Page 6 - So... how many planets, again?

If you also factor in the speed of neptune and the speed of pluto the odds could be even less. And the 164 Earth Year orbit of Neptune... The odds are very low. Those 2 planets have been in existance for 4+ billion years as far as we know. And they still haven't smashed into each other. It might not be possible

Its probably possible, I mean when you have two things crossing paths there is always a chance they could colide, like pryo said. But the odds are very very small, They don't cross paths very often, but I am sure someone has probably figured out the odds, or at least tried.

Can Pluto collide with Neptune? No.

A lot of people hear about Pluto coming closer to the Sun than Neptune and conclude that, when Neptune and Pluto are at exactly the same distance from the Sun, there must be a risk of collision. There are several reasons why this isn't actually so.

The first is that it's a big solar system, and when you're out as far as Neptune and Pluto are, it's a really big solar system. As described above, Pluto crosses the orbit of Neptune twice every 248 years, so it doesn't often get the chance to collide; and even when it does cross the orbit of Neptune, the odds would be very good that Neptune would be someplace else.

The second reason (which is the only one most books get around to mentioning) is that the orbits of the two planets don't intersect. You can think of the orbits of Neptune and Pluto as being like two links on a necklace; if Neptune ran in a circle inside one of the links, and Pluto ran in a circle inside the other link, they would pass each other from time to time, but they wouldn't collide.

The third reason is a tricky one. Whenever Pluto comes closest to the Sun, Neptune is always ninety degrees away, either ahead of Pluto or behind Pluto. This guarantees that, when that "chance of collision" seems to occur, Neptune will very definitely be in a totally different part of the sky... in fact, it will usually be even farther from Pluto than the Earth is.


Google and me =

Ah thats very true, we were thinking of the actually orbits crossing each other, but you bring up a good point, you can think of it like a 2d picture, it has to be 3d, so pluto can be closer, but it never actually passes through the orbit of neptune just goes past its orbit.

Yeah becuase pluto's orbit is at a slant. I figured that about 4 hours ago. I just never bothered to look it up

Lol, the answer to our solution was simple, we were just too dumb to look for it .

Haha! yeah I guess so. Ooopsy..

Not for you, your the one who found it.

Yeah, but google did the work.

That actually could be true I heard that they might be trying to get rid of mercury. I'm not 100% positive but I heard that from somewhere.

hmm, as far as I know it doesn't have to exactly cross Neptun's orbit. It enough to cross close enough to Neptun and it's orbit will change. Am I right?

No. Pluto orbits in a 3:2 orbital resonance with Neptune. Neptune always passes Pluto when they are almost farthest apart.

Other information of interest:

The search for Pluto was initiated because in the 1800's there was something farthur out that appeared to be causing a perturburation in Neptune's orbit. Pluto was found near the predicted region. Better more recent calculation have found that Neptune's mass was incorrectly calculated back then. There was nothing pertubating Neptune's orbit after all. Also, Pluto's mass was not enough to perturbate Neptune's orbit abyways.

The time period when Pluto is closer to the sun than Neptune alternates between aproximately 13 years and 20 years.
Pluto was closer to sun than Neptune from:
= April 30, 1483 to July 23, 1503
= July 11, 1735 to September 15, 1749.
= February 7, 1979 to February 11, 1999

Side and top views of Pluto and Neptune's orbits. Source: Pluto on Wikipedia