I'm new to the forum (and will accept any corrections on etiquette).
I'm creating a presentation for my astronomy club on the Nice model of the solar system and want to illustrate the effect of mean motion resonance. I'm having trouble finding a lay person's explanation of how orbits change when two planets enter a mean motion resonance (where the orbits of the planets occur in a ratio of low numbers). E.g., a 2:1 resonance describes a planet that orbits 2 times for every 1 time of the other. The result is that the planets' closest pass occurs at the same orbital position so that over time, the orbits get changed. I've drawn this in the attached illustration and have animated it in the attached link.
But I don't know if the orbits get tugged so the the inner planet's farthest point from the sun is near the
point of resonance or opposite it. I believe the answer is not intuitive in that I've heard that two satellites will tend to move away from each other. And in the case of Pluto and Neptune, Pluto's closest approach to the sun is when Neptune is on the other side. So my question is, assuming the planets in my illustration are shown at their closest pass, 2:1 for the inner two, and 2:1 for the outer two, would the orbits of the inner and outer planets change as shown in the red or blue ellipse for each? (I'm assuming the middle planet is like Jupiter while the others are much less massive) Thank you.
http://www.brightstarstemeculavalley.or ... nance.html
Planetary Orbits and Mean Motion Resonance
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Re: Planetary Orbits and Mean Motion Resonance
I gather that the basic idea is that when the planets line up with the sun, their gravitational tugs on each other "squash" their orbits a little bit. If their orbits aren't nicely synchronized, these tugs happen in different places along the orbit and all more or less cancel each other out. However, if the orbital periods are synchronized just right, e.g. 2:1, then the tugs all happen at the same place in the orbit and eventually destabilize their orbits.
This isn't really a good explanation. You might try asking at a Stack Exchange site, like physics.stackexchange.com.
This isn't really a good explanation. You might try asking at a Stack Exchange site, like physics.stackexchange.com.
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Re: Planetary Orbits and Mean Motion Resonance
You could try playing around with this for intuition.
A Government founded upon justice, and recognizing the equal rights of all men; claiming higher authority for existence, or sanction for its laws, that nature, reason, and the regularly ascertained will of the people; steadily refusing to put its sword and purse in the service of any religious creed or family is a standing offense to most of the Governments of the world, and to some narrow and bigoted people among ourselves.
F. Douglass