Question: How many different stars and types of stars are out in our galaxy

David Wilson answered on 11 Nov 2014:

Good question. There are three basic types of star. Main-Sequence Stars are stars like the Sun, “normal” stars fusing hydrogen into helium to create energy. When that hydrogen is used up they turn into the second type, giant stars, huge objects many, many times bigger than the Sun. After that they can go one of two ways- either they blow up, leaving a black hole or neutron star, or shrink into a white dwarf. Black holes, neutron stars and white dwarfs are together the third type, stellar remnants. Of course within these types there’s a huge amount of variety, with stars of all different sizes and temperatures. All together, there are about four hundred billion stars in our galaxy (400000000000)!