Alright, throwing startrek's warpdrive out of the picture (inerta would splatter the crew on bulkheads) how is it even theoritical to make the trip between stars in a reasonable time?
Orion's Arm wormhole's are a good idea, the jump gates, even babylon 5's gate system, although i really dont think you would spend very long in hyperspace.
I have been reading some of C. J. Cherryh's work, and wondered about this jump drive that is used in the merchanter series. It seems to me that this involves some sort of way of changing the gravational constant of the universal in a localized area. Also the 'jumps' seem to be limited to about 25 lightyears.
Im not a physicist, but it would seem to me, that the limit of the jump is either due to some form of drag on the object, or some sort of power requirement needed to perform the operation.
Another point, in Cherryh's work, the jump takes place some distance from the primary in star systems and there is a network of null points where there is no star present.
Any thoughts? Comments?
Holy Grail of Astrophysics
Holy Grail of Astrophysics
Remember the Shephard's prayer, "oh god, don't let me screw up"
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Matt McIrvin
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All this stuff is completely fictional, so it could act any way the author wants it to.
Of them, the wormhole method is probably the closest to having actual physics behind it. But even there, nobody knows how to make a stable, usable wormhole without types of matter/energy not known to exist in the real world.
Of them, the wormhole method is probably the closest to having actual physics behind it. But even there, nobody knows how to make a stable, usable wormhole without types of matter/energy not known to exist in the real world.
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Evil Dr Ganymede
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I think any viable FTL (if it exists) would have to work by circumventing Relativity, not breaking it. So you don't go faster than light in realspace, you tinker around with space itself and/or skip the intervening space to get to your destination.
But as Matt said, anything involving that sort of thing would require wacky forms of matter that we haven't found yet and don't have anywhere near enough energy to even manufacture. Er, and a whole new branch of physics too.
I quite like the Alcubierre drive, myself.
But as Matt said, anything involving that sort of thing would require wacky forms of matter that we haven't found yet and don't have anywhere near enough energy to even manufacture. Er, and a whole new branch of physics too.
I quite like the Alcubierre drive, myself.
According to some people in a chatroom i frequent, there is a matter of disagreement concerning the light barrier in the first place.
1) It seems that in particle accelerators, the speed of light is exceeded,
2) light coming from the far side of the sun seems to show up before the planet or object emitting it clears the sun. (personally, i feel that the gravity field has bent the light waves)
As I understand it, doesnt quantom physics open a whole new level of physics dealing with layers of space and time?
I know that in science fiction anything is possible. But, with the recent use of ion drive on a space probe, things are changing fast.
What was considered written in stone yesterday has turned to tissue paper today, so to speak.
Maybe i should have started this out with "Alright, if hypothetically, this works, why are the following limitations in place?" kind of like "we know we can get to the moon and land there, but how we going to do it, if we carry the fuel for the mission, the ship is too big to get off the ground"
And, I admit it, im disabled, bored out of my rabid mind with a life that primarily involves doctors and medical treatments and trying to find anything to get the brain working besides tv.
1) It seems that in particle accelerators, the speed of light is exceeded,
2) light coming from the far side of the sun seems to show up before the planet or object emitting it clears the sun. (personally, i feel that the gravity field has bent the light waves)
As I understand it, doesnt quantom physics open a whole new level of physics dealing with layers of space and time?
I know that in science fiction anything is possible. But, with the recent use of ion drive on a space probe, things are changing fast.
What was considered written in stone yesterday has turned to tissue paper today, so to speak.
Maybe i should have started this out with "Alright, if hypothetically, this works, why are the following limitations in place?" kind of like "we know we can get to the moon and land there, but how we going to do it, if we carry the fuel for the mission, the ship is too big to get off the ground"
And, I admit it, im disabled, bored out of my rabid mind with a life that primarily involves doctors and medical treatments and trying to find anything to get the brain working besides tv.
Remember the Shephard's prayer, "oh god, don't let me screw up"
By "seeming to exceed light speed" your friends are probably talking about phase velocity vs group velocity. Light wave packets can consist of many individual superimposed waves. These individual waves have a phase velocity and can appear to travel faster than the entire wave packet, but the actual speed of light is the group velocity, or the speed of the packets themselves. Googling "group velocity" gives you some nice pages, some with java applets to play with.
There is also another potentially confusing issue of particles inside accelerators lasting much longer than they should, but that is explained by special relativity (time dilation).
Light speed in water is much slower than in a vacuum, and so is often exceeded. Blue Cherenkov radiation (often seen in pictures of nuclear reactor cores, and supposedly emitted from the "warp drives" in Star Trek) is the result.
There are even some theories that suggest that light speed in a vacuum was actually different in the distant past! This was used to explain strange spectra emitted from distant supernovae/pulsars. Who knows, special relativity, QM, and Maxwell's equations are just theories after all.
There is also another potentially confusing issue of particles inside accelerators lasting much longer than they should, but that is explained by special relativity (time dilation).
Light speed in water is much slower than in a vacuum, and so is often exceeded. Blue Cherenkov radiation (often seen in pictures of nuclear reactor cores, and supposedly emitted from the "warp drives" in Star Trek) is the result.
There are even some theories that suggest that light speed in a vacuum was actually different in the distant past! This was used to explain strange spectra emitted from distant supernovae/pulsars. Who knows, special relativity, QM, and Maxwell's equations are just theories after all.
Speed of light in a vacuum?
Hey Dirk, uh, space is not a vacum. Granted it is close, but you have to consider that there are gases, dust and lots of stuff floating around out there.
Since the velocity of anything is affected by whatever it passes thru at any given moment, the only finite speed of light is measured in a man made vacuum.
Looking at some of the math, if the hypothetical jump has to be a certian distance from the primary, that means a 57 day 'climb' out from earth at 1000mps, which hardly sounds comfortable in the least. At 100 mps, it is an 84 week trip just to reach the jump points.
Once a jump is made and you emerge at the next point, the first thing you have to do is dump delta v, according to Cherryh's books.
If this is some form of wormhole that is being used, why dump delta v? you shouldnt be going that fast when you emerge on the other side.
In one thread I found, some one postulated that the mass dirived by velocity would open the wormhole, i tend to agree with the argruements against it.
Anyway, this is just a thought puzzle for me to keep from losing my mind.
Since the velocity of anything is affected by whatever it passes thru at any given moment, the only finite speed of light is measured in a man made vacuum.
Looking at some of the math, if the hypothetical jump has to be a certian distance from the primary, that means a 57 day 'climb' out from earth at 1000mps, which hardly sounds comfortable in the least. At 100 mps, it is an 84 week trip just to reach the jump points.
Once a jump is made and you emerge at the next point, the first thing you have to do is dump delta v, according to Cherryh's books.
If this is some form of wormhole that is being used, why dump delta v? you shouldnt be going that fast when you emerge on the other side.
In one thread I found, some one postulated that the mass dirived by velocity would open the wormhole, i tend to agree with the argruements against it.
Anyway, this is just a thought puzzle for me to keep from losing my mind.
Remember the Shephard's prayer, "oh god, don't let me screw up"
Aint this a kick in the pants?
First, Special Relativity itself was superceded by Einstein’s own more powerful General Relativity (1915), in which faster than light travel is possible under certain rare conditions. The principal difficulty is amassing enough energy of a certain type to break the light barrier. Second, one must therefore analyze extra-terrestrial civilizations on the basis of their total energy output and the laws of thermodynamics. In this respect, one must analyze civilizations which are perhaps thousands to millions of years ahead of ours.
The Physics of Interstellar Travel
Author: Michio Kaku
Okay, so the light barrier can be broken, Einstein says so...
However, economics is now a factor.
Another quote:
For a Type II civilization, a new form of propulsion is possible: anti-matter drive. Matter-anti-matter collisions provide a 100% efficient way in which to extract energy from mater. However, anti-matter is an exotic form of matter which is extremely expensive to produce. The atom smasher at CERN, outside Geneva, is barely able to make tiny samples of anti-hydrogen gas (anti-electrons circling around anti-protons). It may take many centuries to millennia to bring down the cost so that it can be used for space flight.
The following actually sounds like the so called 'stargates"
There are at least two ways in which General Relativity may yield faster than light travel. The first is via wormholes, or multiply connected Riemann surfaces, which may give us a shortcut across space and time. One possible geometry for such a wormhole is to assemble stellar amounts of energy in a spinning ring (creating a Kerr black hole). Centrifugal force prevents the spinning ring from collapsing. Anyone passing through the ring would not be ripped apart, but would wind up on an entirely different part of the universe. This resembles the Looking Glass of Alice, with the rim of the Looking Glass being the black hole, and the mirror being the wormhole. Another method might be to tease apart a wormhole from the “quantum foam” which physicists believe makes up the fabric of space and time at the Planck length (10 to the minus 33 centimeters).
The information is at http://www.physicspost.com/articles.php?articleId=48
The Physics of Interstellar Travel
Author: Michio Kaku
Okay, so the light barrier can be broken, Einstein says so...
However, economics is now a factor.
Another quote:
For a Type II civilization, a new form of propulsion is possible: anti-matter drive. Matter-anti-matter collisions provide a 100% efficient way in which to extract energy from mater. However, anti-matter is an exotic form of matter which is extremely expensive to produce. The atom smasher at CERN, outside Geneva, is barely able to make tiny samples of anti-hydrogen gas (anti-electrons circling around anti-protons). It may take many centuries to millennia to bring down the cost so that it can be used for space flight.
The following actually sounds like the so called 'stargates"
There are at least two ways in which General Relativity may yield faster than light travel. The first is via wormholes, or multiply connected Riemann surfaces, which may give us a shortcut across space and time. One possible geometry for such a wormhole is to assemble stellar amounts of energy in a spinning ring (creating a Kerr black hole). Centrifugal force prevents the spinning ring from collapsing. Anyone passing through the ring would not be ripped apart, but would wind up on an entirely different part of the universe. This resembles the Looking Glass of Alice, with the rim of the Looking Glass being the black hole, and the mirror being the wormhole. Another method might be to tease apart a wormhole from the “quantum foam” which physicists believe makes up the fabric of space and time at the Planck length (10 to the minus 33 centimeters).
The information is at http://www.physicspost.com/articles.php?articleId=48
Remember the Shephard's prayer, "oh god, don't let me screw up"
Re: Speed of light in a vacuum?
jlf wrote:Hey Dirk, uh, space is not a vacum. Granted it is close, but you have to consider that there are gases, dust and lots of stuff floating around out there.
Since the velocity of anything is affected by whatever it passes thru at any given moment, the only finite speed of light is measured in a man made vacuum.
Of course, but remember that you were originally suggesting FTL scenarios in accelerators and such that probably have a straightforward explanation. I was just filling in the gaps.
I thought Kaku's "Hyperspace" was a pretty good book too, although a little dated by now. But it does make a pretty good argument about why wormhole travel is probably the most promising FTL candidate and what we are going to expect. The "exotic matter" requirement probably postulates antigravity generation.
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eburacum45
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We use the quantum foam type wormholes in Orion's Arm; the rotating kerr-type holes don't seem to be traversible.
But the question of delta-v does cause some problems;
if you pass through a wormhole with the far end orbiting a star with large proper motion (say Barnard's Star or Gliese 710), you gain a lot of kinetic energy with respect to the origin;
you could use that kinetic energy to fling projectiles at the home system-
that energy has to come from somewhere.
The only place it can come from is from the hole itself; so travelling to Barnard's star would probably make the hole collapse.
But the question of delta-v does cause some problems;
if you pass through a wormhole with the far end orbiting a star with large proper motion (say Barnard's Star or Gliese 710), you gain a lot of kinetic energy with respect to the origin;
you could use that kinetic energy to fling projectiles at the home system-
that energy has to come from somewhere.
The only place it can come from is from the hole itself; so travelling to Barnard's star would probably make the hole collapse.
eburacum45
We use the quantum foam type wormholes in Orion's Arm; the rotating kerr-type holes don't seem to be traversible.
Funny you should say that, i was setting up an avi for a webpage showing a ship passing through a worm hole. As soon as the ship passed through, the image of the even horizon went *poof*
I think i will keep it like that.
I agree, once on the other side, you gonna have to dump delta v, or overshoot your distination.
Hypothetically speaking, if this type of intersteller travel is possible, then the delta v could be as high as 80%c or more. So, the terminus point of the wormhole would be outside the solar system, and you would be decelerating as you enter. Probably at 1g or close to it.
Im gonna have to dig out my college math books to figure out how far out the terminus would have to be to decelerate enough to put yourself into an orbit around a planet without breaking the laws of physics.
(considering we seem to be bending them in this thread)
Remember the Shephard's prayer, "oh god, don't let me screw up"
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Guest
jlf wrote:I agree, once on the other side, you gonna have to dump delta v, or overshoot your distination.
Hypothetically speaking, if this type of intersteller travel is possible, then the delta v could be as high as 80%c or more. So, the terminus point of the wormhole would be outside the solar system, and you would be decelerating as you enter. Probably at 1g or close to it.
I assume the terminus wouldn't just "hang" in space. If you consider this point, the delta v might also be controlled or mitigated (to some degree) by coordinating the departure time with the orbital phase of the terminus.
In other words, make the jump when the terminus gate's orbital velocity matches the departure point's relative velocity most closely.
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eburacum45
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I wouldn't think that it is a good idea to go through a wormhole at relativistic speeds; they appear to be delicately balanced things, and the added relativistic mass would probably tear the hole apart.
In Iain Bank's new novel, The Algebraist, set in a very OA-like universe, wormholes are destroyed by near misses with relativistic asteroids. The extra mass is enough to stop local space near the hole being asymptotically flat; which is a prerequisite for many of the theoretical wormhole geometries.
In Iain Bank's new novel, The Algebraist, set in a very OA-like universe, wormholes are destroyed by near misses with relativistic asteroids. The extra mass is enough to stop local space near the hole being asymptotically flat; which is a prerequisite for many of the theoretical wormhole geometries.