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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13
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3answers
907 views

Is the total energy of earth changing with time?

Many years ego, Earth was hot. Over time, it has lost energy and has become colder. Is it now in equilibrium or is its total energy changing?
0
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0answers
32 views

How to represent a multiple in the frequency domain

So, in my previous question Where does this formula for prediction of a multiple wave come from?, I get that using this picture: we have so far written the time it takes for a multiple to travel ...
0
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1answer
28 views

Where does this formula for prediction of a multiple wave come from?

On the slide I am reading, it says this: Any surface related multiple can be construced of primaries: $\hspace{5cm}$Multiple = Primary$_1$ (green) + Primary $_2$ (red) $$T_2 = T_1 + ...
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2answers
162 views

Does earths gravitational force vary depending on where you are on the planet?

Does the gravitational force acting on a person ever change just by their position on the planet. For instance, at greater altitudes or closer to the equator.
2
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1answer
370 views

How do you define an aperture for seismic data processing?

Lets consider this in marine seismic processsing. I am assuming you know what a first order primary reflection is, if not, I can define it. Ok, so if we were to have a source $(S)$ and receiver ...
1
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0answers
68 views

3D Surface Related Multiple Elmination (SRME)

Let's assume we are looking at first order multiples of the same surface (i.e no peg leg, etc). I am looking at marine 3D SRME and I am a little confused as to how this works. I understand that in the ...
0
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0answers
164 views

Reference request: Hollow concave Earth hypothesis

Reference request concerning the Hollow concave Earth hypothesis. I am searching for this paper: A Geocosmos: Mapping Outer Space Into a Hollow Earth authored by M. Abdelkader and published in ...
5
votes
2answers
386 views

Why does earth's magnetic field change its direction?

I know that the earth's magnetic field is due to molten metal and ions flowing in its core. It has been found that the Earth's magnetic field changes its direction and it has even flipped once! But, ...
2
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1answer
176 views

what would be the maximum depth of tunnel? [closed]

Perhaps more of an engineering question, but with the subject recently in the news about hyperspeed maglev tunnels I'll chance it here. Say you set up a network of line of sight underground tunnels ...
7
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2answers
299 views

Why do clouds appear black?

I have noticed clouds appearing black during rain. But I don't know what makes clouds to acquire that colour. This phenomenon doesn't appear every rainfall. There has to be distinction to white ...
2
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2answers
1k views

Why England is so cloudy?

Why, physically, some regions of the globe are affected by a noticeable cloudiness respect to others? Is the reason why some places are also rainy the same?
6
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2answers
251 views

Why are we not affected by the radiation of the radioactive decay going inside the Earth?

I was reading the question Why has Earth's core not become solid?, and one of the answers says that The core is heated by radioactive decays of Uranium-238, Uranium-235, Thorium-232, and ...
33
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3answers
2k views

Why has Earth's core not become solid?

The Earth is billions of years old, yet its core has not yet cooled down and become solid. Will this happen in the foreseeable future?
-1
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1answer
105 views

Surface Area Relative to Element Distribution

We tend to find heavier elements like iron and others toward the center of celestial bodies. Lighter elements like carbon, hydrogen, and oxygen are almost always towards the surface. That makes ...
1
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1answer
606 views

What is the deepest man-made underground tunnel? [closed]

What is the deepest tunnel in the Earth's surface? I have meet numbers, around 300km. What is the main problem to make tunnel more deeper? What is the problem with 1000km?
1
vote
1answer
62 views

What is the height of breeze/wind?

How high does a breeze/wind blow? (If you are out in the open and can feel the breeze blowing, till how high is this breeze felt?) And what are the factors that affect it?
1
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1answer
1k views

Why did the Earth cool down?

In physics text books, it has only stated that Earth cooled down and so, water vapour condense and other life form develop and et cetera. But, why did Earth cooled down in the first place? What caused ...
2
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1answer
72 views

Frequency of earthquakes

Are earthquakes getting less frequent across the centuries? I know that more seismic stations have register more earthquakes in the last century, but that doesn't imply there were more. I am ...
0
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1answer
98 views

Is the fraction of radioactive isotopes on the near side of the moon higher than on the far side?

As time passes more slowly in a region of space close to the source of a gravitational field, shouldn't the moon, which always has one side facing towards the earth, have a higher fraction of ...
2
votes
3answers
357 views

Why does the wind direction vary locally?

If the air is flowing with the earth, as it rotates, how do we feel a breeze and strong winds at times, as everyone has experienced, the wind shifts as if from many directions.
0
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3answers
339 views

Do volcano blast changes earth's course?

Volcano blasts are one of the most powerful calamities on earth. When they blast they release large amount of mass in the air just like a jet does. Does such a blast have any effect on the course of ...
2
votes
1answer
64 views

Potential collapse during an earthquake? [closed]

I was asked to determine the shear forces on 12" diameter table legs supporting a few hundred pounds of static weight. How does one calculate or determine the potential force on the legs and/or ...
8
votes
2answers
346 views

rotational oblateness

I am trying to compute the amount of oblateness that is caused by planetary rotation. I picture the force of gravity added to the centrifugal force caused by the rotation of the planet as follows: ...
2
votes
1answer
665 views

Pressure derivatives of the bulk modulus of materials? (Solved) [closed]

Isotherm bulk modulus is defined by $$K=\rho\left(\frac{\partial p}{\partial\rho}\right)_T=-v\left(\frac{\partial p}{\partial v}\right)_T$$ wherein $v=\tfrac{1}{\rho}$ is the specific volume. Studying ...
14
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1answer
399 views

What is the evidence for the super-rotation of Earth's inner core?

What are the geophysical observations that support (or contradict) the hypothesis that the Earth's inner core rotates at a faster rate than the Earth's mantle? Summary of Answers: 1) Studies of ...
1
vote
1answer
89 views

Modeling elastic moduli as a continuous function in space for a single solid material

I've read a number of solid mechanics papers where a single material is modeled with constant elastic moduli (lame parameters $\lambda$, $\mu$). I've also seen composite materials modeled with ...
3
votes
2answers
183 views

What made the 2011 Tohoku-Oki earthquake?

The Ocean Drilling Program recently published results indicating that the 2011 Tohoku-Oki earthquake produced a maximum co-seismic slip of more than 50 meters near the Japan Trench. This is the ...
6
votes
2answers
676 views

Why isn't the Earth's core temperature the average of its surface temperatures?

Assuming that the earth is spherical, that its temperature is continuous, and that some other more or less realistic conditions hold, we might think that the Earth's core temperature should be about ...
8
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3answers
966 views

How is it that the Earth's atmosphere is not “blown away”?

The Earth moves at a high rate of speed around the Sun, and the solar system is moving quickly around the Milky Way. How is it that the Earth's atmosphere is not “blown away”?
7
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2answers
853 views

Is the total mass of Earth's atmosphere essentially constant in time?

Per a few questions and comments on this site such as Huge buildings affect earth's rotation? I wonder, is the mass of the Earth's atmosphere roughly constant? We're burning an incredible amount ...
5
votes
3answers
8k views

Can the Earth's magnetic be used to generate electricity?

Since the Earth has a magnetic field, can it, in theory, be run through a conductive metal coil to create electricity?
6
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2answers
322 views

What is known about the Magnetic North Pole's location before 1800?

I was recently startled to find that the Earth's North Magnetic Pole is moving at upwards of 40 km per year, with an additional ~80 km daily elliptical drift about its mean position due to variations ...
0
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1answer
72 views

Energy conversions, on terrestrial scale, before and during a massive Earthquake

Ethan Siegel is an astrophysicist who is now making a living as science blogger. There is a post titled: Where does an Earthquake's energy come from? Ethan Siegel points out that massive earthquake ...
2
votes
1answer
101 views

What is the Earth's magnetic field in space?

I have looked around a bit, but haven't found a simple answer. At an altitude between 100-1000 km, Is the magnetic field B still around $\sim 10^{-5}\ T$? Is there a simple equation that would provide ...
3
votes
1answer
182 views

What is the most optimal earth's axial tilt in terms of variation of seasons?

What is the most optimal earth's axial tilt in terms of variation of seasons? What would be optimal axial tilt for earth that life would exist and change of seasons would be at minimal level?
7
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5answers
1k views

Why the water remains on the surface of the Earth?

What makes the water stay on the surface? Why the earth does not absorb the water in it?
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1answer
116 views

Energy flows in the core also responsible for another of the planet’s unique [closed]

Energy flows in the core also responsible for another of the planet’s unique features: a strong magnetic field. Scientists believe that the earth has had a magnetic field for at least 3.5 billion ...
1
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2answers
285 views

Does Earth produce metallic elements in its core?

Does Earth produce metallic elements in its core?
4
votes
2answers
2k views

Where does the energy of a lightning strike go?

Lightning contains a lot of energy, so where does this energy go after lightning has hit the ground? Does it travel all the way to the core? What happens after that?
12
votes
3answers
317 views

Radio-dating and the age of the earth

I understand there are a few radio-dating methods to determine the age of the earth, uranium-lead to name one (maybe not the best though). The ratio Pb206 + Pb207 to U allows you to find when the ...
4
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1answer
1k views

What if the earth's core goes cold?

What effects would occur if the earth's core goes cold? Would the planet stay liveable after this happens?
2
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2answers
81 views

Is the altitude of the surface of the ice at the south pole determined by barometric pressure?

In one section of his auto-biography, Alvarez: Adventures of a Physicist, Luis Alvarez describes a tour of Antarctica. This comment about a flight over the south pole caught my attention: The ...
3
votes
2answers
271 views

Earth's core electric charge

Forgive my limited knowledge, but the Earth's magnetic field is created by the conductive liquid in the core and to the best I can tell organizing itself (which means separating charges?). Would this ...
2
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1answer
122 views

Magnetic field line length

If I had a magnetic bar in space that was 2cm wide and 2cm high and was one Earth diameter long and had the same magnetic strength as the Earth, would the distribution of field lines be the same ...
4
votes
2answers
343 views

Can wind blowing on smooth water create speckle interference patterns?

On a calm smooth lake, or even a large rain puddle, I've seen transient rough patches on the surface suddenly appear and disappear, and sometimes move across the water some distance before ...
2
votes
1answer
419 views

Refraction seismology - travel time for wave

I am taking an introductory class in seismology, but have some difficulties understanding the logic behind the formula used to calculate the time it takes for a refracted wave to return to the surface ...
6
votes
1answer
136 views

Amount of thermal energy in the Earth?

Does anyone know the amount of thermal energy that the Earth's mantle and core possess? I don't mean the maximum limit of electrical power we could generate with geothermal plants, but rather: if you ...
1
vote
1answer
98 views

What geological properties of the earth could we deduce by measuring magnetic field strength and direction?

I wonder if it is of any use for a geophysicist, if we measure the magnetic field strength and direction of the earth. Could we make valid statements about the composition of the the earth, earth ...
3
votes
0answers
56 views

Special conditions at layer F2 ionosphere

I saw this graph about the electrons density in different altitudes and difference between night and day, the difference between the 2 electron densities (day and night) decreases till 300 Km (F2 ...
6
votes
2answers
521 views

Plate tectonics and water

In a couple of places already i've read the following assertion: It is believed that plate tectonics might play an important part in maintaining the presence of water on a planet's surface one ...