Questions tagged [orbital-mechanics]
For questions dealing with how bodies interact with each other in space via gravitation.
615
questions
4
votes
2
answers
450
views
Is it possible to have stable system where the moon of earth-like planet is only visible part of the year from a fixed point on a surface?
Is it possible to have a stable system wherein the moon of an Earth-like planet is visible only during certain parts of the year (seasons) from a fixed point on the surface, mimicking the way some ...
- 1,339
3
votes
2
answers
187
views
Could Moon Phases work in a Concave Hollow-Earth?
I'm trying to wrap my head around how phases of the moon(s) would operate in a hollow earth. For reference, I am picturing a situation like this:
In this system, the center of the hollow earth has a ...
- 65
14
votes
4
answers
3k
views
What considerations would have to be made for a spacecraft with minimal-to-no digital computers on board?
I'm writing a sci-fi book where the main method of travel involves collapsing a star into a black hole by putting a satellite equipped with some sort of handwaving mechanism into orbit around the star....
- 143
9
votes
3
answers
3k
views
What would it take for a spacecraft to travel to the sun's nadir and stop?
In a science fiction future universe, spacecraft routinely travel from a distance "above" a star's north or south pole to rendezvous with planets orbiting in the star system's orbital plane. ...
- 107
5
votes
2
answers
215
views
Very large orbit binary/trinary star systems
In my universe, Ancient Aliens once visited Earth with consequences.1 At that time they left instructions2 that 5,000 years3 in the future something would happen.4 The instructions left behind a ...
- 117k
2
votes
2
answers
206
views
What astronomical situation could account for the PERCEPTION of a very erratic day / night cycle for a planetbound population with limited science?
I would like to create a world that is at a roughly medieval level of scientific understanding and which - as far as it appears to the inhabitants of that world - has a highly erratic day and night ...
- 21
7
votes
3
answers
1k
views
Could a planet realistically share an orbit with Jupiter?
So I've been working on a project where I modify the Solar System, and I originally had a small gas planet(like 5-10 earth massses) named Juno orbiting between Jupiter and Saturn. However, as it turns ...
- 507
0
votes
2
answers
93
views
Question about finding an exact lunar orbit
I am trying to find a precise orbit for a moon that would allow it to always be in an eclipse. So, basically, I need help finding a formula for the semi-major axis and mass ratio that would get the ...
- 350
2
votes
1
answer
78
views
Feasibility of a moon-planet orbiting an F star [closed]
I'm building an earth-type planet with typically human-like people, but a few differences. The human's particular area won't have much in the way of seasons being a large equatorial island. I'm ...
- 21
3
votes
2
answers
335
views
How do I change earth's orbit so it is tidally locked to the sun? [closed]
In my world, I need to change the earth's orbit so it is tidally locked to the sun. How can I do this? No matter how unrealistic the solution—whether it be magic or what not—anything that can explain ...
2
votes
1
answer
171
views
Partially tidally locked planed due to elliptical orbit... Possible?
Would it be possible for a planet with an elliptical orbit to be tidally locked to a star, only for a certain part of it's orbit?
If this is possible, then:
could the tidally locked side vary from ...
- 593
1
vote
2
answers
146
views
Reverse engineering the Hill Sphere?
I'm wondering if anyone has run into the issue of "I know the general idea of how big my moon is but not the parent planet" and how to sort of reverse engineer finding out the mass/radius of ...
7
votes
1
answer
435
views
Zero energy transfer between Earth and Moon with space elevators
I'm asking this out of curiosity, mostly as a response to Space elevator from Earth to Moon with multiple temporary anchors and some of the comments and answers there.
Suppose you're able to build ...
- 5,077
1
vote
0
answers
27
views
When would two moons line up? [duplicate]
I am gearing up for a TTRPG (tabletop roleplaying game) and my world is a similar size to Earth with a smilier number of days. However it has two moons. One is slightly larger than our moon but it ...
1
vote
2
answers
228
views
Calculating distance of the frost- and ice line
To begin, my star is a K type star with 0.65 solar masses.
I've inserted my star's mass in two different templates to calculate the frost line, yielding different results (2 AU and 2.68 AU).
...
- 388
2
votes
1
answer
415
views
How could an Earthlike planet have two moons, one similar to the Earth's moon and the other primarily composed of carbon? [closed]
I am building an Earthlike planet that possesses two moons, one similar to the Earth's in terms of chemical composition and one primarily composed of carbon. How could these two moons form? Which moon ...
- 4,464
0
votes
0
answers
42
views
How many giant planets could form in a hierarchical triple star system?
The system in question has a very close binary pair of 2 G-type stars, a G9V and a G7V, orbiting at about 0.2 AU, with a K2V star in a far orbit about 300 AU out around the both of them. There is a ...
- 381
5
votes
2
answers
1k
views
Orbital Mechanics of a shell world
I've created a Neptune sized shell world with properties that I find are not typical of other shell worlds. Its gravity does not come from a gas giant or a black it was constructed around, but from ...
- 4,373
3
votes
1
answer
68
views
How do I approximate sunrise and sunset times in this simplified model of a solar system?
For a small game I'm working on I'm interested in simulating a basic celestial model for a planet, two moons and a sun. The main use is determining when specific eclipses happen and what type they are,...
- 1,363
4
votes
2
answers
214
views
Size of a gas giant with an Earth-sized moon
I am working on a world that is an Earth-sized planet that was captured by a gas giant planet moving inward in the solar system, then becoming a moon. Through magic and hand-waving mechanisms, the ...
- 121
2
votes
1
answer
90
views
How do I get the outer planets to meet in the night sky every 1-2 yrs on my planet?
One of the cultures in my story lives on the dark side of a tidally locked planet. I had an idea that they would mark longer spans of time by the appearance of the three outer planets in the system in ...
- 946
3
votes
3
answers
1k
views
How would an observer from a moon the mass of Earth orbiting a planet 81.3 time more massive be able to tell that they were orbiting with 1660's tech
For questions sake assume that this moon is a perfect recreation of Earth on January 1st 1660 and that the planet looks identical to our moon on the same day.
The Planet would have a mass of 81.3 ...
2
votes
1
answer
90
views
How close could a gas giant be to my planet without it becoming a moon?
This is an M-type system. Let's take Trappist 1 as an example star (0.0898 Mass of the Sun) and Trappist 1e as an example planet (0.772 mass of the earth, approx 0.029 AU from the star). Assume for ...
- 946
1
vote
1
answer
38
views
Distances needed to make this system stable
Let's take the Trappist-1 system, and specifically, I'm thinking about the star itself and Trappist 1e because it's the most habitable of the seven planets:
Trappist 1 star is approximately 8.98% of ...
- 946
0
votes
2
answers
112
views
Day/night cycle on an S-type planet
[Answered myself below] I've seen similar questions have been asked before, but the details are slightly different.
Say you have a tidally-locked, roughly Earth-mass rocky planet in the habitable zone ...
- 946
5
votes
1
answer
266
views
Could this sort of celestial system work?
I am attempting to create a pair of planets, both capable of harboring life. Which happens to also be quite colossal in design. We are talking about 10.13x the size of Earth.
So the system I am ...
- 51
6
votes
1
answer
342
views
What dictates whether an orbit gets disrupted or stabilised due to an orbital resonance?
Context:
I've got an asteroid belt analogue situated between a Gas giant and a Super-earth. I knew about resonances, so I started calculating them and placing some of them in the belt, especially ones ...
- 442
1
vote
1
answer
129
views
Could a terrestrial planet have a stable orbit of rings? [duplicate]
Planet Phileas, similar in size to Earth. Fourth star in a binary star system with a p-type orbit.
Changes may be necessary and I'm open to constructive criticism. This question includes two parts. ...
- 335
1
vote
2
answers
253
views
Can Integral Trees be Sailed?
In the book The Integral Trees by Larry Niven, he presents people living in a novel environment. There is a neutron star (quite old and so cooled off mostly) around a more ordinary star. And orbiting ...
- 4,137
4
votes
3
answers
235
views
Can a rocky planet form between gas giants?
The Question
I am working on filling in the planets of the Ilus system. I am setting up a strange, huge, low density, sort of habitable world in the gap between two gas giants. Is there a way for a ...
- 1,984
2
votes
2
answers
57
views
How can we move the Moon into a more distant orbit by using electrostatic charge?
Earthers wish to change the Moon's orbit in order to adjust the length of a lunar month. They intend to do this by giving the Earth and the Moon equal electrostatic charges thereby pushing them ...
- 49.3k
3
votes
1
answer
187
views
Geostationary orbit around a tidally-locked planet?
Is it possible to have a satellite (natural or artificial) in orbit around a planer which is tidally locked to its sun?
- 8,459
2
votes
3
answers
93
views
Orbital mechanics- 2 objects, different mass same trajectory
I have a multi-ring space station built around an asteroid, but not physically connected. Station has significantly more mass than the asteroid.
As the two approach a star and swing around it, will ...
- 21
5
votes
2
answers
124
views
How many days in a week, and weeks in a month, would be needed for this specific lunar cycle?
So, this world has three moons.
Blue, Red, Yellow.
There are eight months in the year. Each month has a unique "full moon" combination resulting in a different colored sky. That is the ...
- 172
0
votes
0
answers
53
views
Is a binary moon possible? [duplicate]
So, i have heard of triple star systems where two stars orbit each other in a binary pair, and both orbit a third, more massive sun. I was wondering whether this would work on a smaller scale; an ...
- 8,459
0
votes
1
answer
113
views
Is it possible for a star to orbit a planet? [duplicate]
At first the answer seems simple, no, but the more I think about it the more it seems this might be possible.
For the sake of the question don’t think about the probability of this actually happening, ...
- 1,259
3
votes
4
answers
250
views
How To Calculate Moon Cycles To Cause A Lunar Event Every [250] Years?
My first post here, so friendly hello!
I need some bigger brains than mine, or just some other braincells to reverberate off of. I have a world with three moons and I'm trying to calculate the length ...
- 33
6
votes
1
answer
195
views
433 Eros hits the Moon. How much rock hits the Earth?
A la this image I made.
The "how" (nuclear pulse drive "adjusting" Eros's orbit at its aphelion) and "why" (uber-sized Rods from God) isn't particularly relevant — all ...
- 11.7k
3
votes
2
answers
249
views
Could an object exist at the barycentre of two stars
Returning to the powerful clarkean civilisation in this question What compounds could be used to dye a gas giant the colour of a rainbow?
These same artistically inclined omnipotent beings have ...
- 8,459
2
votes
2
answers
106
views
Effects on gravity on close binary planets
Let's say there's 2 planets orbit eachother as close as possible so they're oval shaped but not close enough to reach the roche's limit and be pulled apart. How would gravity be affected on the ...
- 388
2
votes
4
answers
221
views
What configuration should the worlds of a long lasting galactic empire take in the galaxy?
I have come across many galaxy maps showing the dominion/borders of one empire or another in different works of fiction. The first that comes to mind is WH40k for which the galaxy map of the different ...
- 608
5
votes
3
answers
190
views
is it possible for a binary planet system to have long term moons orbiting only one of the planets?
What I'm thinking of is a binary planet system each with rings, 2 moons orbiting the larger one and one moon orbiting the smaller one.
The mass of the larger planet is 5 Earth masses, while the ...
- 51
8
votes
3
answers
2k
views
If someone blew up mars, how screwed is earth?
Mars has a gravitational binding energy of ~5x10^30 jouleS. If a bomb went off on mars that released that much energy, how much danger would the earth be in. Additionally, would debris striking earth ...
- 1,983
6
votes
5
answers
181
views
How fast can a moon pass overhead?
For purposes of realistic, but otherworldly visualisations of foreign worlds I'm wondering what the fastest speed is that a moon will track through the visible sky, as observed from the body of a ...
- 3,090
3
votes
2
answers
217
views
Hot Jupiter L2 Station! Reasons to build, and challenges
I'm working on a somewhat* hard scifi story set in a solar system that contains a hot jupiter. Frankly building a large station in the shade (?) of the L2 point of the hot jupiter sounds metal, and I'...
- 125
6
votes
3
answers
841
views
Is it possible for two moons to align once a year?
The planet is just like earth and the first moon is the same as earth's moon, but there's a second moon further away. I'd like to know how plausible it is for both moons to align once a year. The ...
- 63
3
votes
2
answers
63
views
How far would a planet with these specifics orbiting a sun-like star have to be for solar wind to not strip the atmosphere?
I'm currently writing up a world inhabited by tall, humanoid crow-like aliens, and I have all the specifics down, I'm just struggling to figure out how far said planet, with the characteristics listed ...
- 1,336
2
votes
4
answers
161
views
Is it more efficient to launch a spaceplane from a space elevator to a destination on the planet, or to simply fly the plane through the atmosphere? [closed]
Suppose you have a planet that needs to send and receive cargo from a space elevator at the equator. Due to various environmental factors, surface-based transportation is unviable so all cargo needs ...
- 1,983
4
votes
7
answers
2k
views
Generating gravity
how would I generate gravity in an orbital station without spinning in a really fast circle or making it as big as a planet, or would I have to cut my losses and just moon-base my idea (I'm trying not ...
- 381
3
votes
2
answers
132
views
How would Orbiting Lenses work for a Prophesied Day?
So I was thinking of having religions prophesy of a day where there'd be a massive beam of light coming down from on high at a specific holy spot. How would this be possible with lens orbiting the ...
- 437