[HN Gopher] Carbon's interstellar journey to Earth ___________________________________________________________________ Carbon's interstellar journey to Earth Author : dnetesn Score : 22 points Date : 2021-04-04 10:36 UTC (1 days ago) (HTM) web link (phys.org) (TXT) w3m dump (phys.org) | cletus wrote: | The sequence of events that led to the Earth being here with us | on it is kind of mind-blowing in terms of physics. | | First, the nascent universe had to cool such that nucleons | formed, which then became hydrogen. This matter wasn't evenly | distributed. Some of it under its own weight collapsed under | gravity and birthed the first stars. | | It seems that shock waves in nebulae trigger star formation. This | could be black holes and/or neutron stars merging, supernovae and | possibly other events. | | These stars became the nuclear furnaces for heavier elements. The | death of these stars spread these metals (in astronomy terms; | anything heavier than Helium). This cycle continued until there | was enough matter in the protoplanetary disk to form rocky | planets, of which we are one (of many). | | This article talks about the nuances of how and when carbon | became part of this system. While that's certainly interesting, | it's the heavier elements (than iron) that I find more | interesting. Anyone with rudimentary physics knowledge knows that | this path only forms elements up to iron because beyond that it | consumes energy. | | So heavier elements were seeded in this process through | supernovae and, as we've confirmed in recent years, from neutron | star mergers. So the right sort of stars need to form in the | right way and die and then their remnants need to merge to | scatter these elements. | | I saw one study that suggested the uranium on earth formed by | such an event 80-200 million years before the Earth did. That's | kind of crazy to think about. | | We are literally made of stardust. | jjbinx007 wrote: | It is humbling and also rather difficult to get one's head | around. | | However, when you consider the observable universe is 96bn | light-years across and contains hundreds of billions of | galaxies, and the observable universe is very likely only a | small part of the universe beyond then incredibly unlikely- | sounding things will happen all the time somewhere and some | when. | | It's amazing we know so much considering most of our knowledge | about the universe has arisen in the last c.300 years. ___________________________________________________________________ (page generated 2021-04-05 23:00 UTC)