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A Pipe Through the Earth

R

Rastus

Diamond Member
Imagine a pipe through the center of the Earth, open on both ends.

What I want to know is:

  • What would happen to something that is dropped down the pipe? Will it stop at the center?
  • What would happen to a person that is dropped down the pipe? Will pressure crush them?
  • If the ends of the pipe were in oceans, what would that do to the oceans?
 
Dropping something into the pipe would cause it to fly through almost to the other end, then fall back in, repeating this and losing a little momentum each time until it stopped in the middle.

A person would not be crushed, he would feel weightless. I don't know about the final question.
 
Assuming the pipe can resist the immense pressure present towards the core, is it also a perfect heat insulator?
 
Originally posted by: chrisms
Bounce back and forth?
Click to expand...

They bounce back and forth, although little bit less each time due to air resistance. Eventually they will come to rest in the center of the earth.
 
So yeah, this has been asked several times and the answer is quite complicated. The simple answer is they would oscillate from surface to opposite surface over and over again. If you add in air resistance, then the person would oscillate back and forth, but never regain the altitude from the previous fall, and would quite quickly come to a stop at the center of the earth. If you take into account the pressure gradient, the air would probably liquify under the intense pressure of the air above it, and you would fall into this liquid and possibly float.
 
Originally posted by: mundane
Assuming the pipe can resist the immense pressure present towards the core, is it also a perfect heat insulator?
Click to expand...

I think in hypotheticals like this it's usually a given that factors like that are ignored, as we are exploring the principles, not the technicalities. That's up to the OP though.
 
1. Impossible to build such a pipe, but I will play along.....


[*]Object would get lodged in the center of the earth, but it would probably bounce around for a while.
[*]Person would die from temp / pressure
[*]oceans would pour down the pipe and be vaporized, the steam coming out of the pit of darkness would condense back to rain in the atmosphere, the rising steam would probably slow the rate of water descent. But, there is the possibility that if the pipe was insulated enough that the temp would not be high and the pressure of the entire atmosphere would keep the water from boiling..... might even turn into a solid.
 
If something is dropped down the pipe, wouldn't air pressure increase as it went to the center and decrease terminal velocity?

Could air pressure get so great that some things would float somwhere off-center?

As to iamelephants mentioning my preferences, I have none. Drop a pie down the pipe and discuss it's flavor if you want.
 
I would like to point out that since nobody even knows what the center of the earth is even made of, there is no real answer. The object could spontaneously turn into cheesecake for all we know.
 
Originally posted by: Rastus
Imagine a pipe through the center of the Earth, open on both ends.

What I want to know is:

  • What would happen to something that is dropped down the pipe? Will it stop at the center?
Click to expand...
It will continue to the center, where its momentum will continue to carry it forward. However, it would have reached terminal velocity before then, limiting its momentum, such that it would not reach the same distance from Earth's center after passing the center. Eventually, it would be suspended at Earth's center.
What would happen to a person that is dropped down the pipe? Will pressure crush them?
Click to expand...
Interesting, and I'm not sure what would happen to air pressure. The column of air would extend all the way from the center to ~50 miles above Earth's surface. Don't know what that'd do to the pressure. Seems to me that it'd increase with depth, as it does in any liquid.

If the ends of the pipe were in oceans, what would that do to the oceans?
Click to expand...
The water would simply flow in, as would a liquid in a container with a pipe running out the bottom. The water wants to get to the center of Earth's mass, and with the pipe, there's suddenly a way to get there. How much water flows in depends on the diameter of the pipe.

 
Originally posted by: Jeff7

The water would simply flow in, as would a liquid in a container with a pipe running out the bottom. The water wants to get to the center of Earth's mass, and with the pipe, there's suddenly a way to get there. How much water flows in depends on the diameter of the pipe.
Click to expand...
But the only way for the air inside the pipe to escape is out one of the end of the pipe. And if both oceans give the same pressure, then the air would just stay in the pipe and no water would fill it.
 
The thing is, air happens to be lighter than water.

I really don't know what would happen, but I assume you'd get a lot of bubbles coming from both ends of the pipe as the water rushes into it.
 
But if you take a straw, put your finger over the bottom end and submerge it into a tank of water, no air will come out of it.
 
Originally posted by: MeddyDuo
But if you take a straw, put your finger over the bottom end and submerge it into a tank of water, no air will come out of it.
Click to expand...

Unless it is at an angle.
 
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