I received an email earlier this week about a new Citizen Science Project called Planet 9.

Citizen Science is an effort to get the public to help out with time intensive science tasks, and there's been a lot of effort in recent years by the Zooniverse project to make an online platform (website) where it's relatively easy for scientists to setup a project and allow the public to help them out.

The first project I worked on, several years ago, was the Galaxy Zoo - where the task was to classify images of galaxies. The questions included: does the galaxy have visible spiral arms, do the arms touch the centre of the galaxy, etc. Each image is checked by several people, to get a solid result and weed out people who either don't understand the instructions or are trying to deliberately ruin the results.

The Zooniverse project currently has maybe 50 or so tasks available at zooniverse.org. In recent weeks I've counted penguins in Antarctica, marked particle tracks from the LHC at Cern, classified Muon rings, quantified snow levels in national parks and trained computers how to recognise gravitational anomalies detected at the LIGO experiment.

The Planet 9 effort was a simple one. You were shown an image of a portion of the sky in bands of different colours. These were made by superimposing images of that portion of the sky taken on different nights, each time with a different colour filter applied. The trick to this technique is that any bright objects that have moved between images will show up in a different colour to the background and the other objects around it.

I managed to find about 100 moving objects, but when I went back to have another look with a friend the site told me that they had no more data left. It turns out that 5 million images had been checked in only three days!

"Thank you everyone for ~5 million classifications in 3 days! That's amazing! Classifications are complete for now in this project. Please join our team at backyardworlds.org to continue searching for Planet 9 (and brown dwarfs)!"