Danish Research Center To Explore Mysteries of Earth's Interior 56
An anonymous reader writes "The DanSeis Centre at the University of Copenhagen has just received a grant of more than €3 million from the Danish Ministry of Science, Innovation and Higher Education to investigate and tackle one of geoscience's great mysteries: do mantle plumes, hypothetically buoyant regions of heated mantle material rising towards the earth's surface, actually exist?"
What about the discontinuity of gravity? (Score:5, Informative)
Why is the force of gravity at the core zero?
http://en.wikipedia.org/wiki/File:Earth-G-force.png [wikipedia.org]
http://en.wikipedia.org/wiki/File:Slice_earth.svg [wikipedia.org]
And why the hell is there a Gutenberg discontinuity where gravity increases the closer you get, then drops down to zero?
i.e.
The Gutenberg Discontinuity, is the boundary, as detected by changes in seismic waves, between the Earth's lower mantle and the outer core about 1800 miles below the surface. It is also called the core-mantle boundary.
http://en.wikipedia.org/wiki/Mohorovi%C4%8Di%C4%87_discontinuity [wikipedia.org]
Re:What about the discontinuity of gravity? (Score:5, Informative)
"Why is the force of gravity at the core zero?"
Because the integral of the forces acting on some mass at the center of the Earth is zero. Or to put it differently: You are being pulled by (approximately) equal forces in all directions.
Re:What about the discontinuity of gravity? (Score:4, Informative)
None of these things are even slightly mysterious. None of them are really particularly difficult to calculate, or at least estimate. "Interesting" discoveries from the systematic study of near-Earth and inner-Earth gravity are entirely possible, but one would ordinarily consider the discover of a fifth force, or a short range modulation of the gravitational force, to be "interesting" in this context. In order to make such a discovery, however, one has to know the mass distribution and compute the net relative acceleration one should be observing to very high precision, as one is basically looking for an anomaly, and small deviations from a not-too-well-known or even well-defined base quantity are the most difficult to detect, see the entire (somewhat humorous) debate about global warming for an example).
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P.S. -- Off-topic general query: Wordpress lets one embed latex in comments, and it isn't even particularly focussed on technical subject matters. Is there an equally simple way to embed latex in