Linked Article: Record Set for Hottest Temperature on Earth: 3.6 Billion Degrees in Lab
Scientists have produced superheated gas exceeding temperatures of 2 billion degrees Kelvin, or 3.6 billion degrees Fahrenheit.
This is hotter than the interior of our Sun, which is about 15 million degrees Kelvin, and also hotter than any previous temperature ever achieved on Earth, they say.
I don't see how is it possible that these scientists manage to measure two billion Kelvin. Are there such measuring instruments that can measure extremely hot stuff without melting and still get a proper reading, or is it a theoretical deduction?
Best Answer
Fusion is plasma physics, and in plasma physics the temperature is defined by the average kinetic energy of the ions and electrons in the plasma.
Therefore the kinetic energy distributions have to be measured and they have developed ingenious methods of doing so. Fitting with the black body radiations curves allows an estimate of the temperature.
There are more ingenious methods developed, using Thomson scattering, which allow by scattering light on different ions accurate measurements of temperature.
Very high temperatures can be measured for the stars from their black body radiation and the spectral distribution of the light reaching us also.