Clearly, Halley has a good number of 76-year orbits left before it stops making news. As we live out our lives securely attached to the Earth, breathing its air, and using its water, it becomes all too easy to take planets for granted. After all, our solar system has nine of them, enough so students grumble each year about having to remember them all. Yet the surprising fact is, we do not know for certain whether there are planets around other stars. But as of today, we simply do not have any firm evidence that planets outside our own solar system exist.
Planets Are Hard To Find The problem, as always in astronomy, is one of distance and brightness.
While stars shine under their own power, planets simply reflect the light of their parent star. Furthermore, planets are generally much smaller than stars and the surface or atmosphere on which starlight can reflect is thus very limited. A few years ago there was a flurry of excitement as some astronomers found wobbles in the motions of several nearby stars, suggesting the presence of planets. To understand how these observations were performed, imagine a star with just one good sized planet around it. When the planet is on one side of its star, its gravity pulls the star ever so slightly to that side.