Questions tagged [moons]

Questions about celestial bodies that orbit another celestial body.

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20 votes
1 answer
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If colonists burrowed far enough under the ice on Ganymede or Europa, would the ice provide adequate protection for them from Jupiter's radiation?

This is a hypothetical question I'm asking as a SF writer, and the time setting would be approximately 2,250 AD.
Mike Ackerman's user avatar
5 votes
1 answer
184 views

How is salt transported from the subsurface ocean and ejected with the plumes of water from Enceladus?

My limited understanding is that the plumes of water vapor and ice seen rising nearly vertically from the ice surfaces of Enceladus and other ice/water covered moons of Jupiter and Saturn are not ...
uhoh's user avatar
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9 votes
1 answer
265 views

Which moon is best? (for gravity assists)

Inspired by my answer to Is a ballistic Jovian capture using the Galilean moons possible from interplanetary entry? in which I discovered that Callisto offers a stronger gravity assist than Ganymede ...
BrendanLuke15's user avatar
9 votes
3 answers
779 views

Did the spacecrafts Galileo or Juno use the Galilean moons for a gravity assist before entering Jovian orbit?

Galileo and Juno are the only two spacecraft to have entered orbit around Jupiter. Did either of them use one of the Galilean moons for a gravity brake before in order to enter a stable orbit around ...
Jonathan L.'s user avatar
5 votes
1 answer
838 views

Do Lagrange-like regions temporarily appear around planets with multiple moons?

Lasting Lagrange points only exist where two bodies of mass dominate. But in the midst of for example the synchronous Jovian moons, is there a calendar and map for when a spacecraft can be near enough ...
LocalFluff's user avatar
5 votes
3 answers
348 views

Has any other term been used for a solar day on a solar system body besides "sol" on Mars?

My interest was piqued by this question and answer. For several reasons NASA needed to refer frequently and extensively to a Martian solar day, and "sol" became the nom du jour. There have been ...
uhoh's user avatar
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4 votes
1 answer
1k views

Why are most of Jupiter's moons retrograde?

Jupiter's small moons are likely captured objects. I would've expected half of them to be captured in retrograde orbit, between 90 and 180 degrees inclination. But out of 65 lesser satellites, only 11 ...
LocalFluff's user avatar
23 votes
5 answers
6k views

Can a moon orbit its planet faster than its planet rotates?

Can a moon orbit its planet faster than its planet rotates? Can a moon orbit its planet more than once per the planet's day? It seems possible but I'm not sure. Are there any known examples of this ...
user38319's user avatar
  • 255
12 votes
2 answers
13k views

Would it be possible to "fall off" Phobos? [closed]

Phobos (one of Mars' moons) has the following dimensions: 27 × 22 × 18 km. It has low mass, and little or no gravity/atmosphere. Let's just assume that it's possible to walk around on Phobos without ...
Thousand's user avatar
  • 231
10 votes
5 answers
4k views

Pluto's satellites other than Charon orbits around Pluto or center of gravity between Pluto and Charon?

As the center of gravity between Pluto and Charon is outside Pluto does Pluto's satellites other than Charon such as Nix, Hydra, Kerberos or Styx orbits around Pluto or the COG?
Uday Shankar's user avatar
7 votes
0 answers
142 views

Why couldn't New Horizons try again to search for small moons of Pluto?

I was reading Alan Stern and David Grinspoon's Chasing New Horizons, the story of the quarter-century effort to prepare, enable, and run New Horizons' mission to Pluto. As many readers know, it ...
Oscar Lanzi's user avatar
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7 votes
2 answers
1k views

Would a Foucault pendulum work on the Moon and on the Galilean moons?

I wonder whether the Moon and the Jovian moons spin fast enough for a Foucault pendulum to swing on their poles. For instance, I think that it wouldn't swing on Mercury and Venus because these planets ...
LoveForChrist's user avatar
6 votes
1 answer
2k views

Are there any natural circular orbits?

I just saw How does orbital eccentricity affect positions of Lagrange points $L_4$ and $L_5$? and it questions the difference between circular and elliptical orbits. We know the Moon does not have a ...
James Jenkins's user avatar
4 votes
3 answers
1k views

Data for Moons in the Solar System with Masses

I'm looking for a simple machine-readable table with basic parameters for all the known moons of the planets in the solar system. Stumbling around the internet, I can find plenty of sources like this ...
AlanSE's user avatar
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4 votes
0 answers
120 views

Just how locked is Titan? Does it exhibit libration due to eccentricity? Have residual oscillations not yet damped out been detected or ruled out?

Under Where is the Selk crater on Titan with respect to Saturn? there is @BrendanLuke15's comment which provides a helpful hint: Tidally locked moons have their 0° longitude defined as the 'sub-...
uhoh's user avatar
  • 149k
2 votes
1 answer
162 views

Bombing the Moon: how much debris would there be in stable orbit?

If someone had actually nuked the Moon (e.g. here or Bombing Moon and Mars: What would it look like? ), what's the probability of some debris reaching a stable orbit around the Moon? This would not ...
Everyday Astronaut's user avatar
0 votes
2 answers
327 views

How big a nuke would be needed to break Phobos out of orbit?

Phobos Radius: 11.267 km Orbital period: 8 hours Equatorial rotation velocity: 11.0 km/h (6.8 mph) (at longest axis) With an 8 hour orbit around Mars it must be going at a fair clip already which ...
Pelinore's user avatar
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