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Gravitational Anomalies Beneath Mountains Point To Isostasy of Earth's Crust
StartsWithABang writes: Imagine you wanted to know what your acceleration was anywhere on Earth; imagine that simply saying "9.81 m/s^2" wasn't good enough. What would you need to account for? Sure, there are the obvious things: the Earth's rotation and its various altitudes and different points. Surely, the farther away you are from Earth's center, the less your acceleration's going to be. But what might come as a surprise is that if you went up to the peak of the highest mountains, not only would the acceleration due to gravity be its lowest, but there'd also be less mass beneath your feet than at any other location.
Nothing to see here. Move along.
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I had to read TFA to figure out what isostatic is.
"Bizarrely enough, if we wanted to reach the Earth’s mantle, our best bet would be to dive down to the ocean floor and dig there; we’d “only” have to go through maybe 3 km of crust, as opposed to upwards of 25 km atop the Himalayas. This concept is known as isostatic compensation, and was actually uncovered by the famed British astronomer George Airy."
I think you're missing the point:
The earth's mantle is significantly more dense than the crust. Mountains are made of matter that is less dense than the mantle, so when they go deeply into the earth, there is less mantle "beneath" your feet.
More mountain = less mantle = less dense.
"First they came for the slanderers and i said nothing."
Mass has a relationship with density. The crust is less dense that the mantle, so more crust=less mass. The mountains float on the mantle in a similar way to icebergs on water, ie they displace mantle beneath them, resulting in a 1-you-wide segment down to the core of the earth that contains more crust and less mantle, therefore containing less mass.
Show your math please.
A mountain at 42,164bkm would have the peak in geosynchronous orbit. http://en.wikipedia.org/wiki/G...
The moon is 384,000 km up and even it has to maintain an orbital velocity considerably faster than a jumping person to avoid falling to Earth.
But if someone built a tower 384,000 km high, it would travel faster than the moon. And if you jumped off that tower, you'd also never reach the ground.
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