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Questions tagged [natural-satellites]

Questions on celestial bodies that orbit planets.

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2 answers
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Can individual rings of Saturn be considered satellites?

By this definition, is every small rock orbiting Saturn considered a natural satellites? What is the widely accepted terminology for moons? The Wikipedia article is ambiguous on this. So, what terms ...
EMS's user avatar
  • 103
2 votes
2 answers
114 views

What exactly was "The curse of Sisyphus" and why did it take so long to find out about the radar detection of its companion?

This answer to First satellite of an asteroid (or double asteroid) ever imaged by delay-Doppler radar? mentions that Wikipedia's 1866 Sisyphus; Binary system says: In 1985, this object was detected ...
uhoh's user avatar
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4 votes
0 answers
96 views

What are the odds of a planet with an eclipse every time the moon rotated around the planet?

If the orbital plane of a planet and its moon were sufficiently aligned, the moon could cause a solar eclipse every lunar month. What are the odds of that happening? To answer, I would guess that one ...
user121330's user avatar
3 votes
0 answers
123 views

Two Suns vs Two moons in the Sky

How rare is it to have 2 stars or 2 celestial bodies at least as big as our moon and sun in the sky of a habitable planet? What are the chances of both?
Justintimeforfun's user avatar
2 votes
0 answers
88 views

Simple position calculation of solar system satellites

I'm looking for a simple way to calculate positions of satellites in the ecliptic of the date. I've found an implementation for Jupiters satellites in the Astronomical Algorithms by Jean Meeus, and I'...
someCO_OLguy's user avatar
5 votes
3 answers
196 views

Why are there gaps in the size distribution of solar system moons?

Looking at the moons natural satellites in the solar system, the larger ones appear to fall in a few groups of sizes. Eyeballing the above picture, there appear to be a bunch of big moons (the ...
JanKanis's user avatar
  • 571
1 vote
1 answer
80 views

Natural satellites sorted by albedo

Can I find a list of natural satellites of the Solar System with the average albedo for each one ? Enceladus, for instance has an albedo of 0.81 and Triton has an albedo of 0.76. But has someone ...
usernumber's user avatar
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3 votes
1 answer
260 views

Are there any estimates of the Roche Limit for 152830 Dinkinesh?

The Lucy spacecraft recently flew past the asteroid 152830 Dinkinesh on its way through the asteroid belt and photos show that Dinkinesh has a moon consisting of a contact binary. (Image is Public ...
Dave Gremlin's user avatar
  • 1,071
26 votes
6 answers
6k views

Definition of a moon in an exam: "A satellite of a planet that *doesn't produce light itself but reflects it*" - is there relevance for the emphasis?

In a 5th-grade exam (for 10-11-year-old pupils in Finland), there was a question, "What is a moon?" The model answer was: "A satellite of a planet that doesn't produce light itself but ...
tputkonen's user avatar
  • 369
12 votes
3 answers
5k views

If the Earth had another moon would it be better protected from asteroids?

Would the moons get struck by asteroids instead of the Earth or would the moons attract more asteroids and make it more likely the planet gets hit?
user avatar
1 vote
0 answers
92 views

Why Saturn has more Moons than Jupiter? [duplicate]

Why does Saturn have more moons than Jupiter, I know the grand tack hypothesis suggests Jupiter migrated from 3.5 au to present orbit but given that Jupitern is more massive meaning a larger ...
Arjun's user avatar
  • 1,464
5 votes
1 answer
265 views

Will Lunar Months be the same length Millions of Years in the Future?

If I remember correctly, the amount of time it takes for the moon to rotate around Earth is getting longer over time. Is this true, and if so or the opposite is true and a lunar month is getting ...
Dromeoraptor pennato's user avatar
1 vote
1 answer
208 views

Determining the position of the North Node using math?

I have to be honest. Been learning python for few months but when I saw this code I was blown away, mainly by its simplicity and secondly by not understanding it .. can someone help me understand ...
dimitri33's user avatar
  • 167
1 vote
0 answers
53 views

Question regarding potential moon sizes

I am planning out ideas for a science-fiction world, and I want to make sure that what I include is reasonable and mathematically sound (outside of things like FTL as that is neccessary for the story ...
DanceroftheStars's user avatar
3 votes
2 answers
111 views

Could a super Jovian planet have mild radiation belts?

Will a large gas giant always have powerful radiation belts or could a milder radiation environment exist even around super Jovian planets? I know Jupiter’s radiation belts are so strong due to a ...
Elhammo's user avatar
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2 votes
1 answer
74 views

What secondary and tertiary conclusions can be drawn from the temperature characteristics of lunar soil sent by ISRO Chandrayaan 3?

ISRO Chandrayaan 3 released the following data today about the temperature characteristics of lunar soil. What secondary and tertiary conclusions can be drawn it? More specifically, what may be the ...
Ritesh Singh's user avatar
0 votes
0 answers
49 views

Is there a minimum size for a moon? [duplicate]

Is there a minimum size for a moon? Is there a lower bound below which it's simply considered as being a rock? Or could you can every piece of rock and Ice in Saturns rings as an individual moon.
blademan9999's user avatar
3 votes
3 answers
234 views

Will all satellites get inevitably tidally locked to their planet?

Are there cases or conditions in which an object orbiting another one (e.g. a satellite and its planet) does not get tidally locked to it? For example, in this question, it is mentioned that a large ...
vengaq's user avatar
  • 937
2 votes
1 answer
152 views

Could there be bacteria in the 6000 km water jet of Saturn's moon discovered by the James Webb telescope?

James Webb telescope discovers gargantuan geyser on Saturn's moon, blasting water hundreds of miles into space. If there is life inside the moon Enceladus perhaps now it is airborne. Could water carry ...
user avatar
4 votes
1 answer
151 views

What moons have cleared their orbits?

The Wikipedia article Clearing the Neighborhood lists three numeric parameters that can be calculated for bodies orbiting the Sun as a way to indicate orbital dominance: Stern and Levinson's $\Lambda$,...
Mark Foskey's user avatar
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19 votes
3 answers
6k views

Is it possible to have satellites (natural or not) orbit the same celestial object in different directions ? (clockwise, counterclockwise)

Is it possible to have satellites (natural or not) orbit the same celestial object in different directions, or is the orbital direction dependent on the celestial object's spin? Also, is the direction ...
Demis's user avatar
  • 883
0 votes
1 answer
99 views

In Jovian and Saturnian moons with subsurface oceans, why doesn't the surface sink?

The surface of some of the Jovian and Saturnian moons for which subsurface oceans have been proposed contains materials denser than water like rock. What keeps the surface from sinking under the ...
kYuZz's user avatar
  • 169
2 votes
2 answers
2k views

What kind of effects would two moons have on an earthlike planet?

On Earth our moon has several effects: it generates two high and two low tides a day; it slows down the spin of the planet and stabilizes its wobble, etc. So, what possible effects could two moons, ...
CuriousExplorer's user avatar
2 votes
1 answer
73 views

How close does a double-planet have to be to provide magnetic protection to a smaller body?

A spinoff of my previous question, regarding the Orbital Stability of a Double Planet System. Imagine two closely-orbiting bodies with a semi-major axis of 79,250 km. One of which is 2M🜨, with a ...
Thoth's user avatar
  • 181
3 votes
1 answer
197 views

Orbital Stability of a Double Planet System

I recently found an article claiming a double planet system needs to be at least .5 AU from its parent star to be stable for billions of years. It was specifically talking about two same-mass bodies, ...
Thoth's user avatar
  • 181
5 votes
1 answer
140 views

What are these bumps on Europa?

The surface of Europa is famous for all the criss-cross lines thought to be cracks in the ice above a water ocean that somehow re-freeze. But in the photo below I also see a lot of raised "bumps&...
uhoh's user avatar
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9 votes
2 answers
3k views

How would ocean tides work on a tidally-locked planet?

Since the tidal bulge is always in the same place, how would that affect ocean tides? Would they change throughout an elliptical orbit, due to changing distance from the star? How exactly would they ...
Elhammo's user avatar
  • 1,107
1 vote
0 answers
134 views

What is the brightness and size of Jupiter from the Galilean moons, the closest moon, and the farthest moon?

From the Moon, Earth would appear 4 times larger than the Moon seen from Earth, and the magnitude of a "full earth" is around -17. However, Jupiter from the Galilean moons appear much larger ...
InfinitySwordofDiamond's user avatar
2 votes
0 answers
77 views

If Ganymede had a thick, Earth-like atmosphere, would the surface be protected from Jupiter's intense radiation?

Obviously, this is a totally hypothetical, alternate version of Ganymede, since it would also need to have more mass and a stronger intrinsic magnetic field to hold onto a substantial atmosphere. But ...
Elhammo's user avatar
  • 1,107
34 votes
1 answer
6k views

Why do Jupiter’s moons have so much water?

Why do Jupiter’s moons have so much water by mass? Did all the bodies in the solar system start out with this much water and the planets closer to the Sun simply lost it to space?
Elhammo's user avatar
  • 1,107
2 votes
0 answers
77 views

Besides Luna, are there any models of how moons become spherical and round?

Question Given the theorized exceptional formation of Luna, (Giant-impact Hyphothesis, Wikipedia), are there any similar animated models of how the other, much smaller, moons in our solar system ...
elika kohen's user avatar
2 votes
2 answers
332 views

What would be 1 hour equivalent on these moons of Jupiter and Saturn compared to earth? And their astrobiological implications

Considering the distance from and velocity of Sun, Saturn, Jupiter, thermal energy due to motion other than that adding/combining to velocity, and the individual mass and velocity of the particular ...
Lumbini Ashutosh Tambat's user avatar
6 votes
1 answer
64 views

Does a more massive main proto-body result in more massive satellites? More satellites?

Suppose that we have a forming protostar and an accompanying protoplanetary disk. Does the mass of the protostar have any direct relation to the masses of resulting planets or amount of resulting ...
Max0815's user avatar
  • 1,862
4 votes
1 answer
270 views

If you were standing on a habitable moon of a gas giant, what would the planet look like during the day vs the night? [closed]

If you were standing on the proplanetary side of a habitable moon of a gas giant, and the moon had a thick enough atmosphere to make the sky blue, how would the gas giant look during the day? Would it ...
Elhammo's user avatar
  • 1,107
4 votes
2 answers
204 views

Are there areas within Jupiter's magnetosphere without powerful radiation?

I know Jupiter has powerful radiation belts, but I'm wondering if there are places within the magnetosphere that are relatively calm. I'm asking about Jupiter (a gas giant we know) because I'm curious ...
Elhammo's user avatar
  • 1,107
8 votes
2 answers
3k views

The moon rises at a different time each day, but that difference changes. Why?

Let's say the moon rose at 5pm yesterday and 5:30pm today. The difference is 30 minutes – but that difference changes from day to day and can be anywhere between twenty-some to seventy-some minutes. ...
Treplef's user avatar
  • 81
4 votes
3 answers
156 views

Orbital terminology for satellites relative to one another

Basic question, but I'm trying to describe a planetary system and coming up short on vocabulary. Do either of the following exist?: A word for the closest pass between two satellites orbiting the ...
the-baby-is-you's user avatar
6 votes
1 answer
167 views

Is there a reason Tethys and Dione are the only moons known to have trojans?

Trojans have been found at the L4 and L5 points of most planets. However Tethys and Dione, both moons of Saturn, are the only known moons in the Solar System to have trojans of their own. Is this just ...
user177107's user avatar
  • 2,689
4 votes
2 answers
207 views

Is the satellite of a small star in a binary solar system a moon or a planet?

What exaclty distinguishes a moon from a planet? In a binary solar system that has a large star in the center and a smaller star - among some planets - orbiting that large star, and the smaller star ...
matthias_buehlmann's user avatar
9 votes
3 answers
3k views

Why don't we find planetoids at L4/L5?

We find small objects (asteroids and dust) in the stable Lagrange points (L4 and L5), but AFAIK no moons (by which I mean a mass that accreted into a body, as opposed to debris that has been captured ...
feetwet's user avatar
  • 390
1 vote
0 answers
50 views

Why does Titan's (relatively) rapid migration away from Saturn cause the planet to wobble faster, and eventually (maybe) tip onto its side?

Over the past year and a half, multiple articles in the popular press have come out talking about how unexpectedly rapidly Titan is moving away from Saturn, and how this is causing Saturn to wobble ...
Kurt Hikes's user avatar
  • 5,097
4 votes
1 answer
166 views

Is it possible to have a positive rational number of months (more than 1) in a year?

It is possible for a planet to have orbital resonance with a sun (e.g. Mercury has a 3:2 spin resonance with the sun). It is also possible for a moon to have orbital resonance with a planet (e.g. our ...
Daniel-耶稣活着's user avatar
3 votes
2 answers
263 views

Why doesn't Triton orbit over Neptune's equator?

In this answer, I wrote (on another account) why most moons orbit over their planet's equator. Any rotating planet has an equatorial bulge that shifts its moons' orbits around its equator over long ...
user177107's user avatar
  • 2,689
0 votes
1 answer
295 views

What are the most efficient ways to terraform Neptune's moon Triton? [closed]

I have seen on various sites and on youtube videos pertaining to the terraform of various planets and moons that are not habitable for now but they can be habitable in near future. What are the ways ...
saurabh shukla's user avatar
6 votes
1 answer
619 views

Are satellites of trans-Neptunian objects classified as trans-Neptunian objects?

I can't seem to get a consistent answer regarding the question of whether or not satellites (moons) of trans-Neptunian objects are considered to be trans-Neptunian objects, given that they do not ...
Mark Morales II's user avatar
2 votes
1 answer
124 views

Jupiter's asteroid-like moons and planetary-systems around sub-brown dwarfs

Is it likely that any of Jupiter's small moons were formed in orbit around Jupiter or are they all captured asteroids? I thought of this question because I wondered whether the planetary-system of a ...
sno's user avatar
  • 1,456
1 vote
1 answer
127 views

Can a terrestrial planet orbit an icy planet (or vice versa)?

I know that the composition of planets is dependant on the equilibrium temperature at its orbit - for example, if below a certain temperature, water and other volatiles become solid, allowing them to ...
Ale Kid's user avatar
  • 31
1 vote
0 answers
38 views

How to determine how often a planet's center will be collinear with its moon's?

Expanding on the question: Let's say I have a planet orbiting some star (earth-like, sun-like, for the sake of example). If this planet has two moons, M1 with orbital period of 30 earth-days and M2 ...
PedroGaya's user avatar
25 votes
3 answers
3k views

Why is there a mountain inside the Herschel crater on Mimas?

If the Herschel crater was caused by an impact, why does it have a mountain at its very center, its peak up to 5 mi (8 km) in elevation?
John's user avatar
  • 1,538
2 votes
1 answer
72 views

Has the rotation of Eris and Dysnomia been observed?

Since both Eris and Dysnomia have been captured on a single image, is it possible to shoot multiple images of them to see how they rotate around each other? Has this been attempted? We don't know much ...
John's user avatar
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