Citizen Scientists Helped Produce a Database of 300,000 Galaxies

Ever want to identify your own galaxy, but figure you'd have to work for NASA? Actually, you don't have to. In fact, you don't even need a telescope. More than 83,000 citizen scientists just helped researchers at the University of Minnesota identify, tag, and catalog more than 300,000 nearby galaxies.

Back in 2007, researchers took a photo of a million galaxies imaged by the Sloan Digital Sky Survey (an epic project that uses a nearly 9-foot-wide telescope in New Mexico to take ultra-high res photos of the night sky) and asked the public to help identify them. At the time, they just asked laypeople to classify galaxies as either elliptical, mergers, or spirals. Within a day of that project's launch, they were getting more than 70,000 classifications per hour.

They called the project Galaxy Zoo, and its success led researchers to expand the project. Tuesday, they released their latest database. It's 10 times larger than any previous galaxy listing. An accompanying paper detailing the project was published in Monthly Notices of the Royal Astronomical Society.

"This catalog is the first time we’ve been able to gather this much information about a population of galaxies," said Kyle Willett, the paper's lead author. "People all over the world are beginning to examine the data to gain a more detailed understanding of galaxy types."

This time, Willett and his team asked volunteers to identify more than just a galaxy's shape: The database includes a galaxy's shape, structure, size, and color. If a galaxy was a spiral, they were asked to identify the number of arms. If it had galactic bars, which are areas of a galaxy with a high concentration of stars, they were asked to note it. In order to ensure accuracy, each galaxy was classified by 40 different people. The whole project took just 14 months--if a single trained scientist had done it, the project would have taken roughly 30 years.

"With today’s high-powered telescopes, we are gathering so many new images that astronomers just can’t keep up with detailed classifications," Lucy Fortson, another author on the paper said. "We could never have produced a data catalog like this without crowdsourcing."

Besides serving as a census for most of the known galaxies, researchers are hoping the project will shed light on how black holes and galaxies are formed. The project is ongoing--volunteers are now classifying photos taken by the Hubble Telescope.