Warp Drive Might Be Less Impossible Than Previously Thought 867
runner_one writes "Harold 'Sonny' White of NASA's Johnson Space Center said Friday (Sept. 14) at the 100 Year Starship Symposium that warp drive might be easier to achieve than earlier thought. The first concept for a real-life warp drive was suggested in 1994 by Mexican physicist Miguel Alcubierre, however subsequent calculations found that such a device would require prohibitive amounts of energy, studies estimated the warp drive would require a minimum amount of energy about equal to the mass-energy of the planet Jupiter. But recent calculations showed that if the shape of the ring encircling the spacecraft was adjusted into more of a rounded donut, as opposed to a flat ring the warp drive could be powered by the energy of a mass as small as 500 kg. Furthermore, if the intensity of the space warps can be oscillated over time, the energy required is reduced even more."
But then, a slight solar wind... (Score:5, Funny)
Eject the core!
use the Naquadria drive (Score:5, Funny)
use the Naquadria drive
Less Unpossible (Score:5, Funny)
Nearly not untrue!
Give me a little more non-fake false hope, and I'll use the slingshot effect to go back in time and uncancel the original series!
Re:But then, a slight solar wind... (Score:5, Funny)
Eject the core!
Frog Blast The Vent Core!
Re:But then, a slight solar wind... (Score:5, Interesting)
It's amusing, because the shape they have come to is essentially the same shape as the warp field on the Enterprise.
Re:But then, a slight solar wind... (Score:5, Funny)
maybe not a coincidence, this Harold "Sonny" White who came up with the shape is part of the 100 year starship project, I'm suspecting he was a trekkie who tried out the warp field shape just to see what would happen. but he's too embarrased to admit it!
Re:But then, a slight solar wind... (Score:5, Insightful)
What did I tell you? (Score:5, Funny)
To all those anti-warp drive downers.. HAHAHAHA!!!!
Re:What did I tell you? (Score:5, Informative)
The energy argument was completely secondary. The main objection (which is barely touched on in the article) is that there are some fairly strong proofs that you need exotic matter in order to actually implement the drive. My understanding is that the space-time configuration necessary for the warp drive has been shown to be impossible to create without exotic matter.
Exotic matter, by definition, requires violations of the known laws of physics. In other words, the currently accepted laws of physics indicate that you need to break the laws of physics to make the drive work. This means that while the results in this article might have alleviated some secondary concerns, the main problem with this type of warp drive is still completely unaddressed.
Of course, there are some people who will waive their hands and say "abracadabra - QUANTUM MECHANICS" to try and get around the exotic matter problem. But you are now trying to combine general relativity with quantum effects, so there isn't any firm foundation to base your arguments on.
Re:What did I tell you? (Score:5, Funny)
there are some people who will waive their hands
This I have to see.
Re:What did I tell you? (Score:5, Informative)
No pictures, but its true. There are some people who have waived their hands:
http://www.thedailybeast.com/newsweek/2008/05/28/cutting-desire.html [thedailybeast.com]
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I would happily waive my hands in exchange for a working (and practical) warp drive.
Re:What did I tell you? (Score:5, Insightful)
I would happily throw 90% of the human race under a bus for a working warp drive.
Re:What did I tell you? (Score:5, Funny)
A spelling mistake in a reply to a spelling mistake is probably exotic enough to power a small unicycle. -> They lose their quantum spin
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The negative mass (energy) required is not expressly forbidden. We've just never seen anything with such a property and the existence of it would raise some interesting questions. But you could say that about a lot of things that have come out of particle physics....
Re:What did I tell you? (Score:5, Interesting)
We have seen this effect, just not in regular solid matter; we can see it in certain configurations of regular matter, such as the Casimir effect. So it's not *real* exotic matter, but it does show that negative energy is technically an observable thing. How exactly we can make use of that to do the necessary space-folding is still unknown. It's an incredibly hard, potentially impossible engineering problem, but impossible engineering problems have a tendency to become trivial given enough time and motivation.
Re:What did I tell you? (Score:5, Funny)
We have seen this effect, just not in regular solid matter; we can see it in certain configurations of regular matter, such as the Casimir effect.
Oh let the sun beat down upon my face, stars to fill my dream
I am a traveler of both time and space, to be where I have been...
Re:What did I tell you? (Score:5, Informative)
"... we can see it in certain configurations of regular matter, such as the Casimir effect."
What does the Casimir effect have to do with it? That is merely a demonstration of so-called "zero point" fluctuations. It isn't "negative energy", except to the extent that you have particles and their counter-particles spontaneously arising at the same time. Even so, in the case of the Casimir effect it exerts a net positive energy on the affected mass.
Re:What did I tell you? (Score:5, Informative)
Antimatter certainly isn't common, but it's not "exotic matter" [wikipedia.org]. Stable wormholes and the Alcubierre drive require using exotic matter that has negative mass-energy, which would violate the weak energy condition [wikipedia.org].
The Casimir effect is the best known example of negative energy [wikipedia.org]:
Morris, Thorne and Yurtsever[4] pointed out that the quantum mechanics of the Casimir effect can be used to produce a locally mass-negative region of space-time. In this article, and subsequent work by others, they showed that negative matter could be used to stabilize a wormhole.
Re:What did I tell you? (Score:5, Informative)
The AC is terse but correct. The Casimir effect [wikipedia.org] occurs because vacuum fluctuations are suppressed between two parallel conducting plates that are placed very close together. Maxwell's equations force E=0 inside perfect conductors, which means that vacuum fluctuations with a half-wavelength longer than the separation between the plates can't exist between the plates. Because they exist in the vacuum outside the plates (which is defined to have zero energy), the energy inside the plates is actually negative. The attractive force implies negative energy between the plates because force is the negative gradient [wikipedia.org] of potential energy.
Re:Negative Mass (Score:4, Informative)
"In fact, I propose that anti-matter has negative mass, not opposite charge as generally accepted."
That might have been a viable theory half a century ago or more. But antimatter has been observed to have positive mass.
Re:What did I tell you? (Score:5, Interesting)
In fairness, the claim that it "might be less impossible than previously thought" may be accurate. It could be less impossible and still be pretty much impossible. And I don't think anyone believed that a warp drive could be built without violating some of our current laws of physics.
It's not hand-waving. (Score:5, Insightful)
People have used metamaterials to achieve results that seem to violate the laws of physics (such as materials having a negative refractive index [wikipedia.org]). Speculating that such an exotic material could be produced is not hand waving. Just because we don't know how to do something today doesn't mean we'll never figure it out.
And no, the energy argument was not secondary. Before you could argue that even if we could make the materials necessary it would require a prohibitive amount of energy to work. Now the argument is only about the materials needed.
Re:It's not hand-waving. (Score:5, Funny)
That explains why I rode her all night long. (I kid, I kid. Your grandmother is a very nice lady, who says you should call more often.)
Re:What did I tell you? (Score:5, Interesting)
Exotic matter, by definition, requires violations of the known laws of physics.
That's a very peculiar definition of exotic mater you have there. Elsewhere, "exotic matter" generally refers to matter of a type neither observed nor predicted by current theory. No violation of known physics is implied. It is just that we haven't seen any and there is no particular reason to believe that it exists.
The particular flavor of exotic matter needed for the warp drive is "negative" matter. Negative matter has negative energy. Unlike antimatter where antimatter + matter = lots of energy, negative matter + matter = nothing.
'Last I heard, running the usual math through with negative matter results in some situations that don't make a lot of sense. They aren't necessarily wrong or forbidden, we just don't know what they mean. Math is like that sometimes.
Re:What did I tell you? (Score:5, Interesting)
It is more correct to say that "exotic matter" refers to some substance that has never been observed to exist and possesses one or more properties that are so radically distinct from properties you would find more conventionally that it might as well be magic.
Examples: A frictionless pulley; a shield against gravity; an invulnerable metal.
Re:What did I tell you? (Score:5, Informative)
Re:What did I tell you? (Score:5, Informative)
Moreover, even the Alcubierre drive might be possible with only positive matter if one uses a dynamic metric. I've seen a paper about it a few years ago, but I can't find it.
Re:What did I tell you? (Score:4, Informative)
"Exotic matter, by definition, requires violations of the known laws of physics."
No, it doesn't. Antimatter is one valid type of "exotic matter", and it has been manufactured in labs in various (small) amounts for many decades now, without a physics violation in sight.
Further, there is nothing theoretically preventing us from manufacturing it in fairly large quantities, as long as it can be kept in magnetic containment.
Re:What did I tell you? (Score:5, Informative)
No, nothing can go faster than the speed of light because it will violate causality. Which is more or less forbidden by the entirety of physics.
The only way to avoid this is by some magic-juju like Parallel Universes, Consistency Protection, Restricted Space-Time Areas, or Special Frames (with Special Frames forbidden by Relativity). All of which look like desperate hand-waving, if you examine them closely.
http://www.projectrho.com/public_html/rocket/fasterlight.php#id--Causality
Re:What did I tell you? (Score:4, Funny)
Re:What did I tell you? (Score:5, Interesting)
"No, nothing can go faster than the speed of light because it will violate causality. Which is more or less forbidden by the entirety of physics."
Incorrect. There is nothing we know of that actually works to prevent the violation of causality. There are a number of ways it can theoretically be done.
See Tipler, "Rotating Cylinders and the Possibility of Global Causality Violation".
All rhetoric (like the post at that link) aside, all we really have about it is guesses. The fact that we have never observed anything, so far, that would violate causality says absolutely nothing about the possibility. Further, it is not necessarily true that limited instances of causality violation would render the entirety of physics invalid, any more than relativistic situations render Newton "invalid". They are "special cases". That is all.
Re:What did I tell you? (Score:4, Insightful)
No, nothing can go faster than the speed of light because it will violate causality. Which is more or less forbidden by the entirety of physics.
It is true that faster-than-light travel would mean that we have causal sequences whose order is frame dependent, but would that be a violation of causality?
Re:What did I tell you? (Score:5, Interesting)
Traveling faster than light does not necessarily violate causality.
If I could travel instantly from place A to place B which is 1 light year away, I would arrive at B long before the light arrives. However, the "absolute" time at place B is exactly the same as at place A, the fact that an observer depending on optical information via photons lazily traveling at the speed of light from B to A would only be able to see me arriving there a year later has nothing to do with causality. If I instantly travel back to A, I am still not arriving any earlier than I departed, and hence have not moved in time, only in space - and once again I cannot violate causality.
Re:What did I tell you? (Score:5, Funny)
So what you're saying is, it never occurred to him to think of space as the thing that was moving?
I'll believe it when I see... (Score:5, Insightful)
Re:I'll believe it when I see... (Score:5, Insightful)
If this thing truly "warps" space (no idea if it does) you could travel at effectively faster than light speed through a vacuum while never actually accelerating past the speed of light doing it...
Re:I'll believe it when I see... (Score:5, Informative)
Here is a relatively understandable explanation of why beating a photon to its destination implies time travel, even if you don't locally travel faster than light: http://www.theculture.org/rich/sharpblue/archives/000089.html [theculture.org]. Basically, if you can pass stuff along at FTL between people at sub-light speed, and those people are moving relative to one another, you can send stuff into the past.
There *are* workarounds. A fairly comprehensive list is here:
http://www.physicsguy.com/ftl/html/FTL_part4.html#subsec:specialframe [physicsguy.com]
They're all kind of about relativity being wrong, and there's no evidence any of these are true. Mostly wishful thinking on the part of people that want to believe we can have an interstellar civilization but can't quite let go of causality. Briefly:
1. FTL takes you to a parallel universe. So if you try to kill your past self, there's no paradox and you keep living because it was actually your counterpart in a different universe.
2. There's some unknown physics that would prevent using FTL to violate causality. So even though there's technically time travel in some sense, it has no practical use and therefore you could say it isn't "really" time travel.
3. A specific case of the above: perhaps the act of travelling FTL prevents any other FTL travel within a certain spacetime "radius".
4. Violate relativity by having a "true" frame of reference with a "true" sequence of events. All FTL takes place in that context and is theoretically unlimited in speed. Within any other frame of reference, it looks like a speed limit, but still possibly faster than light speed.
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Now, bashing quantum theory and general relativity together into a consistent whole is something that we've not managed to do yet. Both seem to be true in their respective domains---(almost magisteria to listen to the debates) yet th
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But that's the point of how warp drive works - you bend space so that you don't travel faster than light.
Re:I'll believe it when I see... (Score:5, Interesting)
But that's the point of how warp drive works - you bend space so that you don't travel faster than light.
You locally don't. The warp ship doesn't actually accelerate at all. This is how you get around the relativistic energy equation.
However, someone will observe you traveling faster than light, going from point A to point B faster than light would travel the same distance. If nobody sees you traveling faster than light, then how can you say you did so at all?
And the whole point of relativity is that the laws of physics have to hold everywhere. That observer, depending on their own velocity in space-time, potentially see you arrive at your destination before you left, violating causality according to them.
Given a few such warp ships, you could even arrange it so that that person would receive a message they had written and sent with you before they had actually written it. And then causality is broken for everyone.
But hey, maybe it's not a causal universe! I await their experiments.
Re:I'll believe it when I see... (Score:5, Funny)
But that's the point of how warp drive works - you bend space so that you don't travel faster than light.
You locally don't. The warp ship doesn't actually accelerate at all. This is how you get around the relativistic energy equation.
However, someone will observe you traveling faster than light.
So you use stealth technology. Duh.
Re:I'll believe it when I see... (Score:5, Funny)
But hey, maybe it's not a causal universe!
Dang.
I was really looking forward to Causal Friday.
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Re:I'll believe it when I see... (Score:5, Insightful)
First, objects traveling faster than sound do not violate causality for a bat. Just because the sound they receive is confusing does not mean that the universe broke or that anyone traveled through time. A supersonic object can make two sounds at two different times and a listener at a certain position would hear the sounds reversed. That's confusing, but it doesn't violate causality (except in the strict sense that a bat would sense that events occurred in the wrong order). Sound and light are not the same of course, but getting your data out of order just means that things are confusing for the viewer.
The reason sound and light are not the same is because sound is not synced with time. Being supersonic does not affect time significantly whereas getting closer to the speed of light causes you to experience time differently than others traveling at different velocities relative to you. Furthermore, time dilation and your speed of travel are synced such that light travels away from you at the same speed no matter what speed you are traveling at (assuming you aren't magically warping space).
I don't know enough to comment on how exactly warping space to travel ftl works with special/general relativity, but I've never seen it debunked. The real problem is that there is no known way to warp space to create this warp drive.
Re:I'll believe it when I see... (Score:5, Insightful)
Excuse me as I re-post what I already asked elsewhere in this article:
I don't see how FTL traveling implicates time travel. "Apparent" time travel i understand. But don't really see how it affects causality.
Let's say my sun explodes and I go to a nearby system 2 light years away at twice c. Once there I will warn everybody that the closest star is going nova in a year. Now let's say you want to prevent me from delivering these news. You look up to the sky and see my planet. Obviously it is still there isn't it? So you take my warp ship and try to go to my planet. By the time you get there you are only going to find a 2 years old cloud of hot gas.
If you travel at 4 c you will find a 1.5 years old gas cloud. Travel at 8 c to find a 1.25 years old gas cloud. Travel there at 16 c to find a 1.175 years old cloud.
Travel as fast as you want. You shouldn't ever get earlier than a year after my departure let alone prevent it. Now, it could be that someone find out about this and tries to intercept you by going there at twice your speed. They'll get there before you and it will surely take you by surprise but that's still not time travel from your point of view.
Re:I'll believe it when I see... (Score:4, Informative)
Here you find a better explanation in the links:
http://science.slashdot.org/comments.pl?sid=3124243&cid=41369449 [slashdot.org]
http://science.slashdot.org/comments.pl?sid=3124243&cid=41369345 [slashdot.org]
I'd say you take a few more physics classes.
Re:I'll believe it when I see... (Score:4, Informative)
For chrissake:
Here [everything2.com]
FTL implies at least backwards communication is possible under any method you can think of. If you get get to Alpha Centauri by stuffing yourself in your ass, it will still allow backwards time travel.
Re:I'll believe it when I see... (Score:5, Insightful)
don't need a physics class, as I already have my degrees in the field. All that you reference is true in its own context (spec rel). Alcubierre warp drive is valid within Gen Rel, and does not lead to time travel. It has other issues, but not this particular one.
Re:I'll believe it when I see... (Score:5, Insightful)
you are the one in need of more physics classes, you are linking a SR page (inertial reference frames only, changing relativistic mass to change velocity only) and this drive is outside the realm of SR, it is a GR engine. your SR arguments are meaningless.
Re:I'll believe it when I see... (Score:5, Funny)
A PhD physicist invented the Alcubierre Drive, and physicists at NASA are now working on this warp drive concept, but a couple of armchair physicists on Slashdot think they know physics better than the experts.
Why should physics be different than any other topic?
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an absolute frame of reference.
I'm pretty sure those don't exist. Which is why, from any relative frame of reference, the top speed really is c. You can't go c+1 mm/year in any frame of reference, let alone 2c.
Re:I'll believe it when I see... (Score:5, Informative)
the relative motion would be FTL, but so is the relative motion of two beams of light going in opposite directions when measured from an absolute frame of reference.
Nope. First, there's no such thing as an "absolute frame of reference". That's the really cool thing that Einstein proved, which gets referred to as "relativity". When two beams of light going in opposite directions are measured from any frame of reference, both are going c, neither are going 2c. Even if you were traveling along behind one of the beams of light going at 99% c, each would still only be going c.
Re:I'll believe it when I see... (Score:5, Interesting)
Two ships travel at c in opposite directions for a period of time. When they decelerate and return to the same frame of reference that they started from, the distance between them will be equivalent to one ship having travelled at 2c for the same period. It doesn't matter what the people in each ship perceive from within their reference frames while they're moving.
No, they won't.
Let's say that three ships are stationary relative to each other, sitting right next to each other, and two of them accelerate very quickly to just under the speed of light in opposite directions. Each ship travels for what their clock says is one year, and the third stays where it is. After a year, they stop very quickly, and measure the distance that they are from each other. How far away from each other will they be?
The correct answer is 1 light-year. Only 1, not 2.
From each ship's point of view, when it took off going almost the speed of light, the other ship travelled very slowly in the opposite direction. The third ship that didn't move saw each ship travel away at almost the speed of light. However, from the third ship's point of view, only half a year passed, which explains why they're only 1 light-year apart. That's what we call "time dilation".
Re:I'll believe it when I see... (Score:5, Informative)
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Re:I'll believe it when I see... (Score:5, Interesting)
No.
In the real world, today, the phase velocity of light can easily exceed the speed of light in a vacuum. There is no time travel. There's no information transfer, either, due to the conditions of travel at that speed, but there's no time travel.
From
"On the other hand, what some physicists refer to as "apparent" or "effective" FTL[1][2][3][4] depends on the hypothesis that unusually distorted regions of spacetime might permit matter to reach distant locations in less time than light could in normal or undistorted spacetime. Although according to current theories matter is still required to travel subluminally with respect to the locally distorted spacetime region, *apparent* FTL is *not* excluded by general relativity."
Also worth reading the 'difficulties' of the 'worm bubble' effect, and how those difficulties might be addressed by this new research.
I'm not saying it's possible, but it's too soon to rule it out, either.
[section: not entirely serious, but...]
My personal take is that Gene Roddenberry was an alien whose goal was to nudge us in the generally correct direction without apparently doing so. To do this, he (it?) created a TV series called 'Star Trek' in which all advances we'd need were demonstrated to agile minds. Once it has been conceptualized, if it is possible, someone somewhere will eventually do it...
[/section]
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I know a bit about physics, and can understand part of the problem.
However...
Here's a thought exercise: You have a FTL ship that can reach Alpha Centuri in a second. You then make a U-turn and come back to Earth a second later. How much time has elapsed on Earth? How much time for the passenger of the ship?
Re:I'll believe it when I see... (Score:5, Insightful)
c is in vacuum always c. Regardless of your movement.
Re:I'll believe it when I see... (Score:5, Informative)
This is actually one of the fundamental observations that led to relativity (and why the speed of light is the fastest information or energy can travel).
Light moves away from you at exactly the speed of light, regardless of what your velocity is. If you're travelling at 0.99c (relative to a "stationary" observer) and you shine a light forward, it looks like it's moving at speed c away from you. Shine a light backwards, looks like it's moving speed c away from you. To the stationary observer, both beams of light *also* look like they're travelling at exactly speed c (and you look like you're travelling at 0.99c). So the stationary observer's perception of how you and the beams of light are moving relative to one another is different from your perception of the same thing. (However, both are equally valid.)
Re:I'll believe it when I see... (Score:5, Interesting)
If going 99.9999% C, it would take you an outrageous amount of (outside) time to flick the switch. The universe could end before then!
Still, assuming you did indeed flick the switch, it would be the same as with sound propogation. An ambulance travelling at 99% speed of sound with sirens blaring will emit a higher frequency sound, until after it passes, and then the tone will be dialated the other way.
The light won't move faster. Instead, the frequency will be insanely high. Your infrared emitting tungsten filament bulb will be emitting gamma ray photons.
If you are going 100% speed of light, you will *never* succeed in toggling the switch.
Here is where the whole FTL thing becomes unnecessary:
If you are taveling 50% of C, the degree of seperation between internal and external clocks will be sufficient that even though it takes you 400 years to reach that star 200 light years away, a considerably shorter time will be recorded by the ship's onboard clock.
The closer to C you travel, the less "time" you experience. So, FTL is not necessary. The crew will be alive and well, and feel only a few months have passed on their 400 year journey. Everyone they left back home will be dead and buried, but for them, only a few months will have passed.
If all you care about is *your* lifetime, FTL is not needed to explore the universe.
Re:I'll believe it when I see... (Score:4, Informative)
The light won't move faster. Instead, the frequency will be insanely high. Your infrared emitting tungsten filament bulb will be emitting gamma ray photons.
Not to you, it won't. Only to that observer, relative to which you were moving at 0.99...c in the first place.
If you are going 100% speed of light, you will *never* succeed in toggling the switch.
You can't reach c while having any mass, so if you're going at c, then there's no switch.
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Maybe they don't want to talk to us.
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of couse not! that would create a paradox that can destroy your post!
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Temporal prime directive.
Re:I'll believe it when I see... (Score:4, Insightful)
You can't go backwards in time using FTL. You can violate Causality, but that's not the same thing and isn't actually a big deal.
Picture it this way: You have a ship that can travel to Jupiter in 5 seconds. The method doesn't matter. You leave Earth, go to Jupiter, come back faster than light, and it's still 10 seconds into the Earth's future. You did not go so fast that you ended up in the Earth's past. You did not return while they were still counting down to your launch.
But what DID happen is that you outpaced your own light cone [wikipedia.org].
Since relativistic observers cannot exceed the speed of light themselves, and events can only propagate at the speed of light, then for all events, all relativistic observers will see the cause before the effect. That's Causality. But a lot of people get caught up on the whole "no absolute reference" thing and they take it a bit too far. Once something happens, it's done. You might not know about it yet, but it already happened and there's nothing you can do about it.
So what would it mean if we could outpace our own light cone? Not much, actually.
You could see the effect of some events before the cause, but you wouldn't be able to do anything about it. The cause already happened. The cause has its own light cone, but you're coming at it from a weird angle, so you haven't run into it yet. You might not even see the cause until you slow down and let it catch up to you "naturally".
Similarly, some observers would see you as moving backwards, but that's just because you're moving faster than the photons you're emitting. Anyone who saw that wouldn't be able to do anything about it, though, even if they could travel instantaneously. You've already long since passed them. If they could travel faster than you, they might be able to intercept you in the future by plotting out your course from what they observered, but they wouldn't actually be able to use what they saw to affect the past. Like if I found a blog post from you that said you were hiking from DC to Hollywood starting a week ago, so I figure out how long that will take and board a plane to meet you there. The Universe wouldn't much care.
Re:I'll believe it when I see... (Score:4, Funny)
(Gigglesnort)
I am reminded of various tougne-in-cheek jests by physicists about the universe hating the LHC.
Perhaps if you activated the alcubierre drive, you could only ever travel outside the vehicle's light cone, but never return back to It, because "mysterious, seemingly random events" will always, without fail, prevent you from pressing the button?
Now there would be a funny thing to put in science fiction!
Re:I'll believe it when I see... (Score:5, Interesting)
As far as I understand it warp drive doesnt break the speed of light locally, so I recon no weird time reversal stuff can happen.
In Relativity, traveling faster than light relative to any reference frame, via any method, presents problems with causality. And the whole point of a Warp Drive is that someone will agree that you went faster than light, and thus went backward in time.
When I last read about the Alcubierre drive, one relevant point that was mentioned was that the inside of the warp field is causally separated from the outside, which solves the problems of causality while in transit, but raises the question of how one starts or ends the journey.
The ridiculous amount of energy required was another problem, more of a practical "how would you do that?" issue rather than a "how is it even possibly in theory?" question.
But the thing is -- it may actually be possible to do this in our universe. And the assumptions of constant c and General Principle of Relativity may also be correct. Which may mean that the assumption of causality isn't. What a universe that would be.
Re:I'll believe it when I see... (Score:5, Insightful)
Can I have one? (Score:5, Funny)
BTW: what is exactly ment with: warp drive could be powered by the energy of a mass as small as 500 kg In what time frame? I guess if you "annihilate" so much mass instantly ... you get indeed warped pretty hefty.
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E / m = c2 = (299,792,458 m/s)2 = 89,875,517,873,681,764 J/kg (9.0 × 1016 joules per kilogram).
So the energy equivalent of one gram (1/1000 of a kilogram) of mass is equivalent to:
89.9 terajoules
25.0 million kilowatt-hours (25 GWh)
21.5 billion kilocalories (21 Tcal)
85.2 billion BTUs
or to the energy released by combustion of the following:
21.5 kilotons of TNT-equivalent energy (21 kt)
568,000 US gallons of automotive gasoline
What about the radiation burst? (Score:5, Interesting)
Does this theory at all reduce the chance that when the Warp Drive ship arrives at its destination that it will emit a huge gamma ray burst [universetoday.com]? This planet destroying side effect would sure put a damper on any kind of arrival party for the warp drive ship.
Re: (Score:3)
No, while the early ships might be prone to the gamma ray bursts, the newer ships will have emission controls that will eliminate 99.99 percent of the gamma radiation.
Re:What about the radiation burst? (Score:5, Funny)
"Hey look. An earthlike planet, with nobody living on it. What a coincidence."
"Signal the colony ship."
Ring/toroid shape? (Score:5, Funny)
Original paper (Score:5, Informative)
Says the man trying to sell warp drives (Score:3)
Please.
Less impossible? (Score:4, Informative)
What about the other problems? (Score:3)
Less impossible? (Score:3)
Impossibility Drive (Score:4, Insightful)
I love it when people say things are impossible. Then they go whizzing backwards into forgotten history as the impossible becomes the norm. Tomorrow will be like today. The future will be surprising.
Nedhead's Law (Score:3)
The power requirements for warp drive will diminish by a factor of 23 every year.
only hitch: space is not a vacuum (Score:4, Interesting)
Real world experiment (Score:3, Funny)
White and his colleagues have begun experimenting with a mini version of the warp drive in their laboratory. ...
"We're trying to see if we can generate a very tiny instance of this in a tabletop experiment, to try to perturb space-time by one part in 10 million," White said.
I can imagine how it might go:
White: "More ... power! We ... have ... got ... to get that ... table up ... to ... warp factor ... 0.00000001!"
Technician: "Aye, professor, but I'm already given 'er all the power we've got. She can' take no more"
Grad student: "My calculations indicate a slim chance of success if we reverse the polarity."
Technician: "I canno' do it. You'll blow the whole rig fo' sure!"
White: "We ... have ... no other ... choice. Reverse ... polarity!"
(All occupants of lab now alternately grab railings to the left then to the right.)
If my calculations are correct... (Score:4, Funny)
Won't happen (Score:5, Funny)
Re: (Score:3)
I'm simply convinced that there is no way this massive universe is here without there being a practical way to travel it. There absolutely has to be a way.
So you are an Intelligent Design believer?
Re: (Score:3)
I'm simply convinced that there is no way this massive universe is here without there being a practical way to travel it. There absolutely has to be a way.
So you are an Intelligent Design believer?
That would be Intelligent Traveling believer.
Re: (Score:3)
Ssshhh... You're supposed to forget about all that and enjoy the virtual simulation of ancient times you're currently emeshed in until the proximity alarm wakes us.
Re:still a lot of energy (Score:5, Interesting)
Agreed.
Other important caveats not listed are things like, duration of field perturbation, and effective field size.
If it takes 500kg of raw mass energy equiv, to send something the size of a football on an ftl hop for 1 sec, it is still very very impractical.
If we are talking something the size of manhattan island being shot at FTL for over a year for 500kg mass energy, things are difficult, but interesting.
This still doesn't sole several other noteworthy problems with the alcubiere metric though. Things like hawking radiation snowplowing on the event shock of the warp field, nuking the ship and everything around it when the field drops as the ship leaves FTL.
(Basically, the spacetime bubble the ship occupies behaves the same as the event horizon of a black hole, as far as virtual particle interactions are concerned. The pocket tearing past at ftl speed forces the particle pairs to become real, robbing energy from the warp field, and plastering radioative exotics all over the shock front. When the bubble collapses, that radiation gets released.)
If they can pull it off, alcubierre's metric would only be useful for short jumps, not continual cruising, making it impractical for visiting very distant objects. It would also be an energy hungy monster.
Re: (Score:3)
Things like hawking radiation snowplowing on the event shock of the warp field, nuking the ship and everything around it when the field drops as the ship leaves FTL.
You know, I've now decided upon my personal theory of FTL, and you inspired it. acceleration of an object to FTL *may* be possible, through as of yet unknown means, however, the way the universe deals with the causality issues created by doing so is by using the built up ram pressure to reduce said object to loose electrons neutrons and protons when it drops out of FTL, and there is no way around that. So your options become 'never go FTL, or never stop once you go FTL'
Re:still a lot of energy (Score:5, Interesting)
That's what a tachyon is! (Well.. more or less...)
A tachyon is a "particle", forced to always travel at FTL velocity, because it has "imaginary" mass.
The alcubierre metric makes use of "negative mass energy" to negate 100% of the vehicle's effective mass, and a little more, causing the "vehicle + engine" composite to become essentially an enormous tachyon. (More or less...)
This poses the problem of how to escape the bubble once created; theoretically speaking, doing so would not be possible! However, interaction with the hawking radiation might provide the solution. As the particles intersect the field, they steal energy from the field, by making the pair real. (One of the particles gets glued to the front, the other gets lost to space.) This loss of energy depletes the field, forcing its collapse. When that happens, the ship returns to being causally connected.
(This however, makes the effect useless for anything but *really* distant objects, or with very very powerful fields.)
Re:still a lot of energy (Score:5, Interesting)
I believe that is exactly what I said, when I mentioned that it was a caveat not addressed by the article. "Football sized" had no bearing on the verbiage of the article, and was instead meant to be taken as-is. Eg, an effective warp bubble big enough to barely hold a football is not practical in any sense at the energy cost listed.
In order to determine how far the ship could travel at 10xC with 500kg raw mass energy, we need to know how long (dialated ship time) that energy takes to be released, and how long (external observer time) the bubble will remain stable.
That information was not provided.
Re:But is it impossible for me to get first post? (Score:5, Funny)
guess you were travelling at impulse
Re: (Score:3)
You can't really expect the math to be on Discovery.com. It's a general interest site for the public. It needs to be accessible (though perhaps it wouldn't hurt them to link to it...).
Someone else posted the original paper, which can be found here [nasa.gov].
Re: (Score:3)
Trek really wasn't "hard" sci-fi... it was harder than some (Star Wars, for example, though I like SW too) but it was both too futuristic and too mass-market targeted to go much into really hard sciency explanations.
I believe if you read the various "supporting materials" (Star Trek encyclopedias and such) you'll find information on how warp is supposed to work canonically, but the details are obviously a bit fuzzy. We know it involves the generation of a "warp field" of normal space that surrounds the ship
Re:Make it so. (Score:5, Interesting)
I'll assume, for the sake of argument, that conservation of energy still applies to the discussion. That is, you can't move a chunk of the crust into orbit without expending more energy than the gravitation potential energy thusly imparted into said chunk.
Let's assume the energy to make the handwavium drive go is equal to the potential energy of a 500 kg mass, as it says in TFS. Presumably we've got matter-energy conversion or antimatter fuel to make this work, that's no more implausible than the handwavium required to make the FTL drive work in the first place.
How much energy is liberated by converting 500 kg into energy, say in the form of 250 kg antimatter to 250 kg matter? About two hundred and fifteen times as much as was released by the largest nuclear weapon ever detonated. Make no mistake - that's a huge amount of energy, but nowhere near planet cracking levels. For another point of comparison, the impact that (probably) killed the non-avian dinosaurs was a couple million times as powerful.
Further, if we've got some way of supplying that kind of power, in a package small enough to fit on a spacecraft, wouldn't the power plant itself be a more dangerous weapon than a handwavium suicide run? Dangerous in the sense of city busting, not planet cracking.