All Questions
199 questions
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I've determined how many planets my solar system could plausibly have. How do I figure out what kind of planets they are?
The 12 planets in my solar system orbit the G-type star of Nemo. It's about nine-tenths of the size of the sun, and has a stellar luminosity of 0.67 L☉, a diameter of 1.28 million kilometres, a ...
- 14.9k
3
votes
1
answer
425
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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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9
votes
1
answer
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Feasibility and consequences: the cosmic dance of twins habitable moons
I am aware of being a newbie in the field I am asking my question... please be kind and explain what I did wrong if I make a mistake.
The idea from where the problem bloom
I love worldbuilding. ...
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4
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5
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How to make an Earth with 27 suns work [duplicate]
Viability of Many Suns
This is the first of a thread of related posts on a hypothetical alternate universe/Light Plane.
Other posts from this thread are here:
How To Make an Earth with 27 Suns Work,...
- 3,246
4
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2
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Is it possible for a planet with life to orbit around a white hole?
I have created a planet called Betiler. I don't want Betiler to be in a classic space system like a star and some planets. So I put it around a white hole called Phulom. In my world, wormhole doesn't ...
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6
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How could it be possible for an entire region of space to be filled with Earth like planets?
Ok, I get it, me dumb, you smart. Only smart questions allowed. In any case I'm going to leave the question unaltered in case some others might get something out of the answers.
Thanks to everyone ...
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1
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4
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Could a spacefaring people preserve the idea that their world is the center of the universe?
Cosmology since Einstein makes it clear that it's not quite right to say one body in space "revolves around" another, right? Einstein wrote: "The two sentences, 'the sun is at rest and the earth moves,...
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2
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Could Our Sun Have A Twin Sun? [closed]
Would it be possible for our sun to have a twin star that could not be observed but is equal in size & density & moving at equal speeds, & are at aphelion in juxtaposed 4-point ellipses or ...
6
votes
1
answer
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Could a star half as hot as our sun maintain similar surface temperatures of planets orbiting it if it was half the distance?
I'm trying to build a world that is orbiting a red giant but sustains life similarly to the conditions of earth.Since red giants are about half the temperature (3000 kelvin) of our sun (6000 kelvin) ...
- 1,018
20
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4
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Physiological adaptation of life on a planet orbiting a red giant.
Let's say there exists an Earth-like exoplanet which orbits a normal star, with a similar process regarding the evolution of life on earth, yet the star became a red giant during said evolution.
...
- 1,018
6
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2
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Under what conditions might a planet orbiting a red dwarf star NOT be tidally locked?
From what I've read, planets orbiting red dwarf stars would most likely be tidally locked. Under what circumstances might this change? For example, if a planet had been the recipient of some kind of ...
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6
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3
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846
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Replacing Jupiter with a brown dwarf?
This is a purely hypothetical question but I can't find a satisfactory answer to it.
Let's say somehow Jupiter collects enough mass to be considered a brown dwarf. Let's assume Jupiter achieves a ...
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12
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2
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Can a planet's axial tilt naturally change a meaningful amount in only 100 years from its current cycle?
Could a planet's axial tilt change a meaningful amount (what is needed to make inhospitable biomes even more inhospitable: hotter dry hot desert, colder north) over an extremely short period (~100 ...
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1
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2
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Is this model possible? Fast axial precession + tidal locking
I'm working on a story set in a planet of permanent dusk/dawn, and with a dark side that never sees the light of sun. I know that a planet tidally locked to its star would (roughly) look like this, ...
- 1,151
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To make a gas giant flammable
(Warning: do not try this at home-system)
Preamble
Hello humans, we need advice.
Let's say we have just successfully defeated and killed a Horror From Beyond Reason who happened to be multiple times ...
- 4,697
5
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8
answers
891
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How can a small planetoid hold an atmosphere under artificial means?
Edit: Before I give up on this I wonder how could an advanced civilization create conditions on a small planetoid (Ceres sized?) to keep an Earth level breathable atmosphere? It seems like its ...
- 4,948
12
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1
answer
446
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If I were to put a moon-mass object in Mars orbit, how long would it take to restart the dynamo effect in Mars' core?
Mars has an inactive mantle and core and thus little magnetosphere to speak of. Assume that a lunar mass object is placed in Mars orbit at 300,000 kilometers out (one light-second). Given the tidal ...
user44399
3
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2
answers
436
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Planet Titan, could this work?
So I'm guessing you guys know about the speculation that life exists on Titan. To me, this is very interesting but many point out that it would probably only be microbes and unicellular life because ...
- 3,743
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5
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What do Martians use for months and weeks?
Assume Mars has developed an indigenous civilization of its own, perhaps as seen in Edgar Rice Burroughs' A Princess of Mars.
Much like Earth, Mars' years and days would be significant for any ...
- 85.8k
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4
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247
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A planet with a diurnal cycle on only one hemisphere?
I need a habitable body with 64-hour days and nights... but only on one hemisphere. The other side is perpetually dark.
Is such a thing possible? I'm picturing a tidally-locked moon orbiting a gas ...
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6
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1
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What are the circumstances in which swamps or everglades can have dramatic low and high tides?
I'm actually trying to create an alien ecosystem, so changing orbits, what's exhibiting tidal forces and the geography and such is welcome if needed. I also wonder how stable a setup with dramatic ...
- 1,193
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6
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Why didn't we detect that exoplanet before?
In my world an alien creature claims to be from an earth-like planet orbiting a 500 light-years away solar analog star. It tells us that the planet has x mass, y diameter, z orbital period, that ...
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4
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Could more Earth-like planets exist in our Sun's "goldilocks" zone?
These planets would be similar in size to Earth. Mars and Venus don't need to exist in this scenario.
So how many Earth-like worlds can be squeezed into the sun's "goldilocks" zone? Mars and Venus ...
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4
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That's a big planet, but how big is it?
If a tidal locked terrestrial sized moon with 0 eccentricity, 0 incline, and was orbiting .01 AU away from a gas giant with 12 Jupiter masses (which would have approximately the same radius as Jupiter)...
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How would tidal forces impact two habitable moons in a horseshoe orbit?
I saw this video a while ago, and recently it's gotten me thinking. Towards the end of Artifexian's video on gas giants and habitable moons, he mentions the idea of having 2 habitable moons in a ...
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3
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How would it feel to sail a Rocheworld ocean?
A couple days ago, I posted this question about what it would feel like to walk on a Rocheworld.
For some background, a Rocheworld is a double planet system where the two planets are so close ...
- 2,952
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How Would It Feel To Walk On A Rocheworld?
A while back I saw this video talking about the habitability of double planets and Rocheworlds. I haven't seen any questions about the latter case here, so I decided to take a swing at it.
For some ...
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1
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Could A Torus World Have Rings?
Towards the end of this article (https://io9.gizmodo.com/what-would-the-earth-be-like-if-it-was-the-shape-of-a-d-1515700296) there is mention of the different kinds of orbits the moon of a Torus world ...
- 2,952
7
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4
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851
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Can a dual planet have an orbit around the Sun similar to Earth's?
This is a sequel to my previous question How big could a moon be before its orbit became too unstable or tidally locked to its planet
OK, let's imagine that the thing everyone thought was a moon was ...
- 1,415
0
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1
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90
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Distance between passing planets for atmosphere exchange to occur [duplicate]
If a rogue planet (let's say about as big as the Earth) flew by the Earth, how close would it need to pass to planet Earth for atmosphere to be exchanged between the two planets?
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4
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2
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What would it look like for a planet with two moons and rings during a double eclipse?
Since we just had an eclipse, I began to think: what would it look like if a planet had rings and two moons?
Now, there are two solar eclipses going on at the same time! What would the sky look like?...
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How to calculate the solar day from sidereal day and sidereal orbital period?
I know the orbital period of my planet and the rotational period of my planet. Now how do I calculate the solar day? It would only be a small difference to be sure, but do remember that if we didn't ...
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9
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2
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647
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Radiation from binary star systems and how that would affect a planet orbiting both stars
I am working on a solar system for a world where I intend to place my stories. This world should work by the laws of physics as we understand them so that, even though magic is a thing that exists in ...
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4
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3
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350
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Human colony on distant planet system with very short day-night cycles
I need a planet where the day cycle is short, in particular 16 hours. I read What determines the length of a day on a planet? and Is it physically possible for a planet to have seasons of different ...
- 802
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4
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Could a habitable tidally locked planet have a day and night cycle caused by the eccentricity of its orbit?
I'm trying to think of ways that a habitable tidally locked planet could have something that resembles a day/night cycle. Shadows caused by any moons being out of the question.
Hypothetically, could ...
- 1,252
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Does Earth's direction of rotation affect day length?
Let's say Earth started rotation in the opposite direction without any catastrophic events, would a day on Earth be shorter or longer or just the same considering that speed of rotation and revolution ...
12
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3
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What would the star chart be like if earth had a ring?
Recently, I've seen those pictures showing what Earth would be like if it had rings, and that made me wonder, what would the sky map be like? This ring would appear as a fixed object (pretty much as ...
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5
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Making a slow orbit around a large gas giant
First of all, this website is a dream come true. I'm a total sucker for this stuff.
Secondly, I love astronomy and worldbuilding, and lately, I've been thinking of a hypothetical situation, and was ...
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Is this circumbinary planet set up in a stable manner?
This is the ideal set up for my solar system:
EDIT
It's been pointed out that this is not a stable set up, so I want to clarify that everything in this set up can be changed at will to fit my planet. ...
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17
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How would a torus world (donut shaped) have to rotate in order to have a stable day / night cycle in all of its regions?
In this universe, mass and gravity work differently so stable torus planets are possible (donut shaped).
How would a torus world orbiting a single star have to rotate in order to have a stable day ...
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3
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How to fit three habitable worlds in our solar system?
Assume there are three earth-like worlds in our solar system. These three worlds would also have a single natural satellite roughly at the same mass-distance ratio of Earth to the Moon (about 1.2 ...
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Can an ocean moon with a mass of 0.5 earth masses stabilize the axial tilt of a planet two times bigger than earth?
The world will going to be the homeworld of an hairless feline humanoid race, but I want to see the plausibility of this scenario?
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Would an interstellar exoplanet telescope make sense? [closed]
Since the transit method of detecting exoplanets requires perfect alignment of orbits, would a Kepler-type telescope yield much more exoplanet data if sent out of our solar system even to relatively ...
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4
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What would it take for a continent to be covered in cyclical darkness?
I'm contemplating a world in which there is some sort of cyclical darkness that covers a continent or the whole planet, and humanity has to adjust to deal with the creatures that surface when the ...
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What would the sky look like in the SHADOW of planetary rings?
Background: I'm writing a nomadic society that lives in the shadow of their planet's rings. These rings are as wide as possible to grant them the biggest shadow. The planet has an incredibly long year ...
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What impact is required for a visible (from Earth) ejecta plume on Earth's Moon, and would the Moon survive?
Take the Earth-Moon system as we know it. Now, something causes a large rock to be lobbed in the direction of our moon. Exactly how that happens is deliberately left unspecified; it could be ...
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Making a Planet Seem Uninhabitable
How can I make it so that an otherwise colonizable planet (or moon) can (entirely naturally) seem uninhabitable from a certain point on its surface?
Background: There are a series of immovable gates ...
- 1,768
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How can a planet orbit two or more stars simultaneously?
What would the orbit of a planet orbiting two stars look like? Would the planet orbit the stars simultaneously or one after the other? How strong might be the gravity well of such a system be? Any ...
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Moon rotation & orbit periods differs - can it be made feasible?
I have a mars-sized "planet" orbiting a superearth-sized mother-planet. There is also another satellite with an abnormal elliptic orbit, but it is of minor concern for now.
This is the resume of ...
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Would this Planet be habitable for humans
I Was playing space engine and i was looking for a planet like Earth for quite some time and then i stumbled on this beautiful world covered with liquid water which orbited a main sequence star with 8 ...
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