You have helped classify the morphologies of millions of galaxies through various Galaxy Zoo campaigns! Among those several millions are colliding galaxies (aka galaxy mergers) that are experiencing a significant change in their morphology and physical nature. Previously you have answered questions about the presence of disturbed morphological features (e.g., major or minor disturbance). As the process of galaxy merging can take several millions to a billion years, the merging galaxies we observe present to us in a plethora of configurations depending on their merging stage.

Identifying the stage of merging can help us better associate the impact of mergers to specific changes in the galaxy properties. An alternative approach is to use the disturbed morphological signatures (also called tidal features) as a proxy for merger staging. We are launching a new project Cosmic Disco: Characterizing Galaxy Collisions where you can help characterize the images containing mergers into objective categories.

We are looking forward to doing awesome science with your help! Happy Classifying!