By Nadia Drake
Some people scour the Internet for pictures of celebrities and cats.
![](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2012/07/16196.jpg?resize=300%2C228&ssl=1)
Others search for comets.
After performing a Yahoo! image search for photos of Comet Holmes, which whizzed by Earth in 2007, a team of astronomers used the returned images to reconstruct the comet’s orbit in three dimensions — proving that astronomers can take advantage of data provided by an unwitting group of participants.