Over time, they dance around each other in smaller and smaller circles. This tightly coiled dance pulls and stretches long streams of gas and stars, mixing the two galaxies together like a ball.

Over millions of years, this galactic problem will consume or dissipate the gas and dust needed to fuel the birth of stars, causing star formation to slow and eventually stop.

Observations of other intergalactic collisions and computer modeling have provided astronomers with additional evidence that spiral galaxy mergers form elliptical galaxies.

Once the pair merges, the resulting elliptical galaxy may look like Messier 89, also in the constellation Virgo. Once Messier 89 lost most of the gas needed for star formation, very little star birth occurred. Now, the galaxy is home to ancient stars and ancient clusters.

A supernova aurora, first discovered in 2020 It also appears in the new image as a bright spot in the arms of the spiral galaxy NGC 4568.

Milky Way Connection

Andromeda’s halo, a large envelope of gas, extends 1.3 million light-years from the Milky Way, half the distance to the Milky Way, and 2 million light-years in other directions.

This neighborhood, home to perhaps a trillion stars, is 2.5 million light-years away, about the size of our own large galaxy. This may seem incredibly far away, but on an astronomical scale, it makes Andromeda so close that it can be seen in our autumn sky. High in the autumn sky you can see it as a cigar-shaped patch of mysterious light.

If we could see Andromeda’s massive halo, invisible to the naked eye, it would be three times the width of the Ursa Major constellation, which dwarfs anything else in our sky.