If there was a hole straight through the earth North to South Pole?

[WouldBe]

From http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/barfor.html
the air pressure at the center of the earth would be infinity

At ground level air pressure is 3470KPa
at 64Km down air pressure is 5,300,000KPa

Ouch.

 

[poster342002]

wouldn't the earth blwo up or something?

There was once a Dr Who story called The Underwater Menace, in which a mad scientist planned to destroy the world by draining the oceans into a vent to the Earth's core, which would have caused the resulting superheated steam to crack the planet apart. Fortunately, he was foiled by the Doctor and his companions!

 

[WouldBe]

There was once a Dr Who story called The Underwater Menace, in which a mad scientist planned to destroy the world by draining the oceans into a vent to the Earth's core, which would have caused the resulting superheated steam to crack the planet apart. Fortunately, he was foiled by the Doctor and his companions!

and a large cork?

 

[Idaho]

you'd fall until you reached my secret base. then i'd have you shot by my goons.

Amateur. If you had any class you would tie him to the bottom of a rocket you are going to launch in 10 minutes, guarded only by either an ineffectual guard or by your beautiful female henchwoman who has a track record of getting off with your prisoners.

 

[Jonti]

You'd be squashed, roasted and poisoned. Bit like visiting Venus, really.

 

[WouldBe]

You'd be squashed, roasted and poisoned. Bit like visiting Venus, really.

Don't forget drowned when the arctic ocean runs into the hole.

 

[Jonti]

That's not on Venus

 

[WouldBe]

That's not on Venus

Neither is the pole to pole hole.

 

[Jonti]

Might as well be, tho'.

Well, except for the penguins. Won't anyone think of the penguins?

 

[TeeJay]

...the gravity at the center is zero...

Gravity at the centre wouldn't be 'zero' - it just wouldn't be in the same (single) direction as normal. I suppose it would be 'zero' in the sense that the gravity in all directions would cancel each other out, but this isn't quite the same as there being no force exerted by the nearby mass.

 

[Jonti]

That's true anywhere in space. One can still talk about zero gravity.

The principle of relativity is, roughly, that there's no way to tell the difference.

 

[TeeJay]

That's true anywhere in space. One can still talk about zero gravity.

I didn't think that being in an area of space a long way from any other objects (and therefore gravity has fallen to very very low levels) is the same as being caught between two massive nearby bodies whose gravity cancels each other out, but as I am not an expert in physics, mathematics or relativity so I won't try and argue about it - I can see that maybe it is seen as the same thing (ie 'zero') however it actually comes about.

I suppose the difference between low gravity areas and the 'centre point' is that in space you would float around freely whereas inside the object you would be held at the single 'zero point'.

 

[Blagsta]

In the abscence of friction, you'd fall all the way through the center and deccelerate to the other side, coming to momentary rest at exactly the same height as you jumped from on the other side before falling back again. Assuming your hole is perfectly straight and perfectly aligned with the poles, this would repeat forever. With air friction, you'd accelerate to terminal velocity (about 120mph) which would not get you very far once you'd passed the center. You'd pretty quickly reach equilibrium at the center of the earth. Don't touch the walls, they're hot.

Yes, that's what I said.

 

[Crispy]

I didn't think that being in an area of space a long way from any other objects (and therefore gravity has fallen to very very low levels) is the same as being caught between two massive nearby bodies whose gravity cancels each other out, but as I am not an expert in physics, mathematics or relativity so I won't try and argue about it - I can see that maybe it is seen as the same thing (ie 'zero') however it actually comes about.

I suppose the difference between low gravity areas and the 'centre point' is that in space you would float around freely whereas inside the object you would be held at the single 'zero point'.

The top of a mountain, the bottom of a valley and any point on a plain are all "flat" - but in different ways...

 

[Ten Deseo]

You'd be going so fast you'd go right past the center of the earth for a while, also considering at the center of mass gravity isn't necessarily pulling you toward the center any more but every other which direction. You'd fall "up" once you past it for quite a while. Then you'd slow and go back the direction you came and once again pass the center. This would probably go on for quite a while. Simple harmonic motion does that.

Ten Deseo

 

[Ten Deseo]

Didn't even consider that change in pressure. I wonder how much more pressure than at sea level it takes to create a physically noticable change in the viscocity of air. That pressure is huge, though... my ears couldn't take it. My innards either.