2004: The Year in Space and Astronomy

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<b>2004: The Year in Space and Astronomy</b><br /><br />LINK<br /><br />Astronomers think nothing of peering billions of light-years into the distance. But in 2004, many of the most important discoveries came from observations much closer to home.<br /><br />Nearby Mars grabbed the most dramatic headlines. After landing on opposite sides of the planet in January, NASA's rovers Spirit and Opportunity each turned up evidence that water had altered the planet's surface in the past. The rovers were meant to operate for just three months, but nearly a year later - and for reasons that remain mysterious, they are still roaming the Red Planet. And breathtaking images from Europe's Mars Express spacecraft, which arrived at the planet in December 2003, bolster the case for a watery past.<br /><br />Water could have offered a foothold for life on Mars in the past. But recent discoveries of atmospheric methane suggest life could be thriving on the Red Planet even now, belching out the gas from scattered oases. <br /><br />Another neighbour, Venus, also took centre stage this year as it passed in front of the Sun for the first time since 1882. Previous "transits" led to the discovery of the planet's atmosphere, but this year observers around the world watched the historic event to learn more about how to interpret extrasolar planet observations.<br /><br />Knocked orbit<br />Saturn, too, got its close-up as the joint US-European Cassini spacecraft reached orbit in July after a seven-year voyage. The craft revealed the planet probably captured its outermost large moon, Phoebe, from the Kuiper Belt, a belt of icy bodies beyond Neptune. And it turned up a delicate new ring and mysterious knife-sharp edges in Saturn's famous rings.<br /><br />In October, the craft sent back the first detailed pictures of the haze-shrouded moon Titan, suggesting the moon is not covered in liquid oceans as was thought. A probe will investi