Jupiter and it's distant cousin Pluto:

Both colossal comets?

The New Horizons spacecraft (NASA New Frontiers mission) is bound for Pluto for a dramatic flight past the icy dwarf planet and its moons in July 2015. This unique mission is poised to answer everything that you ever wanted to know about Pluto, its escaping atmosphere, the Kuiper belt and more. While space plasma physics is not New Horizons' primary mission, its contribution to the field of magnetospheric physics cannot be understated. The spacecraft received a Jupiter gravity assist with closest approach on February 28, 2007, placing it on a trajectory straight down Jupiter's magnetotail. I will discuss how the plasma measurements from Jupiter's magnetotail have changed the landscape of magnetospheric physics and describe how the giant planet might have something in common with the diminutive (and former) planet, Pluto.