Dwarf Planet Ceres May Have Had a Global Ocean in Ancient Past

Space.com ^ | November 8, 2017 | Nola Taylor Redd, Space.com Contributor

[ETL]

Lol!

[ByteMercenary]

Sometime back I read an article that proposed that the lack of water on other planets compared to the huge amount on Earth implies that Earth may have been impacted by a Ceres-like planetoid (lots of water in the makeup) or meteor a long time ago.

Not unreasonable I suppose ...

[PIF]

You are mistaken. Actually they were referring to ISaturn's moon Iapetus.

[alexander_busek]

How could you have an ocean at -105 degrees Celcius?

"Nestled in the asteroid belt, the dwarf planet Ceres contains water-rich materials that suggest it once boasted a global ocean in its distant past."

It was warmer then.

Regards,

[alexander_busek]

Sometime back I read an article that proposed that the lack of water on other planets compared to the huge amount on Earth implies that Earth may have been impacted by a Ceres-like planetoid (lots of water in the makeup) or meteor a long time ago.

Mars-sized.

Being water-rich or not is irrelevant, according to the Theia-impact theory.

Regards,

[SunkenCiv]

Thanks ETL. Pretty darned interesting, and dare I say it, Fun.

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When Dawn arrived at Ceres in 2015, it found a mostly flat world with only a single mountain, Ahuna Mons, and craters that were smaller than anticipated and not very rich in geological features.

That suggests to me that there was a massive, geologically recent impact event.

By taking the gravitational measurements of the crust, Ermakov and his team found that the crust of Ceres is very close to the density of water... The connection of the gravitational anomalies with the four features supports the idea that Ceres is geologically active now or was very recently. The team also found positive mass concentrations, or mascons, under the two largest basins. These mascons have been found on Earth's moon, Mars and Mercury. Researchers suspect that mascons on the moon came from a massive asteroid impact that changed the density of the lunar surface and its magnetic field.

[ByteMercenary]

While Theia may explain the origin of the moon, where did all the water come from? If we assume that the pre-impact Earth had similar amounts of water (percentage-wise) as Venus & Mars, must we assume that the percentage of water on the smaller body was the same or greater than Earth’s? If greater, then it is most likely the smaller body was not from our system. If the percentage is similar, that does not explain why Earth has the high percentage of water that we do which is far more than twice the percentage of our planetary neighbors.

Interesting, is it not?

[alexander_busek]

While Theia may explain the origin of the moon, where did all the water come from?

Check your premise!

To begin with, the Earth contains only a paltry 1.4 million cubic km of H2O.

Venus and Mars likely once contained comparable amounts of water. (And Mars still contains an estimated 5 million cubic km of surface and subsurface ice.)

However, Venus and Mars lack a significant magnetosphere to protect their atmospheres from depletion by the Solar Wind.

Secondly, Venus is a lot hotter - so the H2O (volatile) was essentially "baked off."

The gravity field of Mars is weaker than Earth's further contributing blah-blah-blah...

The water probably came from cometary impacts.

Regards,

[alexander_busek]

To begin with, the Earth contains only a paltry 1,400 million cubic km of H2O.

Sorry for the misplaced decimal point!

Regards,