Stars

Stars

There are only some 6000 stars visible to the unaided eye, though there are something like 300 billion stars in our Milky Way galaxy. And our galaxy is average among billions of other galaxies. There are a lot of stars in the universe! Stars are powered by nuclear fusion. The immense gravitational pressures inside stars force lighter elements together into heavier ones, releasing energy. This energy eventually reaches and heats the surface layer of the star, known as the photosphere. The photosphere then radiates this heat away into space as starlight. [TB] {SL}