physics of the Earth and its environment in space. Its subjects include the shape of the Earth, its gravitational and magnetic fields, the dynamics of the Earth as a whole and of its component parts, the Earth's internal structure, the generation of magmas, the hydrological cycle including snow and ...
48
votes
6answers
4k views
Why is there a scarcity of lithium?
One of the major impediments to the widespread adoption of electric cars is a shortage of lithium for the batteries. I read an article a while back that says that there is simply not enough lithium ...
33
votes
7answers
3k 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 ...
21
votes
4answers
981 views
Why does the sky change color?
Why the sky is blue during the day, red during sunrise/set and black during the night?
14
votes
3answers
477 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 supernova. After the death of the stars, ...
13
votes
3answers
569 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. ...
12
votes
1answer
940 views
What would happen if the Earth was tidally locked with the Sun?
I'm thinking of writing a short story set on a version of Earth that is tidally locked to the Sun. I'm not exactly sure how to research the topic. Here's a number of questions about what would happen:
...
11
votes
2answers
3k 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 ...
9
votes
1answer
2k views
What is the source of Earth's magnetic field?
I saw on Discovery channel that the source of Earth's magnetic field is the molten iron and metals in the earth's core. The spinning of these liquid metals produces the same effect as electric current ...
8
votes
3answers
420 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 ...
8
votes
2answers
79 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 ...
6
votes
2answers
1k 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 ...
6
votes
4answers
235 views
Why is the water on the surface of the Earth?
What makes the water stay on the surface? Why the earth does not absorb the water in it?
6
votes
1answer
56 views
Is it possible to determine astronomically/astrophysically whether other planets have ever encountered polarity reversal?
We know of geomagnetic flip in Earth's history by studying geologic data. Given other planets in the system also possess a magnetic field leads to the assumption that such polarity reversal may not be ...
6
votes
2answers
109 views
Would it be possible for geophysicists/geoengineers to develop an artificial way of trapping carbon in the ocean?
There's a mechanism by which the southern ocean sequesters carbon from the atmosphere. It happens when strong winds displace a large slab of surface water, accumulating in a specific region where the ...
6
votes
1answer
30 views
Refraction and scattered light for NLCs
For helping with judging NLC candidates (are they NLC or not) I have a set of formulas to calculate the minimum altitude (in km) of the candidate given an observed altitude (in degrees) of the ...
5
votes
5answers
1k 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, ...
5
votes
2answers
76 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 ...
5
votes
1answer
109 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 ...
5
votes
0answers
140 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
votes
1answer
103 views
Why does air contain $Ar$ specifically?
Air consists roughly of $N_2$, $O_2$ and $Ar$.
Why is $Ar$ the relatively common noble gas compound and not for example the lighter ones $He$ or $Ne$?
4
votes
2answers
305 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 ...
4
votes
2answers
135 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 ...
4
votes
1answer
268 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, $\Delta T$. ...
4
votes
2answers
558 views
Lowest gravity on Earth's surface?
I am trying to determine which on Earth's surface has the lowest gravity. Googling is not finding anything concrete. My natural inclination would be to think of Mount Chimborazo in Ecuador, being on ...
4
votes
5answers
353 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 ...
4
votes
2answers
260 views
How does Earth's interior dynamo work?
I'm interested in getting a basic physical understanding of how Earth's magnetic field is generated. I understand that it's a "dynamo" type of effect, driven by convection currents in the molten outer ...
4
votes
2answers
170 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 ...
4
votes
1answer
281 views
How does the inner core relieve stress as the Earth's rotation slows?
One of the surprises for me in working out the answer to this question: Why is the Earth so fat? , is that the core is more elliptical than the surface, the extra ellipticity builds up gradually to ...
4
votes
1answer
58 views
What sets the length scale of stratified rock formations?
Driving through areas of the American Southwest such as Utah and Arizona, you notice stratified rock formations everywhere. The grand canyon is the best known example. One striking thing is that the ...
4
votes
1answer
268 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 ...
3
votes
2answers
248 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?
3
votes
1answer
142 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?
3
votes
1answer
70 views
Can Earth's Magnetic Field Create Electricity?
If the earth has a magnetic field, can it, in theory, be run through a conductive metal coil to create electricity?
3
votes
2answers
299 views
Water from Icebergs
Thousands of icebergs are calved from polar regions annually, and melt in the oceans. George Mougin, an entrepreneurial engineer, aspires to tow multi-million ton icebergs to areas of the world ...
3
votes
2answers
87 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 ...
3
votes
4answers
791 views
Outcomes of earth slowing down spinning on its own axis
What are the possible outcomes if earth slows down spinning on its own
axis?
To be specific:
Can the decrease in the internal centrifugal (or centripetal) force due to slowing down earth's spin:
...
3
votes
2answers
322 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 ...
3
votes
2answers
135 views
The earth's magnetic field
This might sound like a silly question. Is it possible for the earth's magnetic field to actually destroy or harm earth? (implosion, crushing etc.)
3
votes
0answers
35 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 ...
3
votes
0answers
383 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 ...
3
votes
3answers
260 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
1answer
193 views
How much water is destroyed in photosynthesis, relative to the world's supply?
Water is involved in the photosynthesis. How much water are we talking about compared with the total amount on water on Earth? Is it enough to have an effect on the average age of water molecules?
2
votes
1answer
54 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 ...
2
votes
2answers
1k 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 ...
2
votes
2answers
139 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 ...
2
votes
2answers
112 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 ...
2
votes
2answers
62 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 ...
2
votes
2answers
141 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
71 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 ...
2
votes
1answer
80 views
How far does typical view of clouds/atmosphere extend?
The specific "sub questions" I'm asking are:
When you are looking at clouds just on the horizon, how far away would they be?
How wide (in km) is that total field of vision at roughly cloud height.
...
