More than 40,000 amateur astronomers have scoured astronomical images, finding five supernovae as well as a host of other interesting items professional astronomers did not have the time to locate.
Zooniverse is a program that provides scientific information in a way that allows amateurs to make a genuine contribution to research. One of its projects, Snapshot Supernova, was publicized on the BBC's Stargazing Live and attracted 40,660 volunteers willing to spend hours examining photographs taken by the SkyMapper telescope.
This was old-style astronomical investigation, the sort of thing Clyde Tombaugh did when he compared tens of thousands of photographic plates looking for an object that was visible in one and absent in an image taken months later. Tombaugh's reward was the discovery of Pluto, but in the years since we've usually found ways to automate such painful labor.
However, when it comes to finding supernovae that have bloomed and faded without anyone noticing, human eyes are needed again.
Credit: ANU. The images used to identify the Type Ic supernova SMTJ13254308-2932269. The left and center frames show the same area of the sky several months apart, while the third frame is what is left when the second is subtracted from the first.
Computers are much faster but they need to know what they are looking for. "The wide range of supernovas tells us how different stars evolve and end their lives in different ways," said Dr. Richard Scalzo of the Australian National University. "Identifying them is something that human eyes are very good at. It's hard to train a computer to do it. We had five different people classify each object, and for the borderline objects up to 20 people."
Scalzo is part of the team using the SkyMapper telescope to photograph the entire southern sky 36 times over, with the results to be posted on the Internet for other research teams to use. A billion stars and galaxies have been recorded in the process, and comparisons can be made between images taken at different times.
In collaboration with Zooniverse and Oxford University's Professor Chris Lintott, Scalzo organized a five day intensive where those who wanted to help were given images to examine to see if they could identify supernovae or other objects of interest. Almost two million were classified, although most turned out not to be anything significant. Discussion threads have started on the most promising anomalies.
Once enough examples are found, computer programs will be shown what is, and isn't, a supernova in the hope they will be able to takeover the job. However, Scalzo says this will take a substantial database of SkyMapper images to start the process.
Two Type Ia supernovae, the most sought-after category, were identified, along with a Type II, a Type Ic and a fifth supernova yet to be classified.
In the course of the search, several new variable stars were identified, along with a large number of previously unknown asteroids. "One volunteer was so determined to find a supernova that he stayed online for 25 hours,” Scalzo said. “Unfortunately, he didn't find one, but he did find an unusual variable star, which we think might explode in the next 700 million years or so." Not long to wait for glory really.
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