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Occulis
RealPoor Jedi
Joined: 11 Oct 2002
Posts: 13293
Location: Moral Relativity Central
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Spitulski
RealPoor Guru
Joined: 23 Nov 2002
Posts: 4344
Location: Washington
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 Posted: 09/16/03 - 02:11 Post subject:
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I wouldn't ride a ribbon into space =(.
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Zwadrich
RealPoor Master of Posts
Joined: 12 Oct 2002
Posts: 5015
Location: The Netherlands
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Posted: 09/16/03 - 02:17 Post subject:
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vroom vroom
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compusmack
RealPoor Master of Posts
Joined: 15 Oct 2002
Posts: 6354
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Posted: 09/16/03 - 09:09 Post subject:
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amazing if it ever worked.
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Nahualli
RealPoor Master of Posts
Joined: 11 Oct 2002
Posts: 8461
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Posted: 09/16/03 - 09:25 Post subject:
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Yes, that really is incredible..
But I wonder wouldn't the elevator have the same problem as a shuttle re-entering the atmosphere, aka gravity pulling it so hard it causes all kinds of massive friction, causing it to burn up?
-Nah-
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Stixl
Luke Warm
Joined: 05 May 2003
Posts: 185
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Posted: 09/16/03 - 09:35 Post subject:
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Nah,
don't think so. Picture if you will running as fast as you can and then jumping on the carpet with your knees. rugburn eh?
shuttles are moving at something like 5000 mph during re-entry thanks to gravity (like you said), and they go from a vaccum of space back into our atmosphere. all that energy gets dissipated when they do reentry... i'm pretty sure its the whole atmosphere being seperated at incredibly high velocity that heats up the shuttle, not the actual atmosphere being hot (think.. high mountain, hard nipples)
however "ribbon to heaven" is counter-anchored by a satelite/catapillar transformer in outer space in a free fall, so the ribbon should essentially remain static, based on on position on the ground and through space.
Last edited by Stixl on 09/16/03 - 09:39; edited 1 time in total
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Nahualli
RealPoor Master of Posts
Joined: 11 Oct 2002
Posts: 8461
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Posted: 09/16/03 - 09:38 Post subject:
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I realize that it's not the atmosphere that's hot, in fact just the opposite.
What I was asking was wouldn't the elevator be subject to intense gravitational pull?
What you said about the shuttle returning from a vaccuum makes sense tho. I still don't understand how something can just "drift" into the atmosphere tho.
-Nah-
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sinrakin
RealPoor Master of Posts
Joined: 11 Oct 2002
Posts: 7044
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Posted: 09/16/03 - 09:43 Post subject:
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Great, another target for terrorists...
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Stixl
Luke Warm
Joined: 05 May 2003
Posts: 185
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Posted: 09/16/03 - 09:44 Post subject:
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yar i edited before i saw your reply. i'm pretty sure there putting some really heavy counterweights up there in a freefall around orbit.. and i read something about a catapillar robot or something heh im sure that weighs a bit. so the ribbon wont be lifting huge stuff to space, but I remember doing a problem like this in physics a couple years ago.
Basically the question was assuming normal earth gravity, and an object in orbit at 300,000ft [from center], how much weight can it support.
unfortunately both times i took physics it was 8am classes and I failed. Cool class tho
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Paco
RealPoor Jedi
Joined: 13 Oct 2002
Posts: 12939
Location: Jacksonville, FL
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Posted: 09/16/03 - 09:48 Post subject:
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| sinrakin wrote: | | Great, another target for terrorists... |
dude, the whole planet is a target. what are talking about?
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Luturb
RealPoor Guru
Joined: 11 Oct 2002
Posts: 4042
Location: Livermore, California
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Posted: 09/16/03 - 10:28 Post subject:
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| Nahualli wrote: | | What I was asking was wouldn't the elevator be subject to intense gravitational pull? |
I'm no physicist, but I don't believe gravity is any stronger in the atmosphere than it is on the ground. The reason stuff burns up in the atmosphere is because it's going so fast when it hits the air. During reentry you are moving at terrific speed thanks to the fact the you're basically falling with no friction. If the weight is lowered in slowly maybe there's no problem. It would still be moving around the earth pretty fast though so I'm just guessing.
<bgsound src ="http://www.thesanctuary.com/giftofgab/soundfiles/stairway.wav">
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Eduin
Sir Postalot
Joined: 14 Oct 2002
Posts: 1046
Location: Glasgow
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Posted: 09/16/03 - 10:54 Post subject:
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The stresses on the Space Cable are entirely due to the weight of the cable itself. Remember of course that weight is Mass times Gravity, so gravity is a factor but the main factor is the mass of the cable material itself. That's why you require something with incredibly high tensile strength and very, very low mass. Basically at the orbiting geostationary platform, the entire weight of the cable must be supported by the last few microns of the cable. Of course, the weight decreases as you get near the outside (as gravity decreases and is countered by the freefall) but there is a considerable weight being held, with more weight per metre the closer you get to the earth and this is all cumulative.
Space Elevators are incredibly practical once a material with sufficient tensile strength is developed. Now depending on the material, it *might* be susceptible to attack. The most likely materials which can be developed by humans are going to have huge tensile strength vertically but will be relatively weak horizontally. However, if the material had the same tensile strength in all directions it would be practically impossible to sabotage it by, for example, flying into it (it would be like a tomato (the plane) hitting a brick wall (the cable).
THe best thing about Space Elevators is that once it is constructed it has virtually zero ongoing cost. In fact, should useful materials be discovered and mined in space, the energy required to life items to orbit would be negligible as they could counterweight materials being dropped down the other side, just like a traditional life which uses a weighted slab of lead as counterweight.
Regards,
Eduin
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Stixl
Luke Warm
Joined: 05 May 2003
Posts: 185
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Posted: 09/16/03 - 11:02 Post subject:
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like trying to break a 2x4 at the 4 side instead of the 2.. going to f**k up your hand.
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Xion
RealPoor Guru
Joined: 11 Oct 2002
Posts: 2117
Location: Los Angeles, CA
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Posted: 09/16/03 - 14:12 Post subject:
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| Nahualli wrote: | I realize that it's not the atmosphere that's hot, in fact just the opposite.
What I was asking was wouldn't the elevator be subject to intense gravitational pull?
What you said about the shuttle returning from a vaccuum makes sense tho. I still don't understand how something can just "drift" into the atmosphere tho.
-Nah- |
the earth's gravity is the strongest on the surface, not in outer space. the fact is that an elevator would have a slower, more controlled decent than a space shuttle moving at over 17,000 mph at re-entry
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Bait Masterson
RealPoor Guru
Joined: 11 Oct 2002
Posts: 3842
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Posted: 09/16/03 - 14:35 Post subject:
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The gerat thing about it is, Americans would be the ones to build it if it got made 
because we all know every other country is useless as all f**k
Earths Moon is Property of the United States of America.
so if we relocated America in space we would be free to nuke the f**k out of the rest of the planet (J/K but its fun to dream)
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NickPSH
RealPoor Master of Posts
Joined: 11 Oct 2002
Posts: 5680
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Posted: 09/16/03 - 14:48 Post subject:
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Everyone knows Cephes 5 will never advance beyond that of the other planets fools.
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Okami
RealPoor Guru
Joined: 11 Oct 2002
Posts: 2242
Location: The new board
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Posted: 09/16/03 - 14:59 Post subject:
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can the "anchor" on the other end keep up with the spinning of the earth though. Seems like the cable will have to be ever expanding due to the mismatched speeds, or the cable pulls the other object back down.
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Luturb
RealPoor Guru
Joined: 11 Oct 2002
Posts: 4042
Location: Livermore, California
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Posted: 09/16/03 - 15:13 Post subject:
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| Quote: | | At about a third of the way along the cable - 36,000km from Earth - objects take a day to complete a full orbit. If the cable's centre of gravity remained at this height, the cable would remain vertical, as satellites placed at this height are geostationary, effectively hovering over the same spot on the ground. |
Same reason your sattelite TV antenna can always point at the same place.
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WheresNWS
RealPoor Master of Posts
Joined: 19 Nov 2002
Posts: 6448
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Posted: 09/16/03 - 15:15 Post subject:
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Not sure about this, but doesn't the Coriolis Effect s***w this idea up?
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Maelstrom
RealPoor Guru
Joined: 11 Oct 2002
Posts: 4072
Location: Montréal
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Posted: 09/16/03 - 16:13 Post subject:
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| Bait Masterson wrote: | The gerat thing about it is, Americans would be the ones to build it if it got made
because we all know every other country is useless as all f**k
Earths Moon is Property of the United States of America.
so if we relocated America in space we would be free to nuke the f**k out of the rest of the planet (J/K but its fun to dream) |
In fact every country on this damn planet should contribute and help totaly bs that only the US should pay for something that could help us all 1 day.
If every experts in the world would work together maybe we could progress more.
Of course no religious people would ever wanna help for space mission cause they are affraid that we s***w up whats said in their sooo lovely bible.
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WheresNWS
RealPoor Master of Posts
Joined: 19 Nov 2002
Posts: 6448
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Posted: 09/16/03 - 16:20 Post subject:
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| Maelstrom wrote: | | Bait Masterson wrote: | The gerat thing about it is, Americans would be the ones to build it if it got made :)
because we all know every other country is useless as all f**k :)
Earths Moon is Property of the United States of America.
so if we relocated America in space we would be free to nuke the f**k out of the rest of the planet :)(J/K but its fun to dream) |
In fact every country on this damn planet should contribute and help totaly bs that only the US should pay for something that could help us all 1 day.
If every experts in the world would work together maybe we could progress more.
Of course no religious people would ever wanna help for space mission cause they are affraid that we s***w up whats said in their sooo lovely bible. |
Come again.
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Eduin
Sir Postalot
Joined: 14 Oct 2002
Posts: 1046
Location: Glasgow
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Posted: 09/16/03 - 16:21 Post subject:
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| WheresNWS wrote: | | Not sure about this, but doesn't the Coriolis Effect s***w this idea up? |
No, because you build it at the equator where the Coreolis Effect is either in balance or negligible (can't remember which).
Regards,
Eduin
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Maelstrom
RealPoor Guru
Joined: 11 Oct 2002
Posts: 4072
Location: Montréal
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Posted: 09/16/03 - 16:23 Post subject:
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How come they didnt used this idea in star strek?
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Barnacle Bob
RealPoor Guru
Joined: 11 Oct 2002
Posts: 2135
Location: WHO KNOWS WHERE I'LL TURN UP!
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Posted: 09/16/03 - 16:23 Post subject:
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because a show about an elevator that goes into space would be the gayest show of all time
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Banzai
Guest
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Posted: 09/16/03 - 16:24 Post subject:
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They could subsidize this idea by selling bungee jumps to extreme sportspersons.
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Maelstrom
RealPoor Guru
Joined: 11 Oct 2002
Posts: 4072
Location: Montréal
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Posted: 09/16/03 - 16:25 Post subject:
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| Barnacle Bob wrote: | | because a show about an elevator that goes into space would be the gayest show of all time |
Cant be worse then the damn pistols in star strek now THATS gay
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Occulis
RealPoor Jedi
Joined: 11 Oct 2002
Posts: 13293
Location: Moral Relativity Central
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Posted: 09/16/03 - 16:47 Post subject:
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It's like the NASA guys say. Hard to keep peoples attention when you don't have any smoke or explosions.
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Mogling
RealPoor Guru
Joined: 29 Dec 2002
Posts: 2451
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Posted: 09/16/03 - 16:53 Post subject:
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| Luturb wrote: | | Nahualli wrote: | | What I was asking was wouldn't the elevator be subject to intense gravitational pull? |
I'm no physicist, but I don't believe gravity is any stronger in the atmosphere than it is on the ground. The reason stuff burns up in the atmosphere is because it's going so fast when it hits the air. During reentry you are moving at terrific speed thanks to the fact the you're basically falling with no friction. If the weight is lowered in slowly maybe there's no problem. It would still be moving around the earth pretty fast though so I'm just guessing.
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IIRC gravity is greater the closer to the center of the mass you get so that the gravity higher up would be much less..
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Eduin
Sir Postalot
Joined: 14 Oct 2002
Posts: 1046
Location: Glasgow
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Posted: 09/16/03 - 17:11 Post subject:
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| Mogling wrote: |
IIRC gravity is greater the closer to the center of the mass you get so that the gravity higher up would be much less.. |
"much less" would be a huge exaggeration at the distances we are talking about. However, most of the gravitational force is *balanced* because of freefall when we are talking about space elevators. That's why geostationary works - the object is in freefall at precisely hte right distance to balance the gravitational forces upon it. It also means it is moving very fast (relatively).
Regards,
Eduin
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Banzai
Guest
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Posted: 09/16/03 - 17:20 Post subject:
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So the logistical question I have is would there be a tower build up from the ground or a spool that would be lowered from space?
To me it seems more pratical to have the mass in space and lower it down so the process would be like a huge hammer throw but the cumulative weight from lowering from space could be touchy to adjust.
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