Questions tagged [natural-satellites]

Questions on celestial bodies that orbit planets.

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33
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3answers
3k views

Do moons have moons?

Have we discovered any natural satellites of natural satellites of planets or dwarf planets? Even very small, or relatively short-lived - e.g. ringlets around Saturn's moons, some meteorites orbiting ...
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2answers
374 views

When will the next series of mutual eclipses of Jupiter's moons begin?

When I was young (I won't tell you when) I saw one of the four Galilean moons of Jupiter suddenly disappear while watching through a small refractor. It wasn't a coincidence, I'd seen the prediction ...
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4answers
669 views

What exactly is a “moon”?

Recently some new moons of Jupiter were discovered. However the moons are pretty damn small indeed - only a few kilometers wide. That makes me wonder if they should even be called moons in the first ...
6
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2answers
198 views

Is there a timekeeping word for the orbit of a moon?

For a planet, we can colloquially refer to its period of rotation as a "day" and its period of revolution around its parent star as a "year." Some worlds have unique terms, such as Martian days being ...
16
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8answers
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Moon's orbit around the Sun

The Earth revolves around the Sun and the Moon revolves around the Earth. Out of curiosity I started thinking about the orbit of the Moon around the Sun and expected (assumed) it to be as follows: ...
11
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2answers
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How do moons get captured?

A moon-sized object is running loose in the Solar System, perhaps after a planetary collision. As it approaches a planet, it's presumably following an approximately hyperbolic path. If it goes on ...
3
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2answers
146 views

When would we detect a tiny meter size natural satellite in a geostationary orbits?

A natural, tiny (meters-size, maybe 10.000kg mass) natural satellite could be trapped in a geostationary orbit. I wondered for quite some time: When and how are we able to detect these satellites? I ...
23
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6answers
4k views

Can a natural satellite exist in a geostationary orbit?

While browsing through Physics SE, I noticed a question about satellites in geostationary orbit (unrelated to the one I'm asking here), and for a moment I interpreted it as referring to natural ...
4
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1answer
425 views

Could a habitable satellite of a gas giant have a stable subsatellite?

I have set a science fiction story on a moon, orbiting a gas giant (which orbits its star at approximately the same orbit as the Earth around the Sun), and given this moon its own satellites. The ...
9
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2answers
577 views

Why does Saturn have both moons and rings?

From my understanding, a ring can form around a planet when a moon gets too close to its Roche limit, and gets ripped appart by the planet's gravity pull. That makes sense to me, but I don't ...
5
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1answer
443 views

Why are the natural satellites (moons) of all planets solid?

Why are the natural satelites (moons) of all planets - including the moons of the gas giants - solid or rocky, and not gaseous?
18
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4answers
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Jupiter FM - What are practical and inexpensive ways for the amateur detection of signals from Jupiter, especially of the transit of her moons?

What modifications to a standard AM/FM or shortwave radio are needed in order to be able to detect radio-wave signals emitted from Jupiter? Would it be possible to detect the transit of the major ...
13
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2answers
789 views

How can tidal heating lower Io's orbit?

This answer to the question Is Io a magic energy machine? suggests that the energy from the internal heating of Io due to tidal "squishing" as it moves cyclically closer and farther from Jupiter in ...
19
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2answers
582 views

Moon orbits crossing each other

Some planets, such as Mars, have 2 or more moons. Giants, like Jupiter of Saturn have a lot of moons! How likely the orbit of one crosses another one's orbit? Is it possible for two moons to collide? ...
16
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1answer
552 views

Why do planets and satellites in the Solar system look so wildly different if they came from more or less the same matter?

First, the planets. We have Mercury, which is rocky, no atmosphere. But then we have Venus, which is completely different: thick atmosphere, very hot, geologically active. Then Earth - blue, full of ...
21
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3answers
1k views

Will Saturn's rings become a moon?

Planets form from disks of matter orbiting around a star; some moons form from disks of matter orbiting planets. If this were going to happen around Saturn, approximately how much time would it take?
15
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1answer
458 views

Is it possible for a moon to orbit a planet floating free in the galaxy rather than orbiting a star

This article got me thinking, can a planet hold a moon in orbit if it is just floating in the galaxy by itself not as part of a star system? Can a celestial body even qualify as a planet if it is ...
5
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2answers
295 views

What variables are needed to calculate simple horseshoe orbit times?

EDIT This was NOT a duplicate of Horseshoe orbit cycle times. But that other question has been deleted, regardless. My original question asked for the answer to the equation(s), and provides many of ...
3
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1answer
280 views

Can the Moon provide momentum to an object in Earth's orbit? Gravity Assisted Boost [closed]

Can a satellite maintain an equatorial orbit around Earth near the Moon's orbit to receive partial gravitational boosts by gaining momentum as the satellite passes though the Moon's gravity well? I'...
2
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1answer
122 views

Could a binary system of two planets with oceans reflect each other?

If there were two earth-like planets in a binary system and one of them had landmasses, and the other one had oceans covering a significant amount of its surface, could you see the continents of the ...
27
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3answers
4k views

Why don't the inner moons of Jupiter have tidally-induced volcanism?

Volcanism on Io is caused by the fact that it is tidally heated. There are four moons that are closer to Jupiter than Io with higher eccentricities, yet they don't seem to have any volcanism at their ...
15
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3answers
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Would an analogue of the definition for planets also work for moons?

This is a follow up question to What exactly is a "moon"? The conclusions I draw from James K's answer is that the IAU should define what a moon is. They haven't done so yet, but they should. The ...
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3answers
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Can you explain the pattern of Hill sphere sizes of the objects of the Solar system?

I found this image on calculations of Hill sphere for planets/dwarf planets of the Solar system. From http://en.wikipedia.org/wiki/File:Hill_sphere_of_the_planets.png I found it interesting that ...
8
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1answer
493 views

Effect of Charon on Pluto

Even though Pluto is not known as a planet anymore, theroetically it has/had a moon, called Charon. I've heard about something that their size are so close to each other that while Charon rotates ...
6
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2answers
736 views

Has any moon achieved “retrograde equatorial orbit”?

There are many moons which have low (almost negligible) inclination and can be considered to rotate at the planet's equatorial plane. For instance, Galilean moons have almost negligible inclination (&...
4
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2answers
104 views

How to calculate the frequency of a gas giant eclipsing the sun from a moon?

Say you have a moon around a gas giant which goes around a star. If the moon has an inclination of around 0° relative to the gas giant's orbit, the gas giant will eclipse the star every orbit of the ...
4
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1answer
160 views

What would theoretically be dissolved in the interior oceans of icy moons and planets?

I know we have some indication of "what's in the water" from the plumes of Enceladus, but would other places be the same. For instance, could the deep liquid water of Titan contain dissolved ...
4
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1answer
183 views

How would a small TCO (temporarily captured orbiter) or other natural Earth satellite most likely be detected?

A sentence from the abstract of The population of natural Earth satellites states: At any given time there should be at least one NES of 1-meter diameter orbiting the Earth. The average temporarily-...
3
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1answer
269 views

Io: Why so much sulfur?

Io is the only body in the Solar System whose crust is dominated by sulfur and its compounds. Carbon and nitrogen are also very common in the universe but we don't see them or their compounds in Io's ...
3
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1answer
183 views

How massive must a rocky body be to liquify adequately to eliminate internal mass concentrations that could disrupt natural satellite orbits?

Maybe a slightly weird question, and maybe more appropriate for some future geophysics SE, but I feel like this is what questions like Do moons have moons? are really driving at, and it just almost ...
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2answers
72 views

What would a moon with a six-month orbital period look like from the earth?

This is a kind of follow-up question to "What orbital period would produce one New Moon (and one Full Moon) each year?" Given the six-month orbital period that is needed to produce one New ...
2
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1answer
99 views

Can there be a three-moon system where only two are visible most of the time?

I am trying to build a moon system for a sci-fi work in collaboration with my boyfriend. He's the main writer and wants there to be three moons circling the planet in a way that most of the time, only ...
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2answers
78 views

Should only spherical satellites be considered 'moons'? [closed]

Since Titan and Ganymede fall into the same category as Deimos and Phobos or the components of planetary rings, the category of moons, it's like if all asteroids were considered planets. Tiny ...