Astronomy Without A Telescope

Apparently, we may find a lot of exoplanets that look pretty much like this. Credit: NASA.

Well, not only may up to 25% of Sun-like stars have Earth-like planets – but if they are in the right temperature zone, apparently they are almost certain to have oceans. Current thinking is that Earth’s oceans formed from the accreted material that built the planet, rather than being delivered by comets at a later time. From this understanding, we can start to model the likelihood of a similar outcome occurring on rocky exoplanets around other stars.

Assuming terrestrial-like planets are indeed common – with a silicate mantle surrounding a metallic core – then we can expect that water may be exuded onto their surface during the final stages of magma cooling – or otherwise out-gassed as steam which then cools to fall back to the surface as rain. From there, if the planet is big enough to gravitationally retain a thick atmosphere and is in the temperature zone where water can remain fluid, then you’ve got yourself an exo-ocean. (…) Read the rest of Astronomy Without A Telescope – So Why Not Exo-Oceans? (529 words)

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(C) Steve Nerlich for Universe Today, 2010. | Permalink | No comment | Add to del.icio.us Post

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