do you like the solar system

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The solar system needs more M class planets...

I guess we both misunderstood the tone of our initial posts. Anyway, there is a difference between our concepts of the term orbit and also between our approaches to astronomy. That's ok.

I never see an argument as something to win or to lose but as something where both parties can get some understanding of the other's point of view. In this matter, this argument has been useful (to me, at least).
(Has the word "argument" a bad connotation? Is the word "discussion" more appropriate?)

I tried to keep a friendly tone throughout the discussion but I'm sorry if I sounded condescending somewhere.

See you around.

Actually, I spent a few hours, this morning, researching (through Wikipedia) all the terms.

You may find "halo orbit" worth looking up, for a orbit that does not enclose anything at all.

The term "planet" is still contentious, and there is no consensus at all on "moon". Even the distinction of "planet/moon" from "double planet" isn't happy. I thought the idea of the barycentre lying inside the larger body sounded good, except when I saw it pointed out to be a bit of a pain, as it would be extremely difficult to determine for most remote bodies.

Another rather interesting thought comes from our Moon - which actually follows an elliptical orbit around the sun. It is only slightly(?) perturbed by the presence of the Earth from being in a pure ellipse. I think I read at one point that it is the only moon in the solar system that does not indulge in retrograde motion about the sun.

Currently, there are no satellites of satellites known in the solar system. I suspect that's because any form of stability pretty much requires a large mass-to-mass ratio, and here, there's no planet big enough to have a big enough moon to have it's own moons (although it would appear that Rhea has rings, which isn't far off - give them more time to accrete, and who knows!).

I do believe that where the barycentre lies is in fact the determining factor, though...


That may be due to the formation of Earth's moon being different than how most other moons became moons. See Giant Impact Hypothesis for more. If i remember, most gas giants probably acquired their moons through gravitational capture, while the Earth's was formed by a large body hitting it (such that the Earth-Moon system formed together and thus are fundamentally different than most of the gas giants' moon systems)


If there was a satellite of a satellite, the first-order satellite would have to be gravitationally powerful enough to overcome the host planet's gravity to maintain the second-order satellite, or else the planet would rip the second level satellite out of its orbit of the first-order satellite, thus turning the second-order satellite into a first-order satellite in and of itself.

While earth's moon is quite remarkable for a terrestrial planet (and moreso for its formation), I don't think most moons were captured. Consider the fact that Ceres is quite puny compared to say Ganymede, Titan, whatever large moon you care to name. I think the Galilean satellites more likely formed with Jupiter. And wikipedia agrees!

It just seems odd to me that the denser substances ended up outside the planet, rather than in the center...

I'm pretty fond of our solar system, yes.

Our solar system is okay, but not if you don't include neptune or uranus!! they are simply put; the best

In all honesty I would prefer to learn about other solar systems more.