Jesus, Tris, everyone knows that. Half the physics-type problems in GQ are what-if questions about things that do not exist. Chronos has a Staff Report on doughnut-shaped planets, for Heaven’s sake.
It’s a thought experiment. There’s nothing wrong with ignoring certain effects as long as you know what you’re ignoring. That allows you to bound the problem and scale the different effects and gain an understanding of the laws of nature and why the situation might not exist in the real world. Ignore compressibility? That gives a lower bound. Ignore failure of the ideal gas law? That gives an upper bound.
It’s not magic or imaginary, however much you chuckle and guffaw and sneer. This isn’t a sophomore bull session where everyone’s answers are equally right, no matter how stupid. And a claim that a random number has the same validity as an answer in General Questions is completely asinine.
I don’t understand the problem here, Tris. Is it that the gasses involved at such pressures would begin to react chemically or cease to be gasses, or what? Wouldn’t this simply be a quesiton of finding an equation that involves gravity to calculate air pressure at a certain depth? Because, as I know, air pressure is a function of the weight of air above it. That’s why the pressure is lower as you go higher, not because gravity is actually that much weaker as you go higher. Or maybe it is, whatever. But the formula for gravity as you would go down into a hole can also be found, can it not? Why can’t you simply combine these two formulas?
I’m very far removed from my old physics days, but an answer could be found here, could it not? Regardless of what happens to gasses at this state, I’m sure an answer could be found. Surely it’s not exactly what would happen in real life, but is it necessary to nit-pick to such a degree? Its similar to the way we ignore air-friction in mechanics equations, because although you’ll be off by a bit, you still come out with some useable information.
I mean, shouldn’t we at least try to help with the spirit of the question? We always hear that gravity down there would be non-existent. If we are going to nitpick, why don’t we ask the poster how he would plan on drilling the hole, etc, the fact that the earth is indeed higher than 0 degrees C…
cease to be gasses I think is the problem. They would liquify. They question still holds, though. What would be the pressure at the surface of this “ocean” and what would be the pressure at the bottom (i.e. at the center of the earth)
Let’s not get distracted folks. Some of us, at least, are here to learn something.
I searched for “critical point of nitrogen” and got “about 126 K [-147 deg C] and 3.4 MPa [34 bar]” a few links down. That’s pretty darn cold. If we have our hole lined with a pipe made of Triskadecamusium, which magically insulates it and keeps it at room temperature, are we actually going to get something that is discernibly a liquid at the bottom of it? The wikipedia articles on Jupiter and Saturn don’t even contain the word “nitrogen”, so I couldn’t find anything there.
Atmospheric pressure at the surface is due to the weight of the column of air above due to gravity.
What effect then does gravity have on the same column of air as you descend to the center of the earth?
Did I miss any consideration of this as a factor?
Under extraordinary pressures, both the gasses would react with each other, specifically, oxygen, and nitrogen, and the water vapor in the air. Then the gases under even higher pressure would disassociate on a molecular level. They might get high enough in temperature to completely ionize. I don’t think they reach fusion temperatures, although I don’t know for sure what effect the perfectly rigid containment of the hole has. I think it would make fusion easier to obtain, than a simple ball of gasses, like the sun. The pressure is high enough to pretty much assure that you have a superconcentrated plasma at the bottom. So, all the formulas for air pressure at altitude don’t apply. Since the hole is able to replenish without significant limit from the entire planetary atmosphere, the stuff at the bottom of the hole is not a gas.
This is why I think all the numbers are right, or actually each spectacularly wrong.
Physical objects such as the described hole have a physics unlike the one we are using to describe it. So, the description is wrong, unless we decide to have it be right in our thought experiment. If we do, then it’s like we think it is. That isn’t descriptive physics, it’s magic. I don’t mind it being magic, I just think we ought to be objective about it.