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There is pretty strong evidence falling into groups Seismological As transversal waves do not propagate through liquid. By monitoring the travel times and types of seismic waves globally after earth quakes, one can reconstruct the velocity profile for the different kinds of waves in inner of the earth. Then one can see that the transversal waves are ...


9

Shear-waves propagate in solids, but not in liquids. Pressure waves propagate in both. Earthquakes generate both kinds and seismographs can be built which are sensitive to the two kinds separately. Both kinds of waves have shadows on the opposite side of the Earth, but the differing size and shapes of those shadows show that the outer core is liquid but the ...


4

Is there evidence to support that the earth has a molten core? Yes. We have these things called volcanoes: ;)


4

Alpha decay, which is why it generally comes from natural gas fields where the alphas are trapped with the methane (in the US there are several in Kansas, Oklahoma, and Texas with reasonable fractions). There is a long history of helium in the US, where the Bureau of Land Management has been responsible for the helium reserve since the days of giant ...


3

In your context, the second interpretation is correct. The fact is that falling objects accelerate both on Earth and on the Moon. The sentence is saying that the amount of this acceleration, regardless the source, is six times greater on Earth than on the Moon. In other words, things accelerate towards the surface of Earth six times faster than they ...


2

If you're asking how intense the earthquake feels, this is well described by the peak ground acceleration (PGA). By this I mean that the sensations people report are well correlated with the PGA. The Richter scale measures the energy released by the earthquake, but this is not necessarily correlated with the PGA and therefore with what people feel. It ...


1

Every month there is a new moon. The moon isn't visible on this day. You've seen it before. That's how dark it would be.


1

A few things: 1) time dilation is only a relative effect. A clock on earth would tick differently than one far from the milky way, but people on Earth would notice no abnormal effect. 2) To first order, time dialation effects are governed by the gravitational potential energy at a point. It turns out that the time dilation due to the mass of the ordinary ...


1

You seem to be asking for a distance above the event horizon at which time dilation due to the gravitational acceleration of the black hole would convert 4 billion years to 1 second. As all time is relative, what you really are asking for is the distance above the event horizon at which it would APPEAR to someone on Earth that an event which takes 4 billion ...


1

I doubt this is correct due to how the Richter scale functions. The Richter scale is in log 10. This means that to go up 1, you multiply by 10. Therefore, 7 is 10 times more powerful than 6.



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