Pre-digital age journals are filled with old astronomical images. Sometimes they contain information precious to science, if only we could find them. Now everyone with an interest in astronomy, or a liking for archives, and some time on their hands can help. As with all citizen science projects, there's the possibility of being part of something big.
"There's no telling what discoveries await," said Professor Alyssa Goodman of the Harvard-Smithsonian Center for Astrophysics in a statement. "Turning historical scientific literature into searchable, retrievable data is like turning the key to a treasure chest." If you think that sounds like hype, consider the example of KIC 8462852, also known as Tabby's Star.
KIC 8462852 is possibly the most famous example of citizen science in action, with amateurs alerting Yale's Dr Tabetha Boyajian to strange dips in its brightness. Subsequent attempts to explain these have postulated everything from swarms of comets to aliens building megastructures to capture light. A new twist on the mystery arose when astronomers studying photographs of the star taken up to a century ago reported an additional long-term decline in KIC 8462852's brightness.
That claim remains very much in dispute, largely because we just don't have enough old images of that part of the sky.
For all we know, however, just the image we want could be buried in an early copy of The Astrophysical Journal, or some less prestigious publication. The same applies to thousands of other objects that may have changed their output since astronomical photography became widespread.
To address this, Goodman has co-founded Astronomy Rewind, which will turn those old photographs into something astronomers can search. You might think that this is just a matter of feeding the images into scanning machines, but according to co-founder Dr Alberto Accomazzi, "It turns out that machines aren’t very good at recognizing celestial images on digitized pages that contain a mixture of text and graphics. And they really get confused with multiple images of the sky on the same page. Humans do much better."
Astronomy Rewind is just one of the many citizen science projects run under the Zooinverse banner, allowing people with little or no background in astronomy to expand our knowledge of the skies. Already Zooniverse has led to the classification of 4 billion images, producing more than 100 peer-reviewed papers, such as the discovery of 13 gamma ray pulsars.
If you're worried about making mistakes that interfere with the course of science, don't be. Each image will be checked by five citizen scientists, whose classifications will be compared to ensure they match. It is hoped 1,000 journal pages will be processed every day.
