Quote:
Originally Posted by renormalised
The presence of water would lower the solidus temperature of the rocks, so they'd melt more easily and the process would be accelerated along because of this. The presence of water would aid in melting the planet and allowing it to differentiate.
Of course, some water would come in via comets etc, but it's how much that was initially present which is the subject of the question. Despite the Earth being where it is in the solar system and the temp here having been higher than the b.p. of water in this region of the solar nebula, that doesn't mean that water wasn't present. Being locked up in dust grains and rocky materials can, in fact, shield the water from the heat and radiation that was present. Plus, the speed at which it was incorporated into planetesimals and then the planets themselves would also become a factor in the survivability of the water.
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Yeah .. well here we go again … if the bulk of the water on Earth was present in this zone before the formation of the planet, then it must've been confined in an extremely tight zone ... given that Venus and, perhaps Mars, missed out on the similar volumes of it. (Ok .. ok .. I know .. there
may have been big liquid water on Mars … that's open to debate, as far as I'm concerned, though ..

)
Cheers