The first Galaxy Zoo was published online in 2007 and gathered data by having volunteer scientists examine over a million images taken by the Sloan Digital Sky Survey telescope. The project collected more than 50 million galaxy classifications in its first year, and almost 150,000 people participated. Now, in the second phase of the project, aptly titled Galaxy Zoo 2, these galaxies have been categorized.
More than 83,000 volunteers contributed to Galaxy Zoo 2 by looking at images posted online from the telescope and answering questions about the galaxy depicted in each one. Examples of questions were: Does the galaxy have spirals? If so, which way does the spiral rotate? Is the galaxy elliptical? Is there a concentration of stars extending from it? For accuracy, each image was classified at least 40 times. In the end, over 16 million classifications were made and over 300,000 galaxies were catalogued.
Why use humans for such an ambitious project with all the advanced computing technology that is available? According to researchers, although computers are good at measuring certain things about a galaxy (ex: colors and sizes), human eyes are still the best at determining other characteristics. And these sets of human eyes worked hard to get this data: if one researcher had done this amount of work, it would have taken that person nearly 30 years to complete it. However, the volunteers for Galaxy Zoo 2 finished the cataloging in just a year.
Thanks to Galaxy Zoo 2, we now have a better idea of the different kinds of galaxies that exist near to ours. But researchers aren’t stopping there. For the next phase of the project, they want to learn more about galaxies that existed a long time ago. That means that Galaxy Zoo 3 will need your help. The offer is open to anyone and no credentials are needed. Just visit GalaxyZoo.org. to sign up and get to work.