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Subject: 
Re: John Leo's opinion of "The West Wing"
Newsgroups: 
lugnet.off-topic.debate
Date: 
Thu, 3 Oct 2002 15:21:11 GMT
Viewed: 
858 times
  
David Koudys wrote:

In lugnet.off-topic.debate, Frank Filz writes:
David Koudys wrote:
I often wondered what would happen if we were to drill an 8 foot hole
straight through the planet (of course, this idea assumes the core of the
earth to be a nice room temperature, not molten rock...) and if wer were to
jump down said hole--would we go past the center of the planet, slow down on
the way to the other surface and just basically bounce back and forth thru
the tunnel until we came to rest, free floating, at the exact center of the
planet?

I've wondered this in the past also. If the planet were not rotating, I
think the answer would be that your analysis is correct. Note that you
would be in a zero-G environment (or close to it) at the center assuming
the Earth is close to an evenly dense sphere (or at least each onion
skin layer is of uniform density) since basic Physics says that at a
point inside a sphere of uniform density, only that mass contained in
the sphere centered at the whole sphere's center of gravity and having a
radius equal to the distance the point is from the center of gravity is
involved in determining the gravitational attraction, the "layer"
outside that radius basically cancels itself out.

With a rotating sphere like Earth, I think the problem is that you will
crash into the side of the hole since you will retain the velocity of
the surface, yet as you go down, the velocity of a point in the hole is
lower.

Frank

Never thought about the rotation--there was an H.G. Wells story about a guy
that was granted a wish and his was for the earth to stop spinning--turns
out that when the wish was mentioned, the earth stopped instantly anad
everything that wasn't bolted to the ground went flying in a, now let me
figure this out correctly, earth spins in a counter clockwise direction ...
so if we suddenly stopped the spin, we'd all go flying to the... it's too
late to think about this.. to the east due to momentum.

When I visualized my little tunnel thru the planet, I always pictured it
going from the north pole to the south pole, straight thru that bar magnet I
know is there for all my grade 4-5 science books showed that picture of the
magnet inside the earth.

I don't think that rotation has that effect if the tunnel goes from top to
bottom.

Ok, that would eliminate the rotation.

Why would I always visualize the tunnel going thru the planet from top to
bottom, instead of, say, from North America (around the 49th) to the other
side, (probably the Pacific).  Well, just reading that, my guess is that the
tunnel would then become full of water, right up to sea level on my side of
the tunnel.

Since your original problem statement assumed there was no problem with
a molten core, I think it's also reasonable to assume the water isn't a
problem (you can make a dam from all the earth you excavate from the
hole :-). You're certainly right though, the hole would fill with water,
on both sides (the water will fall through the center through to the
other side also). There will be an imperceptible lowering of sea level
(remember, your 8' diameter tunnel would hold as much water as an 8'
diameter tube which circles less than 1/3 of the globe, obviously
insignificant compared to the total volume of the oceans).

Rats, this little idea I had when I was a kid is turning out to be not feasable.

:-)

Frank



Message has 1 Reply:
  Re: John Leo's opinion of "The West Wing"
 
(...) Would it be a $#*crash*#$ into the side or more of a 'rubbing' every once in a while to stop the sideways velocity. Considering that gravity is pulling straight down, and the original velocity from the surface spin is moving you east at (...) (22 years ago, 3-Oct-02, to lugnet.off-topic.debate)

Message is in Reply To:
  Re: John Leo's opinion of "The West Wing"
 
(...) Never thought about the rotation--there was an H.G. Wells story about a guy that was granted a wish and his was for the earth to stop spinning--turns out that when the wish was mentioned, the earth stopped instantly anad everything that wasn't (...) (22 years ago, 3-Oct-02, to lugnet.off-topic.debate)

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