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Warp Drive Breakthrough
NIck Porcino writes "Warp drive one step closer to reality!
From the abstract:
A spacetime is presented for which the total negative mass needed is only
the order of grams, accompanied by a negligible amoung of positive
energy. This constitutes a reduction of the absolute value of the energy
by 65 orders of magnitude. The new geometry satisfies the quantum
inequality concerning WEC [Weak Energy Condition] violations and exhibits
the same advantages as the original Alcubierre spacetime.
Read it here.
The two big problems to be resolved are 1) how do you get an object inside a warp bubble? 2) What happens to the object when the warp bubble collapses?
"
Being a physics major there seems to be major problems with this idea as a few of you have already pointed out, with the idea of negative mass and negative energy. These things from my understanding can exsist only in two places both which are very hard to find or create those are a black hole and a wormhole. Negative mass some would relate to the idea of hyperspace or extra dimensions. I still believe though that warp drives are a possibility but not beneficial, I think we need to spend more time working with ID jump drives which might not be as far off as some would say.
>energy is abundant at this time in the universe
There is no net energy in the universe. Consider:
(1) Objects far apart have more energy than objects close together (because it takes energy to separate them)
(2) The universe is expanding.
Now there's a theory that the expansion of the universe consumes exactly offsets the energy necessary to separate all the galaxies (and all other matter) from one another. This neatly solves the problem of "When the universe contracts, won't things get hotter and thus violate the law of thermodynamics?" No, because a contracting universe loses energy bacause objects get closer together and this again exactly offsets supposed increased energy as things get crushed together. So the total energy of the universe is exactly zero. Everything's pointless!
The effect was predicted by the Dutch physicist Hendrick Casimir in 1948
Casimr effect
It seems to me that charging a capacitor makes it more massive for the same reason that lifting an object against a gravitational field makes it more massive (though not necessarily heavier, in a nonuniform field). In both cases, you're doing work and storing energy. E = mc^2, so m must increase.
Vanishingly small is the right way to describe the effect. It would take a staggering amount of energy to increase the capacitor's mass by any measurable amount.
Also, the capacitor's mass can only increase from its rest mass. I don't see how you could make it less massive (let alone negatively massive!) by charging and discharging it than it would be just sitting uncharged.
AC
Just a thought here, try not to think of "negative" as the opposite as in the asteroid example, think of it as more a "lack of", where negative mass is a lack of mass where there should be mass. Perhaps an asteroid of negative mass which struck the oceans wouldn;t even notice. Perhaps we are bombarded by negative masses all the time, but dont notice them? Perhaps negative mass is something not-so exotic? Perhaps all this physics talk is making me insane? Probably, or maybe I just channeled Einstein and he wanted to play a creul trick on me. No more Physics today, please.
> Secondly, FTL travel *doesn't* neccessarily lead to time travel.
I thought that one of the outcomes of the "Chronology Protection Conjecture" and related works was that path lengths through the wormhole and conventional space would have to be of roughly equal length to prevent the collapse, thus preventing both time- and FTL travel?
The universe seems pretty complex. Is there anything about it that constitutes evidence that the physical laws of our universe were or were not deliberately designed by some outside entity?
BAsed on what I have learned so far, I thought that energy, as measured, was always relative, because it is so hard to find a total absoulte ground state. Note the energy is made up of enthalpy and entropy, of which entropy is only definable (and difficult at that since absolute 0 cannot be attined experimentally).
:)
Therefore, when we witness the Casimir effect, are we really seeing "negative" energy or just a lower energy state (closer to zero or at zero without being under zero) than has previously existed, or that exists naturally. Thus, on these grounds can we define an absolute zero now? Does this mean the average energy of the universe exists above zero? Is negative energy actaully negative in this regard or just an energy that is below the common state at ehich the universe exists, which would now have to be > 0.
Something for all you guys to chew on and lose sleep over
I recomend that you check out http://www.cco.caltech.edu/~qoptics/teleport.html if you want to find out information on FTL travel. I beleive there was an article on slashdot a while back on this.
Consider three ships stationary relative to each other, in a very dull universe (no other objects besides the three ships). They each synchronize their clocks (ie. they all 'tick' at the same rate.) They then set their computers to fire the engines according to a special program while the crew goes into hibernation. The program for the engines goes something like this: fire for a random time, finally winding up with A and B moving in opposite directions relative to C but at the same rate. Then shut down the engines, and awaken the crew. (For each crew, it appears as if it's ship is just as stationary as it was when the three ships were together.)
Crew A sees itself as stationary, and ship B as moving away, and observes that ship B's clock is ticking at a slower rate than ship A's. They conclude that time is passing slower for B's crew.
Most people claim this time dilation as the paradox of the twins. How can time be one rate for A and another rate for B?
BUT... the REAL paradox comes in when looking at B's point of view.
Crew B sees itself as stationary, and ship A moving away, and observes that ship A's clock is ticking at a slower rate than ship B's. They conclude that time is passing slower for A's crew.
So, A sees (meaning measures) B's clock as slow, AND B sees A's clock as slow.
Here is the real paradox. How can each ship measure the other as being slower than itself?
Now let's consider things from C's point of view:
Crew C sees itself as stationary, and ships A and B as moving away in equal, but opposite directions. Crew C observes that ship B's clock is ticking at EXACTLY THE SAME RATE as ship A's clock. They conclude that time is passing equally for A's crew and for B's crew.
It's like a railroad track. One can observe that the rails get closer together the farther away you look, until they converge at infinity. The reality is that the tracks do not converge. It is just perspective.
Hmmm... if you change the spin state of one particle, how will you know that the spin state of the one on the other side of the universe changed? You'll find out eventually... at the speed of light.
There are some known incompatibilities between Einstein's relativity, and the current model of quantum mechanics. Relativity requires that space be "smooth" but QM shows it's quite broken (on small scales, where Relativity breaks down).
Now there's superstring theory, which isn't quite done yet, but it makes great strides in resolving the conflict. But it requires that the universe have at least TEN dimensions (nine spacial, one time).
There are the three "extended" dimensions we can see, and the other 6 spacial dimensions are curled up and very tiny, according to the theory.
Thud (still an Anonymous Coward)
http://j.bruce.home.mindspring.com
No. The process he's describing is taking two clocks and setting the alarms then separating them. Then after separation you speed up one clock and the other clock is sped up the same amount instantaneously. The only problem is the clocks are both already randomly chanding speed on their own and the only way to find out which speed change was yours is to already know exactly when you changed the speed and by how much.
-Zane
Zane@SPAMNO!.supernova.org
>1. Piezoelectric crystal can be made to expand
>and contract with another alternating current.
>The idea is, push on the capacitors when they
>have low mass, and pull on them when they have
>high mass. The resulting machine should be able
>to float in mid-air or even accelerate, if the
>amplitude of the effect can be made high enough.
I've actually seen a Discovery channel show about this. They were talking about some alternate propulsion schemes the military was looking at. They showed a film of this actually happenning. It was actually on a decent show too, not one of those "UFOs are real" type of shows.
OK, this is kind of bogus. Assume your frame of reference is indeed the solar system, and we measure time by, say, a radio broadcast giving the current time from earth. Warp 1000 light years away. Poof. We appear (by the ancient radio clock broadcasts, which are only just reaching our current position) to have already travelled back in time 1000 years. Whoosh, we rush back at near c. Doppler makes time in transit appear to speed up, with 1000 years elapsing in 'radio time' as we travel, even if our wristwatches tell us it took fifteen minutes. No time travel. (or, as a fop to those who use relativity to define time, "no time travel at the same spacial coordinates".)
If you're still puzzled, try thinking about putting the radio clock at the destination instead of the origin...
smoog
- Metal conducts electricity. Therefore, electromagnetic radiation at the surface of a piece of metal has zero electric field; otherwise the electrons in the metal would flow. (Of course if the frequency is high enough, the electrons can't keep up, and the metal becomes "transparent" to those fields. In other words, metal blocks radio waves, but is semi-transparent/semi-opaque to x-rays, and very transparent to gamma rays.
- A pair of parallel metal plates can have a standing wave electromagnetic field between them, much like pipe organs have standing air waves, or plucked guitar strings are a standing wave, and have a node at the bridge and the nut. When done with radio waves, you have what is commonly called "radar cavities", and indeed all of microwave & radar is based on this principle.
- Quantum space is filled with "zero-point" fluctuations in the electromagnetic field. These are basically electromagnetic waves that zip into existance for brief periods of time, and then cancel each other out again. When they occur between a pair of metal plates, these "unreal" quantum fluctions *must* have zero electric field on the metal plates, else the electrons would move.
- The pair of metal plates thus limit the types of virtual fields between them, resulting in a very weak attraction proportional to the distance between them taken to the fifth power. As someone mentioned, this effect was actually measured in th 1920's (?) and is almost simple enough to use a undergrad/grad school lab experiment.
- The theoretical interpretation is that the field between the plates has less than the average, i.e. less than zero amount of energy between them; i.e. since work=force x distance, and the force is attractive, the work (energy) must be negative.
So what do we have? We need to find a pair of very good conductors, made out of something much much smaller than atoms, and hold them a few hundred planck lengths apart from each other. The negative energy in between them should be enough to satisfy that needed in the theoretical paper.BTW, a planck length is *very* small -- 10^-43 meters if I remeber right. Like a few *zillion* times smaller than an atom.
I read something in Analog a few years back about
how running high frequency alternating current
through large capacitors causes their mass to
vary sinusoidally at about twice the frequency
of the current (and the amplitude of the
variations is proportional to the frequency).
(And I thought if you did this, the capacitor
would just get hot.)
I don't remember what this was called or who
discovered it; it has
something to do with Mach's Law. The effect
was supposed to have been observed, and
vanishingly small. But
1. Piezoelectric crystal can be made to expand
and contract with another alternating current.
The idea is, push on the capacitors when they
have low mass, and pull on them when they have
high mass. The resulting machine should be able
to float in mid-air or even accelerate, if the
amplitude of the effect can be made high enough.
2. The amplitude of the variation can (maybe) be
greater than the total mass of the capacitors,
leading to brief repeating periods of negative
mass. Don't think they last long enough to make
a very good warp drive, though...
Anybody care to burn up some capacitors and
test this?
--edkiser
First thing: If you want to read how traveling back in time to meet your former self might actually work, you MUST, *MUST* read "The Fabric of Reality" by by David Deutch.
He explains for the first time in any place, in a simple thought experiment, how such contradictions get resolved. He uses the language of recursive computing and turing machines, not physics, so you will be quite at home if you're are a CS major.
Secondly, FTL travel *doesn't* neccessarily lead to time travel.
As an example, I give you wormholes. Now, most people understand that all you have to do to cause wormholes to become time machines is accelerate one of the mouths until it has a different clock.
So for instance, let's say the entry point has a clock at 2pm, and the exit point has a clock of 1pm (because it is moving close to the speed of light and has a slower clock)
Now, if you bring those mouths of the wormhole within 30 minutes traveling distance of each other, you could enter the entrance at 2pm, arrive at the exit at 1pm, and fly back to the entrance and arrive at 1:30pm which is 30 minutes before you left. Then, you could stop yourself from going in.
However, there is a fundamental flaw in this argument. Matt Visser used relativistic quantum mechanics to prove that if you bring the mouths of the two wormholes close enough, virtual particles will form closed-timelike-loops *first*, the energy density of the space between the mouths will quickly diverge, and the wormholes will *close*
In other words, as soon as a closed-time-loop is close to being realized, radiation in the space diverges toward infinity rapidly, and the whole jumpgate collapses.
So, if we were talking about Babylon5 or StarTrek, there would be a fundamental law of the universe, which is wormholes can only be moved so close together. If you move them closer such that the travel time for light is less than the difference between their clocks, the wormholes will collapse.
Incidently, Hawking also proposed this, he called it the "Chronology Protection Conjecture", that the universe won't allow time loops to exist, and there would be an infinite radiation wall to travel through in any such loop.
There are many such theorems in physics, such as the "naked singularity" rule for black holes. Can a singularity exist without an event horizon, such that the rest of the universe could view it?
Probably not.
imagine it, a 9600bps link, with -5sec latency!
=)
-Yarn - Rio Karma: Excellent
In quantum tunnelling, the tunnelling particle has been considered to have negative energy, as it enters a region it doesnt have sufficent energy to enter (classically)
Some theorists postulate that it has "borrowed" energy from its surroundings, and has an energy debt, so has negative energy.
Putting negative energy into e=mc**2 gives interesting results for the mass, obviously.
The article was very interesting, but I dont think its been refereed yet, so I wouldnt get excited yet. It seems to rely on "Alcubierre Space" (which I've not seen defined) being either wrong, or adjustable. As its raining, and I should be revising for an exam tomorrow, I dont want to chase up references!
If, as is stated in the paper, microscopic warp bubbles are possible, would it not be possible to have a "warp foam", ie: a huge number of warp bubbles, and have them move together, that would avoid the size problem.
-Yarn - Rio Karma: Excellent
Anonymous Coward wrote:
...use one of these guys to put an olympic sized swimming pool in my closet. The author seems to indicate that the warp bubble is larger on the inside than on the outside.
...implement that inertial damping drive system I've been kicking around.
...avoid speeding tickets on I75 by travelling in a microscopically small bubble of space.
Sure, it would just take many years of research to engineer the closet, and millions of dollars to build the closet. Oh, and if you try to enter the closet to use the pool, your body will be destroyed by tidal forces.
You don't need inertial damping with a warp drive. The warp bubble moves, the vehicle stands still.
I don't think the highway would be all that happy with a Warp Bubble travelling down it, but I don't think the state troopers have warp detectors yet.
----
Open mind, insert foot.
This paper is part of the ongoing abstract research into the possibility of travelling faster than light without breaking the laws of relativity. There are two leading proposals, usually referred in laymans terms as "Warp Drives" and "Wormholes".
The Warp Drive idea was first formalized (i.e. given all the math to show it should work, given sufficient engineering prowess) by M. Alcubierre, so it is sometimes called the Alcubierre Warp Drive. It has three big drawbacks: it requires an absurd amount of exotic energy and matter (some of which we don't yet know how to make), you can't see anything while Warping, and there is no theory on how to stop. This paper addresses the first problem, with the equations given, you need far less exotic energy and matter.
For some excellent laymans info on Faster Than Light issues, check out NASA's Warp Drive, When? site.
----
Open mind, insert foot.
I wonder if BableFish will translate this one?
:)
Wayne
Actually, it's a good bet that the "Physics of Star Trek" is never true. :)
Also, I don't claim to understand the math exactly, but from the paper it looks like the researcher found a way to reduce the amount of energy you need to power a "warp bubble" from astronomical to merly enormous.
I read the internet for the articles.
Despite what the blurb implies, this is all still very theoretical stuff. Don't expect to see warp drives in actual use in your lifetime.
Reading through the paper (which it WAY over my head) it sounds like the researcher found a much more efficent way to travel once we figure out how to fold space-time (with negative energy I guess).
Of course only a few years ago (like 70 or so) I'd be saying the same thing about general purpose personal computers...
I read the internet for the articles.
Yup, yet another Dr Who fan (though I haven't seen it for many years *sob*).
Bill - aka taniwha
--
Leave others their otherness. -- Aratak
TWIUI, you do not travel forwards (any faster than normal) or backwards through time when you go FTL. Instead, you out-race the information of where you've been, and so it appears (to the observer at your destination) you arrived before you left. In fact, if you could come in visibly, the observer would first see you suddenly show up out of nowhere (assume instant accelleration, eg stutterwarp (2300AD, GWD(rip))), and a copy of you leave your destination along the path you came in on. In fact, you should be able to see this yourself if you look backwards (note the assumption of visibility).
Things get even more interesting if the observer is to the side: he sees one ship suddently show up in the middle of is FOV, splitting into two, one retreating along your path (your past image) and one trailing your actual progress. Note: I beleive all these images will travel at the speed of light (or slower?). ie if the observer measures the speed of your travel, it will look like you're going =c.
Bill - aka taniwha
--
Leave others their otherness. -- Aratak
(Disclaimer: I read this in a sci-fi thriller-type book, so take it with a grain of salt).
Somebody opened up a container with anti-matter in it (approximately the volume of a pea). Result? BIG explosion (crater with a diameter of 10 miles if I recall correctly), and a major electromagnetic pulse for thousands of miles around.
Posted by My_Favorite_Anonymous_Coward:
... my money would still be on it being impossible (Due to killed grandfather paradox, lots of bad episodes of star trek, etc).....
That's why I like Dragon Ball so much (One of the greatest japanese manga even written in the golden age (80's-early 90's)) Its explaination is that everytime you use the time machine, you "create" an alternate universe which has the same "you" and same grand dad with the same names, except that the grand dad you save ain't the grandpa who was killed in "your" universe.
James Cameron's original ternimater 2 script has the same alternative universes idea which had old linda hamulton sitting on the park watching children playing game happily ever after (remember the park?) Unfortunately it was replaced by the heroic/cheesy/simpler suicide scene.
I'm no physicist and may be totally wrong, but here goes...
Assume Time Travel is possible. You start here on Earth and somehow travel back 4 months without traveling around outer space at lightspeed. If you did so, taking into consideration that the Earth revolves around the sun, wouldn't you end up in the middle of outer space because the earth would be in an entirely different position than when you left? This is assuming you don't change your position in space in the process, only time.
This, of course, would only matter if you could stay in a stationary location to travel through time and you don't move from that position in the process.
Would it even be possible when stationary?
[please excuse errors in spelling or grammer, I am in a hury]
Could somebody explain this bit of science news in a way I could understand? Thanks!
-- You can actually change my mind with a good argument.
Take two individuals A and B. Pick the earth as a frame of reference. Assume two identical vehicles which are capable of travel a light speed. Person A accellerates to light speed. Person B remains motionless. For each, time is moving forward. Now, when A decides to return from light speed, he has been gone for X years (a short time). B has been stationary for Y years ( a long time). Now, the reference point has also had a passage of time (Y years). Although A has been gone for an absolute number of years fewer than have elapsed at the reference point, (or for B), it still remains that time has moved forward and that A returned to the reference point after Y years relative to the reference point. Thus, it may seem like the shorter period of "time" allows jumping into the past but this is an illusion.
may be slightly unclear...please patch it up if you know how to express it better
Who am I?
Why am here?
Where is the chocolate?
What is your Slash Rating?
Could someone summarize the article in laymans' terms, please? :)
Who am I?
Why am here?
Where is the chocolate?
What is your Slash Rating?
Is a logical contradiction.
The simple fact that travelling backwards in time would allow me to kill my former self, thus preventing me from ever having gone back in time to do so, is a complete logical contradiction, causes me to not care even in the slightest about this or that new theory which suggest FTL travel.
It just ain't possible.
Calling light a wave is a convenient model for describing some of its behavior. Calling light a particle is likewise a model which describes some of its behavior.
I don't think there's really any contradiction there because we're not saying that light IS a wave and that it IS a particle - that would be a contradiction. What we say is that light exhibits behavior of both a wave and a particle, which isn't a contradiction - it's just evidence of how incomplete either the wave or the particle model is for describing the behavior of light.
These are interesting possibilities, and I have considered both before ...
There is also the possibility, equally as compelling and as likely as either, that we are all completely crazy, and that every moment of our perceived life is a hallucination that doesn't have to follow any rules or satisfy any logical constraints. In which case, onwards time travel!
Out of curiosity, does anyone know of any True statement, of any sufficiently powerful logical system, which is unprovable?
The only one I am familiar with is the "This statement is false" self-reference statement (which is basically the statement that Godel used to prove his Theorem, from what I understand). I read recently (in Scientific American) that Godel's Incompleteness Theorem, while a great shock to all scientists who thought they were going to be able to prove everything, has actually not been very fruitful.
Have I missed something, or is negative mass and negative energy still in the "pure speculation" state -- the equations allow for it, and from a symmetry point of view it seems plausible, but last I heard we have no evidence for its existance, no theoretical way to produce any, etc.?
(Note: Negative mass is not anti-matter. Anti-matter has positive mass, and opposite charge/spin/other properties of "normal" matter. Matter plus anti-matter equals energy (which manifests as other postive-mass particles). Matter plus negative matter should equal nothing, zero, zip.)
Mashed potatoes can be your friends!
The problem is the mass increase. As you accelerate to the speed of light, you gain kinetic energy (naturally). We know that energy has mass. Solving the system of equasions (left as an exercise), we find that as v approaches c, mass approaches infinity. Thus, it takes an infinite amount of energy to actually reach lightspeed for ordinary matter (tachyons are another thing entirly).
So far, experimental evidence has matched the predicted values very nicely.
>> 2) What happens to the object when the warp bubble collapses?
If it relies on a Microsoft-based technology, the object goes ***BOOM**** when the warp bubble collapses...
(No further than the construction of the system, but that is irrelevent. You WILL have travelled back in time. God, Star Trek, et al, have NOTHING to do with it. If anyone's stupid, it's those who assume everything and know nothing.)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
I think that basically anything that has to be assumed falls in this catagory--eg, the axioms of Euclidian geometry. You can 'prove' some of them but IIRC to do so you have to assume others which were previously proven.
:-)
Non-Euclidian geometry is an example of what happens when you change the unprovable premises.
Daniel
Hurry up and jump on the individualist bandwagon!
Hey, does anyone remember the 'Future Echoes' episode of Red Dwarf?
Nick
-- "It's a sad day for American capitalism when a man can't fly a midget on a kite over Central Park" - Jim Moran
Your problem is in trying to define a "REAL" velocity. What frame of reference are you using to define your "REAL velocity"? To measure a velocity you need a reference point. You then measure the velocity of your subject *relative* to your frame of reference. Part of the point of relativity is that ALL frames of reference are equally valid. Basically observer-based velocity is the ONLY kind of velocity there is.
And we thought that a Nuclear Power Plant melt down is bad. I woudn't want to be anywhere near an anti-matter storage tank if the containment mechanism broke.
Ex-Nt-User
Mabey you can't go faster then the speed of light. (But that's assuming we understand that part of physics.. which is still in much debate) But by the same token you can "FOLD" space time. (IE wormhole). This would alow you to travel large distances in very little time. Your velocity would be well below lightspeed.. but the distance would have "folded" from light-years.. to light-minutes.
Now if someone came up with a device that could fold space directly infront of a space ship.. you could effectively travel faster then light..
If God had meant men to fly he would have given us wings! It's your type of radical thinking that will be the death of us.
...or He/She/It (whatever - it's still undefined) would have given us brains, creativity, and curiosity to invent wings and other stuff.
Those who believe in an omnipotent and omniscient supernatural being shouldn't claim we could be dangerous to it or its plans.
Man (not just men!!) is gifted (or cursed?!) to reconsider, evaluate, and think about the world we live in. That's human nature. Superstition as well as FUD don't help anyone, we have to be open for discussion, ready to learn and change our opinion whenever it's necessary.
-- Eavy (: Linux Is Not UniX
Wow, someone watched Event Horizon one too many times =)
Can't you follow the link? The site provides Postscript and PDF file formats for this paper (along with a few other odd ones...)
I am not merely a "consumer" or a "taxpayer". I am a Citizen of the State of Texas
It would probably be better to not publicize something like this until it has been read be many specialists
;)
yeah, cause otherwise a bunch of slashdotters are going to go try build one!
While it's not been peer-reviewed, it's still a lot of fun to think about. I'm glad it was posted.
What happened to the other problems with FTL travel?
I'm thinking specifically here about the more slippery definition of "simultaneous" in special relativity, and it's consequences. Assume a ship that can:
a. Accelerate to any sublight speed (and thus any "normal" reference frame) arbitrarily fast.
b. Use "Warp Drive" to move between two points in space time faster than light.
That's all you need, and assumption a. is perfectly in accordance with physical laws (and technically plausible with some externally powered propulsion system).
Throw in the cute fact that for any two points in spacetime that are not in each other's light cones, there is an inertial frame of reference where those two points are simultaneous, and your ship can:
1. Warp 1000 light years away, simultaneous with the frame of reference of the solar system.
2. Accelerate to near light speed.
3. Warp back to earth, but 999 years before it left.
I wish I could link in a diagram of this... but go look in a physics textbook; it's a classic paradox meant to show why FTL travel is impossible.
I've never heard a good explanation of how Alcubierre's theory (not to mention whatever new concept has come up) deals with this.
The book you're thinking of is Timemaster. In it, a space company finds exotic creatures (called Silverhairs in the book) composed of negative matter, and containing wormhole entrances. Using the negative matter, they construct a relativistic starship to travel to the stars, leaving the wormhole intact after the trip for instant travel. After troubles from a competitor, the company's president makes a round trip via several stars to create a working time gate, thus bringing up the consistency problems of time travel.
Any Slashdot reader interested in warp drives or time travel should check it out. Amusingly enough, the book itself was a reference for a real-world scientific paper on the consistency principle for time travel. Robert Forward's other science fiction books are also highly recommended.
Colin
I am not a physicist. Nevertheless, I've had an idea, although it may be wrong-headed.
The problem here is distorting spacetime, as I understand it. Negative energy is just the means to that end.
It's my understanding that gravity waves are produced by moving objects, and that these have both a "pull" and a "push" component - and that the trouble here is to get the "push" component of the warp geometry.
My idea is: perhaps, if objects could be moved in a very synchronized way, the gravity waves could be made to interfere additively such that there are "push" and "pull" distortions of the right shape in the right place.
I would have to look at it again, but one of the arguements against warp drive from a "physics as we understand it" perspective is that it requires so much energy that we have to drag around huge amounts of anti-matter to get enough energy. The Physics of Star Trek was where I got that from, but I am glad to see that that may no longer be true.
-Chris
Yes, causality would be preserved using a warp drive since nothing is travelling faster than light. Warp drive does not increase your velocity, it decreases the distance you must travel.
In other words, as soon as I travel back in time, I have changed something. No matter how small, its effect will grow over time.
If you travel back in time and then come back to the time you left, things will be different.
JET Program: see Japan, meet intere
The Heisenberg Uncertainly Principle is inside the box, at least. If you believe in multiple, parallel divergent time lines (a sort-of "anything that could possibly happen does happen"), then time travel does not present a paradox or logical contradiction.
Time travel causes logical contradictions if you belive that the progression of time is rigidly forwardly linear and that there is a well defined, fixed cause and effect relationship between all causes and effects.
A different way of looking at the universe is that all of the particles in it, along with their motions, interactions, etc. form a gigantic system of equations. Within the bounds of the Heisenberg Uncertainty Principle, there exists the region of space-time states which solves this system of equations. You can think of this region as the "set of allowable time-lines," for lack of a better term. A given element of the set corresponds to one possible complete "existance of the Universe," which includes all time-space points of that Universe. Quite simply then, any time-line which would represent a logical inconsistency is outside of this set, because it is not a solution for the constraints of the system!
It is logical to presume that the proposed logical inconsistency simply would not happen, because it could not exist. That doesn't mean that time-travel is impossible; it means simply that it could never cause a logical inconsistency.
--Joe--
Program Intellivision!
A better way to appreciate things is to look back 100 yrs. At the last turn of the century, the physics community was astounded by some amazing new discoveries. What were these mysterious X-rays? And did you read about radioactivity? I wonder if something besides uranium was radioactive? And electrons! If these things had a negative charge, there just has to be something in the atom with a positive charge. Finally, I just know that someday, man will truly fly through the air.
Moral: Who knows what the future may bring.
General Relativity doesn't help with the causality violation. As long as the presence of the bubble is detectable, and it travels FTL is some frame, it is possible to violate causality, whether or not anything crosses the surface of the bubble. The only way to preserve causality with FTL travel is to have a preferred reference frame. Of course, if you have a preferred frame, Relativity is out the window anyways...
It's not a bug, it's a feature...
-- Give him Head? Be a Beacon?
-- Give him Head? Be a Beacon? :P)
(If you can't figure out how to E-Mail me, Don't.
I would just like to point out that, as this seems to have come out of Los Alamos, this undoubtedly means that the Chinese Army has been warping around the galaxy for twenty years now.
:)
ABSURDITY, n.: A statement or belief manifestly inconsistent with one's own opinion.
An interesting variation on FTL information transfer (not to mention a serious slam of the Copenhagen Interpretation) can be found here.
You will not drink with us, but you would taste our steel? - Walter Matthau, The Pirates
True, but if I'm reading this right the area inside the walls can be significantly larger. Region I in the diagram is a 'pocket which has a large inner metric diameter.' he also states in the abstract that his solution supports the 'transport of macroscopic objects.'
In the ever popular rubber sheet model, it seems he has a large inflated balloon where the lips comprise the warp bubble. Except that the space inside the bubble is also locally flat.
In other words, what he has is not just a warp drive, but also a TARDIS....
Isn't one of the theories about that massive explosion that took place in Tunguska (sp?), Siberia/Russia/whatever in 190X that antimatter was released/crashed to earth/created/whatever?
If I remember my Discovery Channel right, it leveled something like 100,000 square miles of forest, with a force exceeding several atomic bombs.
Anyone know anything more about this? Am I out of my head?
When in danger or in doubt, run in circles, scream and shout. --Robert A. Heinlein
Although intuition does not allow one necessarily to communicate the findings, the realizations are a kind of knowledge. One gains inarticulable information, but that does not mean the information does not have a source. The questions is: at what rate does the information pass from the source to the person? If you believe the materialist scientists the answer is 'not at all.' If you believe ancient mysticism, it is described as appearing like oil pouring from one vessel to another, an instant connection, a constant and simultaneous flow. These concepts are very difficult to articulate so we use poetry. In scientific terms it would be characterized like the previous poster did: two particles seem to join when observed but move apart when not. We come to know things from out of thin air (seemingly); rather, we cannot identify the source. When we do, the physical world and the source are indistinguishable; rather the source appears more real. This effect causes the physical world to appear as
an illusion. It really isn't, the physical world is the hardware conforming to the rules set by the source. Thus, it subordinates to it. I believe that the ancient mystics were mistaken when they said the physical world is illusory. It is real (i.e., in existence) at some level; it is easy to become overwhelmed by the information transfered by concentration on the intuitive capacity. That is why Western science has rejected mysticism and now (later) they approach parity. In the evolution of knowledge, we had to iron out the kinks. Until now the kinds were "what is this physical thing all about." We come to find that the core of morality (rules divined by intuition and experience) i.e, growth, nurturing, death are part and parcel of the physical reality. The physical law of order from chaos is reflected in our society from nature. Behind the apparent chaos is the underlying order, the rules that govern the formation.
This is true of one object relative to another, but NOT true relative to the geometry. The idea is that if you tweak the geometry correct you can do both 1 and 2 as time is just another dimension to the geometry. But it involves special conditions.
One example, that is popularly commented on, is the idea of a very large cylinder spinning at very high 'speeds'. In fact the 'speed' that it is spinning approaches the speed of light. Now at this point if the object is moving at some velocity relative to another it will be less than the speed of light. But the geometry does not and in many cases exceeds the speed of light.
Now lets add a little more complication. Since the hypothetical particle, the graviton, defines geometry in one sense. Or as people who study cosmology say 'Space tells matter how to move but matter tells space how to curve'. Since the graviton is the conveyor of the hypothetical Higgs field but since it is itself not attached to the Higgs field (presumably) the question arises: Can a graviton travel faster than the speed of light? If so what is its speed? Instantaneous? Unlikely. But then again, I will describe.
'You' may not go back in time, but particles, or hypothetical 'strings' do. They exist partially in positive time and partially in negative. Its tough to describe and I won't even try. Now comes the question do gravitons exist partially in negative time. From these thoughts, theories, and hypotheses, it seems that the idea of a 'warp' engine is very possible. It also seems possible that you might exert some sort of effect into brief moments of the past. All that I can say is that cosmology is never a boring subject.
Suddenly, the hairy finger of a familiar monkey tapped me on the shoulder. It was time.--G. T.
The experiment is known as Schrodinger's (spelling?) Cat Experiment. Simply stated, there is no such thing as a binary condition. The experiment is you put a cat in a box and close the lid. You can't hear the cat or know anything more of its presence than that it is in the box. Simple logic states that the cat can either be alive or dead. But this is not true. The cat is neither alive or dead, it is both. At least that is until you observe it, then it is forced into being alive or being dead. This may sound absurd, and it definately takes some getting used to to think in this form of logic, but it is true. The same thing applies to the idea of 'information' transfer. If you have two particles, one of positive charge, and the other negative and seperate them in a 'system' that has a null effective charge such that they can't affect each other (say for example light-years away) and then one flips charge, the other will do so 'instantaneously' (I use this term loosely) or at least faster than the speed of light. Since another particle would have been needed to 'force' the particle into a different state and since that particle would have been restrained by special relativety not to go faster than the speed of light only two conditions that I know of could exist: either the particles were swapped or the system itself exerted a 'force' on the other particle. The first one implies that space 'warped' to move the particles and the second comes down eventually to entropy balance. Myself I think BOTH are true.
Suddenly, the hairy finger of a familiar monkey tapped me on the shoulder. It was time.--G. T.
I forget who told me this, once upon a time... "once its been proven on paper, it becomes merely an engineering problem".
More corporations need to get together and start investing millions into independent research labs, where they're NOT expected to produce results immediately. Raw science, more research into highly advanced projects. Wonderful stuff can happen. We could see a working warp drive in our lifetimes, given the time and resources.
Of course, I'm taking the "how things should be" view again, rather than "how things are"... keeps me from getting depressed, though.
I think you're mistaken.
What I've studied is that information travels at light speed, thus we have the magnetism effect.
--Roman , remove spamless. to mail me.
Actually, no. If only electrons and positrons and photons existed, then you might be able to draw a Feynman diagram with one line representing all electrons and protons, but beta decay takes care of that. A quark can decay into another quark, an electron, and an antineutrino. This provides the start of a new electron line. Similarly, a quark can decay into a positron, another quark, and a neutrino. This provides the end of an electron line. In principle, the reverse reactions could occur as well.
2. Accelerate to near light speed.
3. Warp back to earth, but 999 years before it left.
You could indeed do this with a faster-than-light drive. Where's the problem
The question then becomes, what are the physical consequences of time travel, and does this always result in contradictions? This will either rule out or severely limit what can be done with time travel, and by extension FTL drives.
You run into similar questions with tachyons.
It just ain't possible.
Not strictly true. All that your example shows is that you would not be able to kill your former self. Two of the several solutions that I've heard postulated are:
Under this system, you would certainly not be able to kill yourself, becuase you didn't (you survived to travel backwards in time, didn't you?). This physically corresponds to limiting (drastically) the number of possible events that can occur within a loop of spacetime that folds back on itself in the time direction. This in turn means that such loops are entropically very unfavourable, but they could still in principle occur if a greater increase in entropy happened elsewhere.
This refers to the "multiple histories" interpretation of quantum dynamics. Under this system, when you flip a coin, it lands on both sides - just in different universes. What actually happens is that all possible ways for a probability waveform to collapse happen, in different universes. If you travel back in time, you arrive in another universe, that looks a lot like the one you remember from that time - but in which a time traveller spontaneously appeared and killed the person who would have been you in your universe. This system doesn't impose entropic limits, but how exactly you travel between parallel universes is left as an exercise.
Both of these systems avoid the paradox that you menion.
Your problem is the way your thinking about the question. Relativity tells us that there is no way to tell which one is moving, because there is nothing special about moving at a constant speed. . In one frame of reference you may be moving at a constant speed, while in your own frame yourat rest. There is nothing special about either frame - physics works the same in either frame.
There is no center of the universe and there is no preferred frame of reference.Preventive War is like committing suicide for fear of death. - Otto Von Bismarck
AFAIK it hasn't been proven either way. Travel into the future is very possible, just fly right up against the event horizon of a black hole, and hope that you have some huge friggan engines so you can fly away. When you fly away from the black hole you will notice that time has traveled slower for you than it has for the rest of the universe. Ie, it will have been minutes for you but could have been millenia(sp) for the rest of the universe.
-matt
Actually the speed of light is no more a constant than the speed of sound. Both change speeds depending on the medium, but in opposite directions. Sound travels faster through solids than through gasses, light travels faster through gasses than solids. What most people refer to as the "speed of light" is the speed of light through a vacuum.
As for the speed of sound issue, I think people did believe it was imposible to acheive at one point, and with good reason. As an object travels through our atmosphere it compresses the air infront of it and expands the air behind it. This increases the density of the air directly infront of the object, which also increases the speed of sound travelling through that air, so the faster you go, the faster sound travels. It's easy to say that it's possible once it's been done, but try to imagine people working only with theory. It's a lot more difficult.
Finally, talking in bold doesn't make you right.
-matt
I don't think that the speed of light being negative would matter or not. In e=mc^2, c is being squared, if c is negative it would still be positive when it was squared. The only way e could be negative and still satisfy e=mc^2 is if m were also negative. Unless of course c is imaginary, and I don't even want to begin thinking about an imaginary speed of light.
-matt
aha a Dr Who fan - what does TARDIS stand for????
Time and Relativity Distortion(Dimensional....
arggggghhhh
Alan Day - Dumfries & Galloway, Scotland, UK
Everyone who is concerned with creating a paradox by going back in time to kill themselves thus preventing themselves from doing so and creating a paradox is forgetting one little detail, our universe has an infinite number of facets. Quantum physisists have found that this is indeed true, the only way to determine the characteristics of a particle is to look at it. While this sounds like something you might take for greanted it isn't. Shrodingers (sp?) cat is the most often used example. The properties anything are undeterminable until viewed from an outside point of reference. This can apply not only to particle physics but to dimensional physics. For every moment there is an infinite number of possibilities for that moment for every point in the universe, and you only see one set of facets every moment. imagine points in the universe like coins. Spin them on their sides and let them all land, when they all land, face up or down that is a single moment, now repeat this process with an infinite number of coins with an infinite number of sides to understand what I'm getting at. Therefore you can only create a paradox in so many parallel instances. And therefore not create a true paradox, only one thats limited by the number of instances you actually go back in time and kill yourself.
As to faster than light travel, you would not go back in time unless you actually accelerated near the speed of light, the whole theory of FTL travel is never actually reaching the speed of light, just sidestepping part of the distance between your point of origin and your destination. Which needs no "inertia dampeners" or the like, just a warp feild generator (I say that like you can pick one up at Pep Boys).
I'm a loner Dottie, a Rebel.
You got it backwards: information is what can't travel faster than light, everything else can, in principle. That's what's make any faster-than-light system you can come up with quite useless.
TA
"Electrons can tunnel through insulators at speeds faster than the
speed of light."
Not really. First, electrons themselves travel nowhere near the speed of light (when talking about electronic equipment at least), and secondly, even if the "center" of the wave function of the tunelling electron went faster than light the "tip" of the wave function would not. This has been explained in many papers, including in popular form in Scientific American (with a nice cartoon drawing).
TA
"..because it is only a theory!!"
Why don't you first learn what the word "theory" means when a scientist uses it? It's not the same as what a layman means with "theory". What people in general call a "theory" wouldn't even be considered a hypothesis in scientific terminology.
A scientific theory must be consistent with itself, it must be able to come up with testable predictions etc.
All in all a scientific "theory" is far closer to what most people would call "a fact" than what they mean by "theory" themselves.
TA
dr. who 0wnz!
Negative energy is the same as positive energy except in a world
where time is imaginary. In quantum mechanics you often consider
such a world as an analytical continuation of the real world. However
imaginary time implies (in Minkowski metric) a possibility of negative
interval, in other words in such a world two points can be "closer" than
the same. This whole "warp drive" business, IMHO, gives new meaning
to losing touch with reality.
I think of zero of energy as the energy of a DC photon, i.e.
a photon with zero frequency (obviously a limiting case).
BTW, what did you mean by holding an object quantumly rigid.
If that means holding it in a given position in space then it also
means not knowing its energy, because its momentum would be
undefined.
> 1) how do you get an object inside a warp bubble?
Two words: Klein Bottle.
Now If I could only find the fine Irish Whisky I poured in there.
I have discovered a truly marvelous sig, unfortunately the sig limit is too small to contain i
I have always considered the cat to be a valid observer.
As such, Schrodinger's cat can live.
********* sig: If you don't like the law, get filthy stinking rich, and buy a better one.
I'm afraid I must respectfully disagree with your opinion.
I'm in favor of the free exchange of ideas. I don't like only seeing what the 'peers' think is fit for my opinion.
Yes it lowers the signal to noise ratio, but overall, more signal is getting through.
If we wait for peer review, such as we have been for 50+ years with the dead sea scrolls, the process gets stagnated.
On another note, it is getting peer reviewed now. It just isn't getting censored as much.
********* sig: If you don't like the law, get filthy stinking rich, and buy a better one.
Hey kids, this is theoetical physics. It has very little to do with reality as we know it.
/. watch (or watched (or saw some episodes of)) Star Trek. Which makes it suitable; not just for slashdotters, but for the godzillions of people (not just trekkie scum) that watch or watched the programme.
No arguments. And as it's something we can't associate with everyday experience, we need a suitable metaphor. And guess what? Most of the people on
I dare you try and explain this article without using the word 'warp'.
I thought the black holes would just radiate until they no longer existed. Didn't Hawking or someone postulate that a bunch of mountain-mass black holes form at the beginning of the universe, but radiated away almost instantanneously?
Well, there's Woodward's work. Basically, as a result of Mach's principle, it predicts a transient mass fluctuation in an LRC circuit.
It could be the "impulse engine" of ST fame, or the hover cars off the Jetsons...
(Just maybe, it could also provide a large enough mass fluctuation for more exotic uses, like temporary wormhole stabilisation...)
NB. IANAP (I am not a Physicist (...and boy, does it show...))
Woodward carried out a test, which seemed to confirm the theory. However, an unforseen non-linear response in some of the experimental equipment casts doubt on the first results. Even if the fluctuations were a couple of orders of magnitude smaller than observed, it would still be a major breakthrough. NASA seems to think so too, and are, AFAIK, quietly working on a repeat test in their breakthrough propulsion labs...
Anyway, the theory makes interesting reading.
Here's the relevant links:
chaos.fullerton.edu/Woodward.html
www.inetarena.com/~noetic/pls/wo odward.html
Choice of masters is not freedom.
It's not bullshit, but it's not gospel either.
The key is _when_ the energy concentration gets powerful enough to prevent the wormhole from opening. In one reference frame, the ncecessary energy concentration arrives too late to affect the wormhole; in another reference frame, the energy concentration has the potential to collapse the forming wormhole before it takes.
Unfortunately, since wormholes are still theoretical structures, nobody is quite sure what will happen. The physics involved is still a bit too unformed to give a precise answer as to how much energy is needed, and when that energy needs to be in the formation of the wormhole.
Actually, you're wrong on both counts.
1) You _can_ go faster than the speed of light, just not directly. You can't just turn the engines of a spaceship on "high," you have to skip over some of the space you're travelling through, and your _effective_ speed jumps past the speed of light. Both wormholes and "spacefolding" technologies - both of which are theoretically proven - would enable one to do this.
2) Yes, you can. In fact, we know how to do it today. The problem is, it takes an astronomically large amount of energy. It requires a wormhole in order to achieve it. You take one end of the wormhole and take it on a tour of the solar system at _relativistic_ speeds. You keep the other one stationary. Due to the time dilation, time passes for one a lot slower than it does for the other. Since one end of the wormhole has experienced less passage of time than the other, one end resides in the past, and one resides in the future. Then you can freely travel backwards and fowards through time via the wormhole.
There are other ways to travel backwards and forwards through time, but most are terribly implausible (e.g., infinitely long rotating cylinders spinning at relativistic speeds - I don't understand the full complexities of that particular process). And all have been discovered as parts of solutions to Einstein's equations, which have very little to do with quantum theory. So even assuming only relativity applies, you're still hosed.
The method, as the author himself points out, does have quite a few problems, though. First off, it's a microscopic bubble. He says that the walls can initially be only a few hundred Planck's lengths thick at the start. And as you slow it down, the "warp bubble" will expand, thus making the walls thinner until they actually shrink to lenghts less than Planck's constant, which would cause unpredictable results to say the least.
Also, the authors says that though this is orders of magnitudes less energy, it still requires "unreasonably large energy densities."
And, as another comment said, negative energy isn't exactly something that you can just buy at Amoco, and until a method to easily create it is developed, none of this is realistic.
Still, this is damn cool to say the least. I can't wait to get to work in seconds. And this could possibly do wonders for communication. A superluminal link would be just a little bit faster than my Ethernet connection, I'd guess :)
-- atomly
You can't go faster than light... But light isn't taking the best route....
I'm not sure about this one actually, (Not to mention the fact that relativity (wich is pretty much accepted at the moment :-) ) explicitly states info CAN't go faster than light), because the hidden variable principle would work here to (Admitted, it has a lot of other flaws, but HERE it does work). Simply stated: The spin of both particles is already determined, but stored in a 'hidden variable' wich we don't observe untill the measurement is done...
:-)
Oh, dear, this brings back memories of a few fun discussions on the copenhagen interpretation of quantum mechanics... Would anybody want to give the definition of a measurement?
Not completely: We have, up to know not yet disproved that timetravel is possible... However, If I'd have to guess, my money would still be on it being impossible (Due to killed grandfather paradox, lots of bad episodes of star trek, etc).
Nice, but I prefer a slightly more viable (IMHO) multiple universe theory: Every quantum `decision` that takes place splits the universe...
If you did know that then what on Earth were you thinking? Were you expecting someone to fraudulently obtain a federal government domain name and record their real name in the registration data?
Anyway, back into being-nice mode: you're using the wrong whois server.
Network Solutions don't manage .gov and .mil domains, so asking their whois server about a .gov domain really isn't going to work. Use whois.nic.gov (or whois.nic.mil for a .mil)
$whois -h whois.nic.gov lanl.gov
.GOV domain. For information for other domains please
National Laboratory (LANL-DOM)
Mail Stop B294
Los Alamos, NM 87545
Domain Name: LANL.GOV
Status: Active
Administrative Contact:
Wood, C. Philip (CPW)
(505) 667-2598
CPW@LANL.GOV
Domain servers in listed order:
NSX.LANL.GOV 204.121.3.1
NSX.LBL.GOV 131.243.64.3
NS2.LANL.GOV 192.16.1.2
Record last updated on 11-Mar-99.
Please be advised that this whois server only contains information
pertaining to the
use the whois server at RS.INTERNIC.NET.
Just reading over this, one thing came to mind.
Say if people could travel like this and become the transport method in space, much like that of the car on land here on earth, what would happen if 2 bubbles were to come into contact with each other, like cars do on 635 (LBJ) everyday.
Then if you were traveling backwards, as someone mentioned above, then some one were traving forward and they were to collide what would be the effect there?
Just something to look into and make theories about.
The second one I believe they would just stop in the middle of their travel in time and distance, but the fist I couldn't even come up with what could possibly happen....
"Windows 98 Second Edition works and players better than ever." -Microsoft's Home page on Win98SE.
I ate my tag line.
-=Ellis (D)25=-
Alternately, if the "bubble generator" was inside the bubble, and could propagate the bubble across spacetime, AND the bubble's barrier was impenetrable while generated, you wouldn't need to move the SHIP at all: merely propagate the field, and let the field drag you along.
.
In otherwords, a for-real example of picking yourself up by lifting the seat of your pants. .
Mind you, my physics and cosmology is ~15 years out of date, but as I recall, the net energy of the universe as a whole is a positive number, which (theoretically) can be tapped. As a practice, the number was re-set to zero, but if we're already warping space-time to produce a bubble that moves across it at speeds faster than that which matter can transit, the stressed space-time would likely make it easier to tap the so-called Vacuum Energy, and thus maintain and propagate the bubble. . . .
If my physics IS outdated, then ignore this, but I recall Dr. Charles Sheffield, NASA physicist and SF author discussing tapping vacuum energy as little as 2 years ago, so this MAY be a viable approach, assuming energy density is sufficient for the application.
Getting the negative mass is, alas, an area where my ignorance is sufficient to even guestimate an answer. . .
Flamebait? Whoever moderated that down and selected Flamebait... wow.. you need to get some sleep (mee too..) god night.
Hhm, I don't believe the appropriate theorists have yet decided whether they need 10 or 24 dimensions yet - both fit the theories put forward to date.
Oh joy.
james
>The two big problems to be resolved are
Already well understood:
> 1) how do you get an object inside a warp bubble?
Wander into Main Engineering while your genius son is tinkering with the engines.
> 2) What happens to the object when the warp bubble collapses?
People start disappearing and nobody remembers that they ever existed.
(For the humor-impaired: ST:TNG "Remember Me")
I noticed this message was deemed off topic.
.gov's are listed in whois, but am curious as to why. Considering the roots of the question, this forum felt appropriate.
Slashdot has more than once posted news articles that at first appeared legitimate, only later by the unsuspecting reader to be found a 'joke'. I recall in particular an article proclaiming JWZ's death. Rob pointed out that anyone could easily and simply determine the true nature of the article if they were willing to observe the host's numeric ip address through nslookup and correlate that with a server known to collude with Slashdot.
At any rate, I was unsure at first if lanl.gov (the host domain for the article) was legitimate. It wasn't listed on a whois query.
I am now convinced no
Secondly, don't flame people for thinking Star Trek. Most people who follow Star Trek, follow it because this kind of thing could happen. Im not gonna insist we name any ships Enterprise or that we need to make a deflector dish. I just think the mere possibility of even sending probes to other stars is exciting.
Now, for the real point of my post. I know that these are theories and we got the smartest people in the world on this (some of them post on slashdot
I think Im gonna participate in that SETI@home thing.
--
okay this reminds me of those cheesy startrek conventions - we should have a slashdot convention!!!
-- your knees hurt, don't they?
Quite right, but it's nonetheless interesting to think about the Feynmann diagrams in temporal terms, if for nothing else than acknowledging the possibility that a single electron might compose the entirety of the univese around us (and that at any given moment there are equivalently the same number of positrons out there).
The energy that would be required for warp travel is irrelevent; energy is abundant at this time in the universe. (And worse come to worst, we sacrifice some matter.) Much of the physics we are dealing with is not conventional, and we will soon see a new relevation to change the entire perspective on the reality surrounding us. Warp drives, so cliche as that may be, can exist. Indeed, it is likely that they do. Just to throw you for a loop, it is possible and even probable that the entire universe is composed of a single electron in a parallel time frame for each instance (near infinite). Interesting, no? I say this because a positron, the electron's positive energitic counterpart, is mathematically described as an electron travelling back in time (i.e. negative time). Still, much work is to be done on this yet. The reality constraining us is not what it used to be. We should not forget what we have overcome, lest we fail to overcome the barriers before us now.
Not only is faster than light travel possible, but I believe it has been demonstrated.
:)
Information travels faster than light. (because information doesn't actually travel, for a normal definition of that word) Would someone with a heavier physics background please correct me here? I'm pulling this from memory:
Two particles can be bonded such that their collective spin state is always 0. knowledge (or lack thereof) of a particle's spin state is information. once these particles are bonded, the space seperating them is irrelevant. they can be next to each other or on opposite ends of the universe, and as soon as you change (observe) the spin state of one, the spin state of the other *instantly* becomes defined. the information travels without actually entering the space seperating the particles, which means that it isn't subject to the usual limitations placed on physical objects (namely a ~186,202 miles/sec speed limit).
i'm not sure how modern physics handles this. i believe einstein rejected it, but i think it's actually been experimentally confirmed in the past several years. you could incorporate yet another dimension into your conception of existance (5? 6? n?).
the curious part is how closely this resembles what mystics have been saying for millenia: space is an illusion.
another curious side effect of this is that the speed of light (in very much simplified laymans terms) seperates the "past" from the "future" and keeps them both out of the ever-present "present" (be here now). if you allow for faster than light travel, the chain of causality as we know it must be abandoned. the past and the future get all mixed up, and you have cause following effect etc.
i will cease my rambling now and get back to work
"I think any time you expose vulnerabilities it's a good thing." -Attorney General Janet Reno
I'm reminded of the book by Robert Forward where they find that critter made from negitive matter...I think the name had something to do with puppets...been a while since I read it. Anyway, it played around with what sorts of things you could do with negitave matter
Calmacil
I can't seem to face up to the facts, I'm tense and nervous and I can't relax... --Talking Heads
It's not quite that clear-cut. Ever hear of the experiment with two slits? The idea is that if you aim a light at a barrier with to slits in it, you'll get an interference pattern on a screen placed behind it. The intent is to prove that light is a wave. However, what happens if you send a single photon through this system? Things get interesting. The single photon, an observable particle, travels through both slits and interferes with itself. Now, let's have some fun. Place photon detectors in each of the slits, and see if we can figure out what happens. The results are quite odd. When you're watching both slits to see which path the photon takes, it actually *does* take one path, and does *not* interfere with itself. You don't get an interference pattern on the screen, you get two points. So, it's not just that light sometimes acts as a particle and sometimes acts as a wave, light actually *is* a particle or *is* a wave, depending on how it is observed.
This space unintentionally left unblank.
In fact, it is now well known that GR _does_ permit time travel. Various people have found configurations that contain closed timelike curves, where you can travel forward in time, and find yourself back in your own past. Unfortunately they are all unphysical for some reason (take an infinite amount of energy to construct, an infinite length of time, or are just really unstable). Still no-one knows of any good reason why something like this shouldn't be possible.
1) you cant go faster than light constant
2) (from 1) you cant go back in time.
Uhm, and where exactly did you get your PhD in physics? The entire point of creating a warp bubble is exactly to circumvent the speed of light limitation you mention. Within the bubble, the ship is traveling below the speed of light. The bubble (being a warping of space time itself) is not so contrained. It can *travel* faster and carry a ship with it. This IS consistant with relativity... the ship is breakin no laws within its own frame of reference.
You are probably correct on the backwards in time bit... but it does still make for fun startrek episodes. And speaking of sci fi, don't be so quick to rip on it. It plays an important role in excersizing the imagination and pushing human thought into new territory.
Now if I can only I can get this damn transporter prototype working... ;-)
Thad
The Bolachek Journals
Uh... that was not a troll. I was quite serious, actually. I guess admitting a lack of space/time theory knowledge isn't popular? Oh well. No biggie...
DDuck
In Ster Trek, didn't Zefram Cochrane make the first warp flight in 2061? We're well on our way to actually fulfilling one sci-fi prophecy...
Also, to quote Micheal Okuda, warp drive works because the script says it does.
"There is a pleasure sure in being mad that none but madmen know"
Negative energy is easy; gravitational potential energy is (by definition) negative (because this convention provides an unambiguous zero out in space). Thus if I have a ball suspended in space its net energy is zero; if it falls to earth, the net energy is still zero because its postive kinetic energy is exactly balanced by an equivalent negative potential energy.
Negative mass is a tough one. Mathematically, a moving body with negative mass would have negative momentum (???) and negative _kinetic_ energy (???).
Hmmm.
If you hit a baseball with negative mass, would your bat be deflected forward instead of recoiling? Would the ball accelerate towards the catcher intead of bouncing back towards the fielders?
If you pitched a negative mass baseball, would it go slower the harder you threw? Would it go infinitely fast if you put zero effort into it?
If the earth were struck by a asteroid with negative mass, would the oceans freeze instead of boil? Would the asteroid slow down as it dropped into the Earth's gravity well?
Saying you could go FTL with a little negative mass matter is like saying that if you had the keys to Ft. Knox, you'd be rich. (1) you don't have the key and (2) there are implementation details (like dealing with armed guards). Matter with negative mass, if it exists, would be extremely exotic, and probably impossible to handle.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
if both fields are perfectly aligned and tuned in the same exact way, then they merge and you have a normal fender bender.
Except at FTL speed (So much for normal 8> ).
If they are not aligned, then I could see an interaction between the fields (ala magnetics) and either:
They deflect each other (Hope that Intertial Dampening system that someone said that is not needed is there... Otherwise blue haired grandma is paste upon a bulkhead)
The fields collapse immediately and good bye blue haired grandma in the 2110 Eldorado.
Field Theory is a nasty subject left to people that can process 64 digit numbers in their sleep.
RB
Special relativity is valid only in a flat space-time. In practice, this means it is valid whenever gravity doesn't play a significant role. General relativity is necesary when space-time gets warped, as it does near massive objects. The Alcubierre Warp Drive works by having an incredible density of negative mass which warps spacetime in front and behind you in just the right manner to let you travel faster than the speed of light.
The Alcubierre Warp Drive creates a relativistically correct (my term) space time, which means you can go faster than the speed of light without violating any causality questions. So by construction (but using very hairy math) there is no causality paradox. However, it also warps space time all around the traveller, which could be a bit disruptive.
Also, there is no theory of how one could turn the warp drive on or off. It seems quite possible that one would age significantly either when turning on or off the warp drive. Or maybe just annihilate the populations of any nearby planets. :)
if both are accelerating at nearly equal speeds, would either one gain mass if there were no 'landmarks' to juge by?
You are referring to the increase in mass as a person approaches the speed of light. Actually, that is no longer the preferred way of thinking about it. This comes down to the question of definition of mass. Nowdays physicists define the mass to be the rest mass, and don't say that the mass changes. Unfortunately this has been a wee bit slow to catch on. The reason we define the mass this way is that the older definition was confusing because the mass was not a scalar (relativistically speaking). It also was not the same as the "Newtonian mass" as in the "m" in "F = ma", which makes it a rather deceptive quantity.
I guess these distinctions get a little confusing, but I guess my point would be that part of your problem might be that you have had relativity explained in a way that even Einstein agreed 50 years ago was not the best way.
You are right, there is a center of the universe, or at least one could define one. For example, the center of mass of the universe. However, according to relativity there is no need for us to know what the center of the universe is or in which direction it is moving relative to us. We can just as easily treat ourselves as the center of the universe...
Of course, your speed will depend on the observer, just because it is defined relative to the observer. But the physics (i.e. what actually happens) is independent of the observer. In your example of a tree and an observer falling in the woods, the observer would certainly see that the tree is stationary, but the ground would seem to be travelling at a very disconcerting speed!
We could tell you, but then we'd have to kill you.
If you want to get rid of the bathwater, you've got to throw out a few babies.
The problem is that the two states are highly *correlated*, but you can't actually get any data without communication between the points (i.e. each side will get a random stream of data, but if they compare their data, they can see when it was correlated, and therefore whether spin coupling had happened at that point). Since you need to transmit some data in order to tell, this doesn't let you transfer information faster than c.
It's not that i misunderstood it, it's that i Dont understand it.. i get the idea that things like velocity are determined by the observer, but why does it work that way? What if there's more than one observer who see different things? For instance, if two people are standing on misc. objects in space and are getting further away from each other, without a way to measure red/blue shift from surrounding stars, how would you know which is moving? if both are accelerating at nearly equal speeds, would either one gain mass if there were no 'landmarks' to juge by? If someone managed to stand at the center of the universe and observe everything, would any galaxies which had quietly accelerated faster than they should be able to unobserved suddenly slow down?
It all just seems very human-centric and doesnt seem to make much sense. I'm not saying it's wrong, alot of things in the world dont make sense.. but this is apparently supposed to *shrug*
Dreamweaver
"If a man hasn't discovered something he will die for, he isn't fit to live" -- MLK, Jr.
Okay, i'm no physics major.. but i try to keep current and have read enough to consider myself at the very least a knowledgable layman (yeah, i know the whole thing about a little knowledge being dangerous) and i cant say that i understand why exactly FTL travel is so impossible. I mean, why is 300,000km/s such a fundamental barrier? Okay, objects travelling anywhere near that velocity do behave oddly as we view them.. but who says that's so important? so the math says objects shouldnt exceed that speed without doing x y and z.. 100 years ago the math said a whole lot of things we know are patently false. *cough cough ether cough cough*
Now here's my take on it: relativity says that we cant exceed X m/s without having the rate we move through time change. So then in order to calculate exactly how fast you're moving, you have to do one of two things: calculate your base movement rate from an exact zero state an include your movement across the planetary surface, the revolutionary speed of the planet, speed of planet around the sun, speed of sun around galactic core, speed of galaxy in direction X (not to mention possible rotation of galaxy around unknown object(s) etc) or, the approach normally taken: ignore it. So far as i can tell from what i've read, relativity uses observer-based velocity. If your REAL velocity is 290,000km/s but the guy watching you sees you travel at 60 km/h.. according to relativity, you're doing 60 km/h. Now perhaps it's just me.. but this seems just a little silly. Why should who's watching alter everything? It's like the old 'if a tree falls in the woods and nobody's around, does it make a sound?' the obvious answer being 'yes'. Afterall, falling trees always make noise.. why would they stop? So then according to relativity, if a tree falls in the woods, and the only person around is falling too, it doesnt make a sound because, at the perspective of the observer, the tree never fell over. *shrug* i can understand collapsing waveforms and the uncertainty principle, but observer-based math just doesnt make any sense to me.
Dreamweaver
"If a man hasn't discovered something he will die for, he isn't fit to live" -- MLK, Jr.
Keep in mind that xxx.lanl.gov (where the paper is posted) is not a refereed journal. This paper
may not have been subjected to any peer review, so it's contents should be taken accordingly. Many times serious corrections or withdrawals are made to this pre-print archive. It would probably be better to not publicize something like this until it has been read be many specialists.
jabber: johnynek@jabber.org
Can you say "TARDIS"?
"A less trivial example involves polynomial equations. One can state, for example, that a certain polynomial equation has no roots (that is, solutions) that are whole numbers. Such statements can turn out to be undecidable."
Other results that stem from Godel's work have more to do with limits on automated theorem proving and decidablility with respect to computation. For example, the halting problem. You would think that there *might* be a way to solve the halting problem, but it's provably unsolvable (!) for the same root reasons that some theorems can be stated which can't be proven or disproven. So, Godel's incompleteness theorems do have decidedly (pun intended) non-trivial impact (especially if you were hoping to create automatic theorem provers or code generation programs or something) on math logic and expose a variety of very serious and very real limitations on logical computation.
The current issue of Scientific American has an article on Kurt Godel. Although most of his important contributions were in mathematical logic and theorem proving, he also did some work on relativity and spent a lot of time talking to Einstein. One of his contributions to relativity was a mathematical proof that time travel is not inconsistent with Einstein's theories of relativity. It might be inconsistent with something else we don't know about (or perhaps with something we've learned since then?), but it seems like we should keep our minds open.
What's more, even if the universe is somehow (from what little I know about quantum, I just don't see how) completely causal and logical, that doesn't necessarily make it any less mysterious. Formal logic has been shown to have some startling limitations. Kurt Godel's Incompleteness Theorem demonstrates beyond any doubt that there are True statements, in any sufficiently powerful logical system, which are unprovable. This essentially means that logic can be "undecidable" in some cases. There's nothing that says the universe itself can't have logic/consistency/decidability problems itself.
BTW, I'm not just trying to be argumentative here. Locality of causality and logic is all a very real possibility. Just ask a serious physicist.
About the wormhole that goes back in time, I heard a refutation of this based on the issue that if the distance between the mouths is less than the time it takes light to travel from the back in time mouth to the forward in time mouth, then you would get energy going around (like a bad microphone - speaker setup), and infinitly much energy would be created instantly, destroying either the wormhole or the Universe.
Is this just bullshit, because it seems rather logical?
It's not posted as HTML because the paper requires the use of special character fonts to produce the letters used in the formulae. Besides, you can download and print out the PS version.
suddenly i feel like this whole thing was a big waste of my time when even the physicist's haven't figured out that i am the center of the universe...
*cough* no really.. what's this about the universe not having a center? how can something not have a center... what sort of geometry is this? doesn't the alleged big bang necessarily result in a "center" of the universe like the center of a ripple in a pond?
skywise
Light Be. Light Was. -- YHWH Elohim
The Universe is Flat, only a madman would think otherwise... -- me
-- Roma locuta, Causa finita, Pax vobiscum.
suddenly i feel like this whole thing was a big waste of my time when even the physicist's haven't figured out that i am the center of the universe...
*cough* no really.. what's this about the universe not having a center? how can something not have a center... what sort of geometry is this? doesn't the alleged big bang necessarily result in a "center" of the universe like the center of a ripple in a pond?
skywise
"Light Be. Light Was." YHWH Elohim
"The Universe is Flat, only a madman would think otherwise..." -- me
-- Roma locuta, Causa finita, Pax vobiscum.
I suppose it would be useless to point out that they already create and store antimatter for use in particle accelerators. In fact, they have been for years. I wouldn't want to muddle the discussion with facts, though...
I do not discount your premise at all. In fact, I would appreciate if someone can supply the source. I was only a physics minor, and that was many years ago. One thing I have come to believe is that quantum physics makes unbelievable advances, sometimes invalidating other premises. However, I remember being taught two things:
(1) No force is exerted without an exchange of particles. (i.e. Thus the big search for gravitons and other sub-atomic particles)
(2) All information may be encoded in binary streams. Its efficiency is a measure of the significance of each digit.
I always inferred that as a result, information could not be transfered without a medium, and thus (at least in three dimensional terms) would always be limited by the speed of light.
I must admit; that I am a natural skeptic on time-travel and faster-than-light velocity. Maybe its because they were the only static immutable laws that I could cling to. I am fascinated, and would enjoy more information about the information, particle bonding that you discussed.
Would we have to sacrifice relativity for a fixed frame to measure FTL? One could certainly model an infinite n-dimensional system, whereby within any given dimension all measurements were relative to its cohabitants. A unified relative constant could exist for each frame and only become non-essential based upon the knowledge or a more precise fixed frame (the next layer out).
Thus, any set of relative measures would still apply as long as you remained within a single dimension. The knowledge of the (next) absolute frame of reference would only make it Easier to develop physical law. It would not eliminate the system based upon relative physical law.
Maybe that's a little more mathematics oriented than physics; however, I would be interested in any thoughts.
...use one of these guys to put an olympic sized swimming pool in my closet. The author seems to indicate that the warp bubble is larger on the inside than on the outside.
Actually, he's saying that the volume can be increased while the surface area is decreased or something like that. It's a bit like this:
Take a rectangle with a perimiter of 52.
The rectangle with the least surface area is 1x25 at 25 square units.
The rectangle with the most surface area is 13x13 at 169 square units.
This is the sort of thing he means.(I think.)
Has there ever been speculation about how we can create ANYthing with negative mass or negative energy? I pretty much understand what they are.. just not how they can be made (even in theory). Wouldn't it require control over what's not there? Am I missing something?
They said the earth was flat - they were wrong
They said the earth was the center of the universe - they were wrong again
They said you couldn't go faster that sound - they were still wrong
They say you can't go faster than light...
An efficient method of storing antimatter might not be as far off as you think. The folks at Princeton Plasma Physics (PPPL.gov) are working on a project called the National Spherical Torus Experiment (NSTX). (http://fileroom.pppl.gov/nstxhome/index.shtml)Thi s project's specific goal is to do research on fusion technologies, and part of that involves developing a highly efficient magnetic storage field for the high-energy plasmas needed to create sustained fusion. So far, the most efficient form they have found is the spherical toriodal "doughnut" which contains plasma. I am not sure of the mathmatics of the situation, but I believe that it takes a stronger field to contain the highly volatile plasma than antimatter, which only releases energy if coming into contact with matter, so, in theory, the NSTX approach should be able to be adapted to contain antimatter. Now if we could just figure out a way to create more than a few subatomic particles of antimatter...
Tell a man that there are 400 Billion stars and he'll believe you
Pope John Paul disagrees with contraception (while millions die). And when the Pope says something, people listen...
IOW, so what?
Was Einstien ever prooven wrong??
And since when is Hawking the highest, undisputed authority on space-time?
censorship is a form of noise, which actively seeks to drown out content with silence - Crash Culligan
What happened to bubble memeory?
-- They say you die a little bit each day. Have a nice day!