Scientists have used Chandra to make a detailed study of an enormous cloud of hot gas enveloping two large, colliding galaxies in the system known as NGC 6240. This unusually large reservoir of gas contains as much mass as 10 billion Suns, spans about 300,000 light years, radiates at a temperature of more than 7 million degrees, and glows in X-rays (purple). The Chandra data have been combined with optical data from the Hubble, which show long tidal tails from the merging galaxies, extending to the right a

This is the first image of a celestial object taken with the newly repaired Advanced Camera for Surveys (ACS). The camera was restored to operation during the STS-125 Servicing Mission to upgrade the NASA/ESA Hubble Space Telescope. The barred spiral galaxy NGC 6217 was photographed on 13 June and 8 July 2009, as part of the initial testing and calibration of Hubble’s ACS. The galaxy lies up to 90 million light-years away in the north circumpolar constellation Ursa Major.

This image shows an irregular galaxy named IC 10, a member of the Local Group — a collectiongrouping of over 50 galaxies inwithin our cosmic neighbourhood that includes the Milky Way. IC 10 is a remarkable object. It is the closest-known starburst galaxy to us, meaning that it is undergoing a furious bout of star formation fueled by ample supplies of cool hydrogen gas. This gas condenses into vast molecular clouds, which then form into dense knots where pressures and temperatures reach a point sufficient to ignite nuclear fusion, thus giving rise to new generations of stars. As an irregular galaxy, IC 10 lacks the majestic shape of spiral galaxies such as the Milky Way, or the rounded, ethereal appearance of elliptical galaxies. It is a faint object, despite its relative proximity to us — justof 2.2 million light-years. In fact, IC 10 only became known to humankind in 1887, when American astronomer Lewis Swift spotted it during an observing campaign. The small galaxy remains difficult to study even today, because it is located along a line-of-sight which is chock-full of cosmic dust and stars. A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Nikolaus Sulzenauer, and went on to win tenth prize.