# Tag Info

-1

Yes, indeed. Earthquakes have been on a steady rise since the earliest seismographs. Hard data from the United States Geological Service (USGS), Richter 6 earthquakes and above, 1895 thru 2015: 1895 - 1905 = 11. 1905 - 1915 = 48. 1915 - 1925 = 281. 1925 - 1935 = 524. 1935 - 1945 = 446. 1945 - 1955 = 906. 1955 - 1965 = 1352. 1965 - 1975 = 1285. 1975 - 1985 ...

-2

Hmm, interesting! Some of the rock must be superheated enough to vaporize and ionize as the shockwave, plasma, and EMP travel outwards. If it's like a meteorite crater, then the "spherical" radius that the shockwave travels from the source before it dissipates enough to "stop" is the diameter of the resultant hole.

30

There is an interesting diagram in the wiki article on underground nuclear testing - the picture file is here This shows that the crater you get from a nuclear explosion depends on the depth of burial: I think the most interesting diagrams are the ones labeled (e) and (f) - where the explosion happens at great depth. In that case, you get a "tight ...

6

I would think that there is a cavity after the explosion, as well as - Rock is compressible, and the surrounding rock is squeezed together - There is a bulge on the surface, it's just too flat to be noticeable I don't think the rock would be porous since that would allow radiation to leak out of the site. Added: From Wikipedia: When testing went ...

2

You have to compare the most probable speed of the atoms of He with the escape velocity from the planet. So you are working out whether $$\left(\frac{2kT}{m} \right)^{1/2} > \alpha\ \left(\frac{2GM}{R}\right)^{1/2},$$ where $T$ is the local temperature, $m$ is the He atom mass, $M$ is the planet mass and $R$ is the radius at which you are considering ...

2

The mass of all the oceans on the surface of the Earth is estimated to be 1.35 * 10^18 metric tons, or 1.35 * 10^21 kilograms. The mass of the Moon is estimated to be 7.35 * 10^22 kilograms. The distance from the Moon to the Earth at perigee (the closest distance) is 363,104 kilometers, or 363,104,000 meters. If you assume the oceans cover the entire ...

2

The statement of Newton's law you have given is specifically about the gravitational attraction between point masses. It also comes to mean, through the Shell theorem the force between a spherically symmetric body and another outside the first body: we replace the spherical body with a point at its center. For other geometries you calculate the force ...

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