Hiding in Plain Sight

by Jack Morgan

The Zooniverse research project that I selected was Comet Hunters. Zooniverse is a website that researchers can use to crowdsource analysis of data when they have far too much data to get through on their own. Astronomers in this study were looking to for Comets in the Asteroid Belt. Very few, (four, to be exact), of these had been discovered prior to the study so these researchers were looking to find more of these types of comets, known as Main-Belt Comets, so they can study their nature and what makes them different to regular comets.

One of the reasons so few main-belt comets have been discovered is that the comet-like properties are very hard to detect and only recent, higher resolution cameras have been able to display these traits. Once Astronomers observed the comets, the started taking new photos of the asteroid belt as well as reviewing older photos of  the asteroid belt to search for the comets. Another reason that main-belt comets have been so hard to detect is because the sublimation of the ice that the comets are made of is what causes the comet’s tail, but impacts between normal asteroids in the Asteroid Belt can cause ejections of dust that look similar to the tail of a comet.

pasted image 0.pngThe above image shows a catastrophic asteroid disruption where an asteroid completely breaks apart, and as the individual pieces are are flung outward by centrifugal force, the dust from the event gives the fragments comet like tails.Image credit: Comet Hunters, NASA, ESA, D. Jewitt (UCLA), and A. Feild (STScI).


This means that even if an object in the Asteroid belt appears to have a tail, further study of the object will be needed to determine whether it is a main-belt comet or a disrupted asteroid.

By combining both new and old survey pictures, astronomers ended up with over twenty thousand images to classify. One person working forty hours a week would take over five months to classify every image. While this could be done, it wouldn’t be very practical and it’s likely that there would be mistakes/inaccuracies in the final results, so the astronomers set up a project on Zooniverse to enlist the help of the general public. Zooniverse is the world’s largest platform for people powered research, with the goal of the platform being to enable research to be conducted on a scale that would otherwise be impossible. Most of the data in the projects on Zooniverse is data that can’t be analyzed by computers, so the analysis is opened up to the public with the platform converting the flood of data in these projects into measurable results that the researchers can use to further the understanding of a particular subject.

The Comet Hunters project is still ongoing as of the time of writing, which means anyone reading this can participate. Every subject will have fifteen classification before it is considered to be completed, with the project having more than three hundred classifications so far. Once the project is complete, the objects that have been flagged as potential main-belt comets will receive a follow-up study to see if they continue to exhibit comet like properties. Until then, the researchers will wait as we, the public, continue to sift through the data and look out for more interesting objects, with the potential for any random person to discover something completely new.