• Question: is there a limit to how cold things can get?

    Asked by to Anna, Elaine, Fiona, Kevin, Darren on 24 Jun 2014. This question was also asked by .
    • Photo: Anna Bramwell-Dicks

      Anna Bramwell-Dicks answered on 24 Jun 2014:

      Yes! And it’s known as Absolute Zero.

      Absolute Zero is the theoretical limit for how cold something can be. On the Celsius scale it is equal to −273.15°C! Or, on the Kelvin scale it is 0K.

    • Photo: Zhiming Darren Tan

      Zhiming Darren Tan answered on 25 Jun 2014:

      Yes, there is a limit. You might ask why – and it’s about energy. Getting colder and colder means taking out all the energy you can take out. Atoms move less and less as they cool. Less vibrations. There’s a limit because when they “stop” moving, there’s no way to make them colder!

      But this simple picture is not entirely accurate. You might have heard about quantum physics or quantum mechanics. We think that even at absolute zero, when there should be no more energy, there is still some motion that you absolutely cannot stop. That’s related to Heisenberg’s uncertainty principle, but that’s a story for another day…

      Seems like the record for low temperature is 10^(-10) K = 0. 000 000 000 1 K.

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