Artist?s impression of the extrasolar planet HD 189733b, now known to have methane and water. Astronomers used the Hubble Space Telescope to detect methane ? the first organic molecule found on an extrasolar planet. Hubble also confirmed the presence of water vapour in the Jupiter-size planet?s atmosphere, a discovery made in 2007 with the help of the Spitzer Space Telescope. They made the finding by studying how light from the host star filters through the planet?s atmosphere.

Credit: ESA, NASA, G. Tinetti (University College London, UK & ESA) and M. Kornmesser (ESA/Hubble)