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Questions tagged [planets]

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

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What color should the snow be in this chlorine world?

This question is in the same context (the same world) proposed by Steven L. Gillett in his book: "World-building". And actually there have been some other questions about this same chlorined world. ...
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Origin of life on a waterworld

Take a planet like Gliese 1214 B, which has no land, an ocean 100s of kilometres deep and a seabed of Ice VII. For the purposes of the question, let's assume that the pressure and/or temperature near ...
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What natural phenomenon could lead to greatly varying season lengths? [duplicate]

I'm intrigued by the topos of varying season lengths brought to us in the Game of Thrones universe. I think it makes for a brilliant and versatile backdrop for the story, and it is something I'd like ...
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1answer
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Would a planet the size of Mercury with the gravity of Earth be scientifically possible? [duplicate]

I'm trying to do calculations for a planet around the size of Mercury with the gravity of Earth. Would the gravity be too high for a planet this size? Do I have to change some numbers, or is this ...
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How can I create a new planet/satellite system that generates tides of 6-8 metres?

I'm creating a new setting for a novel. I'd like to build a world where the interaction between the planet and its satellite/satellites can generate a normal tide excursion around 6/8 metres. ...
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How can I launch a projectile to hit something in orbit, using only geological structures and power sources?

As an ancient organism whom currently occupies a large chunk of a planet beneath the surface, I have a pesky issue with an invasive species. These humans have decided to colonize my home, mistaking it ...
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What would plant life on 55 Cancri e be like? [closed]

55 Cancri e is an actual exoplanet which should be around twice the size of Earth so it would be high gravity. It also is thought to be a carbon planet, meaning the role silicate takes on our world ...
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A Decoy Planet made of expanded polystyrene. How big can I make it?

Note: This is different from the previous question Building a full-sized Lego Earth - what would it look like at various levels?. In that case it was about making a solid full-size Earth from Lego and ...
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Can a planet's rings be so thick that someone inside them can't see out?

For a SF story I'm wondering how thick a planet's rings can be? When viewed from the inside, can the ring material be so dense that visibility would only be a couple of meters? What would it take to ...
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4answers
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Is the size of a portal going to limit the propagation of gravity through it?

It's a general question but my specific concern is whether different planets would crash into each other if a portal is made between them. We're assuming bare, naked, "hole in space" portals. This ...
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How can Mars have life but still be “The Red Planet”

Building on this question "Discovery of life on Mars" Mars is habitable (40% the mass of Earth, 6.06 m/s² gravity, escape velocity of 7.88 km/s, a satellite big enough to stabilize its axis and has ...
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Need a specific event that wrecks the surface, allows the race to survive in bunkers, and affords an aftermath suitable for them to rebuild

One rule: it cannot be caused by aliens or AI invading the planet. But it is okay if an alien race causes the destruction in any other way. It's an Earth-like planet. I need the effects of the ...
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If the Earth was part of an ultimate solar system, what would the sky look like?

I once show a picture depicticting the idea of an ultimate solar system: Image Copyright Sean Raymond In this solar system there are 8 planetary orbits, each containing 52 equal-mass, evenly-spaced ...
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3answers
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Life on giant planet | Can centrifugal force reduce gravity?

In my world a space civilization is colonizing a massive solid planet. The planet has an extraordinarily fast rotation. The gravity is severe at the poles, making life impossible, but life flourish ...
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What is the Habitable Zone of a Red Dwarf star?

This question is pretty straightforward: What is the minimum and maximum distance for a planet to be in the habitable zone of an average sized (not biggest, not smallest) Red Dwarf star?
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1answer
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What would a world-ending meteor impact look like from the ground?

I've read a lot of questions about the specifics of meteor impacts on this site, but strangely this one seems to still elude me: Assume a meteor of sufficient mass and speed to wipe out human life ...
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3answers
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Life on a gas giant?

I know of the conceptualized "Sinkers", "Floaters" and "Hunters" that Carl Sagan and Edwin Salpeter of Cornell conceived of - as possible life forms that might inhabit a gas giant. At the time they ...
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4answers
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What are the day and night fluctuations for a moon orbiting a planet the size of Jupiter?

In a nutshell, I'm trying to build a world with erratic day/night cycles. To get the erratic days, I'm working with a habitable moon. It takes 3 full earth days (72 hours) for the habitable moon to ...
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Distance between star systems

I'm writing a story that will eventually escalate from being focused on one planet to the entire star system that planet belongs to, and finally to a big story involving the two nearest star systems ...
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4answers
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Desert planet with forests at the poles

I'm thinking up a Mars or Venus type planet where the poles (or one pole) has a forest growing out of it due to a device that is used to make the planet more habitable by creating a oxygen friendly ...
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2answers
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How can I destroy a planet with antimatter?

So I found the base of these pesky rebels on this planet and I am tasked with destroying the planet to eliminate the rebels once and for all. Unfortunately, my death star has malfunctioned and has ...
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4answers
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Could a terrestrial planet have water for a core?

There’s a planet called eaglypt whose surface is 100% barren desert. However, there is a twist: the planet’s core consists of liquid water, and there are a few places where this water seeps through ...
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3answers
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Building a full-sized Lego Earth - what would it look like at various levels?

Lego representations of Earth have been made at various scales, for example this one: Suppose Slartibartfast made a full-size Earth from Lego (including the oceans being represented as solid blocks. ...
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2answers
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Stellar and magnetic parameters for creating polar radiation hazards

I've got a generally earthlike planet, but my goal is to make radiation exposure in the polar regions a much larger hazard than it is on Earth, while not being an issue in other regions. Nothing ...
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2answers
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What 4D shape could best fit a looping world?

I have an idea for a world such that the world itself is like a large loop. The best way I can think to describe it is going step by step through the "loop". Imagine a planet-like object; a sphere ...
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3answers
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How does having 3 moons change a planet?

I'm working on a story that takes place on a world that has 3 moons. At least 2 of the moons are the same size. They align extremely rarely. Otherwise, it's an earth-like planet. There is one ...
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2answers
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What would happen to the Earth if it were suddenly transported to a completely empty void? [duplicate]

The entire planet Earth is suddenly teleported (never mind how for now) to a completely empty space. No sun, no moon, no stars or other planets. There's absolutely nothing out there and it appears ...
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0answers
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How long would it take to recover from a galaxy-wide war? [closed]

The Great Galactic War has ended. The evil Tatian Empire has been destroyed, and a new power, the Aurean-Ishga Republic, has risen from the ashes. However, there has been tremendous damage done to the ...
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2answers
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Maximum realistic salinity level with thriving aquatic environment?

I'm trying to create a planet which environment is not immediately lethal to humans, (reasonable oxygen level) however after closer inspection turns out not to be specially Earth-like. One issues is ...
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4answers
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Underground Atmosphere

I have a terrestrial planet that is similar to Mars in many ways, a desert-like surface, thin atmosphere, and inhospitable to large flora and fauna as we know it. This planet has ceased tectonic ...
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0answers
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Downsides of a Magnetosphere stronger that Earth's? [duplicate]

It is clear that a planet that possesses a weaker magnetosphere than that of the Earth will present issues (such as less protection from stellar radiation) to a potential human colony. However, are ...
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Can a solar flare or coronal mass ejection cause a planet to heat up? [duplicate]

There is this setting I wish to use of a planet tidal locked to a red dwarf, in a Goldilocks/habitable zone/distance, that gets turned into, mostly, a desert due to a coronal mass ejection or a solar ...
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How can you prevent a theocracy from being inevitable when religious leaders have power over nature?

In this world, religious leaders of a world religion practice a form of ritual magic that is essential to human existence. Certain rituals must be performed at certain times for nature to function ...
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10answers
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Plausible reasons for multiple hot seasons in one solar year

Setup: A planet generally with an earthlike climate, although slightly wetter and warmer as a general rule, with a little more oxygen in the atmosphere, but habitable by unmodified humans. Still has ...
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1answer
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Could a Moon have its own “Rings”, like Saturn's, without the Host Planet having them?

I'm currently fleshing out a sci-fi universe and always looking for fun new locales to populate it with, and I saw this phenomenon in a video game I've been playing recently, and it made me curious... ...
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What would an earth-sized world be like if shaped like Ultima Thule?

Recently, pictures taken by the New Horizons space probe were released depicting the unusually-shaped object Ultima Thule. Now, suppose there was an world the size of the Earth, but in the shape of ...
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What kind of food would be common on a tropical rainforest/ocean planet? [closed]

I have an alien planet with the entire world landmass arranged in two giant rings roughly 10 degrees north and south of the equator. Everything above sea level is beach or tropical rainforest. The ...
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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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Can planets collide and not melt together?

Ok so I've been going around on the internet trying to figure out whether or not when 2 earth like planets of similar densities and makeup collide is it possible for them to bounce off of each other ...
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1answer
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What could prevent a planet from possessing magnets/electricity?

Without changing a planet from being habitable for humans and keeping a similar ecosystem why could intelligent races never access electricity? What systems need to be erased from the planet to not ...
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2answers
308 views

Which unique features should have a habitable planet originating from atmosphere stripped waterworld?

Premises: red dwarfs tend to have violent sun storms in their early years, thus are expected to strip atmosphere of planets that may be in their habitable zones; water worlds (including planets with ...
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0answers
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Suppose I have an Earth sized planet whose oceans are made of pure glass - what would be the effect of striking said oceans with nuclear bombs? [closed]

This question was prompted to me by my answer I gave to this question. In it I stated that an Earth sized planet would satisfy the criteria if it's oceans were made of glass or at least regions of ...
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1answer
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What are materials that could give an atmosphere a deep blue color?

Here's some rough WIP pixel art of the planet I'm trying to create just to give you an idea of what I'm talking about color wise. I'm referencing the dark blue that you see at the poles of the planet. ...
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2answers
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Time in relation to life in the Jovian System

I'd just like to preface this with the fact that I'm super new and I apologise if this has been discussed in some way previously (I have looked at similar topics but they haven't quite given me the ...
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2answers
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Planet Orbiting a Red Dwarf

I'm trying to create my planet orbiting a red dwarf, honestly I've thought other scenarios but it's like every answer opens new questions. I'll just say what I want my planet to be and I'd like your ...
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1answer
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Is a planetary 'temperature inversion' plausible?

It was disputed in the 1940s-50s whether Venus had a hot surface and cool cloud layer or a cool surface and hot cloud layer. As I recall, both were considered at the limits of plausibility at the ...
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3answers
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A planet with different gravity

I am trying to find an explanation to a planet in which the gravity is not constant, thus allowing some continents to be situated 2-3 km above surface while others are "grounded" on the surface. The ...
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2answers
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How far out can a pre-telescope human society (naked eye observations only) detect planets?

There are many questions on WBSE that cover most aspects of building a planetary system. (some examples below): Creating a realistic world(s) map - planetary systems How many planets should I have ...
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1answer
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What size would a planet have to be such that I could throw a tennis ball into orbit?

If I was affixed to the surface of some solid spherical body in space (so as to ignore effects like me floating away), would it be possible for me to throw a tennis ball so that it went into orbit ...
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2answers
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Is it possible to place a permanent probe on Uranus?

Before anyone points the finger saying this is a tasteless joke, there are some actual good reasons to pick that specific planet for exploration among the giants in our solar system: Smallest mass ...