Oxford / Galaxy Zoo

One of the galaxies identified through the Galaxy Zoo program looks like the profile of a penguin with its beak pointing toward the left. Does that elliptical grouping of stars under the penguin's beak look like an egg?

Galaxy Zoo has added another 250,000 galaxies to its menagerie, and is looking for hundreds of thousands of volunteers to put them in their proper pigeonholes.

The latest phase of the global galaxy-classification project kicked off today with a refurbished website and lots of fresh imagery from the Sloan Digital Sky Survey as well as the Hubble CANDELS survey. Researchers used automatic image-recognition software to harvest the 250,000 new images of galaxies, "most of which have never been seen by humans," the project's organizers said in a news release.

Now it's the humans' turn ... again.

More than 250,000 people have taken part in the Galaxy Zoo project since its founding in 2007. More than a million images from Sloan and Hubble already have been sorted, based on the size and shape of the galaxies shown. That process has yielded more than two dozen scientific papers, delving into the statistics of galaxy formation, the process of citizen science, and some of the oddities that the volunteers have come across over the years.

Perhaps the best known of those oddities is Hanny's Voorwerp, a strange green blob that was spotted by Dutch teacher Hanny van Arkel in 2007 and touched off years of study. Just last year, researchers using the Hubble Space Telescope explained how blasts from a black hole lit up a cloud of gas to create the effect.

Other curiosities include galaxies that look like numbers and letters of the alphabet — so much so that there's a website called My Galaxies that can make the stars spell out your message. There are other galaxies that look like animals — enough of them to populate an entire online zoo with celestial elephants, dinosaurs, snails, fish and the Penguin Galaxy you see here.

Who knows what folks will find now that Galaxy Zoo has been expanded?

"We’d like to thank all those that have taken part in Galaxy Zoo in the past five years. Humans are better than computers at pattern recognition tasks like this, and we couldn’t have got so far without everyone’s help,” Galaxy Zoo's principal investigator, Chris Lintott from the University of Oxford, said in today's release. "Now we’ve got a new challenge, and we’d like to encourage volunteers old and new to get involved. You don’t have to be an expert — in fact we’ve found not being an expert tends to make you better at this task. There are too many images for us to inspect ourselves, but by asking hundreds of thousands of people to help us we can find out what’s lurking in the data."

If galaxies aren't exactly in your groove, there are other citizen-science projects to choose from in the Zooniverse. Here are just a few:

• Ancient Lives: Help scholars decipher ancient texts in the Oxyrhynchus collection.
• The Milky Way Project: Sift through Spitzer data to characterize infrared "bubbles."
• Moon Zoo: Classify features in moon images from NASA's Lunar Reconnaissance Orbiter.
• Solar Stormwatch: Track solar activity, as recorded by NASA's STEREO probes.
• Old Weather: Pore through ships' logs to help climate researchers fine-tune their models.
• Planet Hunters: Analyze changes in a star's brightness to spot the signs of exoplanets.
• Whale FM: Help marine scientists figure out what the whales are saying.

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.