Question: How can you figure out how the sun works from such a distance when you cant do any experiments on it?

Nicolas Labrosse answered on 14 Jun 2017:

It’s by looking carefully at the light that is emitted from the solar surface that we can learn a lot about how the Sun works. This has been made possible towards the second half of the 19th century when ‘spectroscopy’ started to be used (spectroscopy is basically splitting up light according to colour, or wavelength).
By doing this we can guess the temperature, the pressure, the direction of motion of the stuff that is emitting the light. We can then use basic physical laws to link together all the quantities that we could measure that way, and guess what is going on inside the Sun, below the surface down to the solar centre.
All of this is sometimes called “remote sensing”: studying a distant astrophysical object, and measuring parameters from the light that we receive from it.
To be honest, I think it’s a wonderful area of science. Just being able to obtain this information by looking at the Sun is amazing when you think of it.
More recently, say since the 1970s, we’ve been able to use computers to solve more complex systems of equations and verify what was until then more based on physics-based intuition. Nowadays, computers are a huge help.