eli5: If absolute 0 is only theoretical, how do we know what it is in Celsius and fereignheit

Question

eli5: If absolute 0 is only theoretical, how do we know what it is in Celsius and fereignheit

In: 0

Answer 1

While we haven’t reached absolute zero, and we never will, we do know right around where it will be. That’s why we set the Kelvin scale to start at that number and have it go up at the same rate as Celsius (a one degree increase in Celsius is equal to a one Kelvin increase), just plus or minus 273.15. We also know the conversion rate to go from any temperature scale to another, so we can just convert there.