As part of Citizen Science Month 2023, we’re sharing excerpts from ‘Into the Zooniverse’, a series of books celebrating the projects and people of the Zooniverse.

You can find and download all editions of ‘Into the Zooniverse’ here.


Out past Mars, millions of asteroids drift silently by in the Asteroid Belt. Most are relatively unremarkable lumps of rock. However, approximately 1 in 10,000 have clouds of dry ice or water that form around and streak out behind them as they hurtle through space.

These active asteroids could have delivered water to Earth millions of years ago, fulfilling one of the conditions necessary for life. Scientists hope that by studying them, we can learn how to make space travel more sustainable, and how life might begin and flourish on other planets.

Active asteroids are promising sources of information, but their scarcity makes studying them a challenge; only 30 have been found since 1949. The Active Asteroids team hopes to quadruple the number of known active asteroids, allowing for a more comprehensive study of these enigmatic objects, but millions of images must be classified first.

In Active Asteroids, Zooniverse volunteers help reach that goal by examining photos of the night sky for signs of asteroids with comae or tails while separating true active asteroids from lookalikes such as galaxies or cosmic rays. Once volunteers sort the dataset, scientists follow up on objects of interest by observing those that are visible, and searching through telescope archives for photos of those that are not. The results of these investigations could help scientists locate new active asteroids, as well as even rarer types of active objects, ultimately granting us a source for a fundamental ingredient of life: water. 

Image credit: Active Asteroids Project

Summary by: Dylan Lussem

Check out this project: here

View the full ‘Into the Zooniverse’ book: here