NASA has released a dramatic image showing a pair of galaxies on a collision course about 450 million light years from Earth.
The stunning image, which can be seen below, shows how galaxies are on a collision course. The edge-on galaxy near the top of the image is VV 340 North and the face-on galaxy at the bottom of the image is VV 340 South. Data collected from NASA's Chandra X-ray observatory satellite and optical data from the Hubble Space Telescope were used to create this image.
Data from the study of VV 340 shows that the center of VV 340 North likely contains a rapidly growing supermassive black hole and it emits more infrared than its sister galaxy. However, only a small fraction of the radiation comes from the area of the black hole.
The distance across the approaching galaxies is about 285,000 light years. Over the course of millions of years, these two spirals will merge into one – a similar way that our own Milky Way Galaxy and the neighboring Andromeda galaxy will likely do billions of years from now.
Collision of galaxies is quite common in the galactic evolution. To be more appropriate, these are not exactly collisions in the general sense of the word, but are gravitational interaction of galaxies. Colliding usually leads to merging as the individual galaxies wouldn't have enough momentum to continue traveling after the collision.
If one of the colliding galaxies is much larger than the other, it will remain largely intact after the merger, but the smaller galaxy will be torn apart and become part of the larger galaxy.
Galaxy collision simulations on computers are quite common which imitates realistic physics, including gravity forces, gas dissipation, star formation and feedback. Dynamical friction slows down galaxy pairs, which may or may not merge at some point, according to the initial relative energy of the orbits.
The video below shows Spectacular Galaxy Collision Visualization of Milky Way with Andromeda: