<p>Orbits are conic sections therefore can be either circular, elliptical, parabolic or hyperbolic. 
Of these 4, only first two form a closed curve under 2 body hypothesis, while the later two extend to infinity.<br>
If you talk about planet,  by definition it has to orbit a star which would require it to have a closed orbit hence circular or elliptical, with respect to the star. For any other kind of orbit the body will just fly away to infinity never to return back.  Infact comets are considered to be parabolic, but in theory they have highly elliptical orbits with their aphelion lying near the edge of the solar system. </p>

<p>But it is possible for a planet to have other kind of orbits if we  consider their motion from a different reference frame such as with respect to another planet. 
So for an inertial frame of reference a planet will have a circular or elliptical orbit, even Pluto. </p>

CC BY-SA 3.0
2015-12-21T10:40:53.183Z
2015-12-21T10:40:53.183Z
Astroynamicist
<p>Certainly.</p>

<p>But you'd have to think in Einsteinian, rather than Newtonian, terms. Inertial frames of reference and all.</p>

<p>If you view our planet as motionless, then the orbit of Venus, for instance, would resemble a telephone coil cord.</p>

CC BY-SA 3.0
2015-12-21T10:45:10.333Z
2015-12-21T10:45:10.333Z
Ricky
<p>Can planets have orbits other than elliptical or circular orbits? All of the planets in our solar system have either a circular orbit or an elliptical orbit (perhaps like Pluto).</p>

CC BY-SA 3.0
2016-01-23T14:22:09.023Z
@LocalFluff that was really quite interesting, and now I am wondering if it is possible to create such interactions using our satellites and if it could serve any practical purposes.
Astroynamicist
CC BY-SA 3.0
2016-01-23T19:21:09.913Z
@Astroynamicist It cannot be created by any human means. Even little Janus has a mass which is a million billion times greater than the space station, and mass is what counts for such orbits. Can't just send any satellite on a special trajectory to achieve that, it is about physically deforming spacetime. If each human created a million personal space stations, they could play with this. Even displacing asteroids or boulders won't do. I think that any practical use of it is locally restricted to the logistics betweens the moons J and E.
LocalFluff
CC BY-SA 3.0
2016-01-24T19:03:44.620Z
@LocalFluff I'd have to agree on the mass limitations, but we can use electromagnests in the same configuration to lower the orbits of space debris. Just a thought.
Astroynamicist
CC BY-SA 3.0
2015-12-21T02:44:39.597Z
See, for example, the [Sitnikov problem](https://en.wikipedia.org/wiki/Sitnikov_problem).
HDE 226868
CC BY-SA 3.0
2015-12-21T08:41:32.187Z
[Janus](http://www.planetary.org/blogs/emily-lakdawalla/2006/janus-epimetheus-swap.html) and Epimetheus, moons of Saturn, have a funny twist to their shared orbit.
LocalFluff
CC BY-SA 3.0
2015-12-21T12:49:21.747Z
@LocalFluff : Woah, that was an interresting read. Thanks for sharing !
Nico
<orbit><planet>
Can planets have orbits other than elliptical or circular orbits?
Austin Phillips
# Can planets have orbits other than elliptical or circular orbits?

(Asked by: username_0 on 2015-12-21)

Can planets have orbits other than elliptical or circular orbits? All of the planets in our solar system have either a circular orbit or an elliptical orbit (perhaps like Pluto).

**Tags:** orbit, planet

> **Comments:**
> **username_3**: See, for example, the [Sitnikov problem](https://en.wikipedia.org/wiki/Sitnikov_problem).  
> **username_2**: [Janus](http://www.planetary.org/blogs/emily-lakdawalla/2006/janus-epimetheus-swap.html) and Epimetheus, moons of Saturn, have a funny twist to their shared orbit.  
> **username_4**: @username_2 : Woah, that was an interresting read. Thanks for sharing !  
> **username_1**: @username_2 that was really quite interesting, and now I am wondering if it is possible to create such interactions using our satellites and if it could serve any practical purposes.  
> **username_2**: @username_1 It cannot be created by any human means. Even little Janus has a mass which is a million billion times greater than the space station, and mass is what counts for such orbits. Can't just send any satellite on a special trajectory to achieve that, it is about physically deforming spacetime. If each human created a million personal space stations, they could play with this. Even displacing asteroids or boulders won't do. I think that any practical use of it is locally restricted to the logistics betweens the moons J and E.  
> **username_1**: @username_2 I'd have to agree on the mass limitations, but we can use electromagnests in the same configuration to lower the orbits of space debris. Just a thought.  

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## 2 answers

### Answer by username_1 on 2015-12-21. Score: 5

Orbits are conic sections therefore can be either circular, elliptical, parabolic or hyperbolic.
Of these 4, only first two form a closed curve under 2 body hypothesis, while the later two extend to infinity.  
If you talk about planet, by definition it has to orbit a star which would require it to have a closed orbit hence circular or elliptical, with respect to the star. For any other kind of orbit the body will just fly away to infinity never to return back. Infact comets are considered to be parabolic, but in theory they have highly elliptical orbits with their aphelion lying near the edge of the solar system.

But it is possible for a planet to have other kind of orbits if we consider their motion from a different reference frame such as with respect to another planet.
So for an inertial frame of reference a planet will have a circular or elliptical orbit, even Pluto.


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### Answer by username_5 on 2015-12-21. Score: -2

Certainly.

But you'd have to think in Einsteinian, rather than Newtonian, terms. Inertial frames of reference and all.

If you view our planet as motionless, then the orbit of Venus, for instance, would resemble a telephone coil cord.


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