Monday, December 03, 2007
The Lopsided Universe
I've always had a passionate amateur's interest in astronomy and once, long ago, hoped it might become more. In college I taught astronomy labs and helped run my campus's small observatory, and "astronomer" seemed like just about the coolest thing anyone could ever put on a business card. I just couldn't convince a grad school to agree with me.
That's all right. The nice thing about astronomy is you can keep up with it as a civilian. You can even do it; I have a small scope I don't pull out too often because my house is surrounded by street lights, but in theory it's a field where amateurs often put together equipment just as good as the professionals' and can still make a contribution.
A few years ago, I was one of millions who turned over a portion of my computer's processing power to help find ETs. A group called SETI at Home (SETI = Search for Extraterrestrial Intellligence) developed a program that anyone could install to help analyze signals captured by a radio telescope. The program works like a screensaver. Whenever your computer is idle it switches over to analyzing data, automatically reporting its results to the researchers and downloading another batch of signals. By distributing the task among legions of ordinary computers, the SETI folks got more done faster than if they'd used the world's most powerful supercomputer. As far as I know my computer never found anything interesting. In fact, as far as I know, the entire project hasn't found much interesting, which is kind of an interesting result in itself. It was fun until they issued an update that gave my computer indigestion and I stopped participating. But it's been a while and I think I might give it another try.
More recently, I've been looking at smudgy little space photos for an effort called Galaxy Zoo. Galaxy Zoo aims to classify galaxies, and its strategy is similar to SETI at Home's: spread out a job too daunting for a small team of researchers among millions of amateurs instead. Once you sign up and pass a test to prove you know what a galaxy looks like, you can log on to Galaxy Zoo and sort them to your heart's content. There's nothing automated about it. You manually click through image after image, deciding whether each depicts an elliptical or spiral galaxy (the two main types) and, if it's a spiral, whether it turns clockwise or counter-clockwise. In practice it's not easy--everything looks like a dim fuzzy blob after a while--but the Galaxy Zoo researchers at Oxford University show the same images to several people to reach consensus. In fact, I got an e-mail from them this morning explaining that each target galaxy has been looked at more than 30 times, and our amateur results agree with a smaller sampling classified by professionals. So far so good.
Here's the bizarre and interesting part: as this article in the U.K.'s Daily Telegraph newspaper explains, the universe seems to have a lot more galaxies spinning counter-clockwise than clockwise.
That is a deeply astonishing result. First, understand that a spiral galaxy that appears to be wound counter-clockwise would look clockwise if we were on the other side of it. The direction of a galaxy's spin is nothing more than an accident of where you happen to be when you look at it. Second, one of the fundamental principles of astronomy is isotropy--that is the idea that, on average, the universe is pretty much the same no matter which direction you look and there's no special vantage point that's better than any other. With that in mind, looking into space from our nowhere-special perspective, you'd expect to see nearly equal numbers of clockwise and counter-clockwise galaxies. If you dump a million pennies on the ground, approximately 500,000 will be heads and 500,000 tails. It's the only result that makes any sense at all.
And yet, I and my fellow Galaxy Zoo galaxy classifiers say the cosmos, as seen from Earth's vantage point, strongly favors the counter-clockwise.
Clearly, I broke the universe.
The researchers are trying to figure out what it means, if anything. Analyzing more pictures might help solve the puzzle. My own suspicion is that they've discovered less about the universe than about the flawed eyes and minds observing it. When confronted by an indistinct image our brains find patterns and fill in details that aren't really there, and I think it's possible that maybe--maybe--there's something hard-wired into us to discern counter-clockwise patterns more readily than clockwise. Like seeing ghostly faces in the static.
That sounds like a reach, but it makes a million times more sense to me than the alternative. In any case, it'll be cool to follow and see how it turns out. Which is the entire point.