We Are Stardust
“ The planets, the stars, the galaxies, we ourselves and all of life — the same star stuff .” - Neil deGrasse Tyson
Summary: Let’s start at the very beginning of the amazing story of the universe. Just as each of us know intellectually that we came from a microscopic fertilized ovum, it’s also true that, as astrophysicists tell us, our entire universe burst from a point far smaller than the smallest elementary particle is today. When the universe was three minutes old, it began creating matter as (mostly) the elements hydrogen and helium, and this process ended, they tell us, a scant 20 minutes into the big bang, having created all the hydrogen there would ever be. It then took at leas t 200 million years of darkness before an “emergent” property of the universe popped into being: stars, which spontaneously coalesced as clouds of gas under the force of gravity until they reached high enough temperatures to start nuclear fusion, progressively creating heavier elements out of hydrogen in the star’s core. In the process, a tiny fraction of the mass was converted to energy as a by-product, which makes stars shine and props them up against further gravitational collapse via fusion heat and pressure. In this way, elements as heavy as iron were sequentially created.
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