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A problem with centrifuge based colonys!
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Darksoul6
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Joined: 02 May 2006
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PostPosted: Wed May 31, 2006 3:00 pm 
Post subject: A problem with centrifuge based colonys!
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There Could Be A Problem With A Centrifuge Used In A Colony.

1. Would A Centrifuge Actually Work In Zero-gravity? From What I Can See The Force Of A Centrifuge Only Works If The Object Is Resting On A Part Of The Centrifuge Before It Spins.

2. Zero Gravity Makes Us Weightless Am I Right? A Centrifuge Works On The Principal Of The Spinning Throwing Weight Outwards. If Were Weightless Theres Nothing To Be Thrown Outwards!

3. Entering/leaving The Colony. If The Centrifugal Force Did Work How Would One Dock/land With It? To Get A Centrifuge To Work It Must Spin Extremly Fast. This Makes It Impossible To Dock/land/leave The Colony As You Would Merley Be Shattered As It Hits You Which Cant Be Avoided.
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Gourdhead
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PostPosted: Wed May 31, 2006 10:20 pm 
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Entering and leaving could be done along the axis of revolution.
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JasonArcher
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PostPosted: Wed May 31, 2006 11:22 pm 
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ouT oF curiositY, whY arE yoU capitalizinG everY singlE worD yoU writE? iT lookS likE morE troublE thaN it'S wortH.
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MirariNefas
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PostPosted: Thu Jun 01, 2006 12:29 am 
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Quote:
1. Would A Centrifuge Actually Work In Zero-gravity? From What I Can See The Force Of A Centrifuge Only Works If The Object Is Resting On A Part Of The Centrifuge Before It Spins.


I don't care about "From What I Can See". You have never been to space, so you haven't seen much. But math and science let us extrapolate beyond our observed environment, and they tell us that centripetal acceleration is independant of a frame of reference.

Quote:
2. Zero Gravity Makes Us Weightless Am I Right? A Centrifuge Works On The Principal Of The Spinning Throwing Weight Outwards. If Were Weightless Theres Nothing To Be Thrown Outwards!


It makes things weightless, not massless. Any mass can be subject to force, regardless of the presence of the planet-bound force we call 'weight'.

Quote:
3. Entering/leaving The Colony. If The Centrifugal Force Did Work How Would One Dock/land With It? To Get A Centrifuge To Work It Must Spin Extremly Fast. This Makes It Impossible To Dock/land/leave The Colony As You Would Merley Be Shattered As It Hits You Which Cant Be Avoided.


Actually, they don't rotate that fast, if they're built on a large scale. We are not talking about the rpm rate of lab-standard centrifuges. We're talking about fewer than ten rpms. And Gourdhead is right, docking along the axis would be easiest. You just fire off some side rockets to rotate your craft at a similar rate, and you're ready to be grabbed by a station-bound docking arm.
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ares2101
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PostPosted: Thu Jun 01, 2006 11:55 am 
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Aside from some motion sickness in those that get it, there's nothing wrong with spinning colonies. So you can feel a slight change when you turn your head, at least you'll never get lost. What what if you get slightly heavier when to walk spinward and slightly lighter when you walk anti-spinward, we'll get used to it. Besides, it's not that much.

On an O'Neill Colony, which rotates a 2 rpms (~400 mph), your weight would change by as much as 2.5% walking against or with the colony's rotation if you were running at 10 mph. Guys would put on or lose a few pounds, the girls would gain or lose a couple, big deal.
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PostPosted: Thu Jun 01, 2006 12:02 pm 
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MirariNefas wrote:
Quote:
1. Would A Centrifuge Actually Work In Zero-gravity? From What I Can See The Force Of A Centrifuge Only Works If The Object Is Resting On A Part Of The Centrifuge Before It Spins.


I don't care about "From What I Can See". You have never been to space, so you haven't seen much. But math and science let us extrapolate beyond our observed environment, and they tell us that centripetal acceleration is independant of a frame of reference.

Quote:
2. Zero Gravity Makes Us Weightless Am I Right? A Centrifuge Works On The Principal Of The Spinning Throwing Weight Outwards. If Were Weightless Theres Nothing To Be Thrown Outwards!


It makes things weightless, not massless. Any mass can be subject to force, regardless of the presence of the planet-bound force we call 'weight'.

Quote:
3. Entering/leaving The Colony. If The Centrifugal Force Did Work How Would One Dock/land With It? To Get A Centrifuge To Work It Must Spin Extremly Fast. This Makes It Impossible To Dock/land/leave The Colony As You Would Merley Be Shattered As It Hits You Which Cant Be Avoided.


Actually, they don't rotate that fast, if they're built on a large scale. We are not talking about the rpm rate of lab-standard centrifuges. We're talking about fewer than ten rpms. And Gourdhead is right, docking along the axis would be easiest. You just fire off some side rockets to rotate your craft at a similar rate, and you're ready to be grabbed by a station-bound docking arm.


Ok ok! No need to flame me! I was just saying though. Think of it like one of those rides you get where you standin against the wall and it spins, making you stick to it. If your floating round in it, it wont have any effect on you will it? I doubt that we will know for sure until someone tries it in space.

And as for "You have never been to space, so you haven't seen much.". Well have you?
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Darksoul6
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PostPosted: Thu Jun 01, 2006 12:04 pm 
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Oh sorry that last post was me. Wink
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MirariNefas
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PostPosted: Thu Jun 01, 2006 1:06 pm 
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Again "But math and science let us extrapolate beyond our observed environment, and they tell us that centripetal acceleration is independant of a frame of reference."

If you doubt me, I encourage you to take some physics classes, rather than wasting your hours pondering concepts that don't work out in the real world. And yes, physics teachers DO know the answer, despite a lack of empirical observation.

It's like an architect building a bridge. How does he know it can carry that much weight until he builds it? Why don't lots of bridges fall down because the architects were wrong? We've got equations for that sort of thing. The world follows certain physical rules. In space we lose gravity, but we don't lose the laws of physics.

Quote:
If your floating round in it, it wont have any effect on you will it?


Try this for a mind game: what happens if you're in a big centrifuge on Earth, but it's full of water. You aren't on the wall or touching the ground of the centrifuge in any way, because you're floating in water. What happens when it spins?
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ares2101
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PostPosted: Fri Jun 02, 2006 10:00 am 
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Quote:
Try this for a mind game: what happens if you're in a big centrifuge on Earth, but it's full of water. You aren't on the wall or touching the ground of the centrifuge in any way, because you're floating in water. What happens when it spins?


This is right, if the water or air filling it starts to move you'll eventually get pulled into the rotation and once you're on the ground, you'll be fully affected. If it's vacuum inside though, yes, you shouldn't be affected until you touch the structure (which would really hurt when you finally did).
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Darksoul6
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PostPosted: Sat Jun 03, 2006 6:02 am 
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Ahh sorry i apolagize! I didnt think of the air having any effect!
Now anyway the only thing to figure out is the effects of it. We would have to get it to the right speed or we would either be crushed against the walls, or nothing would happen.
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ares2101
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PostPosted: Sat Jun 03, 2006 10:44 am 
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http: www artificial-gravity com sw SpinCalc SpinCalc htm

This will give you some good values. Specify size and desired gravity in you're choice of units and it gives you rotational period and speed.
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Niven
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PostPosted: Sat Jun 03, 2006 12:19 pm 
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I highly recommend the following documents by Theodore Hall as compulsory reading for anyone interested in the effects of artificial gravity. The first is 1MB and the second is 3MB but well worth the download.

http: www artificial-gravity com SSI-1991-Hall pdf

http: www artificial-gravity com SAE-2002-01-2431 pdf
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scienceguy
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PostPosted: Sat Jun 03, 2006 1:39 pm 
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I skimmed through the first link. Very informative.

I drew up a picture on how to counter Coriolis forces, but I don't know how to post it from paint. Can anyone tell me how to post something here from paint?[/img]
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Niven
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PostPosted: Sat Jun 03, 2006 3:33 pm 
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scienceguy wrote:
Can anyone tell me how to post something here from paint?


1. First, if you're saving it from PAINT, make sure you save it as a JPEG not a BMP (default format for PAINT). BMP has much larger filesizes than JPEG (which is a lossy format)

2. Then upload it to an imagesharing site such as Imageshack: http: reg imageshack us

3. Then copy and paste the forum link (for Embeddable Code) provided by imageshack into your post here.
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scienceguy
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PostPosted: Sat Jun 03, 2006 4:22 pm 
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Thanks Niven!

Here goes:

[img][/img]
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