How do I tell which direction celestial bodies are orbitting?

[WhiteRaven22]

I think there used to be a chart for this somewhere on the wiki, but I can't find it anymore. I'm trying to figure out which direction each planet orbits the sun, and which direction each of the moons orbit their planet.

Edited December 8, 2013 by WhiteRaven22

[Liowen]

I think there used to be a chart for this somewhere on the wiki, but I can't find it anymore. I'm trying to figure out which direction each planet orbits the sun, and which direction each of the moons orbit their planet.

You could hit M and scroll out with time warp on and see, but I think each one rotates the same way just at different speeds (and plains as well).

[Tex_NL]

Correct. All (stock) bodies in KSP rotate counter clockwise around their axis and orbit counter clockwise around their parent.

[WhiteRaven22]

Thank you! That's exactly what I needed. I'm assumming from Mun and Minmus, that's counterclockwise looking down on the solar system (North pole of Kerbin visible) or East rotations and orbits.

[Liowen]

Yes that would be correct, and you are welcome. I think it would be nice at some point have a planet that is going clockwise to make it more interesting. I believe Duna's moon is tidally locked to the planet, and that makes for some interesting pictures if you land correctly.

[WhiteRaven22]

I believe Duna's moon is tidally locked to the planet, and that makes for some interesting pictures if you land correctly.

Cool! I'll keep that in mind. A trip to Duna and Ike is next on my list.

[Osprey]

Yes that would be correct, and you are welcome. I think it would be nice at some point have a planet that is going clockwise to make it more interesting. I believe Duna's moon is tidally locked to the planet, and that makes for some interesting pictures if you land correctly.

While interesting, it would be impossible given the laws of planetary formation (it basically relies on the direction of the rotation of the protoplanetary disc). That said, it is possible for planetary rotation about it's axis to be different, Venus rotates slower than it's orbital speed, thus appearing to rotate clockwise in relation to the sun, though it still orbits anti-clockwise. Uranus by way of a contrast has such an extreme axial tilt that it is essentially on it's side.

With regards orbiting the sun in a different direction, this is where we need comets to come into their being...

[Liowen]

True I forgot about that, comets would be interesting I agree but would be hard to land on....not impossible though (unless it is a really small body of course).

[WhiteRaven22]

True I forgot about that, comets would be interesting I agree but would be hard to land on....not impossible though (unless it is a really small body of course).

Maybe that's why they took the Magic Boulder easter egg out but left the code for it in the game. Maybe they're going to make it into a comet.

[Tex_NL]

While interesting, it would be impossible given the laws of planetary formation (it basically relies on the direction of the rotation of the protoplanetary disc). That said, it is possible for planetary rotation about it's axis to be different, Venus rotates slower than it's orbital speed, thus appearing to rotate clockwise in relation to the sun, though it still orbits anti-clockwise. Uranus by way of a contrast has such an extreme axial tilt that it is essentially on it's side.

With regards orbiting the sun in a different direction, this is where we need comets to come into their being...

Under normal circumstances you'd be correct about planetary rotation. Neptune rotates, like all other planets, counter clockwise but its largest moon Triton has a retrograde orbit, it orbits clockwise.

It is unlikely Triton formed in Neptune orbit but is believed to be a captured Kuiper belt object.

Edited December 8, 2013 by Tex_NL

[RoboRay]

Maybe that's why they took the Magic Boulder easter egg out but left the code for it in the game. Maybe they're going to make it into a comet.

Maybe they already have.

[Liowen]

Who what?? I guess since I only got the game in October I missed something

[WhiteRaven22]

Who what?? I guess since I only got the game in October I missed something

The Magic Boulder was a fairly well known easter egg in the game up until recently. Here's Scott Manley's video about getting to the Magic Boulder, back when it was still in the game.

Edited December 8, 2013 by WhiteRaven22

[Motokid600]

Did Squad ever say why they got rid of magic boulder? Not like it was a placeholder for anything.. er.. was it?

[Vanamonde]

Are you sure counter-rotating planets are actually impossible, or just extremely unlikely? After all, they've been finding some really weird solar systems lately and are having to fundamentally question our understanding of how solar systems form.

[Rusty6899]

Tex_NL

I don't think it's just Triton. I think the majority of captured asteroids on all of the gas planets tend to have retrograde orbits.

[Tex_NL]

Are you sure counter-rotating planets are actually impossible, or just extremely unlikely? After all, they've been finding some really weird solar systems lately and are having to fundamentally question our understanding of how solar systems form.

I don't think it's impossible but all mathematical models say all 'natural' bodies should rotate the same way.

Uranus has an axial tilt of 97.77° It probably has this extreme tilt due to some extreme collision in the distant past. What if an exo-planet gets knocked over all the way to something like 180°? It would look like it's spinning the other way. Would we be able to see the difference?

Tex_NL

I don't think it's just Triton. I think the majority of captured asteroids on all of the gas planets tend to have retrograde orbits.

Possibly. I don't know.

Triton was just the only one I know for sure that orbits 'the wrong way'

[El Gribbo]

I believe the IAU ends the name of all moons with a retrograde orbit with the letter 'e'. There is a group of moons (more asteroid size really, I think) of Jupiter called the Ananke Group that all end in 'e' and all have retrograde orbits. I think Triton is the only 'moon' sized moon that has a retro orbit. I could be wrong.

[RoboRay]

(SQUAD? Where is the old "DELETE POST" button? Is it ever coming back?)

[Soda Popinski]

I don't see why a captured planet couldn't orbit retrograde. After all, it's believed Jupiter may have ejected plenty of early planets. If one of those made it to Kerbal at the right angle, not only could it orbit retrograde, but at any inclination up to polar.

[Armchair Rocket Scientist]

All right, let's clear this up:

Yes, planets can have retrograde rotation. Venus and Pluto both rotate the "wrong way." In both cases, the backwards rotation may have been caused by a collision.

Moons can have retrograde orbits, though probably only if they are captured bodies. While many moons in are solar system are in retrograde orbits, all of them except Triton are tiny and very far from their parents. Also note that Triton's orbit is unstable; tidal drag will cause it to spiral in and collide with/break up inside the roche limit of Neptune in about a billion years.

There are also a few planets with retrograde orbits, including http://en.wikipedia.org/wiki/WASP-17b. A binary protostar has also been found with part of the protoplanetary disc rotating in the opposite direction of the other part: http://en.wikipedia.org/wiki/IRAS_16293-2422