MACS J0717, some 5.4 billion light-years away from Earth in the constellation of Auriga (The Charioteer), is the result of four galaxy clusters colliding. This image is a combination of observations in visible light, X-rays and radio waves from the NASA/ESA Hubble Space Telescope, NASA’s Chandra X-ray Observatory, and the NRAO Jansky Very Large Array.
Galaxy clusters are enormous collections of hundreds or even thousands of galaxies and vast reservoirs of hot gas embedded in massive clouds of dark matter. To learn more about clusters, including how they grow via collisions, astronomers have used some of the world’s most powerful X-ray, optical and radio telescopes. The name for this galaxy cluster project is the “Frontier Fields”.