European satellite spots Great Balls of Fire
The European Space Agency's XMM Newton X-Ray Satellite has helped an international team of researchers to detect an immense, comet-like ball of gas which is hurtling through a distant galaxy cluster at over 750 km per second. The 'ball of fire' is three million light years across, making it by far the largest object of its kind ever identified. In comparison, our galaxy, the Milky Way, is just 100,000 light years in diameter. Scientists are interested in the role that these gas balls play in the formation and evolution of structure in the Universe. 'This is likely a massive building block being delivered to one of the largest assemblies of galaxies we know,' commented Dr Alexis Ginoguinov, adjunct assistant professor of physics in the Department of Physics at the University of Maryland in the US, and an associated scientist at the Max Planck Institute for Extra-Terrestrial Physics in Garching, Germany. The massive gas ball was detected in Abell 3266, a galaxy cluster made up of hundreds of galaxies and vast amounts of hot gas. It in turn is part of the Horologium-Reticulum super-cluster - one of the biggest galaxy clusters in the southern sky. Using data from the satellite, the scientists are able to see in detail how gas is stripped from the comet's core to form a large tail containing lumps of colder and denser gas. 'Dark matter is the gravitational glue holding the gas ball together. But as it races through the galaxy cluster, a tug-of-war ensues where the galaxy cluster eventually wins, stripping off and dispersing gas that perhaps one day will seed star and galaxy growth within the cluster,' explained Professor Mark Henriksen of the University of Maryland. ESA's XMM-Newton X-ray mission was launched in December 1999. With its powerful mirrors, it is helping to solve many mysteries about the most energetic phenomena taking place in the Universe.