APOD: 2021 July 28 - Ring Galaxy AM 0644 741

Good morning, Rallypoint. Today's Astronomy Picture of the Day (APOD) is titled "Ring Galaxy AM 0644-741." Remember a time when you dropped a rock in a still pond and watched the ripples radiate out from the point the rock entered the water? You are looking at the same phenomenon on a galactic scale. When galaxies collide, they pass through each other. Gas and dust are compressed in a wave of star formation that moves out from the point of impact like the ripples on a pond.

Ring Galaxy AM 0644-74, also known as the Lindsay-Shapely Ring, is about 300 million light years away towards the southern constellation Volans. You can see the suspected intruder galaxy in this Hubble image at the top right. Current models suggest that AM 0644-741 will continue to expand for another 300 million years before it begins to disintegrate.