I agree,
In terra pax hominibus, bonae voluntartis.
The explanation actually requires quite a lot of understanding of science. The astrophysics course at my university is thought to 3rd/4th year physics undergrad students. This is mainly because stars are complicated objects. If you think the earth is complicated (and it is) the sun is just as bad (if not worse).
One way to classify and study stars is to use a Hertzsprung-Russle diagram.
https://en.wikipedia.org/wiki/Hertzsprung-Russell_diagramThis classifies stars into brightness on one axis, and on the other axis, the temperature or similarly related, the colour of the star.
also, check out
https://en.wikipedia.org/wiki/Stellar_evolutionIn general, the life of a star sweeps an arc in the Hertzsprung-Russel diagram. From bottom right, up towards the top and once it reaches its peak and runs out of fusion material, quickly drops back down on the left. We know this because we observe many stars and can deduce this process just by looking at how stars currently behave.
To understand the how the life cycle works, we need to know some fusion. This is the way in which the sun shines (literally).
https://en.wikipedia.org/wiki/Nuclear_fusionThe main point about fussion is that staring from hydrogen, under the right conditions, hydrogen atoms can fuse together to become helium. In turn helium can keep fusing to become litium... and we can keep going up the periodic table in terms of atomic weight until we reach iron. This is called the iron limit.
https://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin.htmlThis is because iron is the element with the highest binding energy per nuclear particle. This means that it take to get from iron to cobalt, we need to put in more energy than is given out in the fusion process. So the process stops there. Anyway, at that point the star becomes so dense that weird things happen. Gravity kicks in.
Understanding the processes of fusion, this chain basically tells us how far in we are in the life cycle of the star. From the light emitted by the star, we can look at it's spectra. That is, break up the light up colours and look at which colours are emmited.
Have a look at
https://jersey.uoregon.edu/vlab/elements/Elements.htmlIf you click emmision instead of absorption, and click on each of the elements, you will see colours appearing at the top of the screen. If you heat elements up hot enough the electrons will excite producing light in the process -- this is not reflection, but emmission, it generates (makes) light. The thing about elements is that the light produced by the electrons of each element is unique. Click on the different elements, to see the partterns. If there is more than one type of element present, the lines will mix, i.e. the spectra of all the elements in the sun will be in the sunlight. By the brightness of each of these lines, we can tell the approximately how much of each element is in the sun. The spectra also contains information about temperature.
Of course this is not the only method. We can use other methods to measure properties like the mass of the sun, density, temperature etc. So it's not just one single piece of information. There are many experiments, models and test done to try and find these things out.
In understanding the fusion process, we can look to how far along the chain we are. With this we also know the time it takes (in a probabilistic sense) for the process to occur. Form this we can estimate the age of our sun, and compare that with the age to all the other stars (suns) we see in space.
Looking back at the hertzsprung-russel diagram, what we see is a snap shot of stars at different points in their life. This is like taking a survey of peoples ages where you live. You get a snap shot of the population and can try to figure out the features associated with younger people and older people. Given some information about a new neighbour moving in, you can then estimate his/her age.
There is absolutely no reason to believe that our sun is any different from the other suns out there. An egocentric, earthcentric or heliocentric view of the universe is usually wrong. We once thought that the sun and all the stars revolved around the earth. We were clearly wrong about that.
https://muse.tau.ac.il/museum/galileo/geocentric.htmlIf you don't believe that our sun is any different from all the other suns we see, then it simply cannot be 6000 years old. There is absolutely no process possible that we know of that can explain our sun being 6000 years old. It's like saying that a baby was born 6 feet tall with a beard.
P.S. Haha... whilst typing tis prometheus wrote the previous post.. and of course you can pick up and astronomy book and read it.
P.P.S Pianistimo -- I disagree with talbergmad about one point. You are not stupid. As you can see, the arguments that I have presented are ridiculously complicated.
As I have pointed out, these ideas don't even kick in until you have a firm understanding about quantum physics, nuclear physics, some plasma physics, and a good grounding of classical mechanics, electromagnetism and many other areas. It's not in anyway reasonable for you to be aquainted with these things.