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Wednesday, 22 July 2015

Water on Ceres?

Update: you can find the actual talk (mentioned below) by Chris Russel here, or if that's not working try going through the websit, here

I am getting married on Sunday, then jetting off on my honeymoon, so there's not a lot of time for me to write at the moment. But the universe has, it seems, given me the chance to leave you all with a real - and possibly game changing - mystery:

Is the dwarf planet Ceres hiding an interior warm enough to have an ocean?

Above: The still unexplained bright spots in Occator crater - they are so bright they are visible to Hubble, orbiting Earth
Right now Ceres is being studied by the Dawn mission, which had previously stopped at the giant asteroid Vesta. It's been guessed for a long time that Ceres could have a significant amount of water ice in its interior, and computer models have predicted that it could have retained enough heat for an ocean to persist near its core for billions of years. Spectral scans from Earth have found water related minerals onn the surface.On top of that the Herschel space telescope has caught a plume of water vapour over the Cerean surface.

So when Dawn arrived we weren't sure what we were going to find... and Ceres's still surprised us: the surface is spotted still unexplained, ultra reflective, bright spots. The brightest of these is located in Occator crater, and is basically just baffling. Although it sits at the bottom of the crater the bright area has seemingly been observed over the rim of the crater, as if it were elevated somehow.

Last night a couple of tweets from planetary science journalists surfaced:

"Andy Rivkin ‏@asrivkin:
Russell: Can see haze in crater with bright spots at some local times. Bright spots "indicate Ceres is active today." #nesf2015

Chris Russell at the NASA Exploration Science Forum"

...and then this one (link here):

"Whatever the cause of the bright spots, Ceres is active today".
Above: A 3D model of Occator crater, as seen at Chris Russels update.

These have both come out of Chris Russells Dawn update at the Exploration Science Forum at NASA Ames.
A few hours later this report (link here) from Emily Lakdewalla of the Planetary Society surfaced.The gist of the update is that the Dawn team have seen some sort of haze over the Occator crater, at various times. The haze is confined to the crater itself - and on a world with next to no atmosphere it's hard to come up with any other explanation than gas escaping from some sort of internal volcanic activity.

If Ceres is still active then, unless we've got something very wrong (always possible) there's probably still liquid water - and a possibility of life - lurking beneath the surface. And if stuff is escaping onto the surface we could examine that liquid water (perhaps) with a follow up mission to Dawn.

Sometimes these big announcements don't work out - this could be a camera fault, image processing artifact, or there might be some other explanation. But it's a good note to go away on, so I look forward to telling you all whether this discovery has been confirmed or not when I come back in three weeks....

Take care all,


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