Questions tagged [planets]

For questions about any large astronomical bodies classified as planets, and their effects on their systems.

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70
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17answers
18k views

How can I move a planet?

There are a lot of answers on Worldbuilding about how to destroy planets - just as an example - and they seem to be the method of choice for many people intent on destroying the world. My objection to ...
106
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6answers
28k views

How would having multiple moons affect tides?

We know that planets can have multiple moons, sometimes quite a few (like Jupiter). Assuming that a planet with several moons were habitable in the first place and has significant oceans (greater ...
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6answers
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Could two planets be tidally locked to each other so close they share their atmosphere?

Could two planets be tidally locked to each other at such a small distance from one another that they share their atmosphere, and material is floating around between the two?
65
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24answers
9k views

The opposite to Worldbuilding: World Destruction

I am looking at different ways to destroy a planet. I am assuming the planet is of a similar size and composition to the Earth just to keep things simple. I am starting at boiling the atmosphere to ...
36
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3answers
7k views

Habitable moon of a gas giant: working out the sizes and distances

I am attempting to create fictional, stable P-Type binary system, featuring a gas giant in a stable orbit, with a habitable Earth-like moon. “Is a Jupiter-sized planet plausible in a habitable zone?” ...
38
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2answers
10k views

How would winds behave on a tidally locked planet?

If an earth-sized planet were tidally locked to a star, and was in the life zone of its star with an earth-like atmosphere, what would its wind patterns be like? The planet would have one hot ...
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5answers
3k views

Are geographically typed planets realistic?

In many science fictions we see planets which are designated by a particular terrain type. For example, Dagobah is a swamp planet, Tatooine is a desert planet, and Kamino is an ocean world. However, ...
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23answers
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What would be best way to re-melt Mars' mantle and core to revive its magnetosphere

Missing magnetosphere on Mars keeps popping up. Most likely caused by Mars core being cold, mantle not bubbly enough. Mars mantle is dormant, core does not move. What would be good way to get it ...
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14answers
33k views

Would the human body support living on planets with a greater gravity than Earth?

I once read a novel about a prison-planet which was chosen to make the prisoners suffer. One of the different "tortures" was a gravity three times higher than that on Earth. Would the human body ...
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5answers
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How do seasons work in a binary system (planet orbits one star, not both)?

I have a planet orbiting one star in a binary system. When the planet is exactly between the two stars it will experience a double day; when the primary sun sets the secondary one rises, no overlap. ...
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6answers
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If we put humans on planets with atmospheres different from Earth's atmosphere, but still containing oxygen, would humans be able to breathe?

From Wikipedia: By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. For example, would humans be able to survive in ...
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16answers
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Resources to justify long-distance space mining missions

Earth is setting up mining colonies on Tau Ceti e. But how can they justify the enormous cost of sending people there? ...Because during the initial exploratory missions, it was discovered that in ...
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3answers
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Making a planet habitable for humanoids: The planet

The question: What characteristics are necessary for a planet to be habitable for humans? What should the generic star and planet be like? The life forms are human, so they Need to have access to ...
23
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5answers
4k views

How would a civilization that has been living on a “cube” Earth differ from one on a “spherical” Earth?

Another question based off of this one here. Let's say on a cube styled Earth-like planet, there was a similar race to humans. If the differences in the planets were minimal (besides, you know, the ...
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6answers
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What's the smallest reasonable natural planet or moon with Earth-like surface gravity?

We all know that equation for surface gravity is $$ g = \frac{4\pi}{3} G \rho r $$ So if we want Earth-like surface gravity of $ g = 9.81 $, then the equation for radius is $$ r = \frac{3 g}{4\pi G ...
117
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18answers
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Could a planet made completely of water exist?

In the Star Trek: Voyager episode "Thirty Days", there was a planet made completely out of water, which is the inspiration for this question. However, that planet was held together by an artificial ...
29
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11answers
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Can a nonspherical planet exist and can it be habitable?

In both fiction and non-fiction worlds, that attempt to keep a sense of realism, planets are spherical. Is it possible for a planet to not be shaped like a sphere? If such a planet is possible ...
33
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3answers
4k views

What are the effects of a planet staying long-term inside of a nebula?

Let's say for some odd reason, a planet (while in orbit of something) travels at all times inside of a nebula. What all would happen to the planet? Could it sustain life (if sunlight was substituted), ...
71
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20answers
6k views

Is it physically possible for a planet to have seasons of different lengths?

Those of you who have read Game Of Thrones will know that in the GOT world seasons do not have a fixed duration, e.g., a winter might last three times longer than the previous one. I find most ...
37
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11answers
5k views

Stumped: How can I get a huge Earth-like planet?

I hope this isn't too broad. I would like an Earth-like planet for November's NaNoWriMo that is just enormous, but plausible. Then I started to get into material composition, proximity to the star, ...
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10answers
2k views

What's the biggest reasonable natural planet or moon with Earth-like surface gravity?

Sister question to: What's the smallest reasonable natural planet or moon with Earth-like surface gravity? - I want us to have both upper and lower bounds for 1g planets available for authors. We ...
37
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10answers
11k views

How can I destroy a gas giant planet?

We have already discussed how difficult it would be to blow up a planet like Earth, basically deciding that you can't do that with any reasonable amounts of energy. But what if I don't need to blow up ...
37
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5answers
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Can a planet survive a supernova?

The Sun has nowhere near enough mass to enter the branch of stellar evolution that would lead to a supernova, fortunately for us. However, there are planets that orbit stars that are destined to go ...
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6answers
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Living Planet Possible?

Although a question about how large a living thing could be has been asked and answered, would a being such as Mogo from DC's Green Lantern series be possible? Mogo is the size of Earth roughly can ...
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6answers
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Is there a theoretical maximum size for rocky planets?

As title suggests, what is the size limit by volume for a rocky planet, if any? Some ideas are discussed here, but I'm wondering if there is more concrete, expert evidence to point either way. If ...
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5answers
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Is this atmospheric composition breathable, and what would it look like?

I have developed a fictional planet with the following atmospheric composition; 60.4% Nitrogen 27.6% Oxygen 9.8% Xenon 1.5% Water Vapor 0.64% Argon 0.06% Carbon Dioxide Is this breathable to humans ...
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8answers
4k views

Can an atmosphere englobe a planetary ring?

Would it be possible for the atmosphere of a planet to reach beyond its planetary ring so that earth-like biology could develop on some of the asteroids there? This question is mainly about whether ...
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2answers
1k views

Orbiting one star in a binary system: what are the effects of the second star on the planet?

This blog post about binary-star systems points out that, rather having the stars be close together, they could be far apart and a planet might orbit just one of them. It gives the example of the ...
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8answers
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How extensive could a habitable twilight zone be on a tidally locked planet?

If a planet always faces the same side to the sun, so that it has a permanent night side and a permanent day side, it will have a twilight zone in between the two sides. This will be a band around the ...
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2answers
3k views

Gravity on a Minecraftian world?

I'm curious what the gravity would be like on an infinite area flat world. The plane of the world would have some finite depth but be infinite in all cardinal directions. This is, in effect, a ...
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2answers
1k views

Life on a planet with multiple gas layers

Could a terrestrial planet have a stable set of layers of atmospheres, and could different lifeforms evolve within those different layers? This question is inspired by the diversity found on Earth. ...
21
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7answers
4k views

Hollow planet with another planet inside it

I was wondering what would happen if there was a planet with a "shell" of stone entirely surrounding it (not connected, just held in place by gravity), with a few holes all the way through the outer ...
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5answers
390 views

Can a planet's axial tilt be changed by carefully planned and set high-energy explosions?

How powerful would a series of explosions have to be to significantly change a planet's axial tilt? In my universe they have highly energy efficient crystals, not only do they store energy but they ...
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2answers
1k views

Terrestrial Exoplanet Skies – I've Built a Visual Sky Chart. Is it Correct?

I'm an artist and I've been trying to find a comprehensive resource that would help me clearly identify likely sky colors for exoplanets that have atmospheres with a similar chemical composition to ...
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2answers
4k views

What would the sky look like from the surface of a planet with rings?

What would a planet's rings look like from the surface of that planet? Would the rings be perceived to be stationary or move across the sky, and would the alignment of the rings relative to the axis ...
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7answers
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What if an Earth-like planet had no axial tilt? (climate and technology) [closed]

Hey guys, thanks for the suggestions and answers - here's a more streamlined question - presently focused on implications on climate and technology. I've also added a little more explanation in the ...
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5answers
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What would the problems with / consequences of a torus shaped planet be?

Take a torus planet: It has the structure of a normal planet (ours): The diagram is not to scale. Assume similar proportions of Crust:Mantle:Cores as the Earth. Is has a similar volume (close to 1.1 ...
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4answers
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Can a gas giant have its own habitable zone?

Gas giants can generate heat via the Kelvin-Helmholtz mechanism. It's oft-repeated that Jupiter actually generates more heat internally via this method than it receives from the Sun. Scale this ...
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5answers
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Can a planet have a figure-8 type of orbit around two separate stars?

Could a planet have an orbit in the shape of a figure 8 around twin (possibly binary) stars? Mostly curious about the physical possibility of such an orbital arrangement; is it stable over a long ...
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7answers
11k views

What would an ammonia-based world look like?

Apart from the obvious difference that liquid ammonia needs a much colder temperature than liquid water (but ammonia-based life forms wouldn't feel that as particularly cold), what would be the most ...
10
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5answers
1k views

How would an earth-like planet with a habitable moon work and how to get there?

I have a planet approximately 3.5 times the mass of the Earth. I have a moon orbiting that planet that has to be habitable as well, because my story will take place on the first expedition to this ...
11
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2answers
3k views

Fusion candle - getting Earth to Jupiter

In A World Out of Time, per Schlock Mercenary, Earth is moved to a new home by lighting a fusion candle. The fusion candle idea is discussed in the Schlock quote: Building a gas-giant colony ship ...
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6answers
3k views

What would the Earth eventually look like, if it was somehow stripped of its atmosphere today?

Consider the present day Earth. Now, through some event (magic, a giant maid with a vacuum cleaner, a disgruntled alien did it, ...), our planet is stripped of its atmosphere. Assume that this happens ...
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9answers
3k views

Could a planet be at the center of the universe, yet still have a sun?

In the past we humans thought that our planet was the center of the universe and everything revolved around us, due to science/math/astronomy and any other means we now believe that to not be true. ...
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12answers
6k views

How would a Martian colony be able to celebrate Christmas?

Accept that we had a reason to go to Mars, managed to build a colony there, and what we found on Mars is valuable enough to ship back to Earth. There is now a self sustainable colony living under the ...
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3answers
1k views

Season cycle that would occur on a habitable planet that orbits two suns?

If there's a habitable planet that orbits two suns like the above orbital route, what would possibly occur on that planet? Would it have two yearly seasonal cycle (compare to earth)? Would it be ...
18
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1answer
1k views

Making a planet habitable for humanoids: The star

The question: What characteristics are necessary for a planet to be habitable for humans? What should the generic star and planet be like? The life forms are human, so they Need to have access to ...
23
votes
9answers
4k views

What are the possibilities of a dwarf planet orbiting opposite Earth's orbit?

I am drafting a short story about a small object orbiting the Sun at the precise 'speed' as Earth's opposite the Sun, undiscovered by us due to its position. The problems I see with this include the ...
15
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13answers
5k views

How plausible is a 'tilted axis' planet with a “south pole” constantly facing toward its star?

The basic concept of this planet is that, the planet has a tilted axis (you probably guessed that already) which results in the South Pole constantly facing towards the sun. This would result in the ...
23
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5answers
3k views

What major event could disrupt planet Earth's orbit around the Sun?

What artificial disaster could disrupt the orbit of our planet? Not necessarily making it leave the Solar System, but maybe changing its trajectory around the sun. And by artificial, I mean that the ...