I spent a lot of time last summer understanding and plotting out HR (Hertzsprung-Russell) charts, which are actually pretty interesting. On the side of the graph you've got the star's luminosity, and on the bottom you've got its temperature (both things we can tell from a distance through analyzing its colour spectrum). When you plot a bunch of stars onto the diagram this way, you can see their relative ages and get an understanding of a star's lifecycle from protostar to either neutron star or white dwarf, depending on whether or not the star starts off as a yellow or blue main sequence.
And you know Moby's song "We Are All Made of Stars"? That's a fact. 98% of the matter that we're made of was generated in stars and expelled into the universe when they died.
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