Look at What Happens When Two Galaxies Collide
Gravity can do some pretty astonishing things out there in the universe. When it’s not ensuring the downward trajectory of your spilled coffee directly onto your shirt here on Earth, the invisible force is playing arts and crafts with cosmic matter: crushing gas and dust into radiant new stars, smoothing clumpy rock into spherical planets, and, my personal favorite, smushing entire galaxies together. Gravity nudges galaxies toward one another—sometimes two, sometimes more—until they meet, their contents whooshing and mixing, and the slow-moving chaos molds them all into one big galactic ball.
Astronomers have observed such events, known as mergers, in nearly every stage of the process. Early on, when the galaxies are , as if they’re convened for a very important space conference. In the thick of it, when gravity has out of their original shapes. And at the end, when what remains is around the orb.
