Grimlock said:Exactly what it says, an elevator going into space.
Frictio n aginst the atmosphere... sheering force... I see problems with this concept
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Grimlock said:Exactly what it says, an elevator going into space.
JBeukema said:Frictio n aginst the atmosphere... sheering force... I see problems with this concept
GoodKat said:Trigshot, I think you are confusing "black hole" with "wormhole".
only if you want to come back or emerge in one pieceTrigshot said:I know the difference, I was simply referencing black holes because they are the only known likely source of actually creating a wormhole. In theory, a massive black hole may actually be a wormhole, but I would imagine testing that theory would be.... difficult.
Ozymandyus said:Hate to agree with JB, but I find it incredibly unrealistic. We'll see wormholes before we see space elevators.
A cable going from the earth to moon - where would it be tethered? It would tear whatever it was apart as they move at different speeds. A tether to a space station in geosynchronous orbit would exert a ridiculous amount of downward pull on the space station. The weather effects on such an elevator would be outrageous, and would also significantly affect both ends of the tether as well as the trip up or down.
Beyond that, the cost of pulling such an elevator up (which would pull DOWN on the space station) would still be significant,approximately equal to just sending a rocket - it just isn't worth it.
Darius said:In addition to this, a counter weight on the tether would provide centrifugal to keep it taught
You're counting on too many things going right. As to how to power the elevator, a solar panel capable of absorbing a wider light spectrum (more then just infrared) could be attached to the bottom. Then, a high powered laser could be shot from the base of the tether that would reach the solar panel giving the elevator power to move itself upwards with its own device. From there, lasers shot from orbiting satellites could hit the solar panel.
The elevator pulling itself upwards would pull the space station DOWNWARDS. I'm pretty certain even a carbon nanotube structure that is a mile+ long would still be breakable and bendable by the sorts of forces we are talking about here, and constructing such a structure would cost such a ridiculous amount of money - I find it completely unfeasible. A rigid structure this tall is just a bad idea. Beyond that, it would have to be a carbon fiber nanotube pyramid, as anything else would collapse into its supports from the weight.Darius said:A tether made of molecularly adjusted carbon nanotube crystals would be able to support it self upright, without putting a large amount of downward force on the space station, and is strong enough to withstand the conditions. In addition to this, a counter weight on the tether would provide centrifugal to keep it taught. As to how to power the elevator, a solar panel capable of absorbing a wider light spectrum (more then just infrared) could be attached to the bottom. Then, a high powered laser could be shot from the base of the tether that would reach the solar panel giving the elevator power to move itself upwards with its own device. From there, lasers shot from orbiting satellites could hit the solar panel. I'm sure by the time this is all possible (if possible), a material or combination of materials will exist that can withstand the weather effects that would occur on a space elevator.
Ozymandyus said:The elevator pulling itself upwards would pull the space station DOWNWARDS. I'm pretty certain even a carbon nanotube structure that is a mile+ long would still be breakable and bendable by the sorts of forces we are talking about here, and constructing such a structure would cost such a ridiculous amount of money - I find it completely unfeasible. A rigid structure this tall is just a bad idea. Beyond that, it would have to be a carbon fiber nanotube pyramid, as anything else would collapse into its supports from the weight.
Energy will be MUCH cheaper by the time such a thing would be feasible, and it would be much easier to just use such a laser to power a shuttle into space rather than an elevator - ultimately the forces involved in moving mass and then slowing it down as it reaches its destination are the same - theres no reason to use such a structure.
Back on topic - teleportation is another possibility - I think its more likely than star trek type hyperspace drives depending on what the claims for science behind them are. Being able to interact with a fourth spatial dimension would clearly allow for all kinds of travel, and whether it would be more analogous to hyperdrives or stargates, I'm not really sure. Probably stargates.
The idea is to attach the tether to a counterweight which swings around Earth providing centripetal (not centrifugal) force to the cable - this force keeps it taught as the elevator climbs upwards.Ozymandyus said:The elevator pulling itself upwards would pull the space station DOWNWARDS
I haven't heard the weather objection before but these nanotubes are incredibly strong. One the thickness of a human hair is expected to be able to support the weight of a car. Plus the base of the space elevator would be situated in the doldrums so should not experience extreme weather like hurricanes.Ozymandyus said:I'm pretty certain even a carbon nanotube structure that is a mile+ long would still be breakable and bendable by the sorts of forces we are talking about here
Unfortunately, this is correct :cry: I think it would be a worthwhile investment though.Ozymandyus said:constructing such a structure would cost such a ridiculous amount of money
Yes, around about 600 tonnes to be somewhat exact. Building the initial structure is going to be the biggest problem of course - all the materials will have to be slowly shipped up and assembled piece by piece. But hey, we did a pretty good job with the international space station which weighs about 280 tonnes so I don't think it's outside the realms of possibility to build it. And once it's done it opens the way for much bigger construction projects.Ozymandyus said:How do you envision such a structure... The counterweight would have to weigh something enormous to keep a cable that would weigh many many tons taught.
Ozy! Not centrifugal, centripetal But again you're right that's why the idea had to wait until something like carbon nanotubes to start becoming feasible. It may be true that the nanotubes are not strong enough, but at least we're getting closer to the type of materials we would need.Ozymandyus said:The tensile strength of the cable would have to be off the charts, as well as the strength of the tether point on the earth that is being pulled by thousands of tons of centrifugal force.
As it is so close to Earth I doubt other celestial bodies will have a huge effect. Especially considering the fact that we can get the ISS to work.Ozymandyus said:Taking into account varying gravitational effects of the moon and the sun on this counterweight is another problem - not sure exactly how it might affect it but it begins to be significant at the masses we are talking about here.
The idea is to be slow and steady, avoiding the need for huge, energy expensive acceleration to overcome the gravity of the planet. Maybe there are other ideas that would work better, but space elevators is the idea that excites me the most.Ozymandyus said:I can't see how it's that much cheaper to accelerate something with a cable than without, if you do it right. If we instead used a tunnel of electromagnets to 'shoot' shuttles/cargo into space like a rail gun, it could potentially be nearly as energy efficient as moving such an elevator, and would be able to do more than move cargo to a single point.
Well from certain reference frames you can talk about a centrifugal force on the Earth. But the important point is the tension in the tether providing centripetal force to the counterweight in order to keep it swinging in a circle.Ozymandyus said:There are still some substantial reactive centrifugal forces when talking about rotating bodies of this mass are there not? I'm not talking about centrifugal force as it is commonly (mis)used. Although I may have confused myself by thinking about the initial inertial stresses involved in accelerating such a counterweight, which isn't an issue in this sort of case.
I don't see all that much difference, instead of the force being provided by gravity it is provided by the tension in the tether. The counterweight would be about 100,000 km up whereas the moon is about 380,000 km away, take into account the relative sizes of the Earth and moon - but I'm not 100% sure might be a valid concern.Ozymandyus said:In any case, tidal effects seem that they would be more of a problem with a tethered mass like this than a free falling mass like the ISS that can freely adjusted to such stresses.
last I heard, teleportation was only successful at the atomic levelOzymandyus said:teleportation is another possibility