Far out cosmology: the first deuterium (Introduction)

by David Turell , Wednesday, November 11, 2020, 19:24 (1471 days ago) @ David Turell

Now measured:

https://www.quantamagazine.org/physicists-pin-down-nuclear-reaction-from-moments-after-...

"In a secluded laboratory buried under a mountain in Italy, physicists have re-created a nuclear reaction that happened between two and three minutes after the Big Bang.

"Their measurement of the reaction rate, published today in Nature, nails down the most uncertain factor in a sequence of steps known as Big Bang nucleosynthesis that forged the universe’s first atomic nuclei.

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"Deuterium’s creation was the first step in Big Bang nucleosynthesis, a sequence of nuclear reactions that occurred when the cosmos was a super hot but rapidly cooling soup of protons and neutrons.

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"The measured rate — which says how quickly deuterium tends to fuse with a proton to form helium-3 across the range of temperatures found in the epoch of primordial nucleosynthesis — landed between the 2016 theoretical prediction and the 1997 measurement. More importantly, when physicists feed this rate into the equations of Big Bang nucleosynthesis, they predict a primordial matter density and a cosmic expansion rate that closely square with observations of the cosmic microwave background 380,000 years later.

“'It essentially tells us that the standard model of cosmology is, so far, quite right,” said Aliotta.

"That in itself squeezes the gap that next-generation models of the cosmos must fit into. Experts say some theories of dark matter could even be ruled out by the results.

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"On the horizon is the next generation of cosmic microwave background measurements. Meanwhile, with deuterium’s behavior now better understood, uncertainties in other primordial nuclear reactions and elemental abundances become more pressing.

"A longstanding “fly in the Big Bang nucleosynthesis ointment,” according to Fields, is that the matter density calculated from deuterium and the cosmic microwave background predicts that there should be three times more lithium in the universe than we actually observe.

“'There are still lots of unknowns,” said Aliotta. “And what the future will bring is going to be very interesting.'”

Comment: Our understanding of how God made the universe is ongoing and our big brains are doing the job. The Standard Model remains as rigidly correct as Einstein's theories.