> Stable states are likely not all that hot, but what about supernova? As context first, at some point temperature just sort of, stops being useful as a compar

> Stable states are likely not all that hot, but what about supernova? As context first, at some point temperature just sort of, stops being useful as a comparison. Not because it can't be computed, but because there really isn't any point of comparison for it. The coldest temperature in Antarctica was -89.2 Celsius [0]. The hottest day in Death Valley was 56.7 Celsius [1]. Tungsten melts at 3400 Celsius [2]. And papers about supernova will casually throw around phrases like "for temperatures exceeding a few 100 keVs" [3], to state that pretty much everything that happens in a supernova will be hotter than that. That's an energy measurement equivalent to about 1 trillion kelvin. The second piece of context, for anything that deals with energy output, supernova are basically the "I win." answer. XKCD's "What If?" series has a good comparison for this, that for pretty much any comparison you can conceive, if the question is about energy output, the supernova wins. > Which of the following would be brighter, in terms of the amount of energy delivered to your retina: (1) A supernova, seen from as far away as the Sun is from the Earth, or (2) The detonation of a hydrogen bomb pressed against your eyeball? ... [The supernova] is ... by nine orders of magnitude. [4] So when temperatures are reported as 100 billion kelvin for the neutron star remnant [5], those are the cold (by comparison only) embers of a dying fire. The supernova itself has a "typical core temperature of 1 MeV" [3], which translates to about 10 trillion kelvin. [0] https://en.wikipedia.org/wiki/Lowest_temperature_recorded_on_Earth https://en.wikipedia.org/wiki/Lowest_temperature_recorded_on... [1] https://en.wikipedia.org/wiki/Highest_temperature_recorded_on_Earth https://en.wikipedia.org/wiki/Highest_temperature_recorded_o... [2] https://en.wikipedia.org/wiki/Tungsten https://en.wikipedia.org/wiki/Tungsten [3] https://arxiv.org/abs/astro-ph/0612072 https://arxiv.org/abs/astro-ph/0612072 [4] Xkcd, What If, #73: https://what-if.xkcd.com/73/ https://what-if.xkcd.com/73/ [5] https://en.wikipedia.org/wiki/Supernova#Detailed_process https://en.wikipedia.org/wiki/Supernova#Detailed_process