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Join the next galaxy quest

Galaxy Zoo 2
The Galaxy Zoo 2 Web site asks Internet users to put galaxies in a series of

categories. For example, which of these galaxies are disks seen edge-on? If you

picked the ones at upper left, upper middle and lower middle, you're correct.

Over the past couple of years, more than 200,000 Internet users have been transformed into galaxy zookeepers. They've been pushing spirals and ellipticals into their separate cages, and occasionally stumbling upon cosmic critters odd enough to generate headlines as well as scientific papers.

Now the researchers behind the Galaxy Zoo are asking their citizen's army to take on an even trickier task - a grand roundup that they hope will produce a "Hitchhiker's Guide to the Galaxies." And you can join in as well, after just a few minutes of online training.

Astronomers started up the first phase of Galaxy Zoo merely to classify a million galaxies from the Sloan Digital Sky Survey's database, marking them merely as elliptical (fuzzy-ball-shaped) or spiral (swirling-arm-shaped). The Zoo's crew clicked their way through the galaxies over and over again, harnessing the wisdom of crowds to do the sort of visual-classification job that computers just aren't that good at.

The project was so popular that it crashed the system on the first day. It became even more popular when one of the Galaxy Zoo's users, Dutch schoolteacher Hanny van Arkel, spotted a curious green blob in one of the snapshots she was supposed to classify. The object was nicknamed Hanny's Voorwerp, Dutch for "Hanny's Object," and it spawned a headline-grabbing whodunit tale. (A passing galaxy and a black hole were fingered as the likely perpetrators).

So far, Galaxy Zoo has spawned four published scientific papers and at least four more that are in the works. And that's just the beginning.

For Galaxy Zoo 2, the organizers are asking users to dig a little more deeply into the sorting game for 250,000 of the brightest, most interesting galaxies in the database: Is the galaxy you're looking at a barred spiral? How many spiral arms does it have? Are you seeing it edge-on?

When astronomers analyze the results, they're likely to find patterns that will shed new light on the distribution, evolution and behavior of galaxies in a variety of cosmic settings. And you never know: There just might be a "Voorwerp" out there with your name on it.

One of the project's founders, Oxford astronomer Chris Lintott, told me in an e-mail that this month's launch of Galaxy Zoo 2 went much more smoothly than Galaxy Zoo 1. Here's what he had to say:

"We've been pleased and pleasantly surprised with the response to our launch, with a million 'clicks' being recorded each day since then. Dr. Arfon Smith, our technical lead, has been working hard to make sure that the site copes with the traffic, but apart from one minor outage we're doing well. It's a far cry from Galaxy Zoo 1 in July 2007 when the sudden enthusiasm almost killed us. We now have well over 200,000 participants in the project, which is great news because the accuracy of the classification depends on the number of people who take part.

"All new visitors have to do to take part is read the tutorial posted at and then dive into classification. I would think it would only take five to ten minutes to get through the tutorial, and then maybe 30 seconds on average to classify a galaxy.

"Our forums are at (or linked from the main site) and they've been full of people sharing their discoveries; the site itself incorporates an 'Is That Odd' option so that users can alert the team to anything noteworthy."

... And speaking of odd galaxies, the interacting galaxies known as Arp 274 are leading in the "People's Choice" vote to select a future target for the Hubble Space Telescope. Voting has been under way for a month, and you have just two more days more to cast your ballot. The winner will be announced on Monday. The Hubble team expects to unveil the winner's picture during April's "100 Hours of Astronomy" celebration.

You don't have to wait that long to see winning images of the cosmos: We've just published February's "Month in Space Pictures" roundup, which includes some real stunners from the Hubble team and other sources. Here are links to more information and bigger versions of each picture, suitable for printing or putting up as computer wallpaper:

I'll be out of the office next week, so the flow of postings on Cosmic Log will slow down to a trickle until I'm back at my desk on March 9.