The Bouguer gravity anomaly means that gravity is not evenly distributed

Originally published at: https://boingboing.net/2020/10/01/the-bouguer-gravity-anomaly-means-that-gravity-is-not-evenly-distributed.html

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I cannot read the legend on that graphic. Does this mean Texas folk feel heavier or lighter than others? (Either way, it may explain a lot!)

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So many “your momma so fat” jokes are in my head right now.

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This has implications for the rate at which time passes too.

Time passes more slowly in (under? with?) higher gravity.

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The question came up at dinner the other night about how sensitive gravimeters are (I know, two geoscience parents…) but I didn’t look it up until this post.

In a demonstration of the sensitivity of the superconducting gravimeter, Virtanen (2006),[5] describes how an instrument at Metsähovi, Finland, detected the gradual increase in surface gravity as workmen cleared snow from its laboratory roof.

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And in addition to using gravity anomalies to map rock bodies, it can also be used for things like tracking changes in the amount of groundwater in an aquifer, which I still find astonishing.

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See also: the gravitational pull of ice sheets. It throws an interesting curve ball into the impacts of global warming. The gravitational pull of the ice on Greenland, for example, raises the sea level around its coasts. When that ice melts, it’ll raise global sea levels an average of something like 23 feet, but locally the sea level will fall (which means it’ll get even higher everywhere else).

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Oh man, I did like geodesy, although those triple integrals always put me off.

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Right - but how much weight can I lose by moving somewhere with low gravity?

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Woah, that shit’s heavy!

ottomn

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[Kurt Vonnegut’s “Slapstick”] world has been ravaged by plagues, wars, and sudden, unpredictable gravitational shifts: on some days, gravity is so heavy that everyone must crawl; on others, it’s so light that all males have erections.
[review source: The Art of Reading.Wordpress]

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Earth’s gravity is unevenly distributed because the matter that makes up our planet is neither homogenous nor uniformly distributed.

Some matter is far more dense than other matter, thus variable gravitational effects arise.

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That’s not how erections work.

The headline made me think that gravity was discovered to be non-uniform at a universe scale, which would shake up astrophysics at a fundamental level. Variations in the strength of gravity at different points on the surface of the Earth is old news. It’s used to detect underground water, oil, or undiscovered cave systems. NASA runs a satellite that measures the variance in the gravitational field.

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The propensity of intensity of density is …oh crap, ran out of 'sity words.

Anyway, I always felt lighter in Pennsylvania

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pretty sure it’s stronger underneath cats when they lie down on you. i’d swear they get heavier. sometimes i can’t even move.

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Where there are ancient meteorite or asteroid impacts, you also get Bouguer anomalies, especially with iron cores.

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Interesting how blue the area around Carlsbad Caverns is

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I believe the gravity in Singapore is 0.5% lower than at either of the poles, due to centrifugal effects from the Earth’s rotation.

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Also, when you lift them up by their front quarters and the bottom of the cat stretches and stretches toward the ground. Gravity in cats is phenomenal!

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This wouldn’t be really noticable unless the comparison was outside the local scope, right? Like old-style scales, the weights would be affected just like the item being weighed, so no lighter or heavier. I imagine the same with digital scales, also? As they would be zeroed within the local scope.

So it isn’t like you could make more money selling gold in a place with more gravity… right? Asking for a friend… :face_with_monocle:

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