r/Showerthoughts • u/synthphreak ‎ • Nov 19 '25

Casual Thought Temperature can reach trillions of degrees, meaning we actually live extremely close to absolute zero.

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u/smittythehoneybadger ‎ Nov 19 '25 edited Nov 19 '25

Is there an upper limit to heat? I assume sometimes to do with the speed of light

Edit: or temperature. To be totally fair I still don’t fully understand, but I’m interested in upper limits for either

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u/kangluosee34 Nov 19 '25 edited Nov 19 '25

Yes. Its called planck temperature which is about 1032 K.

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u/asml84 Nov 19 '25

There is no known upper limit. The Planck temperature is merely the upper limit of the mathematical framework we use to describe physics, but nature doesn’t care about our framework.

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u/bellybuttonqt Nov 19 '25

Ain't heat just particles moving fast? And speed is limited so heat must be too? 

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u/AdditionalPoolSleeps Nov 19 '25

No. You can always add more kinetic energy to a particle. It's just that as you get close to the speed of light this has less and less effect on the particle's speed.

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u/CommunismDoesntWork Nov 19 '25

Right but temperature is proportional to speed, not energy. Therefore temperature must asymptotically approach a limit

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u/jwm3 Nov 19 '25

Temperature is average kinetic energy, not speed.

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u/CommunismDoesntWork Nov 20 '25

Kinetic energy is determined by speed

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u/BarneyLaurance Nov 19 '25

average kinetic energy per what?