Cosmic Sightseeing 4

Time, Life and the History of the Universe in One Easy Bar Graph



I read in Professor Brian Cox’s “The Wonders of the Universe” that the amount of time that the Universe will be hospitable to life is a very small fraction of Time itself—Time being from the very beginning of the Big Bang, to the moment when the Universe completely dissolves away.

I wanted to sketch it out as a bar graph, with the blue area being the amount of time that Life as we know it will be possible anywhere in the Universe, and the red bar being Time itself—from the Big Bang until the distant future when the last bits of matter and energy dissipate into nothingness.

But, to make it to scale…the red bar would need to be very, very long. I was going to need a really wide piece of paper.

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Cosmic Sightseeing 3

I was working on this week’s blog post, and I got a little distracted. I was just floating around, not quite grasping the subject.














So, I’m splitting the post in two.Today, we’ll have a pop quiz!

And in a day or two, another post with the answers and more sightseeing.


Take the Quiz:

What would you say the following things have in common:

An ancient Native American Village…


Pioneer homesteaders…


A gray whale…


Prairie flowers, a damselfly, a monarch caterpillar…


An alligator lizard, its prey, and the rocks that give them both shelter…


The City of Reno, the Truckee River and Lake Tahoe…



NASA photo.


And all the planets, stars, asteroids and cosmic structures in the observable Universe.

Image Credit: ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme Consortium


Leave a comment with your answer! (remember…you can leave comments without giving your real name if you want to.) And tune in to the blog tomorrow to see how you did.

I’ll just give you one hint: the answer is not 42.

Cosmic Sightseeing 2


Falling Up

Whenever I get the chance, I like to sleep outside under the stars. On a clear, dark night, far away from the city…it takes me out of ordinary day-to-day life and plunks me down where I really am: clinging to a tiny rock floating around somewhere in an immense and complex Universe. It gives me perspective.

Artwork this week is provided by artist (and my mother) Barbara Dahn. I think her work is rather cosmically-inspired, don’t you?


Several times, though, while I’ve been looking up and pondering all the countless other stars and planets Out There, I’ve had a strange sensation of reverse-vertigo, almost as if gravity were letting go and I was floating up into the limitless black of the night sky.

It’s a weird feeling of falling up.

Drawing by Barbara Dahn


Falling up is an unsettling feeling…but in a good way, kind of like riding a roller coaster. I’m sure it stems from somewhere in my inner-ear—something about losing sight of the horizon. Or maybe it’s just the starry sky… a reminder of just how small I am and how big the Universe really is.


How far out into space can we see? 

Last week on this blog, we pondered Andromeda, the most distant thing any of us can see with our naked eyes—a mere 2.5 million light years away. But with a wide variety of different telescopes, we can look much farther, as far as 13.7 billion light years.

Drawing by Barbara Dahn


Looking into space is not always a visual “seeing”, especially at the greater distances. (Remember how limited the “visual” portion of the electromagnetic spectrum is?) Often, we are detecting other wavelengths that are invisible to our eyes but detectable by a variety of telescopes: infared, radio, ultraviolet, gamma rays, microwave, etc.


How big is the Universe?

13.7 billion light years is the farthest distance we have detected. At that point, all we detect is microwave background ‘noise’ left over from the Big Bang. We’re basically looking back to the beginning of time. But we’re not seeing all there is…the Universe is likely at least 160 billion light years in size. Or bigger.*

And as far as we can tell… it’s probably flat.**

And it may be only one of many, many, many Universes.***

Drawing by Barbara Dahn


I’m falling up again. How about you?


Drawing by Barbara Dahn


PS – Happy Birthday Voyager 1!

Today is Voyager’s 35th birthday.

The most-distant human-made objects, Voyager 1 and Voyager 2 are on their way out of the solar system. Sometime soon, they will enter interstellar space, where they will wander our galaxy, the Milky Way until one of the following happens:

a. they get picked up by some extraterrestrial life form

b. our entire galaxy gets swallowed into a black hole

c. unknown

d. other


For more information:


*The size of the Universe

**The shape of the Universe

***Multiverse (more than one Universe)

To see The Powers Of Ten—a very cool 10-minute film that takes you to the edge of the Universe and back



Go ahead, make my day…leave a comment! Anything at all…ask a question, make an observation, tell me if you’ve ever fallen up, or down, or sideways…


Cosmic Sightseeing 1

When you have Andromeda, who needs Fairies?

The directions said, “Drive until the road changes to gravel and keep on going until the end.” I liked the sound of that: the end of the road. It’s a rarity these days, finding such out-of the-way places. It feels like going back to a time before our world was covered in asphalt and sealed in plastic. Back to when the stars still shone at night.


We were on our way to a rental cabin on 160 glorious acres of meadow and forest, somewhere between the Methow River and the Sawtooth Wilderness.

Just as promised, the end of the road led us up to the cabin, where we were welcomed by a string of Tibetan Prayer Flags hung across the front doorway. The cabin was beautifully rustic, artfully done by people who seem to have a deep connection to the natural world. In the magnificent setting on a small ridge above the meadow, it seemed magical.

Apparently, we were not the first to think so. Inside, we found a brochure advertising a “Fairy and Human Relations Conference”, a huge celebration held on the property each year. The photos showed hundreds of people dressed in robes, gossamer wings, flowery tiaras and flowing scarves, holding hands and dancing around a huge circle in the meadow. They spend a weekend together every year communing with their nature spirits and other aspects of the ‘faery realm.’

It’s not my thing at all, but lots of people apparently take it pretty seriously. So be it.

This weekend, though, we had the place to ourselves. On our first night there, sitting outside above the darkened, silvery meadow, my thoughts shifted to the stars. I think the mysteries of science are so fascinating, I don’t think much about things like fairies (except for the occasional mutant octopus daydream). The observable Universe is just so interesting, filled with mysterious forces, energies and structures—things like strange quarks, quantum foam, and Dark Matter.

And don’t even get me started on concepts like Infinity. I’ll just go on and on forever.

That first night we sat back in our nifty REI camp-loungers and gazed up at the star-filled sky. It’s always so hard to fathom what you are really seeing when you look upward.

Our star, the sun, is only one of several hundred billion stars in our galaxy, the Milky Way. And sprinkled throughout intergalactic space…there are a hundred billion or so galaxies, each with their own collection of hundreds of billions of stars. I’m not sure how that totals up, but it’s a lot. And that’s just the observable Universe. It’s possible the Universe itself is infinite…(oops, there I go).

As the night sky grew darker and the bright points of starlight began to pop out all over, a faint, fuzzy smear appeared across the sky. It was Andromeda, a spiral galaxy that is our closest galactic neighbor, and the most distant object visible with the naked eye (although, to call Andromeda an object is a stretch. It contains roughly a trillion stars, after all).

Andromeda, also known as M31, is captured in the NASA image from the Galaxy Evolution Explorer. The view shows the ultraviolet light…invisible to our eyes but interpreted by NASA’s telescope.


Andromeda is 2.5 million light years away—just a hop and a skip in galactic terms. That means it takes the light from Andromeda 2.5 million years to reach earth. Right at that moment, my own personal retinas were receiving light waves that were emitted by Andromeda’s stars 2.5 million years ago. I was looking into the past, seeing Andromeda as it looked long ago.

We see Andromeda through a galactic curtain of stars from our own galaxy, the Milky Way. Our galaxy has 200-400 billion stars or so, Andromeda has a trillion.














I wondered…what was Earth like 2.5 million years ago—at the same time as my visual picture of Andromeda?

At roughly that time period, the ancestors of humankind were roaming the African savannahs. They stood completely upright, had short, hairy bodies with long arms—but their faces would have looked fairly human. They were also clever, being the first of our ancestors to make stone tools. It was the very beginning of a new age…the dawn of the Stone Age. *

At night, they surely looked up to the star-filled skies, and wondered what it was all about. How did their primitive, but clever minds process what they were seeing? What were their stories?

And in the distant future…what will the night sky look like?

3 billion years from now, Andromeda and our own galaxy, the Milky Way will merge together. By then, Andromeda will fill the night sky like a glowing, cosmic lightshow.  The entire night sky will glow brightly from the light of new stars born from the energy of the collision of Andromeda and the Milky Way.

It seems like magic.

In 3 billion years, Andromeda will dominate the sky. This image is a mash-up of my earlier sketch and the NASA image. Of course, in reality, 3 billion years from now, the landscape at this location will be completely changed. It could be on the bottom of an ocean, or in the middle of a desert.


For more information check out NASA’s site:

Check out the BBC series or the amazing ipad app “The Wonders of the Universe”. I think it’s worth the price of the ipad just to get this app!

For more on our human ancestors

If you want to stay at this really awesome rental cabin:

If you prefer faeries:


*give or take a few hundred thousand years, and possibly a few evolutionary branchings.

If a rainbow falls in the forest…

…and no one is there to see it, does it have any colors?

Ask a quantum physicist, and she’ll say yes and no at the same time! (Don’t try this, only quantum physicists can do it). It’s one of those paradoxes that philosophers, physicists and psychologists love to ponder. Not to mention certain artist/writers.


It’s all in your head

The world you think of as real—with green trees, blue sky, red and yellow flowers, or six-color rainbows—is a picture your brain creates for you, a reflection of objects in the world as seen through your own personal human eyes. The objects themselves have fixed characteristics—how their molecules are arranged—but they have no fixed appearance. It all depends on who’s doing the looking.


Are you a Super-Human Color Mutant?

I’ve always had trouble painting skies. Even way back in art school, I remember having discussions with fellow students about sky-color. “It’s not phalo blue,” I’d say. “…or ultramarine, or cerulean, or cobalt. There’s another color there! Don’t you see it?”

Blank looks.

Self portrait of young me in art school. Apparently I had a blank look, too. And big hair.











To this day, I’ve never been able to mix sky-color to my satisfaction. It seems there is something else up there…something more violet than green, more green than violet, but different than blue. Something completely un-mixable. I gave up on it long ago.

So, when I recently heard a woman on the radio say that she saw colors in the sky that looked ‘pinkish’, my ears perked up. Way up.

This woman was being tested for a genetic condition that scientists have long suspected in the female population—but have never proven, until quite recently. The very first known ‘tetrachromat’ has been finally been found. Apparently, there are women (sorry guys, this only happens on the X chromosome) that can see more colors than regular humans.

I knew it! Could I be a tetrachromat? Was it possible that all this time I’ve had Super-Powers I never even knew about? Imaginations ran wild. And, probably like every other woman who was listening to that same radio program, I immediately googled ‘tetrachromat’ and did an online color-confusion test.

Anyway, according to the internet, I’m just an ordinary human. And I still can’t mix sky-blue.


How We See the World  — In 3 Easy Steps

Step 1: Size Matters

The universe is filled with waves of light-energy, all essentially the same except for having different wave-lengths. They range from very long to incredibly short. They are all moving at the speed of light.


Step 2: Matter Matters

When the light waves (unpoetically known as electromagnetic radiation), encounter an object, they either pass through it, bounce off it, or are absorbed into it, depending on the size of the waves relative to the molecular structure of the object. The ones that bounce off are the ones that let us see the world.

Step 3: Cones Matter

Photo receptors called rods and cones in your retina become excited when struck by some of the light waves that reflect off objects and travel (still at the speed of light) straight into your eyeball. Your excited retina sends signals to your brain which interprets the signals and creates a picture. Result: your very own personal universe.


What you don’t see

But, human rods and cones detect only a fraction of the full spectrum of light energy that’s out there zipping around at the speed of light: what we call visible light. Drawn as a simplified linear graphic, the full spectrum of light-energy in the universe would look something like this, with the blank areas corresponding to wave-lengths we don’t see: gamma rays, radio waves, microwaves, infared and ultraviolet waves, and x-rays, to name a few.

The little rainbow strip is the only part of the spectrum that we can see…the rest is invisible to us.

But, there are many creatures that can see a much wider portion of the spectrum that we can—far more than even a tetrachromat. In fact, many birds, insects, fish and invertebrates can see into the ultraviolet and/or infared wavelengths. To them, the world must look a lot different than it does to us.



Red + Blue + Green = 1,000,000

Normal human eyes have three different types of color receptors (cones): red, green and blue, plus rods that detect light/dark levels. (A tetrachromat, by contrast, has 4 cones!). But, by mixing signals from only three color receptors, normal humans can perceive at least a million different colors. Our eyes and brains work together to create a palette of incredible richness.

But consider this: some butterflies have at least 5 or 6 color receptors, detecting colors into the ultraviolet range and with extra sensitivity to yellow and blue-green. Doing the math, it’s possible that butterflies live in a world with billions of colors. Of course, no one knows for certain what butterflies see— it could be that they need extra color receptors to make up for their simpler brains—but any way you look at it, a butterfly lives in a very differently-colored world than we do.

Tiger swallowtail butterfly on lupine, done for the Mountains to Sound project.













Oddly, the creature with the most complex eyesight by far is the mantis shrimp, which has 16 color receptors. What a world that must be!

uncredited photo of mantis shrimp from Planet Animal Zone.









Color and Art

There is more to our visual sense than light waves or the number of cones in our eyes. Awareness is a critical element to color perception. Scientists studying color vision believe that even though there are probably a number of tetrachromat-mutants walking among us that have the ability to see extra colors, they probably don’t realize they are any different than anyone else. It is possible to see colors without noticing them.

Most artists tend to be highly aware of color. As someone studying art, you learn very early to focus your awareness on colors you see with your eyes rather than your brain. In order to do this, we try to quiet our natural tendency for what scientists call ‘color constancy’ and artists call ‘local color’.

Color constancy is what Nature has given most creatures in the animal kingdom as an aid to survival—a way to simplify what they see so they fare better in the Eat or Be Eaten jungle out there. A poisonous bright red berry has to be perceived as bright red whether it is growing in the bright sunlight or the deep shade, where it’s red color may actually be barely visible.

But, as any art student knows, if you use bright red pigment to paint a bright red berry growing in shadow, you will fail miserably.

Artists who explore color have learned that the perception of color is enormously complicated. It might be simplest to describe what it is not: color perception is not static, concrete, or singular. It is the opposite of all those things…and then some. Much of the greatest art of the 20th century has been done by artists specializing in what color can do. One of my favorites happens to be my very own father, Richard Dahn:

Richard F. Dahn studied art at Yale University with Josef Albers, whose “Homage to the Square” series and other works pushed the boundaries of perception in the mid-20th century. Dahn’s work, like many of Albers’ students, grew out of the Albers tradition of intense colors, patterns and perceptual interplay.


Richard F. Dahn


Richard F. Dahn


Test your own ability to see with your eyes and not your brain and overcome color constancy:

The question: are A and B the same or different?



Answer: They are the same! (Don’t feel bad if you got it wrong. I had to print it out and cut apart the squares before I believed it myself!)


To hear the fascinating Radio Lab episode about color, tetrachromats, and more:

To learn more about the physics of light and the sense of sight:

To learn more about color vision, color blindness, and new medical breakthroughs:

Leave a comment or question! Do you think you might be a tetrachromat? Have you ever thought about what it would be like to see other wavelengths? Do you know other interesting facts or stories on this topic? Let us know!