Subsurface ocean on Ceres; how?

[Philotas]

I was sure I read something about one of the Dawn websites about the possibility of a subsurface ocean on Ceres. After googling I came up with this:<br /><br /><font color="yellow">""At Ceres our studies will include the role of water in its evolution, hydration processes on its surface, and the possible existence of a subsurface ocean." </font><br />Source: http://www.aas.org/publications/baas/v36n4/dps2004/542.htm<br /><br /><font color="yellow">"Ceres formed 'wet', differentiated into a rocky core and icy mantle, and may possess a subsurface ocean." </font><br />Source: http://www.psi.edu/coverpic/old_covers.html<br /><br />I didn`t get any explanation on how little Ceres could hold a liquid ocean, so a few comments on exactly how, would be welcome.<br /><br />Also, the latest Hubble image shows a bright spot on Ceres. Could it be the result of internal activity?<br />Bright spot: http://hubblesite.org/newscenter/newsdesk/archive/releases/2005/27/ <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

Well, like many other bodies that were likely part of the original asteroid belt that are now moons of Jupiter, Ceres is likely a planetesimal that formed in this region from the primordial soup, or else was once a moon of Jupiter that got ejected by gravitational interactions with other moons.<br /><br />This might have merit, if the Sun's UV tends to strip water from unprotected objects, where Jupiters EM field protects its moons icy crusts and mantles. Cere's might be an ejected Jupiter moon that evaporated some of its crust, enough to accumulate a dark rocky/dusty crust like Comet Tempel. That bright spot may be a recent impact crater that would expose fresh ices.

 

[Philotas]

Ok, thanks. <br /><br />I`m still puzzled by the possibilty that small objects like Ceres could hold oceans. I would like to have some criteria for what that is necessary for such oceans to exist. <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

Ah, well, if the core of Ceres contains a significant amount of radioactive isotopes, geothermal effects could provide sufficient heat to keep a layer of molten salty water between the ice and the rocky core. Keep in mind that very salty water can remain liquid at very low temps and pressures. With many miles of ice above it, the icy mantle should provide sufficient insulation and pressure to allow for a liquid layer perhaps kilometers thick at the rocky benthic region, esp with some level of salts and organic materials to further lower the freezing point and provide the building blocks for life, even.

 

[Philotas]

Ok, thanks again. This one of the reasons why we should have visited Ceres ages ago! If it had just kept its status as a planet it`d probably been visited twice already. <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

So many places to go, so few probes to visit them with....<br /><br />We have not visited all the major planets and their moons yet. But the Dawn, all being well will be launching in a year or so to ceres and Vesta, another interesting body.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[mikeemmert]

Ceres was demoted as a planet because it's albedo is 0.113 and Vesta's albedo is 0.423. Thus, much smaller Vesta appeared somewhat brighter than Ceres. 19th Century astronomers, having no way to measure angular diameter, infrared emittance, or mass, thought that the larger asteroids were all about the same size.<br /><br />I have been following up on the larger asteroids as a result of this thread. I think I might change my vote and call Ceres a planet, it's about half the asteroid belt. But only if Pluto isn't demoted!

 

[mlorrey]

Lets form the Big Tent Round Planet Party and lobby the IAU for the sake of diversity, tolerance, and against prejudice and big-otry, that Ceres, Pluto, Xena, Santa, and all other round balls in their own orbits around the sun be called planets. Round moons should be called planetary moons, for fairness and comity.<br /><br />Amend all the textbooks, expand the science curricula, and teach inclusiveness and acceptance of all round places. Roundness is best for planetariness.

 

[bonzelite]

are you being sarcastic or genuine? i cannot tell from your post. <br /><br />