With their orbits crossing each other will Neptune and Pluto ever collide?

Answer 1

In their current orbits, Pluto and Neptune will never collide, since Pluto is in a 3-to-2 resonance with Neptune. That means that for every two orbits of Pluto, Neptune executes three orbits; thus, they’re never close to one another in their trips around the Sun (instead, Neptune is always 90 degrees ahead of or behind Pluto when Pluto is closest to the Sun). Even though the orbits of Neptune and Pluto seem to overlap, they will never actually collide.

Many of the newly-discovered objects (hundreds of ’em now) out near Pluto have these kinds of resonances. If they didn’t, they’d be more likely to collide with Neptune, and Neptune is probably responsible for shepherding them into these stable configurations.


Ryan Wyatt
Rose Center for Earth & Space
New York, New York

Answer 2

No. Pluto's orbital plane is inclined to Neptune's so that at the two points where the distance from the Sun is the same the two orbits are going over/under each other and are still millions of miles apart. They never intersect.

Answer 3

Their orbits don't cross in three dimensions. Pluto never occupies a point on Neptune's orbit.

Answer 4

Neptune and Pluto have been around for over four billion years. If they were going to collide, they would have done it already.

Answer 5

No, silly. They are too far apart.