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Cake day: June 22nd, 2023

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  • Examples would be Helium-4

    The standard model predicts that hydrogen-1 is the only stable nuclide because electroweak instantons allow three baryons (such as nucleons: protons and neutrons) to decay into three antileptons (antineutrinos, positrons, antimuons, and antitauons), which imply the instability of any nuclide with a mass number of at least three; or for two baryons to decay into an antibaryon and three antileptons, which would imply that deuterium could decay into an antiproton and 3 antileptons.

    This is very rarely discussed because the nuclides that can only decay through baryon anomalies would be predicted by the standard model to have ludicrously long half lives (to my memory, something roughly around 10^150 years, but I might be wrong).

    Hydrogen-1 is stable in the standard model, as it lacks a mechanism for (single) proton decay.


  • Crucially, we are able to determine the distance by redshift via the observations of objects with known distance (like standard candles) and their redshifts. The ΛCDM model only becomes necessary for extrapolating to redshifts for which we otherwise don’t know the distance, but this extrapolation cannot be made without the data of redshifts of known distances.




  • I meant that electromagnetism is ubiquitous in its role in the nature of ordinary matter itself.

    Are magnet’s the most dangerous thing in the universe?

    No, not even remotely. That’s not to say that the extreme magnetic fields of magnetars wouldn’t be awesomely dangerous, but “most dangerous thing in the universe” is an absurdly high bar to meet.

    After all Blackholes are powerful magnets

    The accretion disk consisting of material surrounding a black hole is capable of generating strong magnetic fields, rather than the black hole itself.