Another interesting question is whether or not water was a core component of early planetary material, or delivered later by comet (as assumed because it was to

Another interesting question is whether or not water was a core component of early planetary material, or delivered later by comet (as assumed because it was too hot in the inner solar system for volatile compounds to condense during formation). There's recent evidence that both Earth [1] and Mars [2] have a really large amount of water locked up underground. [1] https://www.syfy.com/syfywire/was-earth-once-a-water-world https://www.syfy.com/syfywire/was-earth-once-a-water-world [2] https://science.sciencemag.org/content/372/6537/56 https://science.sciencemag.org/content/372/6537/56 (We wrote about this in Orbital Index a few weeks back - https://orbitalindex.com/archive/2021-04-07-Issue-111/ https://orbitalindex.com/archive/2021-04-07-Issue-111/ - if you're into this sort of thing, you might enjoy the newsletter.)