Core Temperature of Sun How do scientist know the sun's core
temperature? This is a good question, after all, we have no
direct access to the sun's core, but if we apply some knowledge
of physics, we can get to a reasonable approximation quite
readily. First, we have to understand that the sun is mostly
gas-like particles. If the sun did not have gravity the gases
would spread away since nothing would hold them in place.
However, if all the sun had was gravity, then that would
compress the gas into a smaller volume. Since the sun is giving
off energy, then the gases spread out and the sun is bigger than
it would be if it was not giving off energy. So there are two
opposing forces: (1) the gravity of the sun which pulls the gas-
like particles inward, and (2) the energy output of the sun
which pushes the gas-like particles outward. The sun's size is
the result of the balancing of these two forces. Next, we need
to find the mass of the sun. We can measure the gravity of the
sun, by observing how the planets are