The Dawn spacecraft is now very close to the dwarf planet Ceres, but there are some interesting new findings from its previous visit to the asteroid Vesta. Curved gullies on its surface suggest that small amounts of water may have once been present in the form of wet debris flows—a rather surprising discovery.
The Dawn spacecraft continues to make its way closer to a world which still hasn’t been seen close-up: the dwarf plant Ceres, the largest body in the main asteroid belt. And now, Dawn has taken its best-yet image of Ceres, although it is still 740,000 miles (1.2 million kilometers) away.
The Dawn spacecraft left behind the giant asteroid Vesta last September, and is now en route to the even bigger dwarf planet Ceres, but scientists are still busy studying all of the data that was sent back to Earth while it was orbiting Vesta for over a year. And as often happens while exploring these new worlds, they have made a surprising discovery: long, sinuous gullies on the walls of geologically younger craters.
With all of the news lately about the landing of the Curiosity rover on Mars, it might be easy to forget about the other missions currently going on all over the solar system. That includes the asteroid belt, where the Dawn spacecraft has been orbiting and studying the giant asteroid Vesta since July of last year, sending back incredible photos and information about this unique world.
But now, Dawn has departed from Vesta to continue its mission elsewhere; on September 4, it escaped Vesta’s gravitational pull and is now headed for its next rendezvous – the dwarf planet Ceres. It is expected to arrive there in early 2015, the same year that the New Horizons spacecraft will finally reach Pluto.
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Vesta, while one of the largest asteroids, is still a lot smaller than Earth, and yet it has a mountain that is three times taller than Mt. Everest, reaching about 22 kilometres (13 miles) in height. It sits inside the huge south polar crater, so is similar to many other craters on various planets and moons which have central peaks. It is surprising nonetheless to see such a large mountain on a relatively small body like Vesta, especially since it is so much higher than the tallest mountain on Earth!
The included image, taken by the orbiting Dawn spacecraft, shows a perspective view of the topography, but without the curvature of Vesta, as if you were looking at it standing on a flat Vesta instead of rounded. The resolution is about 300 metres (1,000 feet). The additional slideshow images show various views of the mountain. There is also a large steep-sloped scarp which bounds part of the south polar crater.
There will be a news conference on Wednesday, October 12 at 10:00 a.m. PDT to discuss the latest results from Dawn, to be held at the Annual Meeting of the Geological Society of America, in Minneapolis. It can be watched live on the Geological Society of America web site and on Ustream, which includes a moderated chat.
This article was first published on Examiner.com.
The Dawn science team presented the best-yet images of the asteroid Vesta yesterday at a NASA press conference, including the first full-frame image (below). Dawn is just now beginning its regular science orbits around the huge asteroid, but has already provided new information and data, which will only increase over the next months.
There is also a cool video showing a full rotation of Vesta as seen by Dawn.
Along with the huge crater with tall central mound seen previously, another feature of particular interest is the series of long grooves or ridges which extend partway around Vesta, clearly seen in the video.
The entire press conference can be viewed on YouTube:
The Dawn spacecraft has taken its first closeup photos of the asteroid Vesta since successfully entering orbit last Friday. This is the first time that a main-belt asteroid has been orbited by a spacecraft. There are some large ridges/cliffs as well as many craters, but the most prominent feature would seem to be the large mound inside the huge crater at the south pole (in centre of image below). Some comparisons have been made to Uranus’ moon Miranda in terms of the “chevron-shaped ridges” also inside that crater.
As Dawn refines its orbit closer to Vesta over the next few weeks, there should be many more images showing greater detail; our first closeup look at this very old and intriquing world…