<p>The giant planets, particularly Jupiter, are notorious for bringing about changes in eccentricities and inclinations of smaller bodies(asteroids and KBOs). Jupiter, in fact, throws  almost all the objects that come sufficiently close to it, out of the Solar System.<br>
My question is, <em>how?</em>
<br>Gravity is an attractive force and has a negative potential energy associated with it. If it has any role, all gravity must be able to do is <em>reduce</em> the total energy of the small bodies, eventually circularising it-not doing the opposite job!<br>
Also, I can't imagine how the giant planets manage to alter the inclinations of these small objects. Gravity would, of course, pull these small objects towards the giant planets, but again, that's only bringing it closer to the plane of the Solar System, not increasing its inclination<br>
Or have I got it wrong altogether?I would be glad if you could break this down for me.</p>

CC BY-SA 4.0
2022-01-15T14:14:55.990Z
The premise that jupiter only throws out objects is false.  It can do both. It's the main cause for changing long - period comets into short - period ones
planetmaker
CC BY-SA 4.0
2022-01-15T15:37:13.420Z
@planetmaker Well, that's what my professor said. I find it strange too, because I don't understand how this scattering works physically.
Ambica Govind
CC BY-SA 4.0
2022-01-15T22:05:15.493Z
The answer is gravity from multiple sources, primarily the Sun and Jupiter, and nothing else.
David Hammen
CC BY-SA 4.0
2022-01-16T03:41:07.060Z
https://en.wikipedia.org/wiki/Gravity_assist
Keith McClary
CC BY-SA 4.0
2022-01-16T06:03:43.793Z
This is a good starting point: https://astronomy.stackexchange.com/q/28900/35206
Nilay Ghosh
CC BY-SA 4.0
2022-01-31T08:50:57.960Z
My understanding is that this is a consequence of **destabilising orbital resonances**. The gravity of Jupiter may in some cases exert periodic tugs on some asteroids which are in orbital resonance with it, and over time this can compound to throw the asteroid's orbit off course. (Not making this an answer as I'm not an expert.)
YiFan
CC BY-SA 4.0
2022-01-31T08:52:52.860Z
You might want to search online for explanations of the Nice model and planetary migration, for a more detailed explanation of these phenomena. Also, you might want to ask on Physics SE if no answer comes along here as this is essentially a physics question.
YiFan
CC BY-SA 4.0
2022-02-01T10:32:31.757Z
@YiFan Thanks for the suggestion, I'll do that. And yes, I'll read  up more about this.
Ambica Govind
<solar-system><asteroids><planetary-science><kuiper-belt><asteroid-evolution>
How do the giant planets excite the orbits of asteroids?
Ambica Govind
# How do the giant planets excite the orbits of asteroids?

(Asked by: username_0 on 2022-01-15)

The giant planets, particularly Jupiter, are notorious for bringing about changes in eccentricities and inclinations of smaller bodies(asteroids and KBOs). Jupiter, in fact, throws almost all the objects that come sufficiently close to it, out of the Solar System.  
My question is, *how?*
  
Gravity is an attractive force and has a negative potential energy associated with it. If it has any role, all gravity must be able to do is *reduce* the total energy of the small bodies, eventually circularising it-not doing the opposite job!  
Also, I can't imagine how the giant planets manage to alter the inclinations of these small objects. Gravity would, of course, pull these small objects towards the giant planets, but again, that's only bringing it closer to the plane of the Solar System, not increasing its inclination  
Or have I got it wrong altogether?I would be glad if you could break this down for me.

**Tags:** solar-system, asteroids, planetary-science, kuiper-belt, asteroid-evolution

> **Comments:**
> **username_1**: The premise that jupiter only throws out objects is false.  It can do both. It's the main cause for changing long - period comets into short - period ones  
> **username_0**: @username_1 Well, that's what my professor said. I find it strange too, because I don't understand how this scattering works physically.  
> **username_2**: The answer is gravity from multiple sources, primarily the Sun and Jupiter, and nothing else.  
> **username_3**: https://en.wikipedia.org/wiki/Gravity_assist  
> **username_4**: This is a good starting point: https://astronomy.stackexchange.com/q/28900/35206  
> **username_5**: My understanding is that this is a consequence of **destabilising orbital resonances**. The gravity of Jupiter may in some cases exert periodic tugs on some asteroids which are in orbital resonance with it, and over time this can compound to throw the asteroid's orbit off course. (Not making this an answer as I'm not an expert.)  
> **username_5**: You might want to search online for explanations of the Nice model and planetary migration, for a more detailed explanation of these phenomena. Also, you might want to ask on Physics SE if no answer comes along here as this is essentially a physics question.  
> **username_0**: @username_5 Thanks for the suggestion, I'll do that. And yes, I'll read  up more about this.  

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