Gas Blob Resembles Gigantic Comet

A ball of gas more massive than a billion suns is hurtling like an enormous comet through the interior of a distant galaxy cluster. The massive structure is held together by mysterious dark matter, astronomers said today, but it is steadily breaking apart and becoming fuel for new stars. "This is likely a massive building block being delivered to one of the largest assembly of galaxies we know," said study team member Alexis Finoguenov of the University of Maryland, Baltimore County. The finding is detailed in the June 6 issue of Astrophysical Journal. The gas blob is moving at nearly 500 miles (750 kilometers) per second relative to the galaxy cluster it is embedded within. Called Abell 3266, the cluster is itself moving away from us at a speed of nearly 11,000 miles (17,000 kilometers) per second. Nicknamed "comet," the gas ball is the largest of its kind ever detected. It measures about three million light-years across, or around five billion times the size of our solar system. The gas is estimated to be about 84 million degrees Fahrenheit (about 46 million degrees Celsius). Although this might seem hot to us, it is still relatively cool compared to some interstellar gas. The gas blob is thought to have formed when two galaxy clusters—one large and one small—collided billions of years ago. During the crash, a blob of relatively cool gas from the small cluster was sheared off and sent careening off into space on its own. During its travels, it got sucked in by the immense gravity of galaxy cluster Abell 3266, which it entered some 2 billion years ago. The blob is currently near the center of Abell 3266. http://space.com/scienceastronomy/060612_gas_comet.html