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Phalcone42 t1_itxr3al wrote

Well, there are neutron stars that are functionally one giant unstable element held together by gravity instead of the strong force. The only reason they don't collapse further is because of neutron degeneracy pressure. Considering the relationship between half life and atomic size, coupled with the longevity of neutron stars, i'd say so, but it's a bit of a stretch.

Edit. For a less extreme condition where the nucleus is not so massive as to be stabilized by gravity, it seems that certain types of decay, like electron capture decay, vary with pressure, while others like ß emission does not.

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ToolFO t1_itz8cb1 wrote

Are neutron stars functionally just one giant nucleus?

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RobusEtCeleritas t1_iu3t52l wrote

There's not really any meaningful sense in calling a neutron star a giant nucleus. A nucleus is bound by the residual strong force, and the heaviest nuclei have radii on the order of tens of femtometers or so.

A neutron star is bound by gravity, and has a radius of around a few kilometers.

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Ahandgesture t1_itzjl9d wrote

So the gravity prevents neutron decay after the 830 or so seconds we expect? Or at this point is the matter too exotic at that point to apply thinking like this?

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noldig t1_itzm5gt wrote

Not completely, there is still neutron decay going on, but it is heavily surpressed because of electron degeneracy pressure, and balanced by electron capture

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Ahandgesture t1_itzmhnb wrote

Interesting, thank you for the answer! I wonder what the neutron lifetime in this case is. There's already the discrepancy between beamline and "jar" lifetime experiments. If we could measure neutron decay in a neutron star, we'd probably have another point of discrepancy 😆

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noldig t1_itzmxzz wrote

The lifetime will mostly depend on phase space and temperature, so two quantities a free neutron doesn't care about. But these processes are responsible for cooling neutron stars down so we try to measure it. I have computed the rate a few times but never converted the units haha I will check

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