Proto-Earth was on a fast track to planet formation.
'Starter' Earth grew in a flash. Here's how the planet did it. : Read more
'Starter' Earth grew in a flash. Here's how the planet did it. : Read more
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The article reported, "Schiller and his colleagues made the finding by studying iron isotopes, or different versions of the element iron, in meteorite dust. After looking at iron isotopes in different types of meteorites, they realized that only one type had an iron profile that was similar to Earth's: the CI chondrites, which are stony meteorites. (The "C" stands for carbonaceous and the "I" stands for Ivuna, a place in Tanzania where some CI meteorites are found.) The dust in these CI chondrites is the best approximation out there for the solar system's overall composition, the researchers said. In the solar system's early days, dust like this joined with gas and both were funneled into a accretion disk orbiting the growing sun. Over the course of 5 million years, the solar system's planets formed. According to the new study, the proto-Earth's iron core also formed during this time, snatching up accreted iron from the proto-planet's mantle. Eventually, this proto-planet became the Earth we know today."Proto-Earth was on a fast track to planet formation.
'Starter' Earth grew in a flash. Here's how the planet did it. : Read more
To remind us from the late Mars models based on similar isotope ratios, we can likely constrain Mars accretion to more or less precisely 10 Myrs after system formation [ https://www.space.com/early-mars-formed-slow-ancient-collisions-show.html ]. The paper prefers 10 Myrs from average disk dispersal and terrestrial accretion models. (With crust formation within 20 Myrs.) Simultaneously Moon rock dating has been shown to be contaminated and not relevant for dating the system formation, while the Neptune-Kuiper Belt gap as well as inner planet stable formation and Mars + asteroid belt low masses all require an outer system migration within 10 Myrs https://www.sciencemag.org/news/2020/01/cataclysmic-bashing-giant-planets-occurred-early-our-solar-systems-history ].This new 5E+6 years lifetime starts to place real constraints on origin modeling for our solar system
That variation is why I would like to see a bayesian credibility distribution analysis of some selected newer models, There likely are too many models to analyse them all, but there are some subsets like those I mentioned that concur roughly on the datings.Discussions about giant impacts in the solar system depend upon how much computer models use as input disk mass initially (that includes dust grains), and how long the disk can last. There are wide variations reported now.