How these colliding galaxies could reveal the fate of our Milky Way.
The Antennae Galaxies, also known as NGC 4038 (left) and NGC 4039 (right), are a pair of interacting galaxies 45 million light years away that were first discovered by William Herschel in 1785. Located in the NGC 4038 group along with five other galaxies, they are currently in the process of colliding. This particular image was taken by the Hubble Space Telescope and shows how the collision is affecting the two galaxies.
They began colliding a few hundred million years ago, making them one of the youngest and nearest examples of a galactic collision. The hearts of each galaxy are the two orange blobs at the cores. These consist largely of older stars and also large amounts of dust, shown in brown.
As the two galaxies collide they spur the formation of new stars, shown in blue in the image, while glowing hydrogen gas is shown in pink. Over hundreds of millions of years ejected stars have streamed away from the collision, extending far into interstellar space as two long tails and giving rise to the name ‘Antennae’.
In several hundred million years, after continually crashing into one another, the two nuclei will combine into one giant core and form an elliptical galaxy. Their interaction bears similarities to what will happen when our Milky Way collides with the Andromeda Galaxy in 4.5 billion years, providing an insight into the future of our own galaxy.