here I'll summarize the article for you in one sentence: just think of the earth as it is, only with 8 huge mountains one on each corner.
And enormous ridges stretching between them, of course.
Walking on a cube-shaped planet
61–70 of 79 posts
Re: Walking on a cube-shaped planet
#62Reminded me of Cyberiad: http://en.wikipedia.org/wiki/The_Cyberiad "The Highest Possible Level of Development civilization. A gravely injured hermit comes to Trurl's house and tells Trurl of Klapaucius's adventure: Klapaucius wanders across an old robot, who tells him that he has logically deduced the existence of a civilization that reached the highest possible level of development (hence "HPLD"). He has inferred th…
FWIW, The Cyberiad, a collection of related stories, is a great read for hackers. I come back to it every few years.
Trurl, attempting to build a machine to write poetry:
Re: Walking on a cube-shaped planet
#63Very fun thought experiment. It reminded me that we did a problem in calculus to compute the effect of gravity inside a hollow sphere. It turns out to be ZERO. So, if the Earth's mass, was all densely concentrated in a, say, 1 mile thick shell, you could drill a hole through the shell and experience total weightlessness when you popped out on the "inside" (assuming a total vacuum on the inside - if not - you'd experi…
If the inside was a total vacuum, the moment you finished drilling through the 1 mile shell, the vast majority of the planet's atmosphere would be sucked through the open hole at an insanely fast rate.
> [..] insanely fast rate.
Well, at the same rate as air at 1 atmosphere pressure will fill any vacuum container through a hole of that size.
You seem to suggest that fact that that speed somehow depends on the size of the hollow earth and the quantity of the atmosphere.
The pressure depends only on the height of the air column.
Re: Walking on a cube-shaped planet
#64Earlier quoted context omitted.
[There should be a standard disclaimer for "I'm correcting you because I think you would benefit from knowing, not because I mean to be an ass"] A physician is a medical doctor. A physicist studies fundamental laws of our universe.
[There should be a standard disclaimer for "I'm correcting you because I think you would benefit from knowing, not because I mean to be an ass"] I think it would quickly lose it's tone of respect, and take on one of sarcasm.
Like this one ? [not meaning to be an ass or the colloquial grammar nazi, but that's "its tone of respect", not "it's"]
Re: Walking on a cube-shaped planet
#65Earlier quoted context omitted.
I took the question (which I thought was rather absurd) and rationalized (and imagined it) this way: this cubic planet will not rotate, or it will not be cubic then. I took out gravity as we know it, and imagined I could just "walk" in it. We walk on a sphere shaped planet, yet we do not "slide down" if we stand on the North Pole, yes? Same with a cubic one, as I imagine, the 90 degrees angle will be crossed without…
Your intuitions are betraying you. Gravity as you know it is a very special case, albeit a common one.
It might not even be that common. AFAIK, the 7 billion sentients that have that experience are all located in the same place.
Re: Walking on a cube-shaped planet
#66There are all sorts of rules for drama and character development. What are the rules for incorporating neat scientific/sci-fi ideas into a story? In lots of Larry Niven's stories, the ideas are necessary to solve the central mystery, but not always.
EDIT: In a mashup of The Culture and Dilbert, a godlike nanotech Dogbert forces the hapless Homo Sapiens Dilbert to work on a "cubical".
Re: Walking on a cube-shaped planet
#67Another planetary thought experiment (edit: sorry, credit where it's due: excerpt from The Algebraist by Iain M. Banks): I was born in a water moon. Some people, especially its inhabitants, called it a planet, but as it was only a little over two hundred kilometres in diameter, 'moon' seems the more accurate term. The moon was made entirely of water, by which I mean it was a globe that not only had no land, but no ro…
He's got another novel that deals with a unique world - Matter (https://secure.wikimedia.org/wikipedia/en/wiki/Matter_%28nov...) takes place on/in a shellworld.
Re: Walking on a cube-shaped planet
#68Another planetary thought experiment (edit: sorry, credit where it's due: excerpt from The Algebraist by Iain M. Banks): I was born in a water moon. Some people, especially its inhabitants, called it a planet, but as it was only a little over two hundred kilometres in diameter, 'moon' seems the more accurate term. The moon was made entirely of water, by which I mean it was a globe that not only had no land, but no ro…
I used to think that the ice core would work that way, but water is most dense at 3.7C (or something like that). So, under enough pressure, it would remain liquid.
Re: Walking on a cube-shaped planet
#69Another planetary thought experiment (edit: sorry, credit where it's due: excerpt from The Algebraist by Iain M. Banks): I was born in a water moon. Some people, especially its inhabitants, called it a planet, but as it was only a little over two hundred kilometres in diameter, 'moon' seems the more accurate term. The moon was made entirely of water, by which I mean it was a globe that not only had no land, but no ro…
I used to think that the ice core would work that way, but water is most dense at 3.7C (or something like that). So, under enough pressure, it would remain liquid.
Water has a very complicated phase diagram. I'm not sure how high a pressure water at a core of a planetoid of that size would be, but if it's above 100GPa then it would certainly be solid (Ice X or XI). Below that pressure, it would depend on the temperature.
http://upload.wikimedia.org/wikipedia/commons/0/08/Phase_dia...
Re: Walking on a cube-shaped planet
#70Earlier quoted context omitted.
Interesting point, but I'm not so sure. We take the shortcut of assuming that the earth's gravity is drawing everything toward a point at the center of the earth. But that's not really correct; every bit of matter is drawing everything else toward it. So those giant mountains that comprise the vertexes of the cube would be pulling the oceans toward them. That works against your point. I don't know where the equilibri…
A sphere with some gravitational influence from the points, but with most of the mass towards the center of the cube, it would still be mostly sphere-like, I think.
You are assuming that every part of the cube has the same density. Perhaps the density increases as you get to the corners.