PDA

View Full Version : Question about the effects on Neptune ...



Aimee
2009-Aug-10, 04:13 AM
I'm just curious what the effects are on Neptune when Pluto is in its orbit. I know that when our own moon comes closer to us, it messes with the tides and things like that. Are there any similar issues for Neptune?

astromark
2009-Aug-10, 04:51 AM
Pluto is not so large that its mass or gravity has much effect on Neptune. Neptune is a gas giant. At no time does Pluto get close enough to effect Neptune adversely.

aurora
2009-Aug-10, 03:23 PM
When the orbits of Neptune and Pluto appear to cross (when looking in two dimensions, from above or below the solar system, such as a drawing of the planet orbits in our solar system, in three dimensions you can see that Pluto has a fairly inclined orbit) they are always on opposite sides of the sun. Astromark is correct in saying that Pluto and Neptune never get close to each other.

Dana_Mix
2009-Aug-11, 04:47 AM
As the others point out, they never approach closely. In fact, SOLEX (http://chemistry.unina.it/~alvitagl/solex/) 10.0 gives a minimum distance of 17.7 au over the years -3000 to 7000.

EDIT: One astronomical unit (au) is the average Earth-Sun distance.

Aimee
2009-Aug-11, 01:15 PM
Thank you.

I understood that they never got close enough to collide and things like that, just wondered because I read that Pluto goes into Neptune's orbit.

AndreasJ
2009-Aug-11, 01:38 PM
And even if they ever got close, bear in mind that the size difference Neptune~Pluto is a lot larger than Earth~Moon (Neptune being much larger than Earth and Pluto a lot smaller than the Moon), so even then effects would be small.

Dana_Mix
2009-Aug-11, 07:12 PM
What's more, Pluto comes closer to Uranus than it does to Neptune. During the 10,000 year period I used before, they come as close as 12.1 au, and 13 au six times.

Pluto is smaller than seven moons in the Solar System (http://www.nineplanets.org/pluto.html). So it will have a much smaller effect on a planet.

aurora
2009-Aug-11, 07:12 PM
Any Plutinos that did get close to Neptune probably didn't stay that way very long. As Neptune migrated into its current orbit, any Plutinos would be ejected. Pluto was lucky enough to be able to get into an orbital resonance with Neptune.

astromark
2009-Aug-11, 07:37 PM
So... looking at the minimum distances quoted here... Over 12 au. That's more than twice the Earth Jupiter distance. Think about that., and then the sizes. Pluto is smaller than our moon while the gas giant Neptune.... you get the point. And just how many times in the four billion years has Pluto been ejected or other wise disturbed by its encounters... none maybe. Its inclined orbit keeps it safe, it would seem. It may have been, but difficult to prove, Neptune that put Pluto on that inclination.. The first billion years of this Solar system would have been eventful.

Ilya
2009-Aug-11, 08:12 PM
Any Plutinos that did get close to Neptune probably didn't stay that way very long. As Neptune migrated into its current orbit, any Plutinos would be ejected. Pluto was lucky enough to be able to get into an orbital resonance with Neptune.
It was not luck. There are several hundred Kuiper Belt Objects in a 2:3 resonance with Neptune -- that the very definition of Plutinos (http://en.wikipedia.org/wiki/File:TheKuiperBelt_60AU_Plutinos_distribution.svg) . A large planet such as Neptune actually "herds" small objects into resonant orbits; as Neptune migrated outward, so did Plutinos -- including Pluto.