Re: ballistic subterranean trains

From: Spike Jones (
Date: Wed Oct 03 2001 - 00:39:09 MDT

> > > Spike Jones wrote:
> > >
> > > > Nowthen, since we are talking about frictionless evacuated tunnels...

Well, Ill be damned. I found a density gradient estimate for the
earth, and did a calculation on Damien's train on a frictionless
evacuated tunnel thru the earth idea. I calculated something
that surprised me. Using the density gradient found at

I calculated that the maximum gravity felt by the passengers
is actually slightly higher than 1 g. Or another way to say it
is if you dug a hole straight down the gravity felt by the digger
gradually increases to about 11.7 m/sec^2 or almost 1.2 G
at a depth of about 2900 km, then decreases after that, if
one could keep digging. Anyone know of another paper
or website which has calculated a different value? spike

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