A hole through the Earth

Cord Wiljes cord at wiljes.de
Thu Mar 25 22:40:21 CET 2004


Don wrote:

> can you even conceive of the pressure that an 8,000 
> mile tall column of air would exert on something, 
> anything, much less a living thing?

The main problem in calculating this is the fact that you
have to consider two opposing factors:

- the air gets more and more compressed towards the core, 
  which adds to the pressure - and denser matter weighs more.
- gravity is reduced as you get nearer to the core - and 
  thus the air weights less.

But even a _very_ conservative estimate confirms your
theory:

 - air gets liquid under a pressure of 200 atmospheres 
 - 200 times the height of our atmosphere is 2.000 km
 => the rest of the 4.000 km to the center is liquid air
    (cf. the deepest sea is just 12 km)

(Please don't hit me for this approximation. I know the real numbers
would be even higher, but just to get a feeling it may be sufficient.)

So I stand corrected - no chance for humans, ducks or bowling balls.

Pascal wrote:
> to avoid bruises while falling through the center 
> of the Earth, a straight tunnel will not do. Because 
> of the Earth's rotation, a Duck falling through
> it will follow a Spirography-kind of orbit around 
> the Earth's center.

Wow - cool! Never thought of that. So let's drill the 
hole through the poles to remove this obstacle.

Ole wrote:
> If possible, let's put a stop to this roast duck theory.

Yes, you are right. The velocity gained just by falling is
not high enough to generate the heat to burn a body. 
Meteorites burn because they already have a very high velocity 
when they enter earth's atmosphere.

> The apparent weightlessness experienced in orbit is caused 
> not by being removed from Earth's gravity but
> from being in a permanent free fall around the Earth.

Yes, technically objects in (stationary) orbit are in free fall. 
The centrifugal force equals the gravitational pull of the earth 
and therefore they do not crash.

Cord






More information about the DCML mailing list