Questions tagged [geophysics]

For questions relating to geophysics: the study, behavior, consequences, and technologies involving the physical properties of the Earth.

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How do I determine the locations and strength of earthquakes using a fictional tectonic plate arrangement?

I've got a world that I made using a combination of star system and plate tectonics simulations via a variety of programs. I've used this to build plenty of overlays for my world map—plate boundaries, ...
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3 votes
1 answer
112 views

What kind of atmospheric composition would make the sky look green and still be breathable?

In my story scientists discovered a planet that look green from the telescope and they used a advanced starship to go there and the y found out that the planet is habitable with a breathable ...
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5 votes
8 answers
224 views

What's the clearest evidence for a planet's magnetic field being flipped relatively recently?

Assuming a human-like entity has the ability to visit a planet that is like (or is, if that makes this easier) Earth during two time periods: A time period where the planet's magnetic field is stable ...
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5 votes
2 answers
124 views

Is there a metric for how far underground a nuclear bomb needs to be to safely be tested?

I'm running a one-shot cold war campaign where the PCs are going to sabotage a prototype Soviet giga-ton bomb. Realistically, how far underground would a giga-ton bomb have to be buried to be safely ...
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6 votes
4 answers
164 views

How un-dense could a super-duper-Earth be if that super-duper Earth was bigger than Neptune?

Long story short, I have an Earth-like planet, which is orbiting a mega-Earth (think a super-duper-sized version of a super-Earth), which is orbiting a K-type star, which is orbiting UY Scuti. I want ...
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3 votes
1 answer
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Given the parameters of this planetary system, what would the practical effects be on its surface?

I have a planetary system consisting of an oceanic world [7% Land] with a large precious metal moon [extremely dense with valuable alloys]. The planet has 110% earth mass, with a size of 1.4 Earth ...
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4 votes
1 answer
80 views

What are the implications of this given planetary situation?

My planetary set up is a single planet with 110% Earth density, and a planetary radius of 1.4 Earths. It is a continental world composed of 89% Liquid water oceans, stretching up to 13 km at the ...
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4 votes
1 answer
262 views

How big can a whirligig/planetcake get while still maintaining human-survivable gravity at its equator?

A whirligig/planetcake/whatever punny name you want for it is a super-sized planet (we're talking about Jupiter masses here, not Earth masses) that spins so quickly that it's shaped like a pancake (...
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15 votes
5 answers
4k views

How powerful would a volcanic eruption need to be to blast debris to the height of the ISS?

I'm trying to write a scene in which a supervolcanic eruption destroys the ISS by blasting a shower of tephra to the ISS's orbital height. The ISS is about 400 kilometers up. Let's assume the ...
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2 votes
1 answer
128 views

Could a supervolcanic eruption in the Phlegraean Fields be triggered by detonating a 1-gigaton nuclear bomb and then fracking the resultant salt dome?

So. There's a group of nutcases in my setting; they are an ages-old, all-powerful secret society, yadda yadda yadda, control massive amounts of the world behind the scenes, have agents everywhere of ...
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39 votes
10 answers
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Could an underground civilisation deduce the size and shape of their planet?

Not sure if this still falls under worldbuilding. Let's assume a civilization living with the following restrictions: No access to the surface or ability to observe it (no sky, no atmospheric samples ...
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3 votes
1 answer
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perpetual music geo machine

while traveling the world merchants have noticed the sound of many melodies repeating through night and days, in some regions melodies shift tone or speed based on the time of the day, and each region ...
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4 votes
3 answers
242 views

How many tectonic plates should my moon have?

I have been wondering, what factors influence the number of tectonic plates a planet would have? Are there criteria to choose the number? Case in point, for my habitable moon project, here is the ...
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1 vote
2 answers
264 views

If a lightspeed impactor "clipped" the Earth, would the resultant valley remain stable for geological timespans?

Let's say that some aliens fling a hyper-super-duper-lightspeed impactor at the Earth. They barely hit it. Instead of a direct hit through the center of mass, the impactor "clips" the Earth ,...
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4 votes
2 answers
105 views

What are some means of subjecting Earth to a constant magnetic field imbalance capable of damaging or shutting down unshielded electronics?

I'm trying to make an alt-history in which electronics are constantly effected by higher-than-normal background magnetic effects - think a constant geomagnetic storm, except not necessarily caused by ...
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3 votes
3 answers
306 views

Any advice on what is a realistic way to use plate tectonics to create landmasses and barriers?

Recently I've taken it upon myself to create a brand new fantasy world. I created fantasy settings in the past but this is the first one with such a strong emphasis on realism and staying true to our ...
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2 votes
3 answers
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Would there be a point to windfarms in a country surrounding a bay and is also almost fully surrounded by mountain ranges?

To better demonstrate my question, here's a very shoddily made image I made in Photoshop in under five minutes. Essentially this country is an almost full ring of land with a natural barrier of ...
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3 votes
1 answer
191 views

Mountain heights - theoretical limits

I have a country bounded on three sides by fold mountains. Due to a magical plot device, the force acting to drive the upward motion of the mountains persists indefinitely, acting on the plates ...
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6 votes
1 answer
91 views

Would an asteroid colliding with a terrestrial planet result in the creation of extensive caves nearby the crater?

I just did some research on the Chicxulub crater in the Yucatán Peninsula in Mexico, which is the crater from the asteroid responsible for the extinction of the dinosaurs. Yucatán itself does have ...
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2 votes
2 answers
243 views

How long would it take for earth to dry up?

At current global warming rates, the sea levels are rising because the ice caps are melting. But once the ice caps are all melted, the sea would stay the same. In my world, humanity's money revolves ...
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4 votes
15 answers
2k views

Is there any scientific way a ship could fall off the edge of the world? [closed]

I'm trying to write a story about falling off the edge of he earth during a sea voyage and would like to incorporate as much as detailed and accurate physics as possible. For this to work, I know ...
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10 votes
3 answers
2k views

What pressure, temperature and atmospheric challenges exist for human habitation 1 mile beneath the surface of the earth?

Would air pressure be demonstrably greater in a subterranean city at a depth of 1 mile? Lava tubes leading into a dormant magma chamber -- this would have challenging gasses that would need to be ...
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  • 111
3 votes
2 answers
4k views

Black hole at the center of the planet

Okay, picture a planet so massive, a black hole has formed in its center. The minimum mass of a black hole is 22 micrograms, or the Planck mass, and whatever the core is made of, it needs to be ...
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2 votes
1 answer
114 views

Planet covered in non-Newtonian fluid

Basically, I watched that horrible holiday special. The animated short that introduced our friend Boba Fett, and there’s a planet that’s apparently covered completely by a non-Newtonian fluid. What ...
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2 votes
2 answers
223 views

Could ants thrive on mars if they stayed underground? [closed]

Lets say humans would want to populate Mars with ants. Would it be possible for an ant colony to create a self sustaining ecosystem underground on Mars, by for example farming fungi, like some ants do?...
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3 votes
1 answer
85 views

How to get Rodinia/Pangaea to now in a year?

I was reading this article, and noticed this section: At the opposite end of the plates, the presence of water underground changes how easy or hard it is for one plate to subduct beneath another in a ...
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8 votes
4 answers
2k views

How Would the Mountains Form in This Supercontinent?

Here is a supercontinent map generated randomly from the Donjon website: Now, hold on just a minute. Something looks wrong. The mountains in brown and white are too far inland to be caused by ...
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7 votes
2 answers
336 views

Does extreme atmospheric pressure increase or decrease the power of weather?

The world I have imagined is much like Venus, with an atmosphere at "sea level" 70 times that of Earth, and temperatures at the same altitude approaching 377 degrees Celsius - with much more ...
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10 votes
3 answers
674 views

Inverted Everest world

I want to make a world with a great deal of variation in habitability in terms of temperature and pressure. Some areas would be habitable; others less so, some would require protective clothing and ...
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23 votes
8 answers
4k views

Can the Little Prince's planet actually exist in our universe?

This is a drawing by my daughter which inspired one of the elements in my story/world: The perspective is a little bit mixed here (certainly I don't have a 15 meter-high volcano in this world), but ...
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3 votes
7 answers
615 views

I need a possible way to flood a man-made lake located higher than sea level

I have a scenario where I need a man-made lake to overflow. It’s located higher than sea-level. There are underground streams which could be feeding it. It could have a channel to drain it into the ...
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  • 31
1 vote
3 answers
125 views

(Semi) Believable way to quickly submerge a large landmass

I once before asked a question on how to quickly submerge a large landmass/continent. The answers there basically concluded that literally ''Sinking'' (a la Atlantis) is pretty much impossible to do ...
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2 votes
2 answers
324 views

Can Florida become an island?

I've been building a world set in the near future (decades/centuries) that includes Florida as an island. My intent was for a manmade or natural event to occur at or near the South Georgia Rift, but I ...
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2 votes
3 answers
211 views

Could an enormous structure be used to attract rain by acting as an artificial mountain?

If it were possible to build a giant geodesic dome tens of miles in diameter, what effect would it have on nearby weather? If built in an arid climate like the Sahara or Australia, would it be ...
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8 votes
2 answers
2k views

Could a robot that can survive at the center of the Earth also survive a nuclear explosion?

The robot in question is a very large, worm-like mining robot with a huge drill on its front end, built to survive staggering levels of heat and pressure. It's so resiliant, in fact, that it can ...
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8 votes
3 answers
388 views

Impacts of a moon falling on an Earth-like planet?

In the world my friend and I are making, the dark lord makes one of the planets uninhabitable by causing a moon, about the size of our own, to fall on it. About 7000 years later, it is unnaturally ...
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  • 1,557
6 votes
5 answers
694 views

Need method to eliminate all life on planet [duplicate]

Space faring advanced species needs to 'disinfect' planets in habitual zones around stars. That's all life. They can wait a few thousand years to come back and seed the planet with a new ecosystem. ...
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  • 174
9 votes
3 answers
421 views

How could formamide lakes form on an exoplanet?

I've been recently looking into alternative biochemistries for life and the environments were these could be found. I already asked a question about how ammonia oceans might form a while back. Today I'...
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9 votes
1 answer
405 views

Geothermal gradients if Earth becomes a rogue planet?

Assume Earth has been wrenched out of the Sun's orbit and has become a rogue planet, with its surface equilibrium temperature falling to ~-240C. At what depth will temperatures remain "comfortable" ...
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  • 463
3 votes
5 answers
320 views

How to tackle one or multiple submerged continents

A part of the story I am writing involves two continents that centuries before the story takes place sunk into the sea. I want to have a way to explain this that does not come down to just the sea ...
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  • 1,441
6 votes
1 answer
464 views

How could you build an artificial planet-sized magnetic field?

I'm conceiving of a world where humans can readily terraform worlds that were once considered "dead" due to the planet's magnetic field being long gone. In such a situation, what could humans do to ...
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5 votes
0 answers
77 views

Relationship between Ocean Gases and Atmospheric Gases [closed]

A version of this question is posted in Chemistry SE but doesn't seem to be getting traction there. Perhaps this SE is a bette place for this question? If you think it belongs on a different SE please ...
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11 votes
1 answer
495 views

Defining a superfluid ocean

I'm working on a world where water acts as a high-temperature superfluid. Specifically, H2O's lambda point is above its boiling point. Thus, all liquid water on the planet behaves as a superfluid. It ...
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3 votes
4 answers
3k views

If a world had a massive single giant world tree could it stop an earthquake?

You know stuff like Yggdrasil tree but just a normal tree that is the biggest and tallest in the world. If the roots grow to surpass the continental and oceanic plate either it only cover some parts ...
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  • 8,809
4 votes
5 answers
382 views

How could a very strong impact on a planet create deformations on the opposite side?

Update (6/20/19): I have received some great answer here and they all mostly point to the fact that while effects on the opposite side of the planet are possible, the deformation may or may not ...
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  • 251
1 vote
0 answers
82 views

what effect if the world have a single massive world giant tree? [closed]

you know stuff like ygdrasil tree but just a normal tree but the biggest and tallest in the world, i wonder what the effect to the world ? for an example if the root grow to surpass the continental ...
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  • 8,809
14 votes
4 answers
576 views

Can a liquid sand ocean exist naturally?

I'm talking about this sort of liquid sand: https://www.youtube.com/watch?v=My4RA5I0FKs "Desert-as-sea-analog" is present in many media, but often they lean heavily into fantasy, and it seems not ...
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1 vote
3 answers
168 views

What Else Could Create Jeffrey Linn's Coastlines BESIDES The Influence of Ice? [closed]

Who? Unfortunately, I could not find any background information about Jeffrey Linn, but he is better known for his sea level maps. Specifically, what a particular city would look like if sea levels ...
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0 votes
5 answers
145 views

How Can the Coastlines Look Similar In Spite of the Cooler Temperature

The established fact is that the shape of a planet's continental coastlines is determined by the planet's climate. Higher temperatures mean less ice, which ultimately means higher sea levels. (Case ...
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2 votes
1 answer
140 views

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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