A rare encounter between two gas-rich galaxies spotted by ESA’s Herschel space observatory indicates a solution to an outstanding problem: how did massive, passive galaxies form in the early Universe? Several telescopes have teamed up to discover a rare and massive merging of two galaxies that took place when the Universe was just 3 [continue reading]
April 24, 2013 NGC 4150, an elliptical galaxy in Coma Berenices Image Credit: NASA, ESA, R.M. Crockett (University of Oxford) S. Kaviraj (Imperial College London and University of Oxford), J. Silk (University of Oxford), M. Mutchler (Space Telescope Science Institute), R. O’Connell (University of Virginia), and the WFC3 Scientific Oversight Committee NGC 4150 is an [continue reading]
February 3, 2013 Abell 2125, a galaxy cluster in Ursa Minor Image Credit: NASA/CXC Abell 2125 is a galaxy cluster that lies about 3 billion light-years away from Earth in the constellation of Ursa Minor, and is seen at a time about 11 billion years after the Big Bang, when many galaxy clusters are believed [continue reading]
Astronomers were puzzled earlier this year when NASA’s Hubble Space Telescope spotted an overabundance of dark matter in the heart of the merging galaxy cluster Abell 520. This observation was surprising because dark matter and galaxies should be anchored together, even during a collision between galaxy clusters. These composite images taken by two different [continue reading]
Among the oddities of the outer Solar System are the middle-sized moons of Saturn, a half-dozen icy bodies dwarfed by Saturn’s massive moon Titan. According to a new model for the origin of the Saturn system, these middle-sized moons were spawned during giant impacts in which several major satellites merged to form Titan. Saturn’s [continue reading]
Gravity Lenses Suggest Big Collisions Make Galaxies Denser Using gravitational “lenses” in space, University of Utah astronomers discovered that the centers of the biggest galaxies are growing denser – evidence of repeated collisions and mergers by massive galaxies with 100 billion stars. This image, taken by the Hubble Space Telescope, shows a ring [continue reading]