Credit: NASA and the Hubble Heritage Team (STScI)
Looping arcs of stars and dust create a cosmic letter “W” caught in the middle of this galactic encounter.
Explore the NASA Hubble Space Telescope image of spiral galaxies NGC 2207, on the left, and IC 2163, on the right. The strong gravitational tug of NGC 2207 has already distorted the shape of the smaller galaxy. The larger galaxy looks like a huge saw blade whirling into the smaller galaxy. Or is it the other way around? Gravity flings stars and gas out of IC 2163 in long streamers a 100,000 light-years long. Look for the dark lane of dust from the larger NGC 2207 as it cuts above the smaller galaxy. Looking through this dust makes the light from IC 2163 redder in color. Follow the outer arms of NGC 2207 and explore the huge star clouds. These areas glow blue with new star birth. Several pockets of new stars can be seen in the outer spiral arms of these galaxies.
From this embrace neither galaxy will escape. The galaxies will swirl around each other, coming closer and closer, before merging into a single large galaxy in a billion years. Many of the galaxies we see in the night sky, including our own Milky Way, have gone through cosmic collisions to become larger galaxies.
This pair of spiral galaxies is found about 114 million light-years from Earth toward the constellation of Canis Major, the Large Dog.