Oort Cloud ( View full size )

Spherical cloud of icy planetesimals surrounding the Sun at distances from 2,000 to 200,000 AU (beyond the heliosphere) - Two regions: a disc-shaped inner Oort cloud and a spherical outer Oort cloud - Affected by the gravitational pull of the Milky Way and of passing stars (occasionally sending comets to the inner Solar System) - Still theoretical as no confirmed direct observations of it has been made yet