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Heartfelt congratulations to the Dawn [1] team - this September eighth will mark the end of their year long exploration of the battered protoplanet Vesta [2]. The details of how Dawn has opened up our understanding of this battered world would be several books its own right. But, suffice to say, out view of Vesta has changed from this.....
Video above: A series of images from the Hubble Space Telescope, our best view of Vesta before the Dawn space probe arrived there. Video courtesy of NASA/JPL.
.....to this....
Image above: Dawns view of the south pole of Vesta. Or what's left of it. Dawn discovered that the entire south pole had been blown apart, by not one but two massive impacts from asteroids. The ridges you see around the Vestan equator are caused by the shock waves from these blasts rippling through the rock. to give you an idea of the scale of all this: Vesta is about five hundred and fifty kilometres across. So the scale is BIG. Image courtesy of JPL/NASA.
....including shots like this:
Image above: The image on the left is an infra red view of the Vestan surface, where red represents the 750 nanometre wavelength of infra red light, green the 920 nanometre wavelength, and blue the 980 nanometre wavelength. The image on the right shows the different types of rock present, colour coded by the dawn scientific team. Image courtesy of JPL/NASA.
The mission has mapped the protoplanets gravity field and interior structure [3], surface composition [4], and collected literally millions of high resolution spectra [5] of its surface.
Dawns ion engines [6]* have already begun firing, raising the crafts orbit - September the eighth marks the point when Dawn will have gathered enough speed relative to Vesta to be considered free of its gravitational field once more.
The team are planning the 'Hasta La Vesta' webcast [7], and until then I recommend Dr Marc Raymans latest Dawn journal log [8].
The next target for Dawn is the dwarf planet Ceres [9] - a world nearly a thousand kilometres wide. The surface of Ceres shows signs of alteration by water [10], there's possibility it may have retained a liquid water layer [11] in its interior for billions of years, and even tentative hints of out-gassing [12] over its pole. So the Ceres phase of the mission will prove at least as exciting as the Vesta phase. And it's impossible not to wonder: What will Dawn change our view of Ceres to?
Image above: A gigantic peach, floating in space. Just kidding... I mean the dwarf planet Ceres - this is one of the best images of this embryonic planet that humankind has, via the Hubble Space Telescope. Image courtesy of JPL/NASA.
* If you've ever wondered what the 'TIE' in TIE fighter stands for: Twin Ion Engines. Though Dawn doesn't run armed, unless Marc Rayman is keeping something serious under his hat. What do you mean you've never wondered that? Next you'll be telling me you've never pulled a sickie to watch all six Star Wars films back to back.
List of links:
[1]http://dawn.jpl.nasa.gov/
[2]http://en.wikipedia.org/wiki/4_Vesta
[3]http://dawn.jpl.nasa.gov/mission/journal_04_30_12.asp#interior
[4]http://dawn.jpl.nasa.gov/mission/journal_12_30_11.asp#circling
[5]http://dawn.jpl.nasa.gov/mission/journal_10_06.asp#instrument
[6]http://dawn.jpl.nasa.gov/mission/ion_engine_interactive/index.html
[7]http://dawn.jpl.nasa.gov/news/hasta_la_vesta.asp
[8]http://www.planetary.org/blogs/guest-blogs/marc-rayman/20120726-dawn-journal-the-long-slow.html
[9]http://news.bbc.co.uk/1/hi/sci/tech/6037844.stm
[10]http://news.bbc.co.uk/1/hi/sci/tech/6037844.stm
[11]http://www.universetoday.com/26587/life-on-ceres-could-the-dwarf-planet-be-the-root-of-panspermia/
[12]http://adsabs.harvard.edu/full/1992LIACo..30..113A
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