eli5: Why is it temperatures can go up to the trillions but only down to -273?

Question

eli5: Why is it temperatures can go up to the trillions but only down to -273?

In: Physics

Answer 1

An interesting sidenote about this is that -273° C being absolute zero is a “coincidence” of using the freezing (0° C) and boiling point (100° C) of water.

Kelvins set absolute zero to 0 K, and uses the same increment scale as Celsius, so 273 K is the freezing point of water. Absolute zero in Fahrenheit is -459° F.

We could have easily created another scale like Celcius slided so freezing is “a trillion”, so absolute zero would be about negative “a trillion”. This makes the desparity seem less extreme between high and low temperatures. That scale just would be far less useful to our everyday lives.

Edit: Added ° symbol for C/F (Kelvin doesn’t use it)