Re: "This is the funeral pyre for thought in America today."

Richard Maurer wrote:
Vinny Burgoo wrote:
I got quite carried away looking into this
and I was going to post a lot more detail,
but I'll limit myself to one Fascinating Fact
at the Foot of the Page: the sediment in the
Ganges delta is so thick (20 km in some places)
that it depresses the Earth's crust (it's sinking
about 6 mm/yr under the coast) and weakens the
local gravitational field, which weakening
means that, for reasons that are entirely beyond
my comprehension, sea levels are expected to rise
more slowly in the Bay of Bengal than elsewhere
in the world.


Richard Maurer wrote:
The extra mass depresses the Earth's crust, but
weakens the local gravitational field?


Roland Hutchinson wrote:
Possible.

Depressing the crust is accomplished mostly by
the total mass of the thing,
I imagine, and it's really big.

The local gravity is mostly affected by the density
of what's nearby, and the sediment must be
somewhat fluffy, at least compared to igneous rock
(I think).

But I don't pretend to understand the thing about
sea level rise, either.


I was thinking that all the sediment ended up
under water. If it forms mountains then that is
different. I can readily believe that gravity is
weaker at sea level in some fjords, with the
mountains pulling things up a bit. But if the
sediment is all under water, then it just pushes
out the ocean world wide, and there is heavier
sediment where there was once just sea water,
hence more pull downwards at sea level.
Unless it is trickier than that.

Many Canadians are lighter than Los Yanquis for geophysical reasons. New
Scientist explained why a couple of weeks ago: partly those pesky
tectonic plates, and partly because the Hudson's Bay area hasn't
finished bouncing back up after the last ice age. All bollocks according
to the Creationist climate-change-denying economic neo-liberals, of
course (I wonder why these so often go together. There's a terrible
smell of oil in here).

--
Mike.



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