[EmmaHildyard (OP)]

Louis asks...

What is the theoretical maximum temperature?

(I presume it would be calculated using the relativistic kinetic energy of sub-atomic particles stripped from atoms at the high temperature.)

Where are THE extremes of temperature in the universe? Supernovas?

Can you help?

[yor_on]

I think we need to start with defining how science define a temperature.

" Temperature is different from heat, although the two concepts are linked. Temperature is a measure of the internal energy of a system, while heat is a measure of how energy is transferred from one system (or body) to another, or, how temperatures in one system are raised or lowered by interaction with another. " https://www.thoughtco.com/temperature-definition-in-science-2699014

The 'energy' of something at its lowest state at is 0  K which translate to −273.15° on the Celsius scale and −459.67° on the Fahrenheit scale. Absolute zero is impossible to reach though according to HUP (Heisenberg's uncertainty principle) which simply state that you can't know all parameters. On the opposite side you find the Planck value for what theoretically could be a limit for the temperature "  1.41679 x 1032 Kelvins. This translates to about 2.538 x 1032° Fahrenheit. Since the current theories of physics are incomplete, however, it is possible that it could be hotter. " https://www.wisegeek.com/what-is-the-highest-possible-temperature.htm

you could also think of it as a function of 'c', and there the energy of something of mass reaching that speed is infinite. You can't reach it.

[alancalverd]

The maximum meaningful classical temperature is that at which all the electrons are stripped from the heaviest atom, so you have a plasma rather than an array of atoms, but plasma physicists still talk about temperature as the mean energy of the particles in their plasma, for which there is no upper bound until all the mass of the observable universe is converted to energy invested in a single proton-electron pair.

[evan_au]

Oops! overlap with alancalverd...

What is the theoretical maximum temperature?

Temperature drops when you reduce pressure.
So I imagine that the maximum theoretical temperature in our universe would have been at the first instant of the big bang, when all the mass/energy of the universe was compressed into the smallest volume.

But our current theories are limited in how close they can get to the Big Bang.
And our experimental results are limited by the maximum energy of the LHC generating a quark-gluon plasma.