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Questions tagged [orbital-mechanics]

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

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A planet that cannot be orbited [duplicate]

I'm wondering if it is possible for a planet to be impossible to orbit stably over a significant length of time. The shorter the length of time the planet can be orbited for, the better. It should ...
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Practicality Of Orbital Fusion Reactors for Power

Much of the struggle with terrestrial fusion power seems to be with keeping the ultra-hot plasma contained. In a classic Tokamak configuration, magnets using massive amounts of power, suspend the ...
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Harvesting resources from a geostationary point 100km above sea level

Consider a planet which is entirely Earth-like. Same mass, same rotation, etc. But in this world, resource-rich objects are suspended by some phenomenon at varying altitudes up to 200km above sea ...
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Co-orbits and Tides

I've seen many questions about tides and tidal variations on a wide variety of interesting single star, multi star, single planet, binary planet, single moon, multiple moon, and even ring system ...
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1answer
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Earth tilt changes due to space launches

How many rocket launches are needed to change the axial tilt of the Earth so much that it is noticeable with instruments available today? We can assume that we are talking about the heaviest rocket ...
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Artificial satellite in a Binary Star System

Is it possible for an artificial satellite (in this case, an unmanned communications platform) to maintain a stable orbit directly around the barycenter of a Binary Star system, as in well inside the ...
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3answers
293 views

Let's plot a course between Earth and Gor

We know that Gor, or Counter-Earth, is not stable in a long-term sense. Let's handwave that away, or assume that we are dealing with a temporary span of time in which the instability is immaterial. ...
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1answer
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Semi-Brachistochrone, Is It Possible?

Would it be possible for there to be an almost torchship (essentially a very, very weak one) which could fly almost brachistochrone trajectories? So instead of a full on brachistochrone, where you ...
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How likely is the flotsam of a space battle to be captured by our sun's gravity well?

A light-year distant from Sol saw the collision of a massive space-born battle fleet against an awe-inspiring dreadnought. At one point in the battle, the flotilla fired rail-guns with 100 metric ton ...
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What sort of acceleration would I need for my space ship to reach Eris in 3 months

I have been working on a sci-fi story for a little while now, and have recently discovered that I made a very big error in assuming the position of Eris. The main issue is that I had forgotten to take ...
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4answers
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Rings made out of water? [duplicate]

There have been numerous questions on this site about moons being composed entirely of water. However, is it possible for a planet to have rings made out of water? I think that the ring would ...
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2answers
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Can I arrange my stars in a tetrahedron?

Inspired by this question: Consider a trinary star system, in which the three stars are arranged in an xy plane and all revolving the same direction, equidistant from each other. The inward pull of ...
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Are there any software tools available to map the solar system hundreds of years from now?

I am writing a scifi novel based roughly four hundred years from now, and it occurred to me that the planets and other objects might not be quite where I need them to be for certain travel details to ...
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Would it be more efficient to build fleets in orbit?

My Dino theme park business didn't end well and I reluctantly fall into depression and decided to go into suspended animation to seek a cure. 200 years later, a lady claims she works with the military ...
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Could the moon crash into the earth if we colonised it and increased its mass?

Suppose we begin to colonize the moon. Assuming the building materials and biological material are all imported (not taken on-site), would it be possible for the moon to become massive enough to fall ...
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2answers
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A supermassive black hole is coming our way. When's the latest that we would notice?

I'm trying to build a story around a supermassive black hole, which is ejected from a merger of two galaxies, that is hurtling our own way. What is the smallest realistic distance at which the black ...
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2answers
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Getting Three Comets to Synchronize Their Orbits… Occasionally

I'm working on a flintlock fantasy series and I want to figure out how to get three comets with different orbital periods to occasionally all show up at the same time. All three are "great comets" ...
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1answer
111 views

The dreaded apocalyptic asteroid approaches Earth but lands 'safely' on the Moon [closed]

NOTE- PLEASE DON'T ANSWER HERE. I'M DELETING HERE AND MOVING TO SPACE EXPLORATION SE. https://space.stackexchange.com/questions/32411/the-dreaded-apocalyptic-asteroid-approaches-earth-but-lands-...
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Why would it be unfortunate for a day length to vary in a planet; other than that Java API developers need to work a few hours more? [closed]

Quoting from the Java Docs: Unfortunately, as the Earth rotates the length of the day varies. In addition, over time the average length of the day is getting longer as the Earth slows. I am ...
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2answers
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Habitable zone around a Blue Supergiant

I am writing a story centered around a planet orbiting a Blue Supergiant star. What I want to know is how far away a planet would have to be to be in the habitable zone of such a star. The star I ...
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2answers
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What would be the impact on Titan, Saturn and the Solar system if aliens harvested as much hydrocarbons as possible from Saturn's moon?

The scenario Many science fiction novels are concerned with aliens visiting Earth, but what if aliens have no interest in Earth at all and yet they arrive at the Solar system for the sole purpose of ...
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1answer
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Temperature on a bulls-eye planet planet orbiting a red dwarf star [closed]

I recently attended a talk on current research into exoplanets and it got me thinking. I want to create a setting on a tidally locked eyeball planet for a futuristic sci-fi story. What I want to ...
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1answer
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Could this moon of a gas giant orbiting a neutron star support life?

Making the following assumptions: 1. The three moons of the Gas Giant are safe enough distances from and massive enough not to pull each other apart or send themselves careening into the void. 2. ...
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1answer
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What kind of impact could strip Venus and make it spin faster?

I'm trying to create plausible scenario under which we could colonize Venus. Is it possible that Venus could be hit by a planetoid and the impact strips its atmosphere and makes it spin faster? I'm ...
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Earth Orbit Extreme Change

So recently I got slated for missing some glaring obvious flaws in my story on here, which I really do appreciate. I'm approaching the question from a different angle though, in two parts. What ...
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1answer
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Earth Exploded, Orbiting and double moons

I have a scenario which I am too poorly knowledgeable to address, I'm hoping for some expert input. I'm currently writing a novel, in which a large section of Russia/EU continents were blown up in a ...
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3answers
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What is the maximum orbital time for my moon around my planet?

I fear the math involved is beyond my capabilities on this one. I have what I consider to be more than a Layman's understanding of the physics involved, and I believe I can follow the math well ...
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2answers
57 views

Opaque Solar Shield in Geosynchronous Orbit: Plausibility + Challenges of Maintaining Orbit

Suppose humans of the late 21st century or beyond began constructing a solar shield as a solution to climate change. Suppose for some reason (open to suggestions) they choose to build the shield in ...
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14answers
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How do you non-catastrophically reduce the mass of the Sun by half?

In my previous question, I asked how much mass the Sun would have to lose in order for Saturn's orbital velocity to be its escape velocity. The answer proved to be somewhat unexpected - when the Sun ...
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4answers
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Can the Sun lose enough mass that Saturn's current velocity becomes escape velocity?

Imagine that, through some cosmic phenomena not yet understood, the Sun 'burps' and ejects a vast amount of its mass into the cosmic void. A huge coronal discharge, perhaps. A pressure bubble inside ...
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1answer
131 views

Two planets with the same orbital period [duplicate]

I have the following star system configuration: All bodies always stay on one line. Star is similar to sun by parameters. "Green" planet is Earth-like exoplanet with 1 earth-year orbital period, ...
4
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1answer
169 views

What impact would a giant alien spaceship orbiting Earth have on our planet? [duplicate]

I'm talking about a massive ship, let's say half the mass of the Moon, within the Hill sphere, so that is not snatched up by the Sun and can orbit around Earth. Assuming it's positioned as far as ...
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1answer
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Can a habitable moon rely on the magnetosphere of its parent planet for radiation protection?

Science-based answers, please. Key points: the main concern is radiation protection for sustainability of human life (and accompanying plant and animal life ecosystems, whether earth-like or not). ...
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1answer
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Could a planet's Karman line hypothetically occur under a liquid surface?

The Karman Line is one of the most commonly-used definitions of the "edge of space". As an airplane flies higher in the atmosphere, the air gets thinner and thus the lift decreases. This can be ...
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1answer
174 views

If Earth's Moon Were Ganymede-Like, Part I: Rotation

I know that in the past I posted questions on if specific bodies larger than the moon--Mars in one and Titan in another--but this series deals with questions regarding Earth's effects by a natural ...
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1answer
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Geostationary moon

My planet is very Earth-like with a day length of 26.87h. The moon has a radius of about 1550km, a mass of $5.2\times10^{22}$ kg and orbit 45500 km from the center of planet. My scenario is that the ...
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5answers
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A planetary region with no night and no tidal locking?

Without tidal locking, would it be possible to have a planet with a region roughly the shape and size of the USA and Canada in which it is always "day"? (By day I mean at least as bright as a clear ...
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1answer
168 views

Would this simplex ternary system be stable?

I'm trying to make a trinary star system but I'm not sure how it would work. The primary star is an M0Ve star (red dwarf flare star). The orbits of the other two stars are slightly more complicated. ...
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3answers
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A cure for the 'Kessler Syndrome'? [duplicate]

For those unaware, the term 'Kessler Syndrome' refers to a scenario in which space-borne debris reaches a 'critical mass', destroying spaceborne satellites which in turn produce more debris which in ...
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14answers
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Can I produce a true 3D orbit?

I've been doing a little research (including reading Howard Curtis' Orbital Mechanics for Engineering Students) because I want to build a solar system with a planet that has a true three-dimensional ...
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3answers
138 views

Capturing a moon: Process reality check

Background: I have an icy moon on a collision course with my fantasy world. Mages on this world have the ability to slow the speed of the moon gradually. I want them to use this power to lock the moon ...
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2answers
192 views

How feasible is my Exo Planet - Penumbra

My planet - let's call it Penumbra for now - exists at roughly 1.5 AU from it's sun - which was similar to Earth's - but is about a billion years older. It is 15% more massive than Earth, but nearly ...
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1answer
79 views

Would there be stress on my wormhole between two planetary surfaces due to their orbits?

Building on this question: Settings formed by Uncontrolled Terraforming of Venus and Mars via Portals My government, the Great Council of Duhurang1 has authorized the Minister of Astronomic Science2 ...
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2answers
135 views

Lunar cycles for a two moon planet (one of which is smaller and orbits the first moon)

My planet, is roughly as big as Earth, but has two moons. The first moon, Luna, is essentially the same as Earth's moon, but the second, much, much smaller moon, Selene, actually orbits Luna. Selene ...
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2answers
155 views

Multiple moons but only one of them is tidally locked to its planet?

A habitable planet with multiple moons, only one of which is tidally locked to the planet: is this general scenario possible? I understand that tidal locking takes a very long time to happen. So ...
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Navigation on a tidally locked planet

I have a tidally locked planet on a circular orbit, with an axial tilt of 22.5° That means one side is always in the sun, the other one in the shade. The subsolar point moves along a north-south line ...
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1answer
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The Nightfall / Kalgash System

"Nightfall" by Isaac Asimov (you can hear the story here on escapepod, if you need it) postulates a planet in a multi-sun system. The orbital mechanics of the 6 suns result in all of the sides of the ...
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2answers
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How many habitable planets can I fit into the habitable zone of a Sun-like star and still be stable? [duplicate]

The habitable planets will be very similar in size to earth and are on separate orbits orbiting a Sun-like star exactly the size of our own Sun. How many habitable planets can I fit into the habitable ...
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1answer
139 views

How long can a moon remain non-spherical, and what might it look like when full?

I'm trying to "build" a world in which the moon is always visible at night, and only at night, to the majority of areas on that world. I've been told that an L2 Legrange point could be a viable ...
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1answer
126 views

Describing a planet on a comet like orbit

I have a planet in earth's solar system that is on a comet's orbit rather than like the orbits of the planets we have. I need some help picturing how this would work to meet a few requirements for the ...