Possible Captured Planets Found in Oort Cloud.

A new study suggests that planetary systems don't always form in isolation, and there could be captured planets in the Oort Cloud. The team ran computer simulations and found that the gravitational tug of the galaxy itself can dampen the motion of a rogue planet, and thus a small fraction of celestial encounters will see a star catch the planet and claim it as a new world. Based on their calculations, up to 10% of a star's original planets could be cast adrift into deep space, and there is about a 7% chance that our solar system has a captured ice giant planet in the Oort cloud.