NASA’s Dawn spacecraft is getting closer and closer to dwarf planet Ceres, the most massive body in the asteroid belt. On April 14 and 15, as the spacecraft hovered above Ceres’ northern hemisphere, it shot these newly released images from a distance of just 22,000 kilometers away.
And guess what? After hiding in shadow for the past few weeks, Ceres’ mysterious bright spots are back in sight. In the animation above, you can see the brightest of the bizarre splotches — called “Feature 5” by the team — rise from the right in the last few frames. The bright spot and its dimmer companion are clearly set within a crater that scientists estimate is about 90 kilometers across. Scientists aren’t sure what the bright spots are, but they suspect the splotches are made from water ice, and could possibly be venting water vapor into space.
Dawn arrived at Ceres on March 6 and is the first spacecraft to not only orbit a dwarf planet, but to orbit two distinct worlds (the other being massive asteroid Vesta). The spacecraft’s science observations will begin in earnest on April 23, after it has pulled to within 13,500 kilometers of the dwarf planet. Dawn will spend the next year studying 950 kilometer-wide Ceres, which in addition to being the largest body in the asteroid belt is also notably warmer and more watery than its neighboring space rocks.
— Emily Lakdawalla (@elakdawalla) April 16, 2015
Already, Ceres is presenting a puzzle to the team: In addition to the bright spots, the world is covered in craters with strangely flat bottoms, has a distinct lack of giant impact basins, and a strangely diverse surface that suggests geologic activity in the past.