Starting to take Warp Drive Seriously:

My question is why FTL should cause a reversal of emergent time associated with movement from here to there?
That is not logical.
IMO, in this universe it just may not be possible to travel at FTL. Not everything is possible just because we can imagine it.

This is why we are forced to alter the definition of a FTL particle to a non-physical "virtual particle", which has negative mass. That sounds weird to me. How can a pattern be less than a pattern.

Is FTL the domain of particles with negative properties? Anti-particles?

 

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Imagining it is easy. They've done it in Star Trek since the 60's. Naive intuitions run along the lines of Newtonian mechanics where there's no restriction at all to FTL, so the audience readily accepts the plot.
I also notice that they have no problems with real-time communication with the home base hundreds of light years away, whenever the plot requires it. Again, this relies on that Newtonian spatial coordinate system.
I've show in the example in my prior post how FTL travel must entail time travel. It just follows from the mathematics from Einstein's theories.

Yes, negative mass is another side effect. I don't think they propose make a warp-spaceship out of virtual materials.

Anti-particles do not have different properties than normal particles. To them, we're the antimatter. They don't move FTL or differently in any way. The sun generates antimatter at a substantial pace. Most of that is short lived as it annihilates regular matter.

 

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Did you see this?


and this incredible display;

 

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Actually, the analogy is pretty apt. Compressing spacetime in front of you and letting it go behind is going to leave some sort of wake, probably detectable by something like LIGO.

There's a long straight dike of dirt outside of a building at Texas A&M university, and there's a gap in it where the sidewalk goes through. Stand there in the gap and you are standing in probably the highest neutrino density anywhere within 50 light years. I wouldn't worry too much about the neutrinos. They already move at damn near light speed and hit nothing.

Not to poo-poo your concern. There is plenty of stuff already out there that doesn't pass right through you, and much of it is already moving stupid fast in every direction, so moving fast against that background makes some of it faster and some of it not. In the end, it will probably destroy any craft regardless of what speed it is going. My protests have been more theoretical and not so much worrying about the practicalities of space travel. We can assume an empty path and heavy budgets for our scenarios.

 

Extending the thought. In water a boat has an ultimate hull-speed, which is associated with the length of the water-line of the boat. Hullspeed

Maximum Hull Speed

(Maximum hull speed (in knots) = 1.34 x the square root of the waterline length (in feet)

Waterline Length.....Max Hull Speed

20 feet..........6.0 knots

25 feet..........6.7 knots

30 feet..........7.3 knots

35 feet..........7.9 knots

40 feet..........8.5 knots

45 feet..........9.0 knots

50 feet..........9.5 knots

https://www.sailboat-cruising.com/hullspeed.html

The basic idea is that the "bow-wave" keeps building until its resistance cannot be exceeded.
Would a similar limitation apply to a spacecraft traveling through a "fluid" space?

 

No one says it does, but likewise, you don't just forget what is inside the bubble.
Let me be clear, I don't believe this will ever eventuate and will remain a hypothetical dream.
And I don't know enough about relativity to pass judgement on what the article says, and I do realize that sometimes pop science articles can get it wrong. But again it does say....
"In short, the Alcubierre Metric allows for FTL travel without violating the laws of relativity in the conventional sense."
https://en.wikipedia.org/wiki/Alcubierre_drive

"Rather than exceeding the speed of light within a local reference frame, a spacecraft would traverse distances by contracting space in front of it and expanding space behind it, resulting in effective faster-than-light travel. Objects cannot accelerate to the speed of light within normal spacetime; instead, the Alcubierre drive shifts space around an object so that the object would arrive at its destination faster than light would in normal space without breaking any physical laws.[3]

Although the metric proposed by Alcubierre is consistent with the Einstein field equations, construction of such a drive is not necessarily possible. The proposed mechanism of the Alcubierre drive implies a negative energy density and therefore requires exotic matter. So if exotic matter with the correct properties cannot exist, then the drive could not be constructed. At the close of his original article,[4] however, Alcubierre argued (following an argument developed by physicists analyzing traversable wormholes[5][6]) that the Casimir vacuum between parallel plates could fulfill the negative-energy requirement for the Alcubierre drive."
it does say then......
"Some physicists have presented arguments to suggest that a theory of quantum gravity (which would incorporate both theories) would eliminate those solutions in general relativity that allow for backwards time travel (see the chronology protection conjecture) and thus make the Alcubierre drive invalid."

 

I think I've been arguing somewhere on these lines. They admit in the article that FTL anything is equivalent to backwards time travel. I'm not arguing the impossibility of it, just the implications.

 

Actually, the site the article is from is not by general source of scientific news, and I am certainly aware of sometimes "pop science" claims that may be sensationalised somewhat.
I will also endeavour to get another opinion on it from a relativity physicist on another forum.

 

Just because we find a few hitting anything does not mean they can be taken out of the picture I create...my proposition can be quantified mathematically...we need numbers to reject or accept the notion.
Anyways I am rambling caused by thinking about how big the universe may be.
Alex

 

We need to test to find out I guess but why wouldn't you think it that a bow wave effect could be found...a computer model..that's it.
Alex

 

Concerning bow waves and damage from arbitrarily particles in the path, the article seems to worry more about those not on board:

Translation: Stop the ship off to the side of the destination. Taxi in slowly, just like at an airport.

 

Do the actual examples of the hyper-speed photography not demonstrate something like that? If there was no air resistance inside the bottle why would the photon be restricted to "c" and not propagate @ (c+)?

This is my intuitive guess of "c" being the limit of a photon pushing against the space fluid and building a bow-wave which cannot be exceeded but which produces the kinetic energy (virtual mass) of that photon.

Or more like a boat in a harbor slowing down to reduce the bow- wave....

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I admit these are uneducated "best guesses" of my brain.......

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........and most likely wrong.

But hey, for now it satisfies my curiousity......

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extracts from article:
"Originally proposed by Mexican physicist Miguel Alcubierre in 1994, this concept for an FTL system is viewed by man as a highly theoretical (but possibly valid) solution to the Einstein field equations, which describe how space, time and energy in our Universe interact."
"While the concept was generally dismissed for being entirely theoretical and highly speculative, it has had new life breathed into it in recent years."
"As Agnew related, one of the greatest is the fact that the concept of the "warp drive" is still not taken very seriously in scientific circles:"
"The historically theoretical nature of the idea is also itself a likely deterrent, as it's much more difficult to see substantial progress when you are looking at equations instead of quantitative results."
:::::::::::::::::::::::::::::::::::::::::
As is obvious the scientists involved do understand the still highly theoretical nature of this, and obviously know what they are doing and considering. On the plus side though for your information, as it seems you have failed to read the article....
"The LIGO discovery a few years back was, in my opinion, a huge leap forward in science, since it proved, experimentally, that spacetime can 'warp' and bend in the presence of enormous gravitational fields, and this is propagated out across the Universe in a way that we can measure."
"Since the system relies on the expansion and compression of spacetime, said Agnew, this discovery demonstrated that some of these effects occur naturally."
Who would have thunked it!!
again from the article...
"The sheer amount of positive and negative energy needed to create a warp bubble remains the biggest challenge associated with Alcubierre's concept. Currently, scientists believe that the only way to maintain the negative energy density required to produce the bubble is through exotic matter. Scientists also estimate that the total energy requirement would be equivalent to the mass of Jupiter.

However, this represents a significant drop from earlier energy estimates, which claimed that it would take an energy mass equivalent to the entire Universe. Nevertheless, a Jupiter-mass amount of exotic matter is still prohibitively large. In this respect, significant progress still needs to be made to scale the energy requirements down to something more realistic."

 

Hi Halc...That link of yours, where is it from? Reason why I'm asking is that I have crossed swords with one of the authors, Professor Geraint F Lewis on another forum. He certainly in my view, is no slouch and knows what he is talking about.

 

Wait, this bubble's potential from properties of exotic matter would generate a gravity equivalent to Jupiter, but would comfortably accommodate human pilots?
How would that be accomplished? This gets curioser and curioser.
Has the theory accounted for human participation in this scheme?

 

From your post 26.

 

Ahh yes thanks...the WIKI article. Must admit I did not read all of it. Certainly plenty of food for thought, both ways.