Universe obscured by glow of city lights


By Tom Burns - Stargazing



My wife and I spent the last 12 days traveling around the New Mexico desert. The experience of the sky was spectacular, far better than anything Ohio has to offer.

Don’t get me wrong. You can get a pretty decent view of the real sky from southern Ohio if you are willing to travel to one of our lovely state parks and forests. That’s why I’ve been spending my observing time showing people the glories of the night from the new John Glenn Astronomy Park near the center of Hocking Hills State Park.

But New Mexico is something special because of its relative lack of light-polluting big cities and its variety of climates. We hiked over purest white gypsum sand dunes, down spectacular canyons, and even through what could almost be called forests, if scrub pines, tall yucca plants, and cacti can be called trees. We also went deep underground in Carlsbad Caverns.

And the sky! I have never seen that shade of azure blue at any other place. I have never seen a sunset so pure. And I have never seen so many stars clear down to the horizon.

The places away from urban life provide the best of what nature abundantly offers us, both above and below the horizon — a real sense of the minute details of our planet and its place in the larger cosmos.

I was particularly impressed by Chaco Canyon National Monument, which like many of the National Parks and Monuments, demands that its patrons be off the premises by sundown. As we hurriedly obeyed the rules and rushed out of its stark beauty into one of he most beautifully clean sunsets I had ever seen, I was reminded of a story about the great John Dobson, inventor of the Dobsonian telescope mount and astronomer.

Dobson loved to load his broken-down, “retired” school bus with enormous telescopes of his own creation. He traveled from National Park to National Park showing people the true sky from pull-off overlooks and parking lots.

Such after-dark pleasures were strictly against the rules. As a result, he was often berated by rangers and sometimes kicked out of the park.

At the Grand Canyon, one ranger sniffed, “Sir, the sky is not part of the park.”

Dobson calmly replied, “Sir, the park is part of the sky.”

And that, dear reader, is exactly right. One way of understanding our place in the universe is to examine it carefully on its microcosmic scale, an entity we commonly call “nature.”

However, the part of nature below the horizon is but a small fragment of our larger natural world.

So don’t stop there. After the sun fades, look above the horizon to find nature on its macrocosmic scale.

In other words, the best way to get a sense of humanity’s place in the universe is simply to go outside and look at the sky in late autumn. Of course, the universe is somewhat obscured by the glow of city lights. Why not take a late afternoon drive out to the country to watch the sunset at the place where earth and sky meet and stay outside until the universe appears in all its glory? Don’t forget to take along binoculars or a small telescope for an even better view.

As twilight turns to darkness, look up with the binoculars you were born with, your own two eyes. The western horizon glows with a strange, convoluted band of silvery light. The summer Milky Way is setting in the west, but don’t fret. As the night progresses, the winter Milky Way will rise in the east.

You are looking at the distant stars of your own Milky Way galaxy, our cosmic neighborhood. The sun is only one of the Milky Way’s 300 billion stars, many of which are contained in the milky band you see. A simple set of binoculars is all it takes to make that band explode into countless stars.

We have known that this is so for a bit more than 400 years. For all the time before, we were limited by what the human eye would allow us to see.

The Milky Way is shaped much like an Olympic discus, wider at the center and taped at its edges. This cosmic discus is 100,000 light years from side to side. (One light year is equal to about 6 trillion miles.) Turn on a flashlight at one end, and the light takes 100,000 years to get to the other side.

Turn on a flashlight and aim it at the moon, and the light takes a hair more than a second to travel the distance there. Compare one second to 100,000 years and you’ll begin to get a sense of the enormous size of the Milky Way.

We live near the edge of the Milky Way. As we stare into it, the glow of countless stars and clouds of dust and gas obscure our vision of the larger universe. To get a sense of the texture of the rest of the universe, we must look away from the densest part of the Milky Way.

Thus, just after dark, look high in the east for the constellation Andromeda, where only a thin veil of Milky Way gets in the way. Far beyond the stars of the constellation, you will see a fuzzy, cigar-shaped patch of light called the Andromeda Galaxy.

You are looking at the farthest thing the human eye can see. Its great distance became apparent only a century or so ago. During all the millennia that came before, humans stared up at that tiny fuzzy patch and did not realize that they had reached the limit of human vision.

Granted, with the unaided eye, the galaxy doesn’t look like much, but it will fill the field of most binoculars. From our vantage in the Milky Way, Andromeda is tilted partly on its side, accounting for its oval shape.

At perhaps 200,000 light years wide, the galaxy is twice the diameter of our Milky Way. Recent estimates by astronomers put Andromeda at about 2.5 million years away. The light that you see took 2.5 million years to travel to your eyes. Into the enormous gulf between the two could be placed end-to-end 15 Andromeda galaxies and 30 Milky Ways.

After all my decades of observing the universe, one simple fact leaves my mind gasping for oxygen: Andromeda is the closest large galaxy to our Milky Way.

The universe is composed of trillions of galaxies like Andromeda. If you spent a lifetime, a hundred lifetimes, staring through telescopes at every galaxy you can see, you would see but a tiny fraction of the galaxies that compose the universe. Every one of those galaxies would be far more distant than the faint smudge of light called the Andromeda Galaxy.

Stare upward at those things just once in your life. Stare long enough and you will know humanity’s place in the universe.

Compared even to the smallest star, you are a tiny, fragile creation. Your body is small, but your mind measures out the universe as quick as thought. Perhaps you will come to know that you were given eyes to see these things. You were given a mind to share in the vastness of the universe.

People worry much about the minutiae of their daily lives, as well they should, I suppose. They worry in a larger sense about where our nation and our world are headed, and I do not mean to belittle such concerns. In fact, I worry about all those things myself.

However, a lifetime of looking at the sky has led me to this now-unshakable conclusion: Once people see — once you see — our miraculous place in the universe, the vast beauty and cold efficiency of the cosmos, the smallness of our planet and our tenuous presence on it, the strength and fragility of this thing we call life, and the power and powerlessness we have over the only planet we have ever called home, I know in my heart of hearts that they — and you — will do the right thing.

Staring upward at the Andromeda Galaxy is a good place to start that journey.

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By Tom Burns

Stargazing

Tom Burns is the former director of the Perkins Observatory in Delaware.

Tom Burns is the former director of the Perkins Observatory in Delaware.