NASA May Have Invented a Warp Drive

[sepulchrave]

I think you are misrepresenting the Alcubierre drive, Leonardo. I base this opinion on my understanding of Alcubierre's original paper (a free preprint can be found here).

The Alcubierre metric professes to describe a region of space bounded by 1 'expansion pole' and 1 'contraction pole', with the polarity being expressed similar to the 'north-south' polarity of magnetism. But space doesn't have any 'polarity' and neither is there any true 'north' or 'south' (or any 'direction') in general relativity.

Space doesn't have an innate polarity, but polarity can be created by the distribution of matter (assuming that exotic matter exists, of course).

The Alcubierre metric is created by a particular arrangement of regular+exotic matter.

We can instead view the 'warping of space' described by the Alcubierre metric similarly to how gravity 'warps space', as a monopole field with the 'pole' being the centre of mass - in this case the centre of the exotic matter mass necessary to create the 'negative energy density'.

So, instead of the 'expansion effect' being towards a 'south' (rear) pole it is greatest closer to the centre of mass with the 'contraction effect' being more noticeable the further away from that centre of mass we look/measure. Because this is a monopole field, this 'contraction effect' is expressed equally in every direction 'outwards' from that centre of mass, so there is no gradient upon which the vessel (which contains the exotic matter mass) can 'surf' in one specific direction.

And because the expansion of space tends towards infinity as we approach that centre of mass, the energy requirement to move that centre any 'real' distance in any direction also approaches infinity.

That is valid reasoning, but it is not what Alcubierre proposed.

The Alcubierre metric is considerably more complex than a simple monopole or dipole field. In fact, the actual metric that Alcubierre proposed does not have any poles (see equations 2 to 8 in the preprint).

Alcubierre's paper demonstrates a topologically simple space-time metric that can achieve what would appear to be superluminal travel. Of course, actually constructing this metric is, at the least, extremely difficult, and probably impossible.

Alcubierre does not describe the actual distribution of matter + exotic matter necessary to create this metric, but it could be calculated using the Einstein equations.

A practical spaceship would require some form of conventional propulsion system (as noted by Alcubierre) to move in and out of solar systems. However in deep space the entire propulsion could be achieved by precise positioning and repositioning of the regular + exotic matter which would ``tune'' the Alcubierre metric.

[Leonardo]

I think you are misrepresenting the Alcubierre drive, Leonardo. I base this opinion on my understanding of Alcubierre's original paper (a free preprint can be found here).

Space doesn't have an innate polarity, but polarity can be created by the distribution of matter (assuming that exotic matter exists, of course).

The Alcubierre metric is created by a particular arrangement of regular+exotic matter.

That is valid reasoning, but it is not what Alcubierre proposed.

The Alcubierre metric is considerably more complex than a simple monopole or dipole field. In fact, the actual metric that Alcubierre proposed does not have any poles (see equations 2 to 8 in the preprint).

Alcubierre's paper demonstrates a topologically simple space-time metric that can achieve what would appear to be superluminal travel. Of course, actually constructing this metric is, at the least, extremely difficult, and probably impossible.

Alcubierre does not describe the actual distribution of matter + exotic matter necessary to create this metric, but it could be calculated using the Einstein equations.

A practical spaceship would require some form of conventional propulsion system (as noted by Alcubierre) to move in and out of solar systems. However in deep space the entire propulsion could be achieved by precise positioning and repositioning of the regular + exotic matter which would ``tune'' the Alcubierre metric.

I'm unconvinced that any arrangement of exotic + normal matter could produce the 'spacial gradient' proposed by the metric, sepulchrave - although I do acknowledge that Dr Alcubierre's equations are all fine and do seem to suggest that possibility.

Spacetime cannot be 'directionally controlled' as if it has some type of polarity - because it does not. Spacetime is not a field phenomenon. A field phenomenon can 'alter' spacetime - as we can observe when gravity does what it does - but it cannot do so except omnidirectionally. That effect cannot be 'targeted'.

From my reading of Dr Alcubierre's paper, I conclude that all of spacetime surrounding the 'Alcubierre effect', including what is contained within that spacetime, will move away from the centre of mass equally in all directions simultaneously. Any vessel which therefore contains an 'Alcubierre drive' and powers it up will simply be torn apart and its constituent fundamental elements flung away in a spherical 'expansion'.

[Wondering Soul]

A big fat giant geeeeee.... .... anyone else remember my posts a month or so ago

bread crumbs are so nice....

[White Crane Feather]

It appears the em drive itself might be a reality. I don't knkw about the warp drive, but zipping around the solar systems sounds fun.

http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141

[Merc14]

It appears the em drive itself might be a reality. I don't knkw about the warp drive, but zipping around the solar systems sounds fun.

http://www.ibtimes.c...tch-out-1499141

Shawyer has been pushing this thing since the 90's I believe.

[sepulchrave]

Spacetime cannot be 'directionally controlled' as if it has some type of polarity - because it does not. Spacetime is not a field phenomenon. A field phenomenon can 'alter' spacetime - as we can observe when gravity does what it does - but it cannot do so except omnidirectionally. That effect cannot be 'targeted'.

I am not sure what you are saying here.

In general relativity, space-time is typically defined by the metric tensor, and often the metric tensor is described in terms of the differential space-time interval (usually called ds). The metric tensor can be used to derive the trajectory of free particles (geodesic curves).

In this interpretation (the metric tensor as a description of geodesics), space-time can have an orientation and a preferred direction.

Obviously the free-space metric (the Minkowski metric) has no preferred direction, but the Schwarzschild metric (a monopole mass - a non-rotating black hole, planet, or star) does; test particles placed at arbitrary positions in space-time will naturally fall towards the monopole mass. Technically speaking, the location of the monopole mass breaks the translation symmetry of space: now there is a ``special position'' in the space-time metric, so test particles at various points in space-time depend differently based on their location relative to this special position.

Additional directionality can be built into the metric by more intricate arrangements of mass/energy. For example, the Kerr metric (a monopole mass with angular momentum - a rotating black hole, planet, or star) has dipole-like characteristics. Technically speaking, this monopole mass breaks translation symmetry as before, but now the rotation of this monopole mass also breaks the rotational symmetry of space: now there is a ``special direction'' in the space-time metric, so test particles at various points in space-time depend differently based on their initial velocity relative to this special direction.

Introducing directionality to space-time (in the sense defined above) is often referred to as frame-dragging.

Alcubierre introduces a particular space-time metric that provides particular properties (namely, arbitrarily rapid transport of a region of space time with respect to a distant observer without introducing any time-dilation or other special-relativistic effects). Obviously to achieve Alcubierre's metric, a much more complex arrangement of matter is needed than for the simple Schwarzschild and Kerr metrics.

By taking various covariant derivatives of this metric one could obtain the Christoffel symbols, from those one could define the Riemann curvature tensor, and from that one could calculate the left-hand-side of the Einstein field equations. The right-hand-side of these equations is the stress-energy tensor, which describes the necessary arrangement of matter required to produce the metric.

[lost_shaman]

Not sure if this should be in Science and Technolgy - or Space Exploration... But here goes...

NASA May Have Invented a Warp Drive

The EmDrive, an experimental propulsion device, may be producing a warp field.

According to posts on the NASA Space Flight forum, when lasers were fired into the EmDrive resonance chamber, it was found that some of the beams were travelling faster than the speed of light.

If this is true, then it would mean that the EmDrive is producing a warp field or bubble. A forum post says that "this signature (the interference pattern) on the EmDrive looks just like what a warp bubble

looks like. And the math behind the warp bubble apparently matches the interference pattern found in the EmDrive."

Nothing has been confirmed yet, but it could mean that NASA is one step closer to achieving faster than light travel. This will be especially useful if there are any developments in its renewed search for

extraterrestrial life.

http://www.ign.com/a...ed-a-warp-drive

I'd be interested in reading waspie's comments on this...

Can you reference where NSF comments claimed FTL?

The NSF main page doesn't say that, and the wiki article says the interferometer measured SLOWER than light speed for the LASER.

[Leonardo]

I am not sure what you are saying here.

In general relativity, space-time is typically defined by the metric tensor, and often the metric tensor is described in terms of the differential space-time interval (usually called ds). The metric tensor can be used to derive the trajectory of free particles (geodesic curves).

In this interpretation (the metric tensor as a description of geodesics), space-time can have an orientation and a preferred direction.

Obviously the free-space metric (the Minkowski metric) has no preferred direction, but the Schwarzschild metric (a monopole mass - a non-rotating black hole, planet, or star) does; test particles placed at arbitrary positions in space-time will naturally fall towards the monopole mass. Technically speaking, the location of the monopole mass breaks the translation symmetry of space: now there is a ``special position'' in the space-time metric, so test particles at various points in space-time depend differently based on their location relative to this special position.

Additional directionality can be built into the metric by more intricate arrangements of mass/energy. For example, the Kerr metric (a monopole mass with angular momentum - a rotating black hole, planet, or star) has dipole-like characteristics. Technically speaking, this monopole mass breaks translation symmetry as before, but now the rotation of this monopole mass also breaks the rotational symmetry of space: now there is a ``special direction'' in the space-time metric, so test particles at various points in space-time depend differently based on their initial velocity relative to this special direction.

Introducing directionality to space-time (in the sense defined above) is often referred to as frame-dragging.

Alcubierre introduces a particular space-time metric that provides particular properties (namely, arbitrarily rapid transport of a region of space time with respect to a distant observer without introducing any time-dilation or other special-relativistic effects). Obviously to achieve Alcubierre's metric, a much more complex arrangement of matter is needed than for the simple Schwarzschild and Kerr metrics.

By taking various covariant derivatives of this metric one could obtain the Christoffel symbols, from those one could define the Riemann curvature tensor, and from that one could calculate the left-hand-side of the Einstein field equations. The right-hand-side of these equations is the stress-energy tensor, which describes the necessary arrangement of matter required to produce the metric.

I'm aware of frame-dragging, sepulchrave, but that applies to a body already in motion relative to another body (in rotational frame-dragging this is either a body another is orbiting, or the axis of rotation of a spinning body.)

What Alcubierre proposes is that we can define a direction relative to the 'drive' according to a proposed 'target' - that is his 'x' co-ordinate - apply power to the 'drive' and space will 'warp' and a gradient will be generated by that 'warping of space' along which the vessel will 'surf'.

But general relativity only allows us to conceive a co-ordinate x in space relative to the motion of the observed body (in this case, the stationary vessel/drive) or it's 'attitude' relative to another body - not to any 'objective frame of space' because there is no 'objective frame of space'. As I said previously, space does not have a 'true north', nor an x co-ordinate, or y co-ordinate, etc. Space is not intrinsically cartesian, but an observer can subjectively apply a cartesian co-ordinate system onto space.

In Alcubierre's metric, there is no motion relative to any other body, nor does that body have any 'attitude' relative to any other body. The vessel/drive is a 'free body without any relative motion or attitude' and so no orientation or preferred direction of space can be inferred. His solution is correct for the x co-ordinate of a cartesian space, I agree, but it should be applied to every possible x co-ordinate of every possible cartesian space relative to the vessel/drive simultaneously because there is no 'preferred direction' implicit in the equation.

Unlike a reaction drive producing thrust, there is no direction of motion derived from the application of the Alcubierre metric.

Edited May 2, 2015 by Leonardo

[DONTEATUS]

Lets Get to It ! THe E.M. drive is calling us to Build ! Its all up to us,not just a Dream anymore !

[sepulchrave]

But general relativity only allows us to conceive a co-ordinate x in space relative to the motion of the observed body (in this case, the stationary vessel/drive) or it's 'attitude' relative to another body - not to any 'objective frame of space' because there is no 'objective frame of space'. As I said previously, space does not have a 'true north', nor an x co-ordinate, or y co-ordinate, etc. Space is not intrinsically cartesian, but an observer can subjectively apply a cartesian co-ordinate system onto space.

I think you may be confusing special relativity with general relativity. Special relativity has no preferred directions, because space is flat: the space-like parts of the metric have continuous translational and rotational symmetries.

In general relativity space can have a preferred direction, based on asymmetry in the metric. Of course whether you label this as ``north'' or ``x'' or ``theta'' is a matter of personal convention.

The underlying philosophy of general relativity is that the very topology of space-time is affected by the distribution of mass (and vice versa).

A rotating black hole does have a ``true north''. The rotating black hole introduces curvature in space-time; space-time itself also has a ``true north'.

[+DieChecker]

If the effect does exist. And, since the EmDrive itself shouldn't work, but apparently does, we can't say that the effect isn't there because apparently whatever is going on is outside our modern physics.

The problem would be making the field size large enough to encompass the entire object. That might allow, depending on if the effect can scale, a ship to travel at 0.1 c and in outside space travel at 2 c, or 5 c.

Once the effect is recognized, it turns into an engineering problem to find the limits of the effect and if it can scale in power, and size.

Harold G. "Sonny" White, who investigates field propulsion at Eagleworks, NASA's Advanced Propulsion Physics Laboratory, speculated that such resonant cavities may operate by creating a virtual plasma toroid that could realize net thrust using magnetohydrodynamic forces acting upon quantum vacuum fluctuations.[27]

http://en.wikipedia.org/wiki/EmDrive

[Belial]

Put it in a giant bag then fill it with microwaves to be jettisoned from the rear say

[She-ra]

Came across another article I thought some of you might enjoy reading.

NASA has trialled an engine that would take us to Mars in 10 weeks

And may have inadvertently created a warp drive in the process.

Read article here: http://www.sciencealert.com/nasa-has-trialled-an-engine-that-would-take-us-to-Mars-in-10-weeks

[Merc14]

Came across another article I thought some of you might enjoy reading.

Read article here: http://www.scienceal...ars-in-10-weeks

Finally a test in a vacuum so now we have to start taking this more seriously. They need to launch one into orbit and see if it works for real.

[She-ra]

Finally a test in a vacuum so now we have to start taking this more seriously. They need to launch one into orbit and see if it works for real.

Just for you Merc

[Merc14]

Just for you Merc

Thank you mam! Reports are popping up all over now http://www.extremetech.com/extreme/204921-controversial-quantum-em-drive-gets-real-nasa-testing-lives-to-fight-another-day

Edited May 5, 2015 by Merc14

[She-ra]

Love it! Off to read that now. Thanks!

[Taun]

An FTL drive would be an astounding creation, and the answer to many dreams I've had since I was a small child... But in the last few days I've been a bit concerned as well, about misuse...

[Merc14]

An FTL drive would be an astounding creation, and the answer to many dreams I've had since I was a small child... But in the last few days I've been a bit concerned as well, about misuse...

The FTL aspect was based on tests done in a normal atmosphere and wasn't attempted in these vacuum chamber tests so I'd hold back on the FTL aspects. It would be beyond amazing if there was some game changing find but a super ion drive would be a big deal in and of itself , no?

Edited May 6, 2015 by Merc14

[drsdsatnasa]

stephen hawking's book 'brief history of time' proves time travel and also ixs enterprise theory by harold white in nasa had in going research of warp ship.so time travel is possible.

[Taun]

Can you reference where NSF comments claimed FTL?

The NSF main page doesn't say that, and the wiki article says the interferometer measured SLOWER than light speed for the LASER.

The comment about FTL was not mine, it was in the news article I linked to...

As so often happens, reporters don't always let the facts stand in the way of a good story...