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Hardest question in the World


milan666

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This would be the most amazing example of a simple harmonic oscillator in existence. Neglecting all confounding variables (such as air resistance, the earth's rotation, and the fact that the earth is not perfectly spherical) you would fall, reach maximum velocity at the center of the earth, and then begin to slow down until you reached a 'height' equal to that from which you jumped (in other words, you'd be the same distance from the center of the earth as that from which you started), reach minimum velocity and maximum displacement, and then start again.

 

Wow... I have to say, that made my day. Nothing makes me happier than envisioning the person who has the gall enough to call a handful of respectable, experienced scientists nerds oscillating from one side of the earth to the other. xD

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  • 4 months later...

Old questions, old dreams... still, let's have a go at it.

 

You cannot come out of the hole on the other end, because you need to close it off in order to maintain a vacuum inside.

 

If you just leave it open, you cannot reach the center of the earth. The pressure of all the air above you will cause the air at the center to become solid. You'd slam into a solid block of air well before you reached the center.

 

hmm...

 

More precisely, because the air resistance would become enormous, you'd gently land on a solid block of air well before you reach the center.

 

You need to travel 6378 km to the center of the earth, but at 10 kilometers down, the pressure is already at about 3 bar. Even if that would go up linear at that rate, (which it certainly does not, it goes up much faster, since air is compressible) the pressure at the core would be about 2000 bar. I'd guess the real pressure of an open tube to the center would be somewhere in the millions of bars. And air (or nitrogen) will not behave as your happy friendly near ideal gas. :D

 

Now stop daydreaming, and build that warp drive.

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The pressure of all the air above you will cause the air at the center to become solid. You'd slam into a solid block of air well before you reached the center.

 

Isn't there a temperature above which certain gasses will not liquify(let alone freeze) regardless of the pressure?

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Isn't there a temperature above which certain gasses will not liquify(let alone freeze) regardless of the pressure?

 

yep. but that wouldn't even come into play with the earth. pressure would be nowhere near high enough.

 

2000 bar seems a little low to me but i can't be bothered working it out but i will say it relies on faulty assumptions, the acceleration is NOT 9.8m/s^2 all the way down(or even all the way up)

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Isn't there a temperature above which certain gasses will not liquify(let alone freeze) regardless of the pressure?

 

Eeh... yeah. That's probably true as well. The link I provided before showed that nitrogen can become a (weird) solid at really high pressures. I'm not sure whether such ridiculous pressures are achieved.

 

Is 2000 bar assuming a constant 9.8 m/s^2 all the way to the core?

It was assuming a constant density of about 3-4 kg/m3, and a constant 9.8 m/s2. In short, it was a totally inaccurate underestimation.

 

I was not in the mood to calculate the real pressure. The gravitational acceleration will change, but the weight pressing down also changes (because the gas is compressed). The temperature changes as you go down, which should be taken into account.

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