The Pithy Amateur Astronomer

Source: http://www.physorg.com/news199594786.html

Astronomers Find Planets in Unusually Intimate Dance around Dying Star

Hundreds of extrasolar planets have been found over the past decade and a half, most of them solitary worlds orbiting their parent star in seeming isolation. With further observation, however, one in three of these systems have been found to have two or more planets. Planets, it appears, come in bunches. Most of these systems contain planets that orbit too far from one another to feel each other's gravity. In just a handful of cases, planets have been found near enough to one another to interact gravitationally.