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New Theories / Re: Suns shining for 10 billion years might account for mass of dark matter
« on: 25/01/2022 21:15:09 »
The energy of fusion is nowhere near enough to account for dark matter. Current measurements put dark matter as accounting for 27% the mass of the visible universe whereas visible matter (like stars) account for only 5%. I'll do a bit of math to show how far off it is.
Let's assume a perfect scenario where we can get as much fusion energy as physically possible (which real stars don't actually achieve). We start off with a star that is composed of 100% hydrogen (the simplest, most common isotope with a single proton). We then will fuse all of that hydrogen into just about the most stable isotope we can (iron-56). The mass of a proton is 1.007825 daltons and we will fuse 56 of them together to produce the iron nucleus: that's a total mass of 56.438032 daltons. The iron-56 nucleus has a mass of 55.934936 daltons. 56.438032 - 55.934936 = ~0.5 daltons. So only about 0.9% of the total mass of the hydrogen has been converted into energy (and that's not counting the positrons and neutrinos, which would take away some of that mass as well). So radiation from stars can't be the explanation for dark matter.
Let's assume a perfect scenario where we can get as much fusion energy as physically possible (which real stars don't actually achieve). We start off with a star that is composed of 100% hydrogen (the simplest, most common isotope with a single proton). We then will fuse all of that hydrogen into just about the most stable isotope we can (iron-56). The mass of a proton is 1.007825 daltons and we will fuse 56 of them together to produce the iron nucleus: that's a total mass of 56.438032 daltons. The iron-56 nucleus has a mass of 55.934936 daltons. 56.438032 - 55.934936 = ~0.5 daltons. So only about 0.9% of the total mass of the hydrogen has been converted into energy (and that's not counting the positrons and neutrinos, which would take away some of that mass as well). So radiation from stars can't be the explanation for dark matter.
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