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Friday 28 August 2015

A miniature mission to the Moon, and what the hell ARE those spots on Ceres?

A Miniature Moon mission  to search out lunar ice:
Over the last ten or fifteen years a quiet revolution has been going on in space technology: Like computers in the latter half of last century, they've been getting smaller - and the most popular of the miniature spacecraft is the 10cm by 10cm by 10cm cubesat.  This year has seen cubesats start to come of age, with a cubesat flying with a solar sail, cubesats flying to Mars, and now a cubesat based craft from Arizona state University is set to map water ice deposits on the Moon:

Latest pictures back from Ceres:
Five months ago the Dawn spacecraft pulled into orbit about the dwarf planet Ceres. One of the first things its team noticed - in fact something that had even been noticed by the Hubble space telescope from Earth - were some incredibly reflective spots punctuating the dusty surface. These were so bright that Dawn's camera had trouble seeing inside of then, due to the glare.
Above: Images of Ceres taken by Hubble - the bright spot is the mysterious bright spot in Occator crater. Courtesy of NASA  and Tom Caldwell.
But the Dawn mission is a billion dollar exploration vessel controlled by some of the finest so they've...they've..... oh I can't keep that up, dammit. We still don't know what the bloody things are.
Above: Dawn tracks the bright objects in Occator cater over the course of one day. Courtesy of NASA.
What do we know? We know they're bright, and we know that the brightest spots appear within Occator crater - and apparently are over a long tectonic-fault like structure...
Above: Occator crater, showng the fault lines that pass through it upper left. Courtesy of NASA.
We know that Ceres is rich in water ice, so subsurface water ice thrown up to the surface by an asteroid hit has been suggested - but we also know that ice would rapidly evaporate into space. So another suggestion that has been that they are some sort of salt deposit. The salt would last longer, although not forever - it would still get wiped away my meteorite strikes eventually. But either way the question is how did it get there, and why that spot? To add to the mystery are reports from the Dawn team that they've seen clouds or hazes over the crater. So, as far as explanations go,The main contenders so far seem to be:

Exposed ice
This would make a lot of sense, as  Ceres has lots of ice. Evaporating ice might also explain the hazes. But ice would need to be replenished regularly by some mechanism

Salts could have been left behind in a more ancient time when Ceres core was still warm and salty water could travel to the surface. 

Although this would be the most exciting possibility of all it's also the least likely. A while back the team thought they'd seen something - perhaps a plume from a vent - rising over the edge of Occator but this has stayed unconfiremed. Although most computer models suggest Ceres core froze solid aeons ago, a ew do allow some ectonic activity to continue, and an actve Ceres might also mean one with a subsurface habitable zone.

We'll know more soon, as images of Occator and its mysterious bright spots should arrive in the coming weeks!

As long as they're not neon signs saying 'drink Starbucks coffee....'

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