Welcome! These forums will be deactivated by the end of this year. The conversation continues in a new morph over on Discord! Please join us there for a more active conversation and the occasional opportunity to ask developers questions directly! Go to the PS+ Discord Server.

Physics nerds, can you stand on (some of) the walls in a rotating habitat?

65 posts / 0 new
Last post
Thu, 2012-12-06 11:43
rekuli rekuli's picture
yes, you are really experts,
yes, you are really experts, all of you… you cannot even read properly, because I haven't written anything of „explode” or „within an atmosphere”. if you don't know the difference of experimenting with something in exterior pressure (stabbing a can in the yard on earth's surface) or doing the same with an identical can up in high orbit. It is akin to what happens to the can if you let it dive real deep, just for other reasons. You ought to do your maths on a volume of 10e400 for a rotating O'Neill habitat with a wall thickness of, say, 100cm (calculated to a lower scale, the proportion volume/wall strength is about a typical balloon like those children have) and an atmosphere of 1 bar, and what happens if the pressure is rapidly being pumped out with more than 10 bar (equivalent to a microhole of 1mm). A hint: if you let the air out from a balloon, it is not the exterior pressure that makes the hull collapse, it is the suction of the pressure leaving the balloon. Don't try to tell a dr.phys. (me) anything else. It would be nonsense.
—
Your ego back-up hunts you. Kill it. Your other minds disagree. Ignore them.
Top
Thu, 2012-12-06 11:47
rekuli rekuli's picture
@lorsa: this isn't exactly
@lorsa: this isn't exactly true. On a large body like earth, you don't notice this effect, because it has a vast area of space where air movement, rotation of the surface and physical movement level out due to inertia and friction. If you are in a smaller scale of 6000m diameter and 20000m length, things are quite different. Yes, please, do a model calculation in a 3d environment.
—
Your ego back-up hunts you. Kill it. Your other minds disagree. Ignore them.
Top
Thu, 2012-12-06 12:51
NewtonPulsifer NewtonPulsifer's picture
Guys, you're being trolled.
Guys, you're being trolled. When Dr. rekuli throws out numbers, he gives us 10e400 for volume -but no units. Okay lets assume cubic meters. There's 8.46732407987 × 10^47 cubic meters in a light year. And then he throws out 100cm for wall thickness for a habitat with a volume greater than the observable universe. Anyway, I'm done feeding this troll.
—
"I fear all we have done is to awaken a sleeping giant and fill him with a terrible resolve."- Isoroku Yamamoto
Top
Thu, 2012-12-06 13:39
Smokeskin Smokeskin's picture
rekuli wrote: yes, you are
rekuli wrote:
yes, you are really experts, all of you… you cannot even read properly, because I haven't written anything of „explode” or „within an atmosphere”. if you don't know the difference of experimenting with something in exterior pressure (stabbing a can in the yard on earth's surface) or doing the same with an identical can up in high orbit. It is akin to what happens to the can if you let it dive real deep, just for other reasons.
Haha that makes no sense.
Quote:
You ought to do your maths on a volume of 10e400 for a rotating O'Neill habitat with a wall thickness of, say, 100cm (calculated to a lower scale, the proportion volume/wall strength is about a typical balloon like those children have) and an atmosphere of 1 bar, and what happens if the pressure is rapidly being pumped out with more than 10 bar (equivalent to a microhole of 1mm).
Air is going to leave through the hole at the speed of sound. That's rapid I guess, but I really wish you'd quantify things instead of using qualitative descriptions like you're some liberal arts major. It doesn't amount to much mass air flow though, so pressure isn't going to drop rapidly. Where do you get the 10 bars? And NewtonPulsifiers comment on the volume is gold ;)
Quote:
A hint: if you let the air out from a balloon, it is not the exterior pressure that makes the hull collapse, it is the suction of the pressure leaving the balloon.
The ballon surface is under a lot of tension though which is a major factor in why it tears. A piece or two of scotch tape over where you're going to puncture the balloon and you don't get a pop.
Quote:
Don't try to tell a dr.phys. (me) anything else. It would be nonsense.
Haha that's great, I haven't done any physics since I left high school 17 years ago, and I'm way better at this than you are.
Top
Thu, 2012-12-06 20:34
RustedPantheress RustedPantheress's picture
Dr. Rekuli appears to have a
Dr. Rekuli appears to have a Ph.D in Inaccurate Pop Science. Most of his statements are intuitive and accurate enough... When talking about an entirely different situation. Let's examine some of his metaphors (and stop using the inaccurate ones). Why does a balloon deflate when punctured? It has no internal structure and its natural shape (the default state in which no stresses are placed on it's structure) is deflated. It collapses because its materials return to the default state at the first opportunity, thus forcing the air out at a higher pressure than natural suction. If this happens with a habitat, you obviously have a really stupid habitat and should get a better engineer. And that O'Neil cylinder that you used in Post #53 is huge. 6km diameter and 20km length? I think that's fairly ridiculous. I could put a small mountain range in that thing! If you had an elevator system connecting opposite parts of the hab, it would be a 3klick journey just to the center! You're brilliant at devising reasonably sized habitats! (To drive my point home in the most subtle way possible, have this: [/sarcasm]) Also, learn to type up your thoughts better. I need to read your posts three times before I can get what you're saying. Now, as for the corolis effect, as far as I'm concerned, we need to do some experiments to get some practical data on how these things work out off the earth. Get cracking, and somebody call NASA. Just don't let Rekuli get a hold of the hab plans or we'll all be living in balloons made of aluminum cans.
—
Somebody is using bad science! Snark, facts, snark. Your body is corrupted: Cool, do more science to it. Your mind is warped: That's nice, want a cookie? What do we say to the God of Death? Not today!
Top
Thu, 2012-12-06 22:03
NewtonPulsifer NewtonPulsifer's picture
Something to keep in mind:
Something to keep in mind: If you scaled up a US 12 ounce soda can 100,000x in each dimension to create a big "aluminum can habitat" you'd go from: 6.6cm diameter, 12.1cm tall, .1mm thick outer walls To: 660 meters diameter, 1210 meters tall, and 1 meter thick outer walls EDIT: To be more clear, habs are going to be built more sturdy than the above.
—
"I fear all we have done is to awaken a sleeping giant and fill him with a terrible resolve."- Isoroku Yamamoto
Top
Thu, 2012-12-06 22:19
RustedPantheress RustedPantheress's picture
Who said it was scaled up?
Who said it was scaled up? Bring out the superglue, duct tape, and the output of several dozen soda can factories. On the other hand, I would say that those dimensions are the about the right size for a good O'Neil hab.
—
Somebody is using bad science! Snark, facts, snark. Your body is corrupted: Cool, do more science to it. Your mind is warped: That's nice, want a cookie? What do we say to the God of Death? Not today!
Top
Fri, 2012-12-07 03:36
Smokeskin Smokeskin's picture
RustedPantheress wrote:
RustedPantheress wrote:
Now, as for the corolis effect, as far as I'm concerned, we need to do some experiments to get some practical data on how these things work out off the earth. Get cracking, and somebody call NASA.
The coriolis effect is perfectly described already. It is nothing but simple mechanics translated to a rotating reference frame, where moving objects don't move in straight lines and you need two imaginary forces (coriolis and centrifugal) to describe things.
Top
Fri, 2012-12-07 12:21
rekuli rekuli's picture
:-)) of course there are no
:-)) of course there are no numbers. 1) I got treated like I was a complete fool from the start away, without a chance to have somebody actually read what I wrote and give it a thought if it *maybe* coud contain a bit of probability. 2) conclusion from 1: complete fools (I am too polite to write something like „arrogant, uneducated little college pukes that don't know a quarter of what they believe they do” although I would like to do so ;-) deserve getting trolled. 3) even if I consciously, deliberately went to the extreme, you should check the basics of what I posted, some of it really is true, even if what I wrote in my posts was hugely vague (on purpose to see what you make of it). 4) It is really fun watching you, because you did exactly what I expected… And now, my regards to you all, because I easily get bored when I am in a forum where people take themselves and their object of fandom more important than god, and don't see the forest because of all the trees. What I could deduce from your reactions is that you might know a bit fo terrestrial physisc, but you don't know anything about micro-g and vacuum physics. because your ego gets in the way. PS: If you do the simulations, you should simulate the atmospheric reactions if you start, continue and stop a habitat's spin. It is really interesting what happens.
—
Your ego back-up hunts you. Kill it. Your other minds disagree. Ignore them.
Top
Fri, 2012-12-07 12:43
CodeBreaker CodeBreaker's picture
I <3 this thread so much.
I <3 this thread so much.
—
-
Top
Fri, 2012-12-07 13:15
Smokeskin Smokeskin's picture
rekuli wrote:
rekuli wrote:
4) It is really fun watching you, because you did exactly what I expected…
Clearly your psychology beats your physics. Though predicting that people will react negatively to being trolled with exagerated and hugely vague claims (how you described your actions here) isn't exactly a great feat.
Quote:
And now, my regards to you all, because I easily get bored when I am in a forum where people take themselves and their object of fandom more important than god, and don't see the forest because of all the trees. What I could deduce from your reactions is that you might know a bit fo terrestrial physisc, but you don't know anything about micro-g and vacuum physics. because your ego gets in the way.
How about you just explain how just one thing you said was correct? For example the shooting spinwards the bullet will land at your feet? Or the 10 bars resulting from a microhole puncture? You're a dr.phys., stop deliberatedly annoying us and have a meaningful discussion instead. As you can see from the first part of this thread and other threads we can have reasonable discussions.
Top
Fri, 2012-12-07 14:01
RustedPantheress RustedPantheress's picture
Well, that's why the
Well, that's why the discussion went nowhere: rekuli was being deliberately vague. Baka rekuli.
—
Somebody is using bad science! Snark, facts, snark. Your body is corrupted: Cool, do more science to it. Your mind is warped: That's nice, want a cookie? What do we say to the God of Death? Not today!
Top
Fri, 2012-12-07 16:19
Jaberwo Jaberwo's picture
Sooo... About that mountain
Sooo... About that mountain range in a O'Neill Cylinder. Could we actually do that? :D
Top
Fri, 2012-12-07 19:46
RustedPantheress RustedPantheress's picture
If we had a 6klick diameter O
If we had a 6klick diameter O'Neil cylinder, probably. It would be a small one though, and maybe we could have the peaks meet in the middle. That would awesome.
—
Somebody is using bad science! Snark, facts, snark. Your body is corrupted: Cool, do more science to it. Your mind is warped: That's nice, want a cookie? What do we say to the God of Death? Not today!
Top

Pages