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JV
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Are there any moons in our solar system that have moons?
Or is this not possible, due to instability?
Or is this not possible, due to instability?
JV said:Are there any moons in our solar system that have moons?
Or is this not possible, due to instability?
I guess it depends on our definition of "Moon". There are two asteroids that have their own small moons which I think was considered unlikely until discovery. Ida is a biggie with its own moon. See: http://www.windows.ucar.edu/tour/link=/headline_universe/Eugenia_moon.htmlJV said:Are there any moons in our solar system that have moons?
Or is this not possible, due to instability?
Yes, if an object were in a moon's Hill sphere, it could orbit stabally. But the Hill spheres for moons are very small because of their close proximity to a planet. And Hill spheres can change size as moons' orbits change size and shape over long time periods. So over a long time period moons will likely lose their moons. So I don't think it's just a coincidence that our solar system's moons are moonless. Also, its unlikely that a moon of a moon could even form in such a small Hill sphere.JV said:So it is no problem for a satellite to orbit the moon (stable), as long as it is close enough in the "Hill Sphere".
Apparently it is just a coincidence that there is no example of a moon orbitting a moon in our solar system. At least the chance of it happening was just small, but it is their. Am I right?
From a JPL news release today it seems that moons do have moons:tony873004 said:Yes, if an object were in a moon's Hill sphere, it could orbit stabally. But the Hill spheres for moons are very small because of their close proximity to a planet. And Hill spheres can change size as moons' orbits change size and shape over long time periods. So over a long time period moons will likely lose their moons. So I don't think it's just a coincidence that our solar system's moons are moonless. Also, its unlikely that a moon of a moon could even form in such a small Hill sphere.
I'd bet that in a hundred years from now, when we have millions of other solar systems mapped out, that we will find a few examples.
Just my guesses...
Another discovery was a tiny moon, about 5 kilometers (3 miles) across, recently named Polydeuces. Polydeuces is a companion, or “Trojan” moon of Dione. Trojan moons are found near gravitationally stable points ahead or behind a larger moon. Saturn is the only planet known to have moons with companion Trojan moons.
But at least it qualifies as a "companion" moon to a moon.Garth said:No. Polydeuces is orbiting Saturn roughly in Dione's orbit, in a 'teardrop orbit' (seen in the co-rotating frame) around the L4 or L5 Langrangian positions 600 ahead or behind Dione, or even in a 'horse-shoe orbit' (seen in the co-rotating frame) around both and centred on the L1 position 1800 from Dione.
Garth
A "moon with a moon" is a hypothetical satellite that orbits a moon, similar to how a moon orbits a planet. It is also known as a "moonmoon" or "submoon." This phenomenon has not yet been observed in our solar system, but it is possible in certain conditions.
It is believed that "moons with moons" can form through a process called "capture." This occurs when a smaller object, such as a passing asteroid or comet, is caught in the gravitational pull of a larger moon. Over time, the captured object can settle into a stable orbit around the moon, becoming a "moon with a moon."
A "moon with a moon" can have several potential effects on its host moon. It can cause tidal heating, which can lead to geological activity and possibly even the formation of a subsurface ocean. It can also affect the moon's rotation and orbital patterns, and may even cause the moon to eventually break apart.
As of now, there are no confirmed "moons with moons" in our solar system. However, there are several candidates that are being studied, such as Saturn's moons Titan and Iapetus, and Jupiter's moon Ganymede.
It is possible that a "moon with a moon" could support life, depending on various factors such as the composition of the moon and its submoon, distance from the host planet, and presence of liquid water. However, more research is needed to determine the potential habitability of these objects.