Starting to take Warp Drive Seriously:

https://www.sciencealert.com/scient...-drives-seriously-especially-this-one-concept

Scientists Are Starting to Take Warp Drives Seriously, Especially This One Concept:

MATT WILLIAMS, UNIVERSE TODAY
1 MAR 2020
It's hard living in a relativistic Universe, where even the nearest stars are so far away and the speed of light is absolute. It is little wonder then why science fiction franchises routinely employ FTL (Faster-than-Light) as a plot device.

However, in recent years, the scientific community has become understandably excited and skeptical about claims that a particular concept – the Alcubierre Warp Drive – might actually be feasible.

This was the subject of a presentation made at this year's American Institute of Aeronautics and Astronautics Propulsion and Energy Forum, which took place from August 19th to 22nd in Indianapolis.

This presentation was conducted by Joseph Agnew – an undergraduate engineer and research assistant from the University of Alabama in Huntsville's Propulsion Research Center (PRC).

As part of a session titled "The Future of Nuclear and Breakthrough Propulsion", Agnew shared the results of a study he conducted titled "An Examination of Warp Theory and Technology to Determine the State of the Art and Feasibility".

As Agnew explained to a packed house, the theory behind a warp propulsion system is relatively simple.

more at link......
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https://arc.aiaa.org/doi/10.2514/6.2019-4288

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extract:
"In layman's terms, the Alcubierre Drive achieves FTL travel by stretching the fabric of space-time in a wave, causing the space ahead of it to contract while the space behind it expands.

In theory, a spacecraft inside this wave would be able to ride this "warp bubble" and achieve velocities beyond the speed of light. This is what is known as the "Alcubierre Metric".

Interpreted in the context of General Relativity, the interior of this warp bubble would constitute the inertial reference frame for anything inside it. By the same token, such bubbles can appear in a previously flat region of spacetime and exceed the speed of light.

Since the ship is not moving through space-time (but moving space-time itself), conventional relativistic effects (like time dilation) would not apply.

In short, the Alcubierre Metric allows for FTL travel without violating the laws of relativity in the conventional sense."
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Contemplating: [and living in hope!]
If the Alcubierre Drive is at all possible to achieve, one could contemplate a scenario as follows......
In a 100 years or so, we build a large generation type space faring ship, and send it on its way to the Alpha Centauri system.....A trip that would be destined to take a few 10's of thousands of years to achieve. In the meantime, say 500 years hence, we unearth a "Zefram Chocrane" and achieve an "Alcubierre Drive" or similar and take off also heading to the Centauri system....We would in quick time overtake the previously launched generation ship. Interesting to say the least.

 

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Thanks for that and all the material you bring here for us to enjoy.

You say in theory, they say?...we need to say something like "we speculate or it is reasonable to expect." ..we can't hold up theory to the world as a speculation as is done outside science and then say to those who are casual in their use of the word ..you don't know what theory means when we are just as casual and do the very same thing...they don't have a theory but an idea...if you see my point on this.
Alex

 

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Science, or at least science journalists, can be lazy sometimes...but correct, still highly hypothetical. Still, as I said, living in hope!

 

If we could travel at 1000 times the speed of light how long would it take to get to our neighbour M31. ....mmmm 2000 years
Reaching our closest star is probably more than we can hope for actually.
Current speeds give us between 20000 and 50000 years approx... I would love to know if in the future we pull off travel to the next star. But it's great to see folk don't let the proposition deter their efforts.
Alex

 

FTL is equivalent to negative time travel. If this drive existed, then information can be sent to the past. Until they demonstrate something simple like that, it hardly seems plausible to posit a ship propelling itself to the past.

 

Good point, but I'm not real sure if it applies with the spacetime bubble scenario
"Interpreted in the context of General Relativity, the interior of this warp bubble would constitute the inertial reference frame for anything inside it."
and
"Since the ship is not moving through space-time (but moving space-time itself), conventional relativistic effects (like time dilation) would not apply."

 

I keep hearing that when traveling @ "c", time stands still, but why is that?
Can somebody tell me what speed has to do with the measurement of duration of emergent time? You just get there faster, that's all.

i.e. If it takes light from a distant star a million "light years" to reach us @"c", then at 2 x c the light should get there in 1/2 the time, no? Where does time reverse in this equation?

Then, even stranger; @FTL, time reverses, why ?
Is it something like; "the faster I grow, the shorter I get?"

Seem to me that only at infinite speed time would stand still, due to the fact you get there instantaneously and it is impossible to go faster than infinite speed.

Something like "entanglement". But if entanglement is communication @ FTL, does that mean entanglement involves a reversal of time? The entangled sister particle reverses spin before the other actually has reversed it's spin?
This is very confusing.....

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With the Alcubierre drive, it is spacetime that is moving, with the ship inside a bubble so to speak, so the ship as mentioned, is not moving through spacetime but it is spacetime doing the moving.

With the normal garden variety scenario of speed up to "c", it would take an inifinite amount of energy to get it to that point, hence impossible.
Other better descriptions and answers maybe offered.

 

Well, it seems to me that it would likewise take an infinite amount of energy to move all of spacetime, hence, impossible. Can we just ignore all Laws of Inertia?

Can we not accept the fact that due to the composition and structure of spacetime it is impossible to physically exceed "c"?

You can go back in space, but never in time. Time always emerges as a product of duration, however short, regardless of speed. You cannot have a negative duration of change.

Going back in time seems the most improbable of all other scenarios.

Apparently "c" is the absolute limit of physical change in this universe. Period! Is that illogical in some way?

 

I haven't addressed travelling at high speed in space until a few minutes ago but I have worked most of it out just now
Even though I don't understand GR that well I think it's obvious that at high speed you would run into radiation and nutrinos and lots of stuff really. I think it would become akin to running into a sand Storm so fast it would present as a rock..so my idea is you blast a hole in front of you that slaps back to assist your forward process thereby minimising energy requirements..what ever GR tells us it's gotta work something like that you could think...but the energy required to travel thru rock at near C,that blast is going to eat energy. Maybe a huge pole out front charged up...mmm..still need more energy than you can imagine.
I bet the sums say that.
Damn you Paddoboy I can't stop thinking about the distances...I wonder if places exist where the life interacts with neighbouring planets...in another system..I don't think the Sun's we need could be closer that 2 light years so even there you travelling for a while.
How would you work out how many neutrinos you would run into pet square foot at say 80% C?..is there a way to calculate the stuff you would interact with..would the star light and all that is found in star light present a barrier...
Alex

 

If breaking the sound barrier already creates a sonic boom, what would it take to break a space barrier?

Compressing space in front in order to stretch space behind, you need to be able break the barrier between these two space configurations, no? Can such a equation be reached gradually? Would that involve a kind of "tunneling"?

 

It sounds simplistic but I find the drilling through rock is a good way to imagine what appears empty to at high speed would probably present as rock.
You are a maths guy how much stuff per square foot..how many neutrinos would you hit?
Maybe a vehicle long thin and with a very pointy nose...some sort of charge to help part the way...maybe run electric pulses along to part the way and provide forward motion...you just need a total vacuum in front of you a d I bet that does not exist even in space .at some level...
Alex

 

I have been thinking...we think light is a pretty fast speed...now try this..imagine you can follow a ball falling from the Earth to the Sun and it takes eight minutes.. image you are watching that ball you are going think light speed is very slow.
Alex

 

Here is a movie of a photon @ "c" filmed at 10 trillion FPS (frames per second)

How do you film the Speed of Light?



this may be more illustrative.

 

Yeah so all we have to do is this one thing, namely stretching spacetime out in front and collapsing it behind (er, how, precisely?).....and then the rest is plain sailing.

Brilliant!

 

I would love to study the lightning say over an hour or to and see what Patten may be present..plus sprites.
Blows my mind.
Alex

 

Watch the spontaneous unfolding of the fractal pattern. The fundamental pattern which growing objects follow.

 

Looked on YouTube neat
Alex

 

I'm ignoring what's inside the bubble. I'm looking at the bubble from the outside, treating it as a black box.

Relativity doesn't shut off at a push of a button.

I decide to travel to planet X to mine precious mineral Xanium from it. X is currently 22.4 light years away and moving away from us at half light speed.

I have a conventional ship that goes 0.999c and get there in 2 years, my time. I spend 2 weeks filling my ship, and then take 2 more years getting back.
During that time I age a bit over 4 years.
From Earth, the trip seems to take 45.2 years each way, plus about 16 days while I do the mining, so people back home have aged around 90.5 years while I'm gone.

Now let's do it with the proposed starship EnterTardis that moves at 1000x light speed.
In Earth's frame: When I depart, it is June 1, 2020 on Earth. I arrive on X at a time that is simultaneous with June 9, 2020, and spend 14 days mining the stuff, so from Earth perspective, my departure takes place on June 25, 2020.
In X's frame: The event Earth, May 21, 2009 is simultaneous with my departure event. Earth is about 19.5 light years away, so it takes 7 days to get there. I arrive on May 28, 2009. I have time traveled to the past.
Such is the nature of FTL travel.

I have no idea what my age would be in arrival since their comment above seems to have forbidden me from considering dilation effects of anything inside the bubble. Doesn't matter if I'm old or young when I get back. Point is, I'm rich and I've arrived in 2009.

The problem is, these articles/press conferences assume their audience is dumber than a bag of hammers.

Entanglement is not communication. I found this interesting article that similarly makes all the same errors:
https://www.itwire.com/science-news/energy/59006-quantum-entanglement-sets-a-new-speed-record
There is so very much wrong with that article. You cannot set a speed record with entanglement. If they've done it once at FTL, then they've demonstrated infinite speed in some frame. The fact that they don't say this is probably because they want to sensationalize a trivial accomplishment.
Also, I loved the line that says: "One half of the pair was then observed, and the time for the other half to translate to the same state was measured" which makes it sound like they continuously monitored a photon, waiting for it to change state due to the other measurement. If that could be done, they'd have their FTL communication, which the article admits has not been done.