The Hubble Space Telescope has revealed new details about the giant asteroid Vesta, providing a taste of what the Dawn spacecraft will see when it visits the space rock in 2011.
At 530 kilometres across, Vesta is the third largest asteroid in the solar system. Although there are millions of asteroids in the asteroid belt between Mars and Jupiter, Vesta makes up about 10% of the mass in the belt.
NASA鈥檚 Dawn spacecraft is scheduled to visit Vesta in 2011 and the solar system鈥檚 largest asteroid, Ceres, in 2015. Although a dropped tool slightly damaged one of the spacecraft鈥檚 solar panels last week, the mission team expects to be able to fix it in time for a planned launch on 7 July.
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In anticipation of the Dawn mission, scientists using the Hubble Space Telescope have captured new images of the rotating asteroid, revealing an unprecedented level of detail. They have been assembled to make a in space. Vesta rotates once every 5 hours and 21 minutes.
Solidified lava
The new images show features as small as 60 kilometres across, revealing variations in brightness and colour across the asteroid鈥檚 surface, some of which might be due to lava flows from ancient volcanic eruptions.
Like on the Moon, the darker regions might be basins that filled with lava that later solidified, says Dawn mission team member Lucy McFadden of the University of Maryland in College Park, US, who led the effort to image Vesta with Hubble.
快猫短视频s are especially intrigued by one very large dark area. 鈥淚f we were looking at something on Earth like that, it would be like all of North and South America together in terms of the extent of the body that it covers, McFadden told 快猫短视频. 鈥淲hether it鈥檚 a raised landmass or a giant lava flow, I can鈥檛 quite tell 鈥� that鈥檚 why we need the Dawn mission.鈥�
The images also provide a glimpse of a huge gash left by an impact early in Vesta鈥檚 history 鈥� a crater 456 kilometres across, almost as wide as Vesta itself. The images show the crater from the side, rather than face-on, at the lower right edge of Vesta. A bump at about the 5 o鈥檆lock position on Vesta may be a peak at the centre of the crater.
Hubble previously captured detailed images of Dawn鈥檚 other target, Ceres, in 2004.
