How can the scientist know the composition of the sun whitout collecting matter from the sun?

Answer 1

That is a very complicated question, and perhaps someone more experienced can answer this better than I.

I will do my best till then. Elements are composed of electrons neutrons and protons. Our star is the mostly in the forth state of mater, plasma and therefore is very hot, it is also very large and that makes it very dense, this creates a lot of heat and energy, far more than we have ever created in total in our lifetimes is expended each second by our star.

It is the massive pressures (squeezing) the atoms tighter together, the heat making them move faster and faster, It is because of all of this energy pressure heat and speed that atoms collide here. This is a constant nuclear reaction held back from running away only because gravity keeps it in check.

I think this is is all necessary to answer you, because it takes this nuclear reaction to create the elements we can see.

We see these elements because of the same effect that make lasers work. In this case it takes the tremendous heat and pressures of our star to excite the electrons of elements into higher orbits. When they fall back to their ground state, like a laser pointer emit a photon that we can detect with and instrument. Like a fingerprint all elements have a unique photon signal.

Answer 2

They put different chemicals into flames and see what color it becomes. Then they can tell for example if a star is made of calcium chloride if the star is green.

Answer 3

The use sonars, radars, satellites, and temperature to determine the composition of a planet.