# Science Questions

## Is there a limit to how hot you can make the temperature?

Sun, 1st Nov 2009

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### Question

In an article I read this week, they said that the coldest spot in our solar system was a crater on the south pole of the moon. The temperature’s about - 238 degrees. I realise this is close to absolute zero. But if absolute zero is the coldest temperature we can achieve, is there a limit to how hot you can make the temperature?

Temperature is basically a measure of how much energy each particle has got or each direction a particle moves in.  And so, you can pretty much all the energy away from something and you can't take any more energy away, and so, there’s a minimum temperature as an absolute zero.  But certainly, in any normal idea of physics, anything we know, definitely there’s no maximum amount of energy you can give particles.  So there’s no maximum temperature.  You can keep on giving more and more energy and the temperature will keep on going up. There could possibly be a maximum temperature.  You might find a maximum energy, you can give things due to some bizarre bit of quantum mechanics, but as far as we know, we haven’t found this solid one yet.

#### Make a comment

Cee Jai Bernard asked the Naked Scientists: Hello, My name is Cee Jai (CJ) I'm from Canada and I'm a big fan of your show. I do have a question though. In the news his week, I read an article that the coldest spot in our solar system has been found in a crater on the south pole of our moon with a temperature of minus 238 degrees Celsius. I realize that that is very close to absolute zero, but why does this bother the scientists? Also, absolute zero is the coldest temperature we can achieve, is there a limit to how hot it can get as in the highest temperature possible? Thanks CJ What do you think? Cee Jai Bernard , Tue, 29th Sep 2009

Theortically-speaking, there is no upper limit to tempearature. Mr. Scientist, Tue, 29th Sep 2009

Absolute zero, or zero Kelvin, as it is otherwise known, is a theoretic temperature which, according to the laws of thermodynamics, cannot be attained. rhade, Tue, 29th Sep 2009

Re the hottest temperature possible: there is the Planck Temperature, of 1.416785(71) × 1032 K, beyond which current physics theory breaks down.

Then there is also the speed of light 'c' limit when considering temperature as the kinetic energy of atoms/molecules in a medium. LeeE, Tue, 29th Sep 2009

Could be misunderstood to mean that this is the highest temperature we can go. In all due respect, this is not what the theory states. Mr. Scientist, Tue, 29th Sep 2009

Well, I didn't say that the Planck temperature is the highest temperature that 'we can go', just that the Standard Model doesn't currently work above it.

So basically, if you want to work with higher temperatures than the Planck Temperature you need to use a different model (atm). LeeE, Wed, 30th Sep 2009

Temperature = kinetic energy content.
Lightning = a whole lot of energy

Electric energy of lightning dissipated as heat Nizzle, Thu, 5th Nov 2009

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