Drunken Scientific Discoveries

Marky

Marky

Marky

Soldato
Joined
16 Apr 2007
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UK
Hey all,

Every so often when me and my friends are out and we have a few drinks - The conversation turns into what - at the time - seems to be very scientific and accurate accounts of the world...

I've just remembered one that regularly comes up in conversation and I was wondering if someone could clear it up for us :)

If it was, in fact, possible to dig a hole through the world and come out the other side (The discussion of if you dug a hole in the ground and kept going you would eventually reach China...) - When you reach the core - the very center of the Earth - How would mavity react?

So in my drunken wisdom I decided that if you reached the middle you would basically fall to the core, and bounce from one side of the hole to the other and forever swing back and forth past the core as mavity takes you to the core on each side.

So what would really happen (Imagining that the core wasn't incredibly hot and you would survive this ordeal)? :p

Marky
 
You would go back and forth along the tunnel, travelling slightly less each time due to the effect of wind resistance, until you came to a halt at the very centre...
 
mavity would crush you.

But if you were so awesome you'd survive, you would just circle the core forever... maybe.
 
if you made the tunnel that compensated for the earth not being a perfect sphere and the uneven mavity because of this, and you made it a perfect vacuum, then you would fall down the tunnel, accelerating to the center.

you would reach your top speed at the center of the earth, and you would decelerate all the way to your destination. assuming the start and end point are at exactly the same altitude, you would come to rest at the exit of the tunnel, where hopefully someone would pull you out before you started falling back to the start point again.

there was something on QI about this a while back, and i believe they said it would take ~43 mins
 
Well, mavity would continually pull you towards the centre as you say, and you would be slowed by air resistance and possibly liebniz forces (I have no idea how to spell it, but it's the force which is created through magnetic induction when a magnetic object passes a magnet - the earth being a magnet, and any iron on/in you being magnetic).

More realistically, however, you would be killed by the pressure of the air long before you got anywhere near the centre of the earth. A 1m radius hole to the centre of the Earth would contain approximately 20 million m^3 of air between one side and the core - I really don't remember the formulae for calculating the pressure of that at the core, but perhaps someone else will. I rather suspect it's a lot greater than the pressure at, say, the bottom of the ocean.

Also, you would NOT reach your top speed at the centre of the Earth - low-altiude free-fallers apparently reach terminal velocity after around 400m, and the higher air density in the shaft would reduce your terminal velocity significantly.
 
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A real scientist wouldn't even enterain the question since it is obviosuly not possible to do it and would therefore not waste thier time on the subject. Which is what I would do.
 
BunnyKillBot said:
http://en.wikipedia.org/wiki/Gravity_of_Earth#Altitude

The force exerted by mavity on the surface of the earth is 9.81 approx, but varies with altitude. Take a look at the graph and extrapolate with negative height values. The further down you go, the more and more force is exerted on you by mavity

Your entire skeletal mass would be crushed into a pile of goo.

so it's not just about heat.
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technically though at the centre mavity would be pulling you "outwards" towards all sides of the tunnel equally.
 
Right .. here's my thinking.

Mass causes mavity.

So .. if theoretically there was a room right in the middle of the earth, you would NOT get crushed by the pressure. As the mass is all around you in approximate equal measure.

So for all those 'pressure would crush you' guys -- I disagree. I think you would be ripped apart onto the walls of the room, rather then crushed into a red bloody ball in the centre of it..
 
BunnyKillBot said:
http://en.wikipedia.org/wiki/Gravity_of_Earth#Altitude

The force exerted by mavity on the surface of the earth is 9.81 approx, but varies with altitude. Take a look at the curve on the graph and extrapolate with negative height values. The further down you go, the more and more force is exerted on you by mavity

Your entire skeletal mass would be crushed into a pile of goo.

so it's not just about heat, and mavity shields do not exist ;)
Click to expand...

At the centre of the Earth the net mavity would be zero. You wouldn't be crushed at all. Roughly equal mass on all sides pulling you, you'd hover and feel no mavity.
 
up would not instantly become down, for a while it would be sideways so you would smash into the walls of the tunnel on the way down?

if you could avoid the sides some how, and being cooked I recon you would stop round the center (or whats left of you)
 
edscdk said:
up would not instantly become down, for a while it would be sideways so you would smash into the walls of the tunnel on the way down?

if you could avoid the sides some how, and being cooked I recon you would stop round the center (or whats left of you)
Click to expand...

nah for all the mavity pulling you into the right hand side there would be an equal amount pulling you into the left (and every other possible horizontal angle) so aside from minor variances you should be held in the middle.
 
BDEE said:
A real scientist wouldn't even enterain the question since it is obviosuly not possible to do it and would therefore not waste thier time on the subject. Which is what I would do.
Click to expand...

Rubbish. Einstein often thought about the likely consequence of travelling faster than light, despite HIM proving it is impossible.

Just 100 years ago everyone KNEW it was IMPOSSIBLE to get to the moon. Scientists thought about it.

And don't get me on to Schroedinger's cats!!!
 
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