Saturday, December 8, 2012

Long Ago and Far Away: How Galaxies Disprove Creationism

Several times lately, I've found myself explaining to my conservative Christian friends what I find so objectionable about creationism. My biggest beef is with young earth creationism (YEC), which holds that the earth was created just as described in Genesis, in six days, just a few thousand years ago. In my explanations, I've been saying the same thing over and over again: YEC is objectionable because someone who is willing to believe it isn't just rejecting evolutionary biology and parts of geology--they're basically rejecting all of science.  All the major branches of science--astronomy and physics, chemistry, practically all of biology, and even anthropology and archaeology--are unanimous in telling us the earth is incredibly ancient.  I keep saying this, but I just realized I haven't really explained what I mean, by giving examples from sciences other than biology. In this post, I'd like to do just that, giving an example from astronomy.  The most distant galaxies tell us that the universe is far older, and far grander, than the authors of Genesis could have imagined.

If you get out a star map and consult the skies, you'll see that the Little Dipper is embraced by a dragon; a serpentine constellation known as Draco. Draco, however, has been conquered by another constellation: Hercules. In old maps of the constellations, Hercules is kneeling, club aloft, with his foot on Draco's head. Of course, this is all mythology--the constellations are just random arrangements of unrelated stars, but it's interesting mythology. Even if Hercules and Draco exist only in our minds, the stars are real. If you had super-vision, you could walk out at night and look right through Hercules, past the stars to the distant galaxies beyond them. If you did that, you would see what the Hubble Space Telescope can see: the great cluster of galaxies in the image above.

Take a second, if you will, to look at this image and reflect on just what you are seeing.  Those aren't stars; those are entire galaxies. When you look up at a starry sky, almost everything you see with your naked eyes is inside our own galaxy. In this image, we're looking beyond our galaxy, at a whole cluster of other galaxies. Each one has billions of stars; more stars than you could count in a lifetime. The objects in this photograph are almost too big to fathom, but here's my favorite way of trying: a beam of light goes fast enough go from New York to San Francisco nearly 100 times in a second, yet it would take that beam of light over 100,000 years to cross a galaxy the size of the Milky Way. If the galaxies in the image are like our own, many of the stars inside each one are circled by planets. There might even be life on those planets, perhaps on millions of those planets. There could be ancient, advanced civilizations, as sophisticated compared to us as we are compared to flock of geese. That's speculation, but not wild speculation. When you're looking at an image containing trillions of suns, a whole lot of things seem possible.

The big, fuzzy football at the center of the image is Hercules A, which is a giant elliptical galaxy. Like many giant ellipticals, it's grown fat by devouring other galaxies. In fact, if you look closely, you can see a smaller galaxy that may be in the process of being engulfed. Giant elliptical galaxies are huge even by galactic standards. They may contain over a trillion stars; a trillion thermonuclear fireballs, each one far larger than the earth. In fact, the data indicate that Hercules A is about a thousand times as massive as the Milky Way.

That's all very impressive, but there are countless galaxies as big as Hercules A across the universe. Why focus on this one? Because Hercules A has a secret.To see it, you have to look at it in a different light.  Literally--you have switch from visible light to another part of the spectrum, and form an image out of radio waves. In the picture below, a radio image from the Very Large Array, a set of 27 enormous radio dishes in the New Mexico desert, has been superimposed on the visible light image above.

Here we can see that Hercules A is dwarfed by twin jets of subatomic particles emerging from its center.  Each of these jets is about 1.5 million light years long, which means it would take a beam of light (and I mentioned how fast those go) about 3 million years to get from one end to the other. What's causing the jets is a humongous black hole at the center of the galaxy, weighing about 2.5 billion times as much as our sun. Matter is swirling into the black hole and disappearing, forming a giant disk of luminous plasma at the center of the galaxy, perpendicular to the jets. All this creates powerful magnetic fields, which funnel electrons and other particles out from the center of the disc in both directions.  Moving at nearly the speed of light, these particles form the jets in the image, which give off radiation in the form of radio waves.

That's all pretty astounding, even before we consider how truly weird a black hole is. We're talking about something so massive that nothing can escape, not even light.  Space and time themselves stretch and warp at the edge of the black hole until the known laws of physics break down. Physicists admit they have no idea what happens inside a black hole, and won't know until some new Einstein can unify quantum mechanics and general relativity. Respectable scientists at places like Oxford and Yale talk about how black holes might give birth to new universes, or to wormholes that link far-flung regions of our own universe by taking a sort of shortcut through space-time. So, all in all, Hercules A is rather impressive.  But I started this post talking about creationism, particular young earth creationism. What does a distant galaxy have to do with that?

First, it shows how little the writers of Genesis understood about the universe. They were smart people, but they were writing long before modern science. The earth was flat for all they knew, and the stars and planets were absolute mysteries to them. They couldn't have known that the stars shone with their own light, while the moon and planets reflected the light of the sun. They would have had no clear concept of a galaxy, even though the great band of the Milky Way would have been visible in those ancient desert skies. It would be millennia before Immanuel Kant speculated that the cloudy blobs we see in our telescopes weren't just nebula in our own Milky Way, but "island universes" in their own right. And this wasn't confirmed until the early 20th century, when Edwin Hubble realized just how far away galaxies are, and that they are all rushing apart as the universe expands. Modern astronomy has shown us a universe far grander than the writers of Genesis could have imagined. They were doing their best, but they were living in the early Iron Age. If they had had telescopes, they might have written a different story.

The other thing distant galaxies tell us about young earth creationism is that it can't possibly be true, at least if it suggests that the universe was created at the same time as the earth. If Adam was created right after the whole universe was created, he would have looked up on the first night to see a sky devoid of stars, because the starlight wouldn't have arrived yet. The closest star visible from the northern hemisphere is Sirius A, the Dog Star. It's 8.6 light years away, which means that light takes 8.6 years to get from there to here. That means Adam would have had to wait over eight years to see the first star appear in the sky. Over the years, more and more stars would have appeared, but there are some stars so far away that Adam never would have seen them, even if he lived 930 years, as Genesis 5:5 tells us he did. In fact, some of the stars in the night sky are so far away that, if the Earth really were ten thousand some-odd years old, we still wouldn't see them. Their light wouldn't have reached us yet because they are over 10,000 lights years away. And that's just what's inside our own galaxy.

If the Earth were that young, we wouldn't be able to see a single galaxy beyond the Milky Way. Our closest galactic neighbor is the dim, recently-discovered Sagittarius Dwarf galaxy, which practically hugs the Milky Way at a distance of 70,000 light years.  Hercules A, by contrast, is 2.1 billion light years away. Since we can see it in our telescopes, that means the universe is old enough for its light to have reached us--and that would have taken around 2 billion years (the expansion of the universe complicates the calculations for faraway galaxies, so that's a ballpark figure). Hercules A, then, tells us that the universe is at least 2 billion years old.

If we're seeing two-billion year old light when we look at Hercules A, that means we aren't seeing it as it is today. We're seeing it as it was two billion years ago. The farther back astronomers look, the farther they are looking back in time. If paleontology worked that way, studying evolution would be a cinch. A paleontologist could look off in the distance with a telescope and see bison in the foreground, mammoths in the middle distance, and dinosaurs in the background. That might solve the creation-evolution debate.

As remote as it is, Hercules A is far from the most distant galaxy known. The farthest known galaxy right now is 13.3 billion light years away. If we can see it, the universe must be over 13 billion years old. In fact, other measurements indicate that the universe is 13.7 billion years old. That means that we can see galaxies as they were just a few hundred million years after the universe began.

None of this makes any sense if you believe the universe only thousands of years old. If you do, the only way you can explain the fact that we can see distant galaxies is by saying God created the universe so it just looks like light from those galaxies had been traveling for billions of years. Some creationists really say this, talking about how the universe was created "with the appearance of age". In other words, according to this theory, if the Hubble Space Telescope had been present on the first day of creation, and had picked up a beam of light forming an image of Hercules A, the beam of light would have had to be created at the same time as Hercules A itself, but over two billion light years away from it. If that's true, then that seems like a pretty elaborate deception on God's part.

But it gets worse. If the light carries an image of Hercules A as it would have looked 2 billion years ago, but the universe is far less than 2 billion years old, then the light beam is showing us something that never happened.  That would mean the pictures above are pictures of something that never was.  They are just illusions created by God.  Now, some hard-core young earth creationists would actually accept this explanation. Some people really believe that things like fossils were put in place to test our faith in the Bible. These people would rather believe in a God who intentionally deceives us than believe that the universe really is far older than humankind.

Needless to say, I can't accept that. Genesis is an ancient, mythological text. Perhaps there is wisdom to be found in it, but not by taking it as literally true, because it isn't. The universe is far more awe-inspiring than the authors of Genesis could have known, and we are lucky to be living in a time when science is making its wonders known to us.  If there's a God, he's a lot greater and more sophisticated than the God suggested by Genesis, who creates a puny little universe through crude hocus-pocus. Those who believe in God and also accept the lessons of science, with its ancient galaxies and evolving earth, have concluded that science has made God greater than the ancients could have known.  This isn't a God who creates some spring chicken of a planet and fashions people out of clay. This is a God who flings galaxies. As for me, I don't claim to know if there's a God or not, but if there is, he would have to be a magnificent cosmic architect compatible with real science, not the deceptive tinkerer imagined by creationists.


A Radio-Optical View of the Galaxy Hercules A

Visiting the Very Large Array

Star Tales: Hercules

I got the argument that young earth creationism would require God to create images of things that never existed from the book Finding Darwin's God, by Kenneth Miller, a respected biologist who is also a devout Christian.

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