Questions tagged [geophysics]

The study of the physical processes and properties of the planet Earth. Applicable to many subjects about Earth, such as its shape, its magnetic field, and ocean currents.

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44
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3answers
4k views

Why don't the Earth's oceans generate a magnetic field?

Many questions have been asked here about why the Earth has a magnetic field, e.g., What is the source of Earth's magnetic field? How does Earth's interior dynamo work? How can an ...
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1answer
70 views

What's the minimum possible size of a round astronomical body?

What's the minimum possible size of a spherical shaped rocky planet or satellite? Is it possible to occur a spherical shaped planet without having a molten core?
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0answers
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How many waves are in the ocean? [closed]

XKCD #2741 mentions in the title text It's cool how, when there's a number lots of people are curious about, but which isn't easy to measure, some random guess will get cited everywhere and become ...
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How quickly can methane hydrate dissociation create overpressure in sediments?

Can it overpressurise the sediments or it degrades way too slowly to do that? How does the pressure dissipates in the sediments?
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2answers
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What is the pressure at the centre of the Earth? [duplicate]

If the (net) gravity (at the centre of the Earth) is $0$, then what is the pressure? Some say it's astronomically big, but how can that be? Is it because of the (high) temperature? I can't think of ...
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How can methane hydrates form in the Qilian mountains in China?

It's 5000 meters above sea level, I tought hydrates required high pressures to form, I know it's located below permafrost but I still don't understand how could it form in such high places.
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Atmospheres and oceans on lower gravity planets

Using Earth as an example, how much less gravity could the planet exert and still retain its atmosphere and oceans? Or is it a matter of size, mass, magnetosphere, place in the solar system, all of ...
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1answer
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How much does wind speed change in an area/over time?

I am currently planning to implement wind force into a physics simulation and have a hard time figuring out how to best approach the problem. My main concern here is how consistent wind speed is. How ...
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What is an earthquake like in terms of kinematics?

I would like to know how the Richter value of an earthquake converts into frequency and amplitude. Are there sub-frequencies? Is the vibration along one or multiple axes?
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3answers
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Had the centrifugal force of the rotation of Earth in the past forced liquid, hot Pangea to be positioned near the Equator?

Had the centrifugal force of the rotation of Earth in the past forced liquid, hot Pangea to be positioned near the Equator? Maybe also a question for 'GSE' but if we deal with centrifugal forces and ...
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4answers
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Paradox about greenhouse effect?

I know about the greenhouse effect, but isn't earth receiving the same amount of energy but getting hotter than with that same amount of energy? My guess is that earth reflects less light, but then ...
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At the time when Earth was hot liquid why the Si-Al layer covered only partially the Si-Mg layer?

At the time when Earth was hot liquid, why did the Si-Mg layer covered the entire surface, while a less denser Si-Al layer covered only partially the Si-Mg layer? I am very curious as to how a ...
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What is Earth’s total external magnetic flux?

What’s the total magnetic flux of Earth’s exterior magnetic field (webers)? I know Earth’s magnetic field is a little complex, so for simplicity let this be the integral of the surface-normal ...
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Why can't the Earth's core melt the whole planet?

Earth core temperature is range between 4,400° Celsius (7,952° Fahrenheit) to about 6,000° Celsius (10,800° Fahrenheit). Source Why can't the Earth's core melt the whole planet? In other words, what ...
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1answer
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Is General Relativity (GR) compatible with the expanding Earth hypothesis? [closed]

There is a lot of convincing evidence that the Earth and all the other planets and their moons are expanding with time. Prof. Samuel Warren Carey's summary of the evidence: https://www.youtube.com/...
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Is there a modern accurate formula for the length of the sidereal year?

Newcomb (1898) gives the following formula for calculating the tropical year: $$365.24219879 - 0.00000614T$$ And the following for calculating the sidereal year: $$365.25636042 + 0.00000011T$$ Where T ...
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1answer
54 views

Calculate the radius of Mercury's core with density, equatorial radius [closed]

I have a task where I don't know how to solve the second part. Some data on the planet Mercury: mean density $5400$ $kg/m^3$, equatorial radius $2440$ $km$, oblateness $0.0$, period of rotation $58....
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2answers
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Is there a correlation between the Earth's spin, the moon, and temperature?

Based on NASA's arcticle, changes to land, ice sheet, ocean, and mantle flow affect Earth's spin. Does the moon's elliptical orbit around Earth also affect Earth's spin? What effect does distance play?...
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1answer
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Why are the Earth and Moon so different?

The suggestion was made that the Earth and the Moon are two parts of a once whole object. If that is true then they must share the same basic composition. They also receive fairly similar amounts of ...
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1answer
54 views

What exactly are the 2 points where a magnetic needle becomes horizontal?

Textbooks and websites say: A magnetic needle rests making different angles with horizontal when suspended at different places of the earth In the explanation, they say that the magnetic needle ...
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2answers
108 views

How to explain the Earth's Equatorial bulge without centrifugal force?

There are many answers to the question why is the Earth bulged at the equator, see e.g. here, but almost all of them involve centrifugal force. Since it's a fictitious force, how to we explain this ...
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1answer
27 views

Does the Earth's magnetic field reversal and the corresponding magnetostrictive stress and strain make any contribution to the Earth's oblateness?

If the changing magnetic field in a power grid's transformer can induce stress and strain on the transformer core, then can the changing magnetic field of the Earth, similarly, place stresses and ...
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1answer
65 views

If the moon became a black hole, how much lower would the temperature be on Earth's surface?

I read that if the Sun became a black hole the Earth would become colder, but the effect would be negligible because the mass of the hole is still there so there would still be tides. But, how much ...
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Would the Earth have cracked differently than 'pole to pole' at Atlantic ridge if had been rotating slower?

When a thick hot peace of glass is left to cool down it will break on the surface. Have the same happened to Earth and did the fast rotation provoked the crack at the middle Atlantic to gain this pole ...
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3answers
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Does the inner core of the Earth drop?

If standing on earth, I experience the planet's gravity. Rain drops are accelerated to move toward its centre and reach the crust. These attractions are mutual. This contrasts to e.g., the ISS with ...
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1answer
52 views

What will pole reversal cause to modern world and civilization?

I don't think it's just a matter of reorienting maps and recalibrating compasses. In any case, how long does a inversion last? hours, days, weeks, years? If it lasts days or more.... would Sun fry ...
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Why is deep water cold while deep soil is hot?

The temperature of deep water is around 3 or 4°C. However, in the Earth's crust, temperature increases with depth (e.g., 66°C in some underground mine). So, why would the water be cold? If the heat is ...
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1answer
40 views

What would be the increase of gravity if we create a new world slightly bigger than the earth? [closed]

I need to know what would happen if I increased the earth's size by a small percentage to make a fictional world similar to earth. So my thought process is this: My thinking started with increasing ...
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1answer
58 views

Clarifying the relationship between pressure and temperature?

From the ideal gas law, we are aware that PV = nRT, which seems to suggest a direct relationship between pressure and temperature, or that as temperature increases, pressure increases. In my geography ...
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1answer
35 views

Can gravity be measured by proximity?

Can the topography of a terrain be measured by a gravimeter to give a clear image of the surface or sub-surface of a planet or does gravity scatter like light? In other words can the changes in ...
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2answers
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Schumann resonance frequency

I keep hearing that Schumann resonances have been increasing rapidly in recent years. And that it was relatively stable before. I failed to find any scientific data proving or disproving this. I would ...
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2answers
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Gravity force inside the Earth

It is a well known exercise on classical Newton's gravity that assuming that the Earth has an ideal round shape to compute its gravity force at the given distance from its center. (Answer: it is equal ...
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Can Earth's Magnetic Field Be as Less as -85μT and as Much as +70.46μT?

What did create the question? I was analyzing a data set where the researchers have used objective data. They have calculated earth's magnetic field through sensors and that research was conducted in ...
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How does the NASA InSight lander determine the depth of a Marsquake?

With only one lander with this type of equipment at one location, how can the InSight lander's investigators be so sure of the depth of the Marsquakes it detects?
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1answer
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Would a 1km edge length solid tungsten cube sink through the Earth crust?

This question was inspired by this question on worldbuilding SE. Suppose you have a giant cube with $1$km edge length made out of pure tungsten and you put it somewhere on the ground. This is the size ...
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3answers
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Finding a single component of a strain tensor ($E_{yy}$) knowing $E_{xx}$ and $E_{yx}$

I know $E_{xx}$, $E_{yx}$, and $E_{xy}$ but I can't figure out how to find the value for $E_{yy}$. I think it has something to do with the phrase 'homogenous $2D$ strain' as a big hint since there's ...
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0answers
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The Earth's Core [closed]

4 questions about the Earth's core Does the earths core rotate differentially to the earths crust or surface? and what is the differential rotation, if any? Due to the increased pressure (of 3.6GPA) ...
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0answers
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How far could one tunnel towards the Earth's core? [closed]

Using current technology and virtually unlimited funds, how deep could we dig a shaft/tunnel with 1m bore (or larger), and what would be the limiting factor(s)? If we push the envelope of current ...
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7answers
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Why isn’t the center of the Earth cold? [closed]

If the pressure of the Earth is keeping the inner core solid, keeping it rigid to take up the least space, and temperature is dependent on how much the atoms are moving, why isn’t the inner core cold? ...
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4answers
737 views

Why is the bottom of the Mariana Trench not frozen?

I have found following information on Wikipedia: The temperature is $1$ to $4\,°\mathrm C$ and the pressure is about $0.156$ GPa. The Graph tells us that it's liquid. However, I don't quite ...
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2answers
452 views

How do rocks store information about Earth's magnetic field?

When a particular rock is being formed in a rift (by the solidification of magma, which is composed of ferromagnetic materials), the rock "stores information" about the Earth's magnetic field at the ...
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1answer
57 views

Does the moon formation theory consider the necessary precision in the angle of ejection of material caused by the collision?

When Newton considered that a projectile fired horizontally at 8km/h from a very high mountain would enter orbit, I suppose that he also understood the importance of the firing angle being strictly ...
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Does human made global warming of atmosphere drive the increase of volcanic and tectonic activity?

I read in the handbook that the heat transfer coefficient between magma and soil is very small. What then is the mechanism of the predominant influence of global warming due to greenhouse emissions on ...
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0answers
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How much higher is muon flux at Earth's poles?

https://futurism.com/make-a-cosmic-ray-detector-at-home-and-test-relativity-2 This article states that the Earth's magnetic field funnels incoming muons towards the magnetic poles. Quantitatively, ...
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85 views

How gravity is responsible for cone-like shape of a mountain?

I searched on web and found that that the most important factor for conical (approximate) shape of a mountain is the action of rivers. I understood it well but I again searched more on web because ...
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1answer
141 views

Why the Earth's inner layers temperatures are layered and not distributed?

so I was having a debate with a flat earther, and he sent me this image which I couldn't explain well. at first, I thought that the different pressure levels inside the layers cause these levels of ...
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Transmission Spectrum of Rock

Maybe a very specific question, but what wavelengths are sand grains transparent to? Also, how can one image underground minerals through rock? Is there a certain Infrared band that sandstone (...
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2answers
52 views

Influence of gravity upon gases [closed]

Are gases influenced by gravity? If yes: so how you can demonstrate that? Is there are a difference in distribution of gases in the air? So CO2 will be close to surface more than O2? Si no: why ? (I ...
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1answer
54 views

Calculate how thick the continent is [closed]

I have a task that I'm stuck on: For simplicity's sake, we assume that a continent consists of an even thick surface of granite that floats in peridotite. If a continent protrudes 5.0 km above the ...
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3answers
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Why is dry soil hydrophobic? Bad gardener paradox

When I forget to water my plants, and their soil becomes very dry, during the next watering I can see that the soil becomes hydrophobic. I can even see pockets of air between the repelled blob of ...

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