Is there only one solar system?

Sol does refer only to our star, the Sun. There are many planets, but only one named Earth. There are many stars, but only one named the Sun. There are many planetary systems, but only one named the Solar System. There are many galaxies, but only one named the Milky Way. read more

They wonder how many solar systems are in our galaxy. Well, I wish I knew the answer to this thought-provoking question, but not only do I not know, no one does. Even so, this question brings up some thrilling ideas. For many years scientists have studied our own solar system. But until the last few years, we knew of no other solar systems. read more

A spaceship exploring the outer reaches of our solar system could go a long time without seeing much. And, indeed, for most of the past century astronomers figured there was little enough to see: only one small icy planet, Pluto, and its oddball moon Charon. read more