New discovery shatters previous beliefs about Earth’s origin | Hacker News Reader

New discovery shatters previous beliefs about Earth’s origin

sciencebulletin.org

20 pointsupen12 comments

>How the Earth was formed and what type of planetary materials were part of that formation are issues that have puzzled generations of scientists. Is this saying anything about the big bang theory or just earth's early composition?

I don't think it says anything about the Big Bang. The earth is supposed to have formed from the remnants of supernovae, not elements produced by the initial nucleosynthesis of the Big Bang. Indeed, most of the elements earth is made from are believed to have come from the insides of stars, not from the Big Bang.

In fact the Big Bang didn't even create any elements, it was way to violent for that.

Only after things had cooled did the first atoms form, which I believe was almost exclusively hydrogen.

Fusion inside stars and supernova did the rest.

Lots and lots of Helium too, and (it's believed) Lithium as well. That's it though, everything else is stardust or the interaction of stardust with cosmic rays and the like.

Ah according to Wikipedia it's believed to be around 25% helium-4, that's more than I thought it was. The rest is almost entirely hydrogen though.

It's amazing when you consider the abundance of heavier elements in our universe today, that virtually all of it was created in stars, isn't it?!

There is no abundance. You simply happen to be living in a planet, by definition made out of heavier atoms.

Even active stars are mostly hydrogen.

Considering that "in the beginning" was mostly hydrogen and helium, I'd say that the present state of affairs is an "abundance". Granted, nothing is in abundance other than spacetime though if you want to be picky about it through.

not quite true... big bang nucleosynthesis is believed to have created substantial amounts of helium and lithium, in addition to primordial hydrogen.

Most references I've found state that not much lithium was created by nucleosynthesis during the big bang, saying that most of it came afterwards from cosmic ray spallation of heavier elements that were created by stars.

These all seem to cite papers from around 1970 through the early 2000s, though. Has subsequent research changed what is accepted on how much lithium comes from the big bang?

So... what does this imply for the formation of the planets in our solar system?

They have not appeared around the same time in some sort of a massive breakdown of a large amount of matter and none is a direct extrasolar capture, but they did catch substantial extrasolar matter.

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