Neutron stars may be bigger than expected, measurement of lead nucleus suggests

Re:Neutron stars may be bigger than expected, measurement of... by hinkley on Tuesday April 27, 2021 @05:20PM (#26961722)

I was shocked to learn how long it takes a photon produced at the center of the sun by a fusion event to reach earth. The layers upon layers of subatomic particles that are all interacting in these tight quarters is simply astounding.

I've heard this same theory on supernovas from a number of people in or around physics, but I always wonder how handwavy it is, whether we actually understand how that works yet, and how different (confusing) the real process is from the given one.

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Re:Neutron stars may be bigger than expected, measurement of... by btilly on Tuesday April 27, 2021 @08:32PM (#26963935)

We understand this one surprisingly well.

The seminal paper from 1957 is https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.29.... that figured out all of the reactions involved. Then used their predictions of the process to predict the distribution of observed isotopes of all of the elements. Those predictions were surprisingly accurate and have been refined more. See https://www.sciencealert.com/this-awesome-periodic-table-sho... for the outcome of that.

Incidentally the photon takes so long to escape because it gets absorbed and reemitted over and over again in a drunken walk. A supernova is fast because most neutrinos just escape, but with enough being stopped to rip the star to shreds.

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