random. This one is roughly the size of my fist. I don’t carry a ruler with me, but I did have my pocket knife so I put it here for size reference. Improvising with what you have is a perfectly acceptable way to explore the world.

A few paces from our tree, I found this rock. You’ll see it is covered with our old friends, lichens. This rock is partially buried in the dirt near my house and has likely been undisturbed for the entire time the house has been there (almost 30 years) — plenty of time for slow growing lichens and mosses to creep across the face of the rock, undisturbed as they push their frontiers quietly outward.

I’m definitely going to look under this rock, but one of the basic tenets of observing in science is there are two kinds of experiments — passive ones that leave the object of your attention in the state you found it, and active (possibly destructive) ones that manipulate the object for the purpose of study. This dichotomy is most dramatic at the extremes of physics — in quantum mechanics, the act of observing changes the nature of a system instantly and irrevocably (the point in the famous gedanken experiment known as “Schroedinger’s Cat”), and in astronomy we can’t do anything except watch passively (astronomy is a “spectator sport”).

Before I move the rock at all, I look around to see what I can see, in case my investigations destroy something interesting. This isa tiny sprout, pushing up under one edge of the rock.

Before I move the rock at all, I look around to see what I can see, in case my investigations destroy something interesting. This is a tiny sprout, pushing up under one edge of the rock.

Lifting up this rock is going to change it — I fully plan on putting it back, but there will be subtle changes none-the-less, so I carefully look around it before I move it at all, looking to see what I can notice. First, I don’t have a ruler that I can use for reference in pictures, so I use what I have at hand — my trusty pen-knife. By placing it in a picture, I can later know “how big is that rock?”  During my initial inspection, the most significant thing that caught my eye was this little leafy plant, creeping up the edge of the rock. What’s it doing there? Did it try to grow straight up and just encounter the edge of the rock? Has there been a dormant seed under the rock for 30 years, or did the seed luckily fall directly next to the rock?

[L] Moving the rock revealed a long root behind the little sprout. [R] I almost didn't notice the earthworm -- I thought it was another root! Our filters are powerful and can hide the world from us!

[L] Moving the rock revealed a long root behind the little sprout. [R] I almost didn’t notice the earthworm — I thought it was another root! Our filters are powerful and can hide the world from us!

Lifting the rock up, I find the truth — the leafy sprout is on the end of a very long root of some kind. Many plants grow new copies of themselves using propagative roots — roots that strike out under the ground, and then at some point sprout from buds on the roots and produce a new shoot growing above the ground. It looks like this might be of that variety — why else would this tiny sprout have made a gigantic root that threads its way under a rock that has been buried in this spot for almost 3 decades? I should find me a botanist and ask!

If you look closely, you’ll also notice an earthworm (an annelid) bunched up against the side of the root, probably more than a little disturbed that I had lifted the rock up. Worms play an important role in the processing of all the soil beneath your feet — their tunneling provides passageways for air and water to permeate the soil; their ingestion of dirt and organic matter breaks it down into deposits rich in the chemicals needed by plants (nitrogen, phosphates, potassium).

After my inspection, I dutifully put the rock back where I found it, replacing it in the divot in the ground I had lifted it from, covering once again the running root of our early spring sprout and returning our earthworm friend to darkness. There are many interesting things to be found around you. The challenge, always, it to notice. Don’t let the efficient habits of filtering prevent you from seeing what’s hidden under rocks. No interesting rocks around you? Look under sticks and logs. Look for interesting splashes of light or clouds you’ve never seen before. Look under leaves, and look under piles of leaves — what’s different?  Snap pictures of what you see, jot some notes down, and share what you find online so we can see it too!

See you out in the world — I’m the guy on the side of the sidewalk, trying to take a picture of what I can see inside the big crack on the curb.  Wanna take a look?:-)

coolThings

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This post is part of an ongoing series about the #AdlerWall. I encourage you to follow along with the activities, and post your adventures, questions and discoveries on social media using the hashtag #AdlerWall.  Links to the entire series are here at the first post of the #AdlerWall Series.

#AdlerWall 01: Write Down What You See

by Shane L. Larson

writeWhatYouSee

Have you ever had an awesome thought, maybe on your commute to work, standing in line at the grocery store, or waiting for your kids to get out of ballet? Did you say to yourself, “I’ve got to remember that! I should write that down.”  Then fast-forward to later that day, and you can’t remember what your brilliant thought was?

Our thoughts are ephemeral things; they come and go like the morning dew. Committing them to long term memory requires concerted effort, which if neglected, sees the thoughts evaporate away, lost forever. Fortunately, humans have invented a device to preserve our fleeting meanderings of mind: paper.

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

Study of a Tuscan Landscape.” This sketch of the Arno Valley is the oldest known work of art by Leonardo da Vinci. [Image: Wikimedia Commons]

Paper is very often the central medium in creative endeavours like art and science. Paper is used by creative minds to explore their craft and store their musings for the future. One of my favorite examples is the earliest known sketch by Leonardo da Vinci himself. “Study of a Tuscan Landscape” was a sketch made in 1473 of the Arno Valley. Ink sketched on a piece of vellum, just 15cm x 22cm. Made more than 570 years ago, it deftly captures the master’s keen eye for looking differently at the world. His mind was exploring perspective and a view from on high, his pen capturing the meander of the Arno River and the hulking walls of Castle Montelupo. His interest and observations would continue, and just more than 25 years later would produce another stunning piece, “Bird’s Eye View of a Landscape”, his rendition of what he might see if he could soar over the Tuscan landscape with the birds.

"Birdseye View of a Landscape." Leonardo da Vinci's imagining of what a bird might see, if flying over the Italian countryside. [Image: Wikimedia Commons[

“Birdseye View of a Landscape.” Leonardo da Vinci’s imagining of what a bird might see, if flying over the Italian countryside. [Image: Wikimedia Commons[

Modern, spacecraft view of the Galilean moons, which were only dots to Galileo. Top to bottom: Io, Europa, Ganymede, Callisto. [Image: Wikimedia Commons]

Modern, spacecraft view of the Galilean moons, which were only dots to Galileo. Top to bottom: Io, Europa, Ganymede, Callisto. [Image: Wikimedia Commons]

Another favorite record of mine is one of Galileo’s early sketches of the moons of Jupiter. When he first turned his telescope to the sky, Galileo was faced with many visions of the Cosmos that had been previously unimagined. Among these was the discovery that Jupiter had its own system of moons.  This was no sudden and easy realization — when he first saw them he thought they were stars that just happened to be near Jupiter. But over time Galileo saw them trail along with the planet. He embarked on a concerted and ongoing series of observations that when linked together revealed the truth: the little lights were moving around Jupiter. This was no easy feat! From Earth, the orbits of the Galilean moons are, more or less, edge-on. We don’t see them tracing out little circles on the sky — instead we see them slowly moving left to right along a line. The innermost and fleetest of the moons, Io, takes 1 day and 18 hours to make a complete circuit. The outermost moon, Callisto, shuffles along at a slower pace, retracing its steps every 16 and a half days.

Galileo's notes from 1611, from observations attempting to determine the orbital period of the moons of Jupiter, written on the back of an envelope! [Image: Morgan Library]

Galileo’s notes from 1611, from observations attempting to determine the orbital period of the moons of Jupiter, written on the back of an envelope! [Image: Morgan Library]

To ferret out these patterns requires an organized effort. If you simply watch Jupiter through a telescope multiple times, you will see the moons move, even over the course of an evening. That is exactly what Galileo did, and each time he peered through the eyepiece, he sketched what he saw. The sketches presented in Sidereus Nuncius (Galileo’s book, that announced his discoveries to the world) are very clean and organized, and familiar to astronomy enthusiasts. But I think some of Galileo’s original notes are more interesting, because they capture a very human side of the endeavour. My favorite is now in the collection of the Morgan Library. This is a record of Galileo’s observations of the Moons of Jupiter in January of 1611, when he was trying to work out how long it took each moon to circle the planet. The beauty of this is the scrap of paper is an unfolded envelope. I imagine Galileo peering through his telescope, and on the spur of the moment deciding to watch over several days to work out the orbits, so he grabbed what he had at hand. The next night, having fully intended to record it in his proper notes, he used the same scrap of paper because time had gotten away from him that day when he met an old friend at the market. And so on — it’s the way science goes, constantly intermingling itself with everyday life.  I love this old envelope — it gives new meaning to the old adage of doing science “on the back of an envelope.

Though-out history, paper has been the medium by which we preserve knowledge. It has evolved into a fine art-form in the production of books, which harbor the collective memory of our species. But the mass production and archiving of knowledge on paper in libraries, universities, and bookstores has a much more personal face at the level of individual people: their notebooks.

Notebooks are, quite often, as personal to people as the shoes or t-shirts they choose to wear. Some people swear by spiral bound notebooks (often adorned with pictures of kittens or flaming electric guitars) that you remember from grade school; others have moved on to composition books. Artists often have sketchbooks or watercolor books. Others swear by cahiers of the Moleskine style, or by tiny pocket notebooks they can keep in their pocket next to their smartphone.

A collection of notebooks from around the Larson household. This is only a small sample -- I didn't even have to try that hard to find them! [Image: S. Larson]

A collection of notebooks from around the Larson household — every person has their own personal preferences. This is only a small sample — I didn’t even have to try that hard to find them! [Image: S. Larson]

I have many notebooks lives. My scientific life is contained in my research notebooks. These are an ever increasing number of 3-ring binders, with loose-leaf pages within. This includes my own musings and calculations, graphs, articles I have read, print-outs of code, and pictures of my whiteboard. My amateur astronomy life is captured in a series of paired notebooks — one set are my astronomical diary, capturing the times I was out, who I was with, the weather where I was, the telescopes I used, and what I saw those nights. I also have a sketchbook where I try to make some kind of sketch of everything I see. They aren’t great, but they are a record of what I saw, of what I noticed.

My astronomy observing notebooks are my constant diary of the dialog between me and the night sky. [Image: S. Larson]

My astronomy observing notebooks are my constant diary of the dialog between me and the night sky. [Image: S. Larson]

But my constant companion, which my friends will recognize, is my idea notebook. I carry it with me everywhere. I use 5” x 8.25” hardback journals like Moleskines or Insights. I strongly prefer blank pages, but I’m often using lined journals because I’m a sucker for “special edition” journals, connected to pop culture elements, like superheores or famous novels. I like this size because it is small enough to carry around, but is also large enough to have some space to work.  I almost always have it in one of several treasured covers from Oberon Design.

My idea journal is my constant companion, no matter where I go. Here it is on the rim of Upheval Dome, an impact crater in Canyonlands National Park. [Image: S. Larson]

My idea journal is my constant companion, no matter where I go. Here it is on the rim of Upheaval Dome, an impact crater in Canyonlands National Park. [Image: S. Larson]

I put everything in my idea journal — sketches and Zentangles, calculations and research ideas, travel notes, movie ticket stubs, diary entries about cloud formations, notions for Lego models, ideas for posts here at writescience — anything I might not want to forget.  It all goes there, so I don’t forget it. The funny thing about memory is the act of committing it to paper means I often remember what I was thinking later, even without looking it up!

The #AdlerWall implores you to write down what you see — so you can remember, and so you can relate your experiences to someone else, even if that someone is only a future version of yourself.  Try slipping a small notebook in your pocket, and make little jots down in it as you explore the suggestions on the #AdlerWall.

But be warned: sometimes, when faced with a new, empty notebook, with pristine pages unsullied by pen or pencil, it is hard to write that first thing. This is Fear of Ruining the Notebook. Not everyone suffers this phobia, but I have it in spades, as do many others. So to combat it, I have developed a strategy: I have a standard ritual I start with every notebook, initially marking and adorning some pages. This uniquely identifies every notebook as mine, and it gets me past those first panicky moments when faced with pure, blank pages.  The ritual goes like this:

  • Inside the front, on the leaf connected to the front end-page, I write my name and email address — there is often a place for this.
  • On the bottom of that page, I usually put a sticker of… something. NASA missions, national park stickers, anything I happen to have.
  • On the inside end paper, along the seam, I write my name in black sharpie, as well as a glyph I made up in my youth to mean “me”
  • On the other side of the end leaf, facing the first true page of the notebook, I put a portrait painting of Carl Sagan, with the opening paragraph of Cosmos.
  • On the first page of the notebook, I write some kind of stylized intro graphic that says, “New Moleskine.”

I don’t know WHY I do all these things; I probably don’t need to do them all, but I do. If I were superstitious, I would say it would be bad luck to NOT do these things. But irrespective, it breaks in the new notebook and I can start using it!

Typical first pages in all my idea notebooks -- part of my ritual to get over Fear of Ruining the Notebook. [Image: S. Larson]

Typical first pages in all my idea notebooks — part of my ritual to get over Fear of Ruining the Notebook. [Image: S. Larson]

If you are following along and doing the #AdlerWall project, you will likely find you need a way to capture what you see in the world around you. We of course live in the future — your smartphone can capture what you see in pictures, or voice memos, or electronic text.

But you may find something comforting and liberating in using paper to record your journey. Anything can work, as Galileo’s unfolded envelope shows. But just in case you think its too embarrassing to show people your bird sketch on the back of a lunch napkin, or you’re afraid you’ll lose the sunrise inspired haiku you wrote on the back of a coffee shop receipt, maybe a little pocket notebook is a good starting point — something smaller than your phone, that you can always have on hand in your purse or back pocket.

It doesn’t matter what you do; just that you do it.

See you out in the world — I’m the guy sitting on the curbside, making rubbings of leaves I found on the sidewalk. In my notebook.:-)

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This post is part of an ongoing series about the #AdlerWall. I encourage you to follow along with the activities, and post your adventures, questions and discoveries on social media using the hashtag #AdlerWall.  Links to the entire series are here at the first post of the #AdlerWall Series.

 

#AdlerWall 00: Engage!

by Shane L. Larson

One of the sad truths of the modern world is that many of us have unpleasant memories of school. Indeed, students of all ages, from elementary school through college, often regard the entire educational endeavour as a long and arduous battle, and have no greater ambition other than to survive.

Sometimes, we don't let people learn by preventing them from responding to their passions [Calvin & Hobbes, by Bill Watterson]

Sometimes, we don’t let people learn because we don’t let them build on their passions [Calvin & Hobbes, by Bill Watterson]

But there is another great truth in the modern world: we live in an age where your education need not be confined to a small room with rows of desks. Virtually everything our species knows about the Cosmos has been written down, and is available to the masses. Long after most of us have walked out of the murky hallways of our schools, almost all of us rediscover the joy of engaging with the world. We rediscover what learning is about.

Some of us cook. Some of us dance. Some of us paint or craft. Some of us write apps. Some of us write fiction. Some of us read about history. Some of us learn guitar. Some of us garden. Some of us birdwatch or stargaze.

friendsDoingStuff

We are engaged and learning about the world through all the myriad of things that we “do for fun.” We are learning for learning’s sake because it tickles some long forgotten corner of our minds, and brings out a bit of the wonder and joy we experienced when everything in the world was new and every adventure was an experiment.

Somewhere in the process of “growing up,” that simple wonder and joy gets weeded out of our souls, ostensibly to make room for “being responsible” and “acting grown up.” But our brains do not forget — that’s why people learn to love learning again on their own terms.

Can you learn to re-engage with the world, to reclaim the carefree sense of exploration you had as a child?

Of course you can! But like all skills in life, it takes practice. You have to break down your old habits, and connect new neural pathways in your brain so your natural behaviour tends toward being an explorer, not a Walter Mitty.

At the Adler Planetarium in Chicago, there are two giant explorer walls. Each one is covered with ideas, suggestions, and encouragement to go out and engage with the world. People I talk with often say, “These will be great to do with the kids.”

The "Explorer Walls" at the Adler Planetarium in Chicago, located in our stairwells. [click to enlarge!]

The “Explorer Walls” at the Adler Planetarium in Chicago, located in our stairwells. [click to enlarge!]

Of course your kids will love doing this stuff. But these activities are also for you. Simple activities like these awaken corners of your mind that you may have forgotten, or that you don’t exercise nearly enough. Not all of the activities will be interesting to everyone; perhaps none of them seem interesting to you. They are provided as guides, as impetus to look at the world somewhat differently than you do every day.

I’m a teacher by trade, so I often think about what it takes to get people to do something new. I just imagine the little secret voices in your mind that are throwing rocks of doubt that keep you from learning. There are insipid little notes tied to all of those rocks.

This will be scary. This is intimidating. It might be boring. What if I do something wrong? I don’t know how to do this!

My job is to take all of those little notes and burn them. My job is to show you the path, provide an example or two, and give you a little nudge out the door.

The Cosmos is all around you, all the time, constantly clamoring for your attention, if you can train yourself to notice! It's funny, it's awe inspiring, it's mystifying.

The Cosmos is all around you, all the time, constantly clamoring for your attention, if you can train yourself to notice! It’s funny, it’s awe inspiring, it’s mystifying.

This is as easy as walking out your front door. The world is there, right out there, within reach. You don’t need a big trip to find your place in the Cosmos. It’s easy to start, and you can’t screw it up! Voltaire’s aphorism applies here: “Perfect is the enemy of good.” Exploration is dirty, not perfect. Let it happen, and the Cosmos will let you peek behind the curtain of wonders.

For the next few weeks, I’m going to follow my very advice to you. I’ll embark on a journey to do everything (and maybe then some) on the Adler walls. I’ll head out into the world, I’ll peer into my life and surroundings, I’ll wander and wonder. I’ll document what I find and discover right here, and as I often do, I’ll ramble on about what it means about us and our place in the Cosmos. So come… take a walk with me.

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PS: As you follow along, post some pictures or stories for your friends and family to see on Facebook, Twitter and Instagram.  When you do, include the hashtag #AdlerWall, so we can share in the joy of discovery with you.

PPS: One of the things on the #AdlerWall says “Take a photo everyday.” This hardly seems necessary that this should be a thing in the modern age, where smartphones are taking pictures of every latte and kitten on the planet. Never-the-less, let me exhort you to take a picture every day, but make it of something new — something you’ve never noticed before, something you don’t understand, a single moment of majesty and grandeur in life or nature. Whatever it is, make it a new one for you. I’ll do the same, and we’ll come back to this at the end.

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This is the introductory post in an entire series about the #AdlerWall. I encourage you to follow along with the activities, and post your adventures, questions and discoveries on social media using the hashtag #AdlerWall.  Links to the entire series of posts is as follows:

 

My Brain is Melting — GW150914 (Part 2)

by Shane L. Larson

It has been just more than a week since we told the world about our great discovery. It was a cold winter morning in Washington DC, the temperature hovering just below freezing. In a room at the National Press Club, the world press had gathered, and at the behest of NSF Director, Frances Córdova, LIGO Executive Director, Dave Reitze, took to the podium.

“Ladies and gentlemen. We have detected gravitational waves. We did it!” Mic drop. (Well, he should have; in the movie dramatization, he will. You can watch the moment here on YouTube, or the full press conference.)

Dave Reitze makes the announcement to the world that LIGO had detected gravitational waves.

Dave Reitze makes the announcement to the world that LIGO had detected gravitational waves. “We did it!”

So began a ninety minute press conference delivering the news of the first gravitational wave detection to the world. In the days that followed, social media and press outlets exploded in a veritable tidal wave of excitement and awestruck wonder. On twitter, the hashtags #gravitationalwaves, #LIGO, and #EinsteinWasRight have accumulated more than 70 million tweets in just one week.

Everyone has the same sense that we scientists have — this is a doorway, now open, to a Universe we have only imagined. Beyond the threshold are certainly things we have predicted and speculated about, but also many wonders yet to be found or understood.

We have done our best to explain what we are doing with LIGO, and how it works. We have made a Herculean effort to describe the astrophysical significance of the discovery. We have tried mightily to explain what Einstein’s ideas about spacetime and gravity are all about.

But this is hard stuff to think about, it is hard stuff to understand, and it is hard stuff to explain. It is well outside our normal everyday experience, so it is easy to feel like your brain is melting.

brainMelt

You shouldn’t worry that these things are hard to understand. It took physicists 41 years to even decide gravitational waves were real, and then another 59 years to build an experiment capable of detecting them. There is no doubt these are hard, brain melting matters. But the beauty of the discovery of gravitational waves is that this can be understood!

A large number of my colleagues in LIGO (and myself) have spent the last week collecting and responding to questions emailed to us, asked in public forums, and delivered on social media (if you have more questions, ask in the comments below, or please email question@ligo.org). All of them are thoughtful, genuine, and demonstrate a pleasing curiosity and wonder about the nature and workings of the Cosmos. I am constantly amazed by the questions people ask.

Here are a few of the more common brain-melters we have been asked, and some meager attempt to answer them. The questions are marked in red, to make them easy to find. Some responses are more complicated than others, and you may or may not want to read them all. They are here to help stem the meltdown, if you find your brain is still reeling.:-)

What does this mean for ordinary folks?  Far and away, this is the most common question I’ve been asked, particularly from the press. What does this mean for the world? How will this help my golf game?

LIGO’s discovery is what we call “fundamental physics.” It is a discovery that tells us something about how the Universe works and why it behaves the way it does. Figuring out how to use knowledge like that to make your life better or turning it into a gadget that’s useful in your kitchen or garage takes time — we’ve only just now made the first detection of gravitational waves, and are trying to wrap our brains around it.  Scientists and engineers will have to think a long time, maybe decades, before they can make this knowledge “useful for everyday life.”  That’s always how it works with scientific discoveries. How it will impact our everyday lives is not for us to know — that is for the future.

In the modern era, many of us navigate using GPS technology, built directly into our smartphones.

In the modern era, many of us navigate using GPS technology, built directly into our smartphones.

That is not to say that there isn’t some amazing future application. We only have to look at the history of general relativity itself to know the truth of this. Einstein worked out general relativity between 1905 and 1915. This was an age before cars and electricity were mainstays in everyday life. Yet Einstein had the where-with-all to understand that gravity could be thought of as the warpage of spacetime, and that one consequence of that warpage is clocks tick at different speeds depending on how strong the gravity is.

Did you know that little, obscure fact of general relativity is used by you and most other people every, single day? It is an essential part of how the GPS in your phone works. It took nearly a hundred years for the “fundamental physics” we call general relativity to be turned into an essential piece of technology that now gets millions of us from place to place in the world every day. Without GPS and general relativity, you’d still be navigating using paper maps. Einstein had to rely on his neighbor to tell him where to find a pub; you have a smartphone.

Is it really that important? I think this is one of the most important discoveries in astronomy in the last 100 years. It is as important as discovering that there are other galaxies beyond the Milky Way, it is as important as discovering the expansion of the Universe, it is as important as discovering the Cosmic Microwave Background.

The reason I think this is just about everything you’ve ever heard about the Universe, or seen a picture of, has been discovered using LIGHT. Telescopes are just instruments that do what your eyes do (collect light), though telescopes collect much more light than your eye or collect light that your eye cannot see (like infrared or ultraviolet light).

Gravitational waves are different — none of us have a “gravitational wave detector” as part of our bodies. Gravitational waves are something that we predicted should exist, and we built an experiment that showed us our ideas were right.  The beginning of gravitational wave observations will change how we see the Universe in ways that we cannot yet imagine.

Dr. France Córdova, Director of the National Science Foundation.

Dr. France Córdova, Director of the National Science Foundation.

As a scientist and a teacher, I can appreciate the importance and utility of the collection of knowledge. But LIGO’s discovery goes far beyond the mere acquisition of yet another fact to post on Wikipedia. What the scientists and engineers working on LIGO have done was often regarded as impossible to do. But as Dr. Córdova intoned at the LIGO press conference, we took a big risk. Through a judicious application of sweat, brains, and stubbornness, we endured a decades long effort to design a machine to do the impossible. We encountered countless challenges and obstacles, and diligently overcame every single one of them to arrive at this day. That should make every person sit up a little bit straighter and prouder. That should make every single person aware that whatever challenges or problems we face on our small world, we have the means to overcome them, if we have the will to commit our time and brains and resources to them.

The black hole collision LIGO observed was more than 50 times brighter than all the stars in the Universe. How can that be?  The comparison is “the gravitational energy released by the merger is about 50 times the energy released by all the stars in the Universe during the same time.”  This is an example of a “Fermi problem” which astrophysicists use all the time to figure out if our numbers are right when we are doing complex calculations.

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, but very little has changed. The constellations change over thousands of years, but the sky is still full of stars, and the Milky Way still arches over the sky, giving the impression that the Universe is unchanging. [Image: Shane L. Larson]

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, bathed in the light of the stars of the Milky Way. [Image: Shane L. Larson]

Astrophysicists measure brightness in watts, just like you are used to expressing the brightness of a light bulb in watts — the “wattage” tells you how much energy is released in a fixed amount of time. The higher the wattage, the more energy is released in a given moment, so the brighter the star (or bulb). Astronomers call this the “luminosity.” We can estimate the luminosity of all the stars in the Universe and compare it to what LIGO measured from the black holes. [[I’m going to use some scientific notation here to write some mind-bogglingly big numbers; a number like 106 means a 1 followed by 6 zeroes: 106 = 1,000,000. ]]

If you express the luminosity of the black holes (3 solar masses in just about 20 milliseconds) as a “wattage,” the brightness is about 3.6 x 1049 watts, or about 1023 times brighter than the Sun.

The Hubble Extreme Deep Field (XDF).

The Hubble Extreme Deep Field (XDF). We can use images like this to estimate the total number of stars in the Cosmos.

Now suppose we make the assumption that all the stars in the Universe are just like the Sun. This isn’t true, of course — some are brighter, some are dimmer, but on the average this is a good starting guess. There are about 100 billion stars in a galaxy like the Milky Way, and if you look at an image like the Hubble Extreme Deep Field, there are on order 100 billion galaxies in the Universe. So there are 100 billion x 100 billion = 1022 stars in the Universe. If each one of them is the brightness of the Sun, the total brightness of stars in the Universe is 1022 times the brightness of the Sun.

But we said the black hole merger seen by LIGO was 1023 times brighter than the Sun, so: 1023/1022 = 10. The black hole merger was 10x brighter than all the stars in the Cosmos. With a careful calculation, we could get the 50 number you hear from LIGO, but 10 is pretty close. This is the nature of Fermi problems — they don’t give you the exact number, but they quickly get you close to the exact number so you can understand the Universe.

What do you mean “spacetime is stretching LIGO’s arms?” What is spacetime? Spacetime is the substrate, the matrix upon which everything in the Universe is built — as we like to say, spacetime is the “fabric of the Cosmos.” It is, of course, easy to say that, but difficult to wrap your brain around. We’re used to not thinking about space at all; it is the nothing between everything. But it is exactly that nothing of which we speak — if we were not here, if nothing were here, there is still space.

Imagine a gravitational wave shooting through LIGO, directly out of the screen at you. (A) When there are no waves, the arms are at their fixed lengths. (B) When the wave first hits LIGO, the spacetime in one arm stretches and in the other arm compresses. This changes how long it takes light to go from the corner to the end of the arms and back again. (C) As the wave passes by, the arms change back and forth between stretching and compressing.

Imagine a gravitational wave shooting through LIGO, directly out of the screen at you. (A) When there are no waves, the arms are at their fixed lengths. (B) When the wave first hits LIGO, the spacetime in one arm stretches and in the other arm compresses. This changes how long it takes light to go from the corner to the end of the arms and back again. (C) As the wave passes by, the arms change back and forth between stretching and compressing.

How do you measure the length of something in space? Most of the time we use a ruler or a tape measure. You lay it down along the thing you are interested in, like LIGO’s arms, and you see how many it takes. Imagine that you put down kilometer markers along LIGOs arms, just like you see on the highway — one at 0km, 1km, 2km, 3km and 4km. When spacetime between the ends of LIGO changes, the entire arm stretches. You still think the arm is 4 kilometers long, because the markers are still evenly spaced (the spacing is just larger than it was before, though you may not be aware of it). We need a way to measure the stretching without relying on the kilometer markers.

Visualization of LIGO interferometry. (A) When no gravitational wave is present, the laser timing is set up to make a "dark fringe" at the output [square panel on the right]. (B) At the output, the light is like waves canceling each other out. (C) When a wave stretches or compresses the arms, it changes how the light is added together at the output. [Frames from video by Caltech/LIGO]

Visualization of LIGO interferometry. (A) When no gravitational wave is present, the laser timing is set up to make a “dark fringe” at the output [square panel on the right]. (B) At the output, the light is like waves canceling each other out. (C) When a wave stretches or compresses the arms, it changes how the light is added together at the output. [Frames from video by Caltech/LIGO]

A reliable way to measure the distance in a space that is changing and stretching, is to time a beam of light as it makes its way through the space you are trying to monitor. In LIGO, we use laser light. Imagine two photons, injected into LIGO at the corner, with a photon traveling down each of the two arms (in terms of the the optics, there is an element at the corner called a “beamsplitter” that splits a laser beam and sends part of it down each of the two arms). When there are no gravitational waves distorting LIGO, the two photons arrive back at the beam splitter and are combined to make an interference pattern, which is a brightness pattern that depends on how the photons arrive together. We set it up so the pattern is a “dark fringe” — the two photons cancel each other out (what physicists call “destructive interference”).

A simple demonstration of how sensitive interference can be to small shifts in space. These interference patterns are made with regular circles (as opposed to moving waves) and create Moiré patterns. The difference between the left and right image is a shift of only 0.05 inches, but the pattern difference is easy to see, indicating the shift happened.

A simple demonstration of how sensitive interference can be to small shifts in space. These interference patterns are made with overlapping patterns of regular circles (as opposed to moving waves) and create Moiré patterns. Here the horizontal dark region in the left image is analogous to LIGO’s “dark fringe.” The difference between the left and right image is a shift of only 0.05 inches, but the pattern difference is easy to see. What was a “dark fringe” now has a sliver of white, indicating the shift happened. [Image: S. Larson]

When a gravitational wave goes through LIGO it stretches the spacetime in one arm, and compresses the spacetime in the other arm. That means the photon in the stretched arm arrives back at the beam splitter LATE (it had farther to travel) and the photon in the compressed arm arrives at the beam splitter EARLY (it had less distance to travel). The result is the brightness pattern CHANGES. The changing pattern of brightness is exactly in tandem with the passing gravitational wave, telling us about the shape of the wave as it passes by.

They said the stretching that LIGO measured was a fraction of the width of a proton. But I remember from Chemistry that atoms are always moving, so how can you make such a precise measurement? Remember that LIGO is not measuring the distance shift in single atoms — it is watching the mirror, which is comprised of many atoms, each of which is moving exactly as you remember from Chemistry.

Everyone on a boat is doing their own thing, but they are all moving together as the boat moves on the waves.

Everyone on a boat is doing their own thing, but they are all moving together as the boat moves on the waves.

When we make our measurements, we are looking at the behaviour of many, many photons that have travelled down the arm together, hit the mirrors, and made the return journey. Sure — some of the atoms are going one way, and some are going some other way, but overall they are all moving together, going wherever gravity is pushing the center of mass of the mirror. When we read out the light, we are looking at all of those photons that hit the mirror at the same time and using that information to determine where the mirror is.

It’s a bit like having a big gravitational wave discovery party on a boat. If you are on the shore, watching all the physicists and engineers having a good time, you see they are all going every which way on the deck. But they are all on the boat, which moves them all together in response to the underlying waves of the sea.

Will this help with time travel? quantum gravity?  Einstein’s great discovery with general relativity was the idea that gravity can be described as the interaction of mass with the shape and warpage of spacetime. The unification of space and time into a single entity — spacetime — is a huge conceptual leap that is sometimes hard to come to grips with because of the way we think about space and time.

In our everyday lives we measure space with rulers and car odometers, and we measure time with wristwatches and calendars. If they are the same thing, why don’t we measure them the same way? The idea that the two are connected takes some getting used to, though as I like to remind people: when you go somewhere, you are usually comfortable saying your destination is “25 minutes” away or saying “20 miles” away!

You think about travel as travelling through space or travelling through time without even noticing! You are used to being a "spacetime traveller."

You think about travel as travelling through space or travelling through time without even noticing! You are used to being a “spacetime traveller.”

Since gravitational waves are moving ripples, propagating warpage in spacetime, it is natural to ask: can this discovery can help us understand space and time? Can we understand “time travel” and “warp drive?

Time itself, despite being part of general relativity, is still a great mystery to us. But what we often forget is that we are time travelers. Even as you are reading this, you are traveling through time from this moment, heading toward next Tuesday. It is not possible, so far as we know, to go backward toward last Friday, and that is a great mystery. It appears to be true based on experimental evidence, but we don’t yet understand how the laws of Nature — general relativity — tell us that. So in as much as gravitational waves will dramatically improve our understanding of how spacetime works and behaves, that deeper understanding could lead us down a path of thinking that will ultimately give us more insight into the mystery of time.

In a similar way, the LIGO detection does not address the enduring questions about the microscopic, quantum nature of gravity. The gravitational waves are a “big world” phenomenon, created by strongly gravitating astrophysical objects. But based on our experience with other quantum physics, we expect that there will be a clear (though not now obvious) connection between quantum gravity and general relativity. The more we expand our understanding of general relativity, it becomes more likely we will stumble on the deep connections that would lead to ultimately understanding quantum gravity.

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I encourage you to continue asking your favorite physicist your questions and share what you learn. Also, send questions to: question@ligo.org

Remember: no question is a dumb question. If you are wondering something, I’ll bet you a jelly donut someone else has the exact same question!

The Harmonies of Spacetime — GW150914

by Shane L. Larson

I have a good friend, Tyson, whom I don’t get to see nearly often enough. We are both privileged to be among the first generation of scientists who will know the Universe by observing the faint whisper of spacetime, bending under the influence of massive astrophysical systems. We are “gravitational wave astronomers.”

Picking crab with Tyson (far right) and family. [Image: Sabrina Savage]

Picking crab with Tyson (far right) and family. [Image: Sabrina Savage]

A while back we were sitting on his back porch late into the evening, picking crab and talking about everything. It was the kind of common, easy conversation among friends that ranges over movies, politics, family, childhood memories, inside jokes, and so on. But at one point, the conversation drifted back to science and to the near future. Tyson said something that really just kind of made us all stop in shocked silence: “If we’re really going to detect gravitational waves in the next 3 or 4 years, they are already closer than Alpha Centauri and heading right for us.”

Whoa.

Little did we know then how prescient that observation was. We are both part of a project called LIGO — the Laser Interferometer Gravitational-wave Observatory. And this morning our collaboration made the big announcement.

Frame from a visualization of the binary black hole merger seen by LIGO [Visualization by "Simulating Extreme Spacetime" (SXS) Collaboratoin]

Frame from a visualization of the binary black hole merger seen by LIGO [Visualization by “Simulating Extreme Spacetime” (SXS) Collaboration]

On 14 September 2015, the two LIGO observatories detected a very loud gravitational wave event. Our analysis since that day has told us that it was the merger of two black holes — one 29 times the mass of the Sun, the other 36 times the mass of the Sun. The two black holes merged, forming a new, bigger black hole 62 times the mass of the Sun. We named the event after the date: GW150914.

All of this happened about 400 Megaparsecs from Earth (1.3 billion lightyears). If you are adding up the numbers, you see that there are 3 solar masses missing. That is the equivalent mass that was radiating away from the system in the energy of the gravitational waves.

Make no doubt about it — this is one of the most momentous discoveries in the history of astronomy. It will be up to historians of science to place this within context, but I would rank it right up there with the discovery of the nature of the spiral nebulae and the discovery of the Cosmic Microwave Background.

There are many important and stunning parts of this story. Let’s me tell you just a small slice of how we got to today.

LIGO: LIGO is two gravitational wave observatories that work together as a single experiment. The are located 3002 kilometers apart, with one in Hanford, Washington and the other in Livingston, Louisiana. They are enormous, 4 kilometers to a side — so large, they can be seen in satellite photos.

(L) Aerial view of LIGO-Hanford Observatory [top] and in Google Maps [Bottom]. (R) Aerial view of LIGO-Livingston Observatory [top] and in Google Maps [Bottom].

(L) Aerial view of LIGO-Hanford Observatory [top] and in Google Maps [Bottom]. (R) Aerial view of LIGO-Livingston Observatory [top] and in Google Maps [Bottom].

The observatories are “laser interferometers” — laser light is injected into the the detector, and split so it flies up and down each of the two arms. When the light returns back to the splitter, it is recombined. When you combine laser light in this way, it can be combined such that the beams cancel out (making what we call a “dark fringe”) or they combine to make a bright spot (making what we call a “bright fringe”); in between combinations have a full range between bright and dark. We sit on a “dark fringe.”

Schematic of the LIGO interferometers, showing the basic layout of the lasers and optics locations. [Image: S. Larson & LIGO Collaboration]

Schematic of the LIGO interferometers, showing the basic layout of the lasers and optics locations. The lasers travel up and down the two 4 kilometer long arms, and are recombined and detected at the photodetector. [Image: S. Larson & LIGO Collaboration]

When a gravitational wave hits LIGO, it stretches and compresses the arms. The result is that it changes how long it takes the lasers to travel from the splitter to the end mirror and back. If that happens, when the lasers are recombined the brightness of the fringe changes.

What Happened? Both the LIGO detectors run more or less continuously, and we get our primary science data when they are on at the same time. In the early morning hours of 14 September 2015, at 4:50:45am Central Daylight Time, a signal was detected in the Livingston detector. 7 milliseconds later, a signal was also detected in the Hanford detector. These detections are sensed automatically by sophisticated software that looks for things that are “out of the ordinary.” Notable events are logged, and then humans can take a look at them. In this case, we knew almost immediately it was significant because it was in BOTH detectors, and it was a strong signal (we use words like “loud” and “bright” to mean strong, but we don’t really “hear” or “see” the signals in the usual sense; these are descriptive adjectives that are helpful because of the analogy they make with our normal senses).

Spectrograms of the event at Hanford and Livingston. The darker areas are what a "typical" spectrogram might look like; the bright swoops are the (very noticeable) signal! [Image: LIGO Collaboration]

Spectrograms of the event at Hanford and Livingston. The darker areas are what a “typical” spectrogram might look like; the bright swoops are the (very noticeable) signal! [Image: LIGO Collaboration]

One of the easiest ways to see the signal is in a diagram called a “spectrogram” which shows how the signal in the detector changes in time. Once we had the first spectrograms, the emails began to fly.

Finding Out: We all get LOTS of email, so it took a while before everyone in the collaboration actually realized what was going on. I didn’t hear until the night of September 15. AT 9:35pm CST I got an email from Vicky Kalogera, the leader of our group, that said “have you caught any of what’s going on within LIGO?” We had a round of email with unbearably long delays between them, but by 11:35pm, I had our initial understanding/guesses in my hands. That was enough to do what we all do in science — we make some calculations and extrapolations to understand what we have seen, and to plan what we should do next. We want to figure out what the new result might mean! Here’s the page out of my Moleskine, where I started to compute what a detector in space, like LISA, might be able to see from a source like this.

My journal page from the hour after I first found out about the event. [Image: S. Larson]

My journal page from the hour after I first found out about the event. [Image: S. Larson]

The Importance: There are all kinds of reasons why this discovery is important. If you take your favorite gravitational physicist out for pizza, they’ll talk your ear off for hours about exactly why this is important. But let me tell you the two I think the most about.

First, this is the first direct detection of gravitational waves. It is the first time we have built an experiment (LIGO) and that experiment has responded because a gravitational wave passed through it. This is the beginning of gravitational wave astronomy — the study of the Cosmos using gravity, not light.

Second, this is the first time that we have directly detected black holes, not observed their effects on other objects in the Universe (stars or gas).

The Astrophysics: The two black holes, caught in a mutual gravitational embrace, had spent perhaps a million years slowing sliding ever closer together, a long and lonely inspiral that ended with their merger into a single, bigger black hole. This is the first time we know conclusively of the existence of black holes that are tens of solar masses in size. Such black holes have been predicted in theoretical calculations, but never seen in the Cosmos before.

A more technical simulation of the binary black hole merger; gravitational physicsists and astronomers will be comparing the data to their simulations to examine how well we understand "real" black holes. [Image: SXS Collaboration]

A more technical simulation of the binary black hole merger; gravitational physicsists and astronomers will be comparing the data to their simulations to examine how well we understand “real” black holes. [Image: SXS Collaboration]

Our next big question is “how often does this happen?” If it happens a lot, that is a potential clue pointing to where such black holes come from. If it is a rare event, that also tells us something. So now, we wait — this is just the beginning of LIGO observations, and after a few years of listening for more, we’ll know how common these are.

The People: Science is a way of thinking about the Universe, and so often when we talk about science we talk about Nature — all the wonder, all the mystery, the rules of the Cosmos. But science is a uniquely human endeavour and every momentous discovery is the culmination of countless hours of sweat, uncountable failures, and equally uncountable tiny moments of success that culminate at a profound moment of knowing something new. It would not be possible without the dedication of enormous numbers of people. The world gravitational wave community has been working toward this day for decades. More than 1000 authors appear on the discovery paper, and there are thousands of others who have worked and are working on the project, who are not in that list of authors. It has been a heroic effort on the part of physicists, astronomers, optical engineers, data and computer scientists, technical and support staff, professors and students.

Just some of the thousands of people who have made LIGO a reality and the detection of GW150914 possible. [Images from the LIGO Collaboration]

Just some of the thousands of people who have made LIGO a reality and the detection of GW150914 possible. [Images from the LIGO Collaboration]

Teasing out the secrets of Nature is hard. Since before recorded history began, our distant ancestors  have plumbed the mysteries of the Cosmos using tools that Nature gave us — our five senses. Astronomer Edwin Hubble once opined “Equipped with his five senses, man [sic] explores the universe around him and calls the adventure Science.” (Harper’s Magazine 158: 737 [May, 1929]).

Today, we add a new sense to our quest to understand the Cosmos. TODAY the Era of Gravitational Wave Astronomy opens. Within the next few years, we will no longer live in a world where our view of the Cosmos is limited to what light alone can tell us. TODAY, we see the Cosmos anew, with senses attuned to the fabric of space and time itself!

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I’ve written about gravitational waves here at WriteScience before. In many of those I’ve explored what the physical description and meaning of gravitational waves are, and what the endeavour to detect them is all about. If you’d like to take a stroll down memory lane, here are links to those old posts:

Many of my colleagues in LIGO are also blogging about this momentous discovery. I will add their links here as they appear, so you can read their accounts as well:

 

The Red Sands of Mars

by Shane L. Larson

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My grandfather and me, when I was in middle school.

I had the good fortune of knowing all my grandparents. My maternal grandfather, Robert Steele Kelher, Sr., was a chemist. I have vivid memories of spending time with him when I was young, but I don’t recall much of what we talked about. Now that I’m all grown up and a physicist, I often wish I could chat science with him. But one conversation I do remember vividly, was about Ford Thunderbirds. My grandfather once told me he had always dreamed of owning a Thunderbird. But in those later days of his life, when we would walk around the backyard together just chatting, he said he was glad he never got one; he was sure it would never have been as great as he imagined. He preferred the simple joy of savoring the idea of owning a Thunderbird.

I stumble across this memory now and then, and think about my own longings. This week, I am reminded that I often dream of Mars. I imagine an alternate reality where I get up in the morning and don a spacesuit instead of Levi’s, and walk the cold red deserts looking for clues to where we came from, clues to how Mars has changed over the aeons, and clues to what its future fate may be. But interspersed with those idle scientific longings and ponderings of an “other career” are daydreams about living and playing on Mars. What I wouldn’t give to spend a week, camping on Mars near the abandoned hulk of Spirit, once our faithful emissary on the Red Planet. Spirit was one of two Mars Exploration Rovers that landed on Mars in 2004, the ’57 Thunderbirds of their time. It spent a more than 2000 days roving across Mars, covering a total of 7.7 kilometers. Sprit has a twin, called Opportunity that is still roving, and this week we celebrated its 12th birthday on Mars.

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I often dream of camping on Mars, maybe next to the Spirit rover.

I’m not yet as old as my grandfather was when we talked about Thunderbirds, but as I get older, I’m beginning to think that my future will forever be confined to the surface of the Earth. My wonderful daughter fears that she is preventing me from becoming an astronaut (an idea she is firmly against, especially after seeing “The Martian”). She has repeatedly seen us throw space probes and rovers at Mars, but she doesn’t have the perspective to know that while sending humans into space is possible, it is not easy.

Despite my fear that I was born a bit too early to be part of the generations that live and work in space, I feel fortunate that I have lived through the first age of Mars exploration. I’ve been witness to the years when our species obtained its first up close views of the red sands of Mars, and found the landscapes to be not as alien as we might have expected. Pick up any picture, any panorama from Mars and take a good look. Looking across the rubble strewn plains, across the shifting dunes of sand toward soaring mountains rising in the distance, you could easily believe you are looking at a picture of the American Southwest.

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The “Rocknest Panorama” taken by the Curiosity rover in 2012. It does not look unlike places you might find on Earth. [Image: NASA, PIA16453]

But this is not Earth. This world is Mars. It does look like Earth, in many ways, and that is part of the reason it captures our imagination. Like people, every world is unique — they have their own individual characters, their own long histories, their own destinies to fulfill in the Cosmos.  But also like people, they are similar as well — the laws of Nature that govern the Earth govern Mars. We can take what we know about Earth, and what we don’t know, and use it to learn about Mars.  Mars has its own remarkable moons, atmosphere, climate, and orbit; it has a long history of physical processes that shaped the evolution of its surface. Understanding the similarities and differences between Mars and Earth is one part of the long quest to understand our own planetary home.  Understanding the similarities and differences is one of the principle reasons we send our robotic emissaries to other worlds.

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The Hubble Space Telescope view of Mars, centered on the dark plain known as Syrtis Major [Image: Hubble Space Telescope]

Why does Mars fascinate us so? More than any other world (except perhaps the Moon), Mars has captured the imagination of humans.  It is the only planet whose surface can be studied telescopically, and even from Earth there are tantalizing views of a dynamic and changing world.  The polar ice caps grow and receed with the seasons, visible even in a small backyard telescope. The vast dark plain of Syrtis Major darkens and fades with the Martian seasons. The planet clearly rotates when viewed from afar, and every so often, globe girdling dust storms blanket the planet, a doleful display that other worlds have dramatic weather patterns of their own. We can see much, and what we can see itches our curiosity and engenders questions.

The Martian atmosphere is thin (only about 1% as thick as Earth’s), but it is still strong enough to toss dust around the planet in globe-girdling dust storms that envelop the world for months on end. Our spacecraft have watched (and encountered!) swirling dust devils meandering across the plains, and rimes of frost condense out of the cold winter air. Once, long ago, we think the atmosphere was thicker, thick enough to move liquid water around the planet in a vast hydrological cycle like ours on Earth.  What happened to Mars’ atmosphere? Why and how did it change, and what does that mean about our long term future? The Martian poles are studded by brilliant white ice caps that grow and shrink with the Martian seasons. As the poles grow and shrink, does the ice entomb a layered record of Mars’ storied past, like the Earth’s ice does?

marsAtmosphere

We see familiar atmospheric and hydrological phenomena on Mars, similar but not identical, to what we see on Earth. L to R: Dust devils (seen by Mars Reconnaissance Orbiter), frost (at the Viking 2 site in Utopia Planitia), south polar ice cap (seen by Mars Global Surveyor).

One side of Mars is bulged out in a geologic area known as the Tharsis Bulge. It is a vast volcanic plateau dominated by four massive shield volcanoes, the largest of which is three times higher than Mount Everest as as wide as the state of Washington — it is the largest mountain in the solar system.  We call it Olympus Mons.  How did this massive volcanic landscape form? Why is it higher than the rest of Mars?  Was it created in some astronomical cataclysmic event, or is there something about Mars’ geologic past that made it prone to massive mountain building?

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Topographic map of Mars. Hellas (dark blue, right center) is lowest point on Mars; Olympus Mons (white peak, farthest left center) is highest point on Mars.

Since the 1960’s we’ve been sending spacecraft to Mars, and they’ve been dutifully sending back pictures and discoveries that lead to more questions. Mars, more than any other world, is the objet du désir. So as the Space Age unfolded, it was the target of many “firsts.”

Mars was the first planet to ever be visited by interplanetary spacecraft. On 15 July 1965, Mariner 4 flew past Mars, returning the first up close pictures of that distant shore. The very first picture was returned to Earth, but with some anomalous housekeeping data that suggested something might be wrong with the spacecraft’s tape recorder. While the issues were being sorted out and the computer was processing the data, the flight team had enough time to hand draw the first image directly from the data, pixel-by-pixel in true paint-by-number style. The first picture we saw was hand drawn (the computer later caught up and confirmed it could draw just as well as the Mariner 4 flight team). In all, Mariner 4 returned only 22 pictures, but those pictures showed us a barren, rocky world pock marked by craters, not (we thought) unlike the Moon.

Comparison_of_hand-drawn_and_digital_first_TV_image_of_Mars

The hand drawn image of the first Mariner 4 image (left) and the final computer generated image (right). [Images: NASA]

In November 1971, the Mariner 9 spacecraft successfully inserted itself into Martian orbit, becoming the first spacecraft to orbit another planet. Orbiting mars for 349 days, it returned more than 7000 pictures. Hidden among that treasure trove of images were amazing discoveries, including enormous volcanoes larger than any we have ever seen on Earth, and a vast chasm that girdled the planet, now called Valles Marineris — the Valley of the Mariner Spacecraft.

mariner9_Discovery

Mariner 9 showed us the first close up images of the caldera atop Olympus Mons (left) and the Valles Marineris (right). We have far better pictures of both today, but these were the first time humans had ever seen either. [Images: NASA]

Mars was the first planet to ever be landed on. On 20 July 1976, Viking 1 settled down in a rock-strewn red desert called Chryse Planitia — Greek for the “Plains of Gold.” Viking 2 landed just 45 days later, 6475 kilometers away in an equally stunning Martian plain called Utopia Planitia. Together, the Viking landers worked on the surface for 3621 days, returning images, monitoring the atmosphere, and sifting the sands of Mars for indications of life.

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Landscapes of Mars. Chryse Planitia seen by Viking 1 (L) and Utopia Planitia seen by Viking 2 (R). [Images: NASA]

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The Curiosity rover was lowered onto Mars by a flying robotic sky crane. [Image: NASA]

Mars is, to date, the only planet ever visited by rovers. The first was Sojourner, a micro-rover the size of a toaster oven that travelled a grand total of 100 meters in 1997. It was followed in 2004 by two larger Mars Exploration Rovers called Spirit and Opportunity. Today we celebrate Opportunity‘s 12th birthday on Mars; Spirit roved for six years before it fell silent in 2010. And in 2012, and even larger rover named Curiosity was lowered to the red sands of Mars using an ambitious and daring landing technology called a sky crane. All told, the rovers have covered nearly 60 kilometers among them, and the total is still climbing as Opportunity and Curiosity continue to roll.

All these “firsts” are fun and amazing to be sure. They inspire a kind of astonishment and awe that goes hand in hand with the uncontrollable urge to blurt out, “I can’t believe they just did that!” But in the end, the things that speak to me the most about Mars, the tantalizing bits that draw the mind and the soul into pondering the shifting red sands, are the pictures. The pictures inspire an unrequited longing to walk where none have walked before.

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My grandfather, R. S. Kelher, Sr.

As I myself have grown older, I’ve learned to appreciate my grandfather’s thinking about his dream Thunderbird, especially in a society that seems increasingly commercialized. But when I think about Mars, when I imagine even just a few moments of being able to shuffle around in the light gravity, to turn over a stone scoured by a billion years of Martian weather, to let the red, red sands sift through my outstretched fingers, the longing for that experience is almost overwhelming. Given the chance, I think I’d trade the daydream for the opportunity. But Grandpa? You should know I remembered what you said, and I thought hard about it first.