Galaxy Zoo - classifying galaxies one user at a time

Here's what they say:

Welcome to GalaxyZoo, the project which harnesses the power of the internet - and your brain - to classify a million galaxies. By taking part, you'll not only be contributing to scientific research, but you'll view parts of the Universe that literally no-one has ever seen before and get a sense of the glorious diversity of galaxies that pepper the sky.

Why do we need you?

The simple answer is that the human brain is much better at recognising patterns than a computer can ever be. Any computer program we write to sort our galaxies into categories would do a reasonable job, but it would also inevitably throw out the unusual, the weird and the wonderful. To rescue these interesting systems which have a story to tell, we need you.

It was over at the Bad Astronomer's place that I found this highly addictive yet productive pastime: Galaxy Zoo. I'll let Phil explain:

One of the big problems in recent astronomy is that we’re collecting data faster than we can analyze it. This is no joke; modern survey telescopes equipped with digital detectors can generate many gigabytes of data every night. Sweeping across the sky, they look for asteroids, exploding stars, anything that changes from one night to the next. Computers can analyze the data, and in many cases they’re pretty good at it.

But not at everything. For example, you get an image that, to your eye, has a few hundred faint fuzzy galaxies in it. Your job is to identify the type of galaxy: elliptical, spiral, peculiar, whatever. Better hurry! By tomorrow, you’ll have 20 images just like this one, but of different parts of the sky. You think, I’ll program my computer to do this! One popular piece of software, called Source Extractor, or (seriously) SExtractor for short, can do a decent job. But it isn’t perfect.

Sometimes, you just can’t beat a human brain.

Chris Lintott, a UK astronomer (perhaps better known as the co-host of the beloved program "The Sky at Night") felt the same way. He and his team want to categorize thousands, hundreds of thousands of galaxies in the Sloan Digital Sky Survey images (if you think your camera is nice… the Sloan survey uses a 142 megapixel array). Why not open it up to the public, they thought, and let people get it a try?

So they created Galaxy Zoo. You sign up, take a brief test to see how well you can identify galaxies (it’s fun!), and if you can get a high enough score, off you go! You are sent a galaxy image (a program looks at all the data and decides if an object is a galaxy or not) and asked if it’s an elliptical, a merger (a product of two galaxies colliding), or a spiral. You click the appropriate button, and the next galaxy is automatically served to you.

The interface is slick and clean, and they really do give you everything you need. They send the same galaxy to multiple users, and see what kind of consensus they get on the morphology (shape) of the galaxy.

And in many cases, the galaxies sent to you have never been seen before. What treasures lie in that data, never before seen?

Now’s your chance to find out. Go and explore space. Warning: it’s addictive. The hardest part is stopping.

He's right - on all counts.

I'll add that they give you a tutorial and a practice before they test you - you don't at all need to already know anything about this.