What are extrasolar planets?

For countless generations, human beings have looked out at the night sky and wondered if they were alone in the universe. With the discovery of other planets in our solar system, the true extent of the Milky Way galaxy, and other galaxies beyond our own, this question has only deepened and become more profound.

Read more at: http://phys.org/news/2015-05-extrasolar-planets.html#jCp

What do you think?