Post by cronicbadger on Jun 28, 2018 21:29:34 GMT 10
New research suggests that, basically, an asteroid shower in the formative years of our planet seeded Earth with most of the precious metals that we now recover from mining and fossicking. The heavy metals that were present as our planet accreted six billion years ago had already fallen to the core - and there it remains to this day. Occasional mantle plumes may have brought some of those metals to the surface, but the article suggests the later asteroids brought much of the material we now mine. Bear in mind this was while the planet was still forming, still plastic, so the new metals were still mixed into the mantle, but had more opportunity to be thrust back up to the crustal layers.
www.geologyin.com/2016/07/does-gold-come-from-outer-space.html
Out of this comes another question: If this is true, and then maybe true for other planets in the universe, then does it impact on Drakes's Law? That is, if the metals useful for technological advancement such as iron, copper, gold, silver and lead require seeding on a forming planet after it is solid enough to prevent the metals from sinking to the core, then what is the chance of an essential metal-laden asteroid bombardment occurring at just the right time. Does this mean there is even less chance of developed life in the universe than previously thought?
Further, how did those asteroids become laden with heavy metals - they would have had come be broken from a large planetary mass that collected gold in the standard way - ie capturing (via gravity) the gold atoms expelled from supernovae. So those asteroids must have been from planets formed a few billion years before Earth was formed. And then, how long does it take for a star to age to the point it explodes?
My brain is exploding!
www.geologyin.com/2016/07/does-gold-come-from-outer-space.html
Out of this comes another question: If this is true, and then maybe true for other planets in the universe, then does it impact on Drakes's Law? That is, if the metals useful for technological advancement such as iron, copper, gold, silver and lead require seeding on a forming planet after it is solid enough to prevent the metals from sinking to the core, then what is the chance of an essential metal-laden asteroid bombardment occurring at just the right time. Does this mean there is even less chance of developed life in the universe than previously thought?
Further, how did those asteroids become laden with heavy metals - they would have had come be broken from a large planetary mass that collected gold in the standard way - ie capturing (via gravity) the gold atoms expelled from supernovae. So those asteroids must have been from planets formed a few billion years before Earth was formed. And then, how long does it take for a star to age to the point it explodes?
My brain is exploding!
