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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2answers
405 views

What is the dominant cause for ocean waves at a beach?

What is the dominant cause for ocean waves at a beach? Are they the result of wind/pressure difference? If so, the waves do seem to exist in similar intensity even during relative quiet times of the ...
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2answers
420 views

A lightning protection device physics

Here is a description of the principle of the operation of a new lightning device: During a storm the ambient electric field may rise to between 10 to 20 kV/m. As soon as the field exceeds a thresold ...
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3answers
303 views

Ozone Hole in the South Pole

Perhaps this should be a chemistry question, but it seems to have physics attributes. There's a perennial ozone "hole" around the south pole created by destruction from Cl based chemicals like CFCs. ...
2
votes
2answers
119 views

Seismic science questions

We just (20mn ago) suffered from another strong aftershock (of the initial March 11th earthquake) in Japan. I have some questions related to seismic science. Why is there so much time between the ...
41
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7answers
4k views

Why is the Earth so fat?

I made a naive calculation of the height of Earth's equatorial bulge and found that it should be about 10km. The true height is about 20km. My question is: why is there this discrepancy? The ...
3
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1answer
671 views

live Kp index data

I need to create an online service displaying latest Kp index. Where I can take the data? The data should be in machine-readable format, i.e. text files, XML, or CGI gateways, for instance. No ...
17
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3answers
1k views

How does uranium from supernovae explosions end up in mineral veins in a planet?

The reply to a question about nucleosynthesis, that heavier than iron elements are produced in supernovae explosions, raised for me the following question which I could not answer by googling. ...
4
votes
2answers
521 views

Can the earth's magnetic field be generated by heat from a natural nuclear reactor?

I've come upon Dr. J. Marvin Herndon's theory that the earth's magnetic field is generated by a hot nuclear reactor operating in the center of the earth. This is backed by various papers, some of them ...
3
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2answers
2k views

Physics of tsunami: the relationship between wavelength, sea depth and the height of the water

If I understand correctly, when an earthquake occurs, energy will be transferred to the water, resulting in water waves. As the waves reach seashore, because the sea depth is getting shallower and ...
8
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3answers
512 views

Why does energy in earthquake waves seem to go up with the three halves power?

My question might be based on a false premise, so here's why I asked. If you look up the meaning of the moment magnitude scale for measuring earthquake size, the articles usually say that each ...
4
votes
1answer
154 views

Readings of the detectors at Japan and Izu-Bonin-Mariana Trenches

Given the relevance of this subduction system, I would expect that a wide range of detectors (temperature, vibration, seismometers, whatever) are deployed in the depth of these trenches. What would be ...
4
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2answers
170 views

How good is current tsunami prediction?

We all know that predicting tsunami and earthquake is difficult, with too many variables involved. But with the advent in data collection and computing power and better models, one should be able to ...
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4answers
2k views

Electro Magnetic Waves can cause matter displacement?

After watching this video: http://www.youtube.com/watch?v=j1jIjx0XF_U The experience is made with a speaker that generates a sound wave or mechanic wave. Can you use this to establish a link to ...
10
votes
6answers
741 views

Tsunami dampening mechanisms

Encouraged by the zeitgeist let me ask the following: Is it feasible (now or in the future) to build systems a certain distance of a vulnerable coastline which can serve to dampen a tsunami before it ...
5
votes
1answer
310 views

A “global warming” problem

Suppose that a someone decided to calculate, for a given amount of heat added into a planet's atmosphere(an ideal gas), how much is the corresponding temperature rising of the atmosphere, $\Delta T$. ...
5
votes
1answer
380 views

Why are cold thunderstorms rare?

FYI: I imagine the physics of thunderstorms involves wind stripping electrons from condensed water cells (raindrops or snowflakes). Like a Van De Graaff generator, sort of; I'm also using Wilson's ...
12
votes
2answers
6k views

What is the net charge of the Earth?

This question arose in a seminar today about the solar wind... This is my vagueish understanding of the problem - please correct if you see errors! The 'classical' picture of atmospheric electricity ...
8
votes
3answers
3k views

How long does it take an iceberg to melt in the ocean?

This is a quantitative question. The problem is inspired by this event: On August 5, 2010, an enormous chunk of ice, roughly 97 square miles (251 square kilometers) in size, broke off the Petermann ...
18
votes
3answers
1k views

Why the distribution of elements on Earth?

I've been wondering exactly why the elements are distributed the way they are on Earth. The heavier elements have their origins in the centers of stars, or in supernovae. After the death of the stars, ...
6
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5answers
4k views

What sustains the rotation of earth's core (faster than surface)?

I recently read that the earth's core rotates faster than the surface. Well, firstly, it's easier to digest the concept of planetary bodies, stars, galaxies in rotation and/or orbital motion. But, ...
2
votes
2answers
154 views

Utility of displacements potentials in geophysics

In the elasticity theory, you can derive a wave equation from the fundamental equation of motion for an elastic linear homogeneous isotropic medium: $\rho \partial^2_t \overline{u} = \mu \nabla^2 ...
24
votes
4answers
2k views

Why does the sky change color?

Why the sky is blue during the day, red during sunrise/set and black during the night?