It's About Liberty: A Conservative Forum
Topics => Science, Technology, & Medicine => Topic started by: trapeze on March 03, 2011, 04:14:45 PM
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LINK (http://www.foxnews.com/scitech/2011/03/03/tuning-laser-pull-push-researchers-design-working-tractor-beam/)
[blockquote]
There's no escaping it: Though the tractor beam is a staple of sci-fi space-faring scenarios, it's also extremely counter-intuitive. How does one pull something in via an outward-shooting beam?
A few Chinese researchers think they've found the answer via a theoretical method that should generate a backward-pulling force from a forward-traveling stream of photons.
Tthe Fudan University team won't be capturing rebel tranports with their beam any time soon -- it only works (theoretically) at the nano-level -- but it does achieve an interesting turnabout of physical force. We know photons exert an outward momentum; this is what allows solar sails to harness sunlight to generate small amounts of thrust. But carefully tuned to meet two conditions, a system can be created to turn "push" into "pull."[/blockquote]
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This isn't the same thing as a tractor beam, but I've seen proposals to use spacecraft to alter the course of asteroids by maneuvering close to them and using thrusters. There is a mutual gravitational attraction between the spacecraft and the asteroid, so the spacecraft doesn't have to actually touch the asteroid for its thrusters to have an effect. That's pretty cool.
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I'm imagining some kind of artificially created space-differential - like a created low "pressure" area (I know there's no pressure in space, but bear with me), where a beam "removes" space from a chosen area in a controlled manner, and as the surrounding space moves in to fill the void, any solid matter occupying that space would also move toward the void, effectively drawing the object continuously toward the origin of the beam until it could be secured.
::thinking:: ::cool:: ::unknowncomic::
ETA: Like "pulling" a toy boat toward you by scooping water toward you with your hands directly in front of the boat. Only with space.
::thinking:: ::cool:: ::unknowncomic::
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I'm imagining some kind of artificially created space-differential - like a created low "pressure" area (I know there's no pressure in space, but bear with me), where a beam "removes" space from a chosen area in a controlled manner, and as the surrounding space moves in to fill the void, any solid matter occupying that space would also move toward the void, effectively drawing the object continuously toward the origin of the beam until it could be secured.
::thinking:: ::cool:: ::unknowncomic::
ETA: Like "pulling" a toy boat toward you by scooping water toward you with your hands directly in front of the boat. Only with space.
::thinking:: ::cool:: ::unknowncomic::
Problem isn't that there is no pressure in space...there's no anything. Nothing to displace.
No, in order to create a true tractor beam I think you would need to be able to harness, direct and focus gravity. You would need to then have a source of gravity like a micro black hole. Something to shield it with and a way of projecting its effect of gravity.
BTW...one of the things that I find more than a little annoying about all of the scifi pics since Star Wars is the way that they have spacecraft behave as if there is both gravity and air in space so that the craft fly around as if they are in an atmosphere.
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I'm imagining some kind of artificially created space-differential - like a created low "pressure" area (I know there's no pressure in space, but bear with me), where a beam "removes" space from a chosen area in a controlled manner, and as the surrounding space moves in to fill the void, any solid matter occupying that space would also move toward the void, effectively drawing the object continuously toward the origin of the beam until it could be secured.
::thinking:: ::cool:: ::unknowncomic::
ETA: Like "pulling" a toy boat toward you by scooping water toward you with your hands directly in front of the boat. Only with space.
::thinking:: ::cool:: ::unknowncomic::
Problem isn't that there is no pressure in space...there's no anything. Nothing to displace.
What? No anti-matter? No plasma? No tachyon particles? There's gotta be SOMETHING they can move around...
::thinking:: ::whatgives::
No, in order to create a true tractor beam I think you would need to be able to harness, direct and focus gravity. You would need to then have a source of gravity like a micro black hole. Something to shield it with and a way of projecting its effect of gravity.
Or... with a few modifications, they could reconfigure the forward sensor array to transmit anti-matter directly from the warp-core into a variable-pulse feedback loop generated by the forward shields. Theoretically that should create a mini-singularity, which could then be harnessed by a force-field, beamed directly into a class-one probe, and fired at the object. After the probe is launched, we'll have exactly 47 seconds to reconfigure the transporter before the probe reaches its target. On impact, we can disengage the force field, so the object should theoretically be trapped inside the singularity, at which time it can be safely beamed back into a containment field in the deck 6 cargo hold.
Make it so.
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...BTW...one of the things that I find more than a little annoying about all of the scifi pics since Star Wars is the way that they have spacecraft behave as if there is both gravity and air in space so that the craft fly around as if they are in an atmosphere.
No doubt. I can't remember now which movie it was, but I saw a sci-fi movie where the spaceship scenes were utterly silent, and I was like, "Oh yeah baby!" Spaceships that make noise are a pet peeve, although as an audio technician/sound designer, I get it. I just disagree with it. Sometimes silence in film IS the sound.
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2001 accurately depicted the soundless environment of space. I get the aversion to Star Wars use of sound, but it really wouldn't be the same sort of film if it was held to "hard sci-fi" standards. It's more of a fantasy/adventure with space and technology as a backdrop.
IDP's idea of a tractor beam is essentially the same concept behind warp drives. AFAIK research shows it to be a theoretical possibility, but the energy requirements present an almost insurmountable engineering hurdle. I also wonder if it could be localized to the extent that it would function as a tractor beam.
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...BTW...one of the things that I find more than a little annoying about all of the scifi pics since Star Wars is the way that they have spacecraft behave as if there is both gravity and air in space so that the craft fly around as if they are in an atmosphere.
No doubt. I can't remember now which movie it was, but I saw a sci-fi movie where the spaceship scenes were utterly silent, and I was like, "Oh yeah baby!" Spaceships that make noise are a pet peeve, although as an audio technician/sound designer, I get it. I just disagree with it. Sometimes silence in film IS the sound.
Mine too! However, Battlestar Galactica in Sensurround at the theater was way COOL. Speaking of sound in space. Did you here that solar flare yesterday?
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I remember the first time that I heard of a micro (or quantum) black hole. It was in the short story "The Hole Man" written by Larry Niven in the early seventies. I think I read it in the late seventies. A quantum black hole is held in a containment field found in an abandoned alien artifact on Mars. The protagonist shuts off the containment field as the antagonist is passing under it, the black hole dropping through him, killing him and ultimately dooming the planet to eventual destruction as the hole now continuously orbits Mars' interior destroying everything in its path one molecule at a time.
The artifact was (if I remember correctly) thought to be some kind of alien communication device, one that transmitted gravity waves.
Anyway, you could make a tractor beam with magnetism but anything sufficiently strong enough to exert the required pull on a craft would almost certainly mess up the biologicals on board. That's why I thought that gravity would be better. The containment and focusing would be the trick. Too much gravity would be as bad as too great a magnetic field, killing the occupants with tidal forces.
Anyway, Niven had lots of great concepts like that when he was in his prime. If you are at all inclined toward scifi you could do a lot worse than to start out with Niven's Known Space series of short stories and novels which culminates with the multi-award winning Ringworld.
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Current theories regarding an expanding universe, put dark energy as the major cause. Could not a tractor beam repress the dark energy within its beam and have the pressure of the outside dark energy push the object up the beam...if a technology is advanced enough to control gravity this should be a walk in the park.
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You know what's really sad in all of this is that the people who were first to put a man on the moon (and several times thereafter) are, forty years later, reduced to discussions such as this.
I was supposed to have a flying car by now.
I saw 2001: A Space Odyssey this weekend on satellite and in so many ways it was depressing. We should be on the moon full time forty years after getting there. With our new Obama economy we can look forward to that maybe in the next century. And when we get there we will have to stay out of the way of the ChiComms.
And if the next dinosaur killer asteroid gets here first, well, hard cheese, humans.
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Not only were we supposed to be on the moon full time, we were supposed to be able to fly there on Pan-Am.
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Where's my George Jetson saucer, damnit!
::cussing::
The Jetsons Tv Intro (http://www.youtube.com/watch?v=OZL3l8iCA4k#)