Stars Those Uncountable Stars T here are zillions of stars in the universe some of which have objects orbiting them. But they are so far away that we can't tell whether those objects are planets and moons or just large rings of material.
Stars come in all sizes, temperatures, and ages.
Small red stars are burning their energy very slowly and are very cool. Their lifetimes are measured in trillions of years, and they end up as heavy little cinders. Yellow stars, like our sun, take billions of years to use up their fuel and end up as very dense white dwarf stars. Blue giant stars last for millions of years and, after an explosion, finish their lifetimes as rapidly spinning, very dense pulsars, each surrounded by a gas cloud from the explosion. Super giant stars last only a few million years because they are burning their fuel so fiercely.