New answers tagged moons
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The others before me have written plenty about why and how it's not possible normally due to size and density requirements you have set up as a premise. The only way I can think of to make it possible, is make the planet hollow. As long as the outer shell weighs 100x of earth (for 1g, I calculated), the rest should fit into the math more or less. This raises ...
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Orbits are basically falling to Earth and missing. Earth's moon is about 1/4th that of Earth, and while your planet takes up more space than Earth but has the same gravity, it could be possible that an Earth sized moon could occur. The dwarf planet "Charon" is about the same size as Pluto, the body which it orbits, though like manythings about Pluto, it's ...
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The planet is 10 Earth-Radii, with a 1 Earth Gravity value. It is a habitable planet. It has a thin atmosphere. It also has 3 moons and a ring system.
Apart from the whole "habitable" and "thin atmosphere" thing, you've basically described Saturn. Saturn is ~95x Earth's mass, and 9.5x Earth's radius at its equator. Surface gravity is a bit over 1g, too. ...
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Your planet would have 0.1 x the density of the Earth, i.e. about half the density of water. It might be some kind of weird smallish gas giant with the right chemistry in its atmosphere to support some kind of life, but definitely not a traditional Earthlike habitable planet. It definitely won't fulfil your description of having a thin atmosphere.
Your ...
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Yes it is entirely possible for this situation to occur for a time. However such a situation would probably not be stable long term. Geostationary orbit is well outside of the roche limit for the Earth-Moon system so the Moon should not be disrupted by tidal effects, however the effects on the Earth's tides would be interesting to say the least.
Probably ok ...
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"It depends", as always.
In most plausible situations, you'll find that any moon of a gas giant will be tidally locked to its parent, eg. on a bit of the moon facing the planet, the planet will be in pretty much the same location in the sky at all times. I say "pretty much" because there are effects like libration which I can't fully quantify, but for all ...
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This doesn't work around Sol, at the very least.
You calculated that a mega-Jupiter (13 Mj) would have the right angular diameter at ~49M km, which is right around 1/3rd AU. For it to eclipse the sun (which needs to be 1AU away to have the correct angular diameter) then the mega-Jupiter would need to be orbiting the sun with a semi-major axis of only 2/3rd ...
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I note that astronomical bodies are requested with diameters and distances that give them angular diameters of about 0.5 degrees. An object will have an angular diameter of about 0.5 degrees when it is at distance of about 114.59165 times it's diameter.
The first thing that Overlord - Reinstate Monica should realize is:
The length of seasonal cycles on ...
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I'm pretty sure it can't be done with a gas giant. The problem lies in the stability of the habitable moon's orbit.
An object's orbit around its primary is stable as long as it is within the Hill sphere of the primary (the region dominated by the primary's gravity), while being outside the Roche limit (the distance at which tidal forces will break the ...
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TL;DR: maybe. Orbital stability is pretty borderline, and some fairly unlikely circumstances have to arise to produce something that looks like maybe it will fit your needs. Tidal effects and orbital resonances will mess with the figures below, so they're only approximate
Lets start with a star the size of the sun, putting the orbit of the planet at 1AU. We ...
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the Moon exploded and a planet about the size of Mars appeared
If N'valdir is further away then the moon; but both the earth and N'valdir are caught in a gravity well with the moon. The moon then breaking apart due to tidal forces. That could have left both communities time to wonder if the result has a stable barycenter.
If stable then I would expect the ...
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If the planets are on a collision course, they can't be stopped
Simple physics, really. A planet has mass, and it takes force to move that mass. The more mass, the more force. How much mass does the Earth have? 5.9 * 10^24 kg. Mars is slightly less, 6.4 * 10^23 kg. So if we were to move one of them, we'd have to move the Mars one. The problem is that we don'...
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