The Gemini North Telescope, located on the summit of Mauna Kea, Hawaii, observed mutual spiral galaxies about 60 million light-years away in the constellation Virgo.
The galactic pair NGC 4567 and NGC 4568, also known as the Butterfly Galaxy, have just begun to collide as gravity pulls them together.
In 500 million years, the two cosmic systems will complete their merger to form a single elliptical galaxy.
At this early stage, the two galactic centers are currently 20,000 light-years apart, and each galaxy retains its pinwheel shape. As galaxies become more entangled, the force of gravity will cause multiple events of intense star formation. The basic structures of galaxies will change and distort.
Over time, they will dance around each other in circles that get smaller and smaller. This tightly looped dance will pull and stretch the long stream of gas and stars, mixing the two galaxies into something that resembles a sphere.
As millions of years pass, this galactic entanglement will consume or disperse the gas and dust needed to trigger star birth, causing star formation to slow and eventually stop.
Observations of other galactic collisions and computer modeling have given astronomers further evidence that mergers of spiral galaxies produce elliptical galaxies.
Once the pair merges, the resulting structure may look like the elliptical galaxy Messier 89, located in the constellation Virgo. Once Messier 89 lost most of the gas needed to form stars, very few stars were born. Now, the galaxy is home to old stars and ancient clusters.
A supernova afterglow, first detected in 2020 Galaxy NGC 4568 is also visible in the new image as a bright spot on one of its spiral arms.
Milky way merger
Andromeda’s halo, a large envelope of gas, extends 1.3 million light-years from the galaxy, about halfway into the Milky Way, and as much as 2 million light-years in other directions.
This neighborhood, which probably contains about 1 trillion stars, is similar in size to our own large galaxy, and is only 2.5 million light-years away. This may sound incredibly distant, but on an astronomical scale, it makes Andromeda so close that it is visible in our autumn sky. You can see it as a faint cigar-shaped light, high in the sky during the fall.
And if we could see Andromeda’s massive halo, which is invisible to the naked eye, it would be three times the width of the Big Dipper constellation, dwarfing anything else in our sky.