When I was a child, as many many other children everywhere, have fantasized about making a hole in the backyard and continue it till the other side of the earth.
As I grew a little and was aware the the center of the earth was a little hot, I began to imagine ways to cool my subterranean ship, in a way that could be shielded from the heat outside.
After growing a little more, I became aware that the center of the earth was not only hot but liquid, so another engeneering problem began to populate my before sleeping imagination, How to make a ship able to move in a solid, and also in a very hot liquid.
Now that I am even older, I imagine that problems such as proggresive absence of gravity as the ship approaches the center could be a problem, as the radiation there and the risk to break the mantle as make a hole in it, would it be possible to create a volcano as a side effect of our subterranean jorney?
Could you remark other engeneering problems that could be present if we intent to make a hole across the earth?
Wow, i thought i was the only crazy bastard that actually tried to do this. ^_^; i actually got into a wicked fight one time over whether we would come out in China or Australia.
Pressure would be another problem. i can't see the "progressive absence" of gravity being a big deal (it won't be progressively absent, it will be progressively balanced out, so that at the centre, you would be pulled at on all sides), and the radiation there is all heat, isn't it?
sounds like a fantastic idea....could you please make a small sub-tunnel near my house in northern England so I can travel a bit easier please?
You'd need to make a few tunnels though, at different points of the earth, so as to allow other continents to benefit (unless there are some people you don't necessarily WANT popping up near you !) 
A) Can't be done.
B) You're all mad.
C) So am I.
I've thought about this briefly when I was younger and then following some physics classes late in high school I learned a few things. Firstly, at the centre of the earth there is no gravity. You are not pulled at equally, there just is not force (depending on which model of gravity you take, either way you have no acceleration at the centre). So if you could somehow get a tunnel right through the earth, remove all the air ie. a vacuum and jump in, you would accelerate all the way to the centre and then start slowing down. You would reach the same height on the other side and if you could somehow jump out and it would only take 42 minutes or so this site claims. There are probably a who bunch of difficult equations to work that out but we'll take their word for it.
The hot core of the earth, oceans and ground water prevent this from ever happening on earth, but it could be done on the moon. But I'm not sure how much use it would be! | scotty wrote: |
| I've thought about this briefly when I was younger and then following some physics classes late in high school I learned a few things. Firstly, at the centre of the earth there is no gravity. You are not pulled at equally, there just is not force (depending on which model of gravity you take, either way you have no acceleration at the centre). |
You might want to double check those old high school physics books. ^_^; Gravity does not just disappear at the centre of the Earth. The mass of the Earth is still there, it's all around you. Hence, the gravity pulls you from all around. At the centre of the Earth, that pull would be equalized, the gravitational force in all directions balanced, and you would hang in place.Well if you could make it through, (a la the movie 'the core') one big problem to overcome would be that for the entire second half of the trip, you would be traveling upwards against gravity. Supposing a tunnel was possible, it would be better to dig it from both sides, and meet in the middle, so that gravity would help you both ways.
I suspect most kids who have a modest amount of scientific curiosity think about the idea of tunneling through the Earth at some point in time. Of course, conventional wisdom (in the US) is that you would theoretically wind up in China, but we know that if the hole was straight "down" it would have to end up in the southern hemesphere, possibly reaching Australia but more likely in the open ocean.
I was surprised to hear about the ingenuity of some who considered solutions to the enormous engineering problems as they got older and became aware of them.
As I understand it, we would be weightless if we floated at the center of the Earth. The "presense" of balancing gravitational forces from all sides of the Earth would have no physical effect on us. This is similar to the fact that we do not "feel" a gravitational pull from the Sun, because we are in balance with the motion of the Earth and can only feel the difference in forces. Of course, the existence of a pull from both sides is essential to understanding the physics of the situation.
If we can imagine the ability to line the tunnel with a super strong shield, surely with active heat transfer to keep internal temperatures normalized, then perhaps we can dream some more. The most difficult aspect I envision is keeping the active drilling area within acceptable environmental limits, and extending the shield immediately to each new section drilled. I fear someone will post an equation about the limitations of air conditioning systems, showing any such hope to be a fantasy.
you wouldnt even have a house after tapping the core.
and if you kept it open we wouldnt even have a planet.
| PANTONEPIRATE wrote: |
you wouldnt even have a house after tapping the core.
and if you kept it open we wouldnt even have a planet. |
Care to explain why?
Also, about the gravity in the middle of the earth. Is there, or is there not gravity at the center of the earth? | Ghost Rider103 wrote: |
| Also, about the gravity in the middle of the earth. Is there, or is there not gravity at the center of the earth? |
Yes - there is gravity pulling equally in all directions (the effect of which would be to cancel out).
