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RATH3SUNG0D2017 t1_iyiuogj wrote

Plutonium is a decay product of U-238, so natural deposits of uranium do have some amount of it, i.e. it's not man-made, but we bring enough uranium together to probably have an above-average amount compared to other unadulterated planets/space rocks.

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Nieshtze t1_iyj09y1 wrote

Wouldn't most of these exotic trans-uranium elements be formed in some quantity during events like supernovae? There's enough radiation and particles flying around in that event that I'm sure every isotope is formed (if only for a few short microseconds) due to the massive scale and energetics of the reaction.

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cjheaford t1_iyj4ysx wrote

Plutonium is P-239. How can 238 decay into a HEAVIER atom?

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OlympusMons94 t1_iyjajjv wrote

U-238 can undergo spontaneous fission, which results in the emission of neutrons. If a U-238 nucleus absorbs a neutron, it becomes U-239, which quickly decays to Np-239, and then Pu-239.

But there are other isotopes of Plutonium besides Pu-239. This includes Pu-238, which can also occur naturally in small amounts as a result of double beta decay of U-238.

Yet another naturally occurring isotope of Plutonium is Pu-244, which has a relatively long half-life of 80.6 million years. This is produced by the r-process, and some trace amounts of this have been found in the ocean floor.

ETA: https://en.wikipedia.org/wiki/Plutonium#Occurrence

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cjheaford t1_iyjbmin wrote

Very interesting. Thanks for taking the time to explain!

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RATH3SUNG0D2017 t1_iyjcj4f wrote

Beta decay! A neutron emits an electron and antineutrino and becomes a proton.

Edit: If you'll entertain wikipedia as a source, https://en.m.wikipedia.org/wiki/Beta_decay

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Nieshtze t1_iys24p7 wrote

That doesn't answer his question. Beta decay does not increase mass of the parent nucleus, only increases the atomic number.

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