Questions tagged [natural-satellites]

Questions on celestial bodies that orbit planets.

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3
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33 views

Would magnetic reversals on Ganymede affect radiation levels at the surface?

Currently the intrinsic magnetic field of Ganymede is anti-aligned with respect to the Jovian magnetic field. If this situation changed to become aligned, either due to magnetic reversals of the ...
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Help identifying a very slow-moving object during meteor shower photography

I just wonder if anyone could shed any light on this puzzle. Two nights ago whilst I was out photographing the Lyrids meteor shower from the UK something else showed up on my images when I checked ...
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1answer
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Brightness, altitude & azimuth for satellites?

I'm using the heavens-above website to identify a satellite I've seen several nights this week. The question is related to how I can search the satellites table with the information I can provide. ...
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Is the process responsible for Triton's nearly perfect circular orbit going to happen in my fictional world?

First of all, I'd like to point out that I'm a worldbuilder and I like my worlds to be as physically possible as... possible. I am in the process of building a world with a habitable moon orbiting ...
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27 views

New temporary moon of earth [duplicate]

A new temporary moon named 2020 cd3 has been discovered. How can we determine that this is temporary and why does it have such an orbit which is such irregular in shape ?
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What is the precise definition of a moon? [duplicate]

With the recent discovery of Saturn's 20 new moons (elevating its position on the rank of planets with the greatest amount of moons, surpassing Jupiter), it makes me wonder: what are the requirements ...
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669 views

Up to 384 minor planets (including Pluto) qualify as planets?

In 2006, the International Astronomical Union redefined the definition of planet in order to exclude Pluto, Eris, and several other objects whose category was disputed. This new definition of a planet ...
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What's the first written record of the moon being tidally locked to the earth?

I couldn't find references as to who first noticed (wrote down) that the moon was tidally locked to the Earth. This, to me, doesn't seem obvious from first glance, and looks like something only found ...
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Is Earth's moon the only one where a total eclipse of the sun covers the entire sun?

Is Earth's moon the only one where a total eclipse of the sun covers the entire sun? Are any other moons the same size as the sun as viewed from their planet like Earth's moon?
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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 ...
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1answer
117 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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1answer
129 views

Why is Io's volcanism chemically so different from Earth's?

Volcanic gases on Earth are mainly water, carbon dioxide and sulfur dioxide, but on Io there is a notable absence of water and carbon dioxide in volcanic gases, since sulfur dioxide is the dominant ...
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1answer
60 views

How long do solar eclipses last on Metis?

How long does Jupiter obscure the sun, from the perspective of Metis, the innermost moon of Jupiter? In other words, how long does Metis remain in the shadow of Jupiter? If it varies by time of year,...
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173 views

Would it be possible for life found on moon of rogue planet

I have heard that there are at least three Basic requirement for life exist in the universe, they are: Source of Energy Complex chemistry (including solvent/medium for chemical reaction) Protection ...
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191 views

What is the difference between a moon and a random chunk in the rings

Jupiter has 79 (known) moons, Saturn 82, Uranus 27 and Neptune 14 (numbers come from Wikipedia). These planets also all have rings. The rings are made up of chunks of rock and ice. There also are ...
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1answer
116 views

What do you call it when a satellite goes once around its planet?

When a planet or a satellite turns around itself, its called a rotation. When a planet goes once around the Sun, it's called a revolution. What do you call it when a satellite goes once around its ...
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147 views

Tallest cliffs, by falling duration

If you threw something over a certain cliff on a moon of Uranus, it would take over ten minutes to hit bottom. By this measure, local fall time rather than absolute height, what are the near ...
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3answers
244 views

Could a Jovian or Saturnian moon keep its atmosphere if the system was within the habitable zone?

Currently the atmosphere of Titan is 1.5x thicker than Earth's atmosphere, but it's also much much colder. It's been said that an astronomical body can keep it's atmosphere if the escape velocity is ...
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358 views

Why does Titan have an atmosphere while similar moons such as the Galilean moons don't?

The Galilean moons of Jupiter are similar in size to Titan and are also protected by their parent planet's magnetic field. How come only Titan is able to maintain an atmosphere?
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When was it realised that most major moons orbit in the equatorial plane of their parent planets?

Inspired by the discussion of the moons of Uranus providing a clue to the planet's axis of rotation in this question, I'm wondering when it was realised that the major satellites are typically located ...
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Speed of Moonrise relative to fixed point on ground

Due to the curvature of the earth, and the way the moon interacts with the atmosphere (especially close to the horizon), is there a known function that describes the speed of the moon relative to its ...
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1answer
160 views

How do a planet's moons and a planet's rings interact?

I am making a video game which features a planet and its moon. And I thought I would add rings too. But that got me wondering... how do a planet's moon and a planet's ring influence each other? Does ...
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1answer
259 views

Are all satellites thought to be the result of collisions with the planets?

The leading hypothesis for how the Moon was formed was that another object collided with the Earth, throwing off a large lump of matter which formed into the moon. Is this thought to be the case with ...
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3answers
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What orbit is the smallest or takes the least time to complete?

What orbit in our solar system would take the least time to perform 1 orbit? What is the fastest possible orbit to complete in the universe?
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1answer
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Various moon orbits

Orbits can follow certain patterns, as I am aware. Some include a circular orbit around the bulk of the planet, a polar orbit spinning about the pole... What I'd like to know, for a planet with two ...
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1answer
845 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 ...
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160 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 ...
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109 views

Could there be additional Neptunian satellites between Larissa and Hippocamp?

Plotting the moons of Neptune in terms of semimajor axis and eccentricity using the values given on the Wikipedia page for the moons of Neptune, there appears to be a fairly large gap between the ...
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Is there any known moon of a moon? [duplicate]

As far as I understand, a moon is an object in permanent orbit around a planet, dwarf-planet, asteroid, etc. If there was another object permanently orbiting this moon, would that be a moon-moon? Is ...
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1answer
103 views

How was Cruithne's orbital time calculated?

How was it determined that Cruithne takes 770 years to complete its cycle with Earth? Janus and Epimetheus were disovered long enough ago, and have short enough cycle times, that we've had time to ...
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1answer
2k views

Which Saturn satellite passes closest to Saturn's rings and at what distance?

I was using Stellarium to watch Saturn from its moon Pan and I saw the rings were very close to this moon. Now Saturn's rings extend for a large distance so several moons see them from close. I was ...
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364 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 ...
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319 views

Why is Uranus able to support a regular satellite system?

Uranus has an obliquity of 98° which means that the mutual inclination between a satellite orbiting in its equatorial plane and the orbit of Uranus around the Sun would exceed the critical angle for ...
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632 views

How long is a "lunar month" in Jupiter?

For Earth, the lunar month is well known. But Earth has only one moon. But on Jupiter, how long does it takes for the same moon configuration to appear in the "sky" of the planet? For the sake of ...
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1answer
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How do they measure sub-centimeter wave height on a moon of Saturn?

Michael Stevens from V-Sauce has a video called The Mandelbrot Set on a different channel. At 12:56 he says: There’s a moon of Saturn that has liquid hydrocarbon ...
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1answer
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Can a moon have a moon? [duplicate]

Is it possible for a natural moon to have a natural moon? What is the limit to when satellites on satellites becomes to unnatural for it to be possible?
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Moons of migrated giant planets: Icy, Rocky, or none at all?

My understanding is that gas and ice giants form outside the "snow line" of their protoplanetary disk, then sometimes through gravitational interactions they are able to migrate into the inner star ...
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334 views

Natural satellites for Mercury

Would it be possible that Mercury had a natural satellite but the gravitational pull from the Sun became so overwhelming from it growing over the years that it just sucked in Mercury's moon?
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1answer
472 views

How many moons in the solar system have water?

I've heard of a few moons in the solar system that have water, like europa and enceladus. However, I can't find information about whether there are other moons as well. I'm guessing there are more, ...
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1answer
392 views

Is there enough light to grow plants in the ocean of Europa?

What is the underwater temperature of Europa? I know Jupiter emits infrared light but does it emit any light able to support plant life of any type on near by Moons? Can under water volcanic activity ...
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1answer
192 views

Why haven't more captured small moons been found?

Shouldn't captured moons have the same size distribution as asteroids? And asteroids are more common the smaller size they are. Moons are likely captured if they are in highly inclined orbits, and ...
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2answers
433 views

What is the minimum size to be a natural satellite?

Would a smaller satellite be more stable around a smaller planet where the same satellite would not be stable or last around a larger planet? I added the picture to show how moon size planets can ...
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Could a moon be passed from one planet's orbit to another?

Like if you had two planets that had a close orbital path could the moon be pulled away from the first planet?
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93 views

How far from the Sun can an Earth TCO (temporarily captured orbiter) go after leaving?

Objects which are temporarily captured into an Earth-Moon system orbit (temporarily captured orbiters or TCOs) by definition will leave this orbit. While the term suggest an Earth orbit, it's really ...
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1answer
72 views

Why are gravitational perturbations stronger at larger semi-major axes?

Why are mechanisms such as the Kozai-Lidov effect more prominent at at large semi-major axes? If we had a binary system of a primary and secondary body, with the third perturber as the Sun. Why is it ...
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767 views

What is minimal aperture/magnification to recognize phases of Galilean moons?

Given you take a (non-amateur) refractor telescope, what are aperture and magnification required to recognize phases of the four Galilean moons? What did Galileo see: http://www.astro.umontreal.ca/~...
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258 views

Is it possible for a planet to have multiple moons in a nearly stationary orbit?

I have done a lot of searching online and while I have been able to find out that theoretically a moon could exist in a near-synchronous/stationary orbit, I am wondering if it is possible for multiple ...
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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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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 ...
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1answer
387 views

How did "oddball" Valetudo, Jupiter's new prograde moon, end up in a wider orbit?

I just saw this question and that got me to this NASA page which led me to this scientific article. “Our other discovery is a real oddball and has an orbit like no other known Jovian moon,” Sheppard ...