Questions tagged [orbital-mechanics]

For questions dealing with how bodies interact with each other in space via gravitation.

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12
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10answers
2k views

Can a moon orbit a planet's southern pole?

I am interested in the idea of a moon orbiting only the southern pole of a planet. Could it theoretically be possible (though unlikely) that a moon would, for instance, orbit a planet parallel to the ...
4
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0answers
83 views

How Would These Planets Affect Earth's Eccentricity?

A cleaner, narrower-focused improvement of How This Alternate Solar System Influences the Milankovitch Cycle, so not a duplicate. For further clarification, eccentricity is the shape of a planet's ...
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2answers
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What if Jupiter and Mars swapped orbits?

I am wondering how will it affect earth or none at all. Seeing that Jupiter by far is a gas giant and has really strong gravitational pull while Mars is mostly dormant, weak gravity and a terrestrial ...
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3answers
93 views

Would tidal acceleration mean doom for this system?

So we have a Super Earth of ten Earth masses, just on the threshold, and it has three Mars sized moons (so a mass ratio of 100/3, more than Saturn Vs 3 Earths). They go 40,000km, 100,000km, 250,000km ...
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4answers
499 views

After surviving a black hole/wormhole, what are the chances of Earth start orbiting in a new solar system?

In the event of our sun suddenly becoming a black hole or wormhole of sorts. It transports the earth to another solar system similar to ours. Would it be possible for our planet to start circling ...
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1answer
72 views

Habitable Planet in the L2 Lagrange Point of a Hot Jupiter

If orbiting in the L2 lagrange point of a large planet (doesn't actually have to be a hot Jupiter, just large enough to fully shadow the smaller planet), how close could you get to the host star ...
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12answers
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Habitable Planet with Highly Eliptical Orbit

Would it be possible for life to develop on a planet with a highly elliptical orbit? (Similar to a comet, but possibly less extreme.) If so, what conditions would be necessary and what would the life ...
4
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2answers
125 views

Space elevator off Europa without running into a nearby moon?

Would it be possible to build a space elevator off Europa? (The space elevator would only be for the purpose of getting items out of Europa's gravity well relative to Jupiter. At that point, the ...
6
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4answers
147 views

Could some natural process on a moon do enough stationkeeping to sustain an impossible orbit?

I have several stories where I've wanted a moon in some weird orbit that is not allowed by orbital mechanics. In the past, I've had to change stories to bow to physics. Today, I had a thought while ...
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2answers
91 views

The major effects on the habitability of exomoons orbiting this Brown Dwarf

I'll need to give some background to this question. I'm interested in the idea of a densely inhabited star system, and having large exomoons is one way that they can all orbit roughly at the same part ...
2
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1answer
62 views

General effects (and narrative practicality) of a moon with an extreme elliptic orbit

This is more for fluff and illustrative exotica, but I'm keen on an idea where my new world has a moon that orbits elliptically, but has a fast inward close orbit followed by a longer round trip the ...
3
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1answer
68 views

Ideal sun type and corresponding effects for a terrestrial planet with 256 days in a year?

The planet has 256 days in a year, split up into eight months, each with 32 days. My planet is a bit smaller than Earth: Think, enough space for the continents of Earth’s western hemisphere and the ...
3
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1answer
54 views

plausibility of this double planet system? [duplicate]

So, I'm about to start a new worldbuilding project for a fantasy world, but I want to try to make the basic world at least somewhat plausible; the magic in the setting is going to be pretty low-key, ...
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4answers
120 views

Is this planet-moon system possible?

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. The moons are rather large. The largest one is ...
6
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1answer
90 views

What would the effects be on a planet whose moon orbits at a speed just faster than a geosynchronous orbit, so there are more months than days?

Would anyone be able to check some math/ let me know if I'm thinking of this the correct way? I had an idea of the moon appearing basically stationary in the sky, but in fact it orbits just faster ...
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2answers
91 views

Inverse orbital direction

Is it possible that a planet/moon will have inverse direction comparing to the rest orbiting material? For example Mars would go in counter direction comparing to other planets in solar system. If ...
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5answers
8k views

Can two moons have intersecting orbits yet be guaranteed not to collide?

Working on a D&D campaign. As a physics nerd, I'd like the orbital mechanics of the planet, its sun, and its moons, to follow standard Newtonian/Keplerian mechanics. I'm trying to come up with ...
5
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2answers
82 views

Navigation on a planet with an eccentric orbit

On this planet, there is a nomadic tribe of humans who are the descendants of unwilling colonists from thousands of years prior. They are a nomadic tribe because of the incredibly extreme seasons, ...
4
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1answer
144 views

Are elliptical rings feasible?

Around a rocky planet or small gas giant, could there be a system of rings that follow an elliptical orbit? I have used a gravity simulator (this one) to test it, but the way it handles its particles ...
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2answers
67 views

Feasibility of extra-lunar capture

Using our own Earth and Moon as a template is it possible for a second large body (One quarter to a third of the Moon’s Size) drifting close by to be captured in a stable and permanent orbit? ...
9
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4answers
188 views

How can an Earth-like moon meet these angular diameter conditions?

NOTE: If there is anything about this question that needs clarification or editing, please don't hesitate to let me know in the comments. Get ready, because you're in for quite a ride. I have tried ...
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2answers
146 views

Binary World Mechanics

I’m trying to develop a realistic system with a limited understanding of astrodynamics. Is it possible to have two binary worlds capable of sustaining atmosphere and complex life orbiting one another ...
6
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5answers
366 views

What star can give an earth-like planet a 1-day year?

I did the orbital period for a planet orbiting a mass = 1 sol with a 24-hour year, it’s got a semi-major axis of 1.82 million miles - far and away beyond the Roche limit, still beyond the corona, but ...
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1answer
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What is the highest theoretical escape velocity a 2 billion metric ton vehicle can achieve using a >20° gravitational slingshot?

I want to send a flying saucer (a $\frac{1}{10}$ scale Independence Day City Destroyer - calculated as a sphere cap 112m high with 1.2km segment radius, $\rho$ about 43.3kg/m3) away from the sun as ...
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2answers
144 views

Creating “Sunfall” on the moon of a gas giant

I'm attempting to figure out the orbital physics of a system that has a habitable body that has intense periods of waxing and waning sunlight. I've come to the assumption that the best body for this ...
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9answers
1k views

Realistic ways a Planet or Large Moon could have Variable Day/Night periods

Hello I imagine this is a pretty straightforward question, perhaps already covered in another post, but I wanted to get extra perspectives and options for achieving this type of planet or moon. So ...
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2answers
114 views

Can an Unstable Ternary Star System Last Several Hundred Years?

After reading the following question, I know that there are not that many solutions to the 3-body problem, and I know that a ternary system is unstable. The 3 stars all orbit each other in a rotating ...
12
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3answers
5k views

Can planetary bodies have a second axis of rotation?

Is it possible for a planetary body to have a secondary axis of rotation? For example let's say there's an Earth-like body that is spinning with its North Pole facing the Sun. Imagine that the North ...
0
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1answer
675 views

Stabilizing Synchronized Orbit

The planet in my story, Ser, is actually in reality a moon orbiting a larger body called planet Rea. Ser is located in the L1 Lagrangian point, which means it takes the same amount of time to orbit ...
7
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2answers
186 views

What are the size limits on an spin-gravity space station?

A spin-gravity space station, a ring-shaped structure that creates a faux gravity on the inside of the ring via inertia, has been depicted as no bigger than a house and as massive as a solar system. ...
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7answers
2k views

Gravity on an Orbital Ring

Added 9-15-19: Thank you all for your comments. I will be reading them through carefully. I have quickly skimmed through the answers and I do appreciate your corrections on terminology and ideas, and ...
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1answer
53 views

A Stable Red Giant Trinary System

In an alternate universe, we have a spot in the Orion Arm where we have nine Earth-like planets orbiting three red giants. Judging from the size and luminosity of each star, it's been conferred that ...
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3answers
2k views

Moons that can't see each other

Could 2 moons that orbit same terrestrial planet never see each other if they orbit the planet at same time? Moons have different mass and gravity.
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2answers
271 views

Is there a website that will run orbital simulations because I don't have a PhD in math

I'm just trying to write a RPG adventure for a sci fi company. So when I have to figure out what kind of orbits, masses, major axis, etc are needed for the system I need to design and I see: $T=2\pi$...
5
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2answers
169 views

What could cause a planet to be in shadow for a 6 earth month period every couple of earth years?

My previous question ruled out having a moon orbiting a gas giant. I've got an interesting ecosystem (my bad, biome was the wrong word) that evolved based upon the idea that the world is eclipsed for ...
4
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2answers
266 views

If Earth Were a Gas Giant's Moon

Here is what we know of Earth: Mass: 5.972 sextillion metric tons Diameter: 7,917.5 miles Density: 5.51 grams per cubic centimeter Rotation: 24 hours Revolution: 365 days Core: 760 miles wide, ...
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3answers
229 views

In Search of a Super-Bright, Super-Stable Star

Long ago, I asked a question on how to make possible turning the nine realms of Norse mythology--Midgard, Asgard, Vanaheimr, Jotunheimr, Alfheimr, Hel, Nidavellir, Niflheim and Museplheim--into nine ...
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2answers
2k views

Could a planet have a naturally occuring moon at one of its Lagrange points?

Would it be possible for a planet to naturally have a moon or large natural satellite at one of its Lagrange points? If so would it then also be able to have a second moon that would be orbiting this ...
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1answer
89 views

Could a single highly elliptic orbit be used to redirect to another planet?

I'm modeling this on the Voyager 2 flight path. I want to have this flight at this particular time, and not wait for a more advantageous launch window. Based on this orbital configuration (1st ...
4
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1answer
108 views

How Far Can The Stars Ve and Vili Orbit The Main One, Odin?

In this solar system, there are three K-type main sequence stars, or "orange dwarves", named Odin, Vili and Ve. At the center of this solar system, Odin is 80% the mass of our sun. The middle star, ...
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5answers
2k views

In order to successfully have 3 orbital rings around a planet how do you have to orient them?

I am writing a short story about an overworked planet whose civilization has achieved space elevators and orbital rings. The planet, which is earth-sized, has three complete orbital rings in stable ...
5
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1answer
161 views

How many terrestrial moons can my planet hold?

I have a Gas Giant with 13x the mass of Jupiter. How many satellites of Earth size and mass can it hold safely in its orbit? Edit: This gas giant lies smack dab in the middle of its parent star's (...
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3answers
329 views

Super earth habitability

I'm trying to build a super Earth that's capable of sustaining human life for space exploration in a way that's close to reality. So far I'm lacking some understanding of planetary science and human ...
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4answers
2k views

Where should a runway for a spaceplane be located?

If a spaceplane like the Rockwell X-30 existed and was flying to a location in geostationary orbit, would it be substantially more efficient to take off from a runaway at the equator, or would it not ...
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0answers
145 views

I'm inventing a new calendar. What are good criteria for the choices of first day, first year, and first hour? [closed]

I'm inventing a new calendar: It will be used worldwide. It uses an intercalary (366th) day to be inserted every 4 years. If extremely successful (unlikely I know), it will replace the Gregorian ...
10
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1answer
233 views

Moons in Binary Orbit

Writing a werewolf story, and decided for a bit of flair, so I wanted two moons in orbit. Did a bit of digging, and I found out that to do that, I'd need to either have them in separate orbit (no ...
3
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5answers
171 views

Axis of rotation of a wheel space station [duplicate]

Is it possible for the axis of rotation of a rotating wheel space station in orbit to be aligned with the center of the Earth? I'm wanting a situation where a person on the station could look out one ...
3
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4answers
194 views

Rotation period of a planet around a star (sun)

Is it possible for a planet to be much further away from its star than earth is from the sun (because for example the star is much brighter/Hotter) yet still have a comparable (as in not tens if not ...
8
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3answers
280 views

Which moon is most favourable as a refuelling station?

My hypothetical gas giant has five major moons. Three of those moons are icy bodies with abundant water ice and volatiles. Any of these could provide fuel for translunar spacecraft, or for spacecraft ...
10
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3answers
487 views

Can I render satellite deployment impossible, or at least impractical, by exploiting the Kessler syndrome?

I want to render impractical the deployment of satellites by exploiting the Kessler syndrome. Why, you ask? Maybe I'm an evil overlord and I don't want those pesky satellites flying over my lair. ...

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