New images reveal largest galaxy collision ever seen

Nature : A new composite image of four galaxy clusters colliding has been created using the Karl G. Jansky Very Large Array, the Chandra X-Ray Observatory, and NASA’s Hubble Space Telescope. Called MACS J0717+3745, the merging cluster is located some 5 billion light-years from Earth. Its massive size and complex shape are probably the result of the sheer scale of the collision. In fact, scientists estimate that atomic particles in the massive cluster are being smashed together at energies up to a million times those achieved in current particle accelerators, such as the Large Hadron Collider. Because of a phenomenon known as gravitational lensing, astronomers have also been able to use MACS J0717+3745 to study other distant galaxies whose light has been bent and magnified by the giant cluster’s gravity. The new data were presented last week at the annual meeting of the American Astronomical Society in Boston.