By Janet Raloff
Nonscientists and researchers alike have a chance to see something no one else ever has—a few of the million far-off galaxies that the Sloan Digital Sky Survey has recently photographed. The price of admission: People viewing the new images online must do a little work for the astronomers in charge, classifying individual galaxies as either spiral armed or elliptical collections of stars.
On July 11, the University of Oxford in England, the University of Portsmouth in England, and Johns Hopkins University in Baltimore jointly launched Galaxy Zoo. This Web site (http://www.galaxyzoo.org) describes how to differentiate between the two galaxy shapes, then lets visitors view previously unstudied images from the Sloan survey.
This is “no gimmick but a project where we need the public to be able to get at the science,” says Oxford astrophysicist Chris Lintott. Computers can’t match the human brain in classifying galaxy shapes, but there aren’t enough astronomers in the project to do the job, he says.
Once the online helpers have sorted the galaxies—and in the case of spirals, determined whether their arms swing clockwise or counterclockwise—the researchers will be able to characterize the properties of like-type galaxies, such as their sizes, the ages of their stars, and whether they host active black holes.
In just 10 days, Galaxy Zoo registered more than 80,000 volunteers. “It’s simply amazing,” Lintott says. During one peak period, “we were getting 70,000 galaxy classifications an hour.”
