nothing can go faster than light

[qqwertz 781]

4 hours ago, charliearon said:

"I need warp speed, now, Mr. Scott!" 🚀

https://www.msn.com/en-us/news/technology/researchers-accidentally-create-a-warp-bubble-the-first-step-in-faster-than-light-travel/vi-AARyXYg

I just had a look at the publication in the European Physical Journal (https://epjc.epj.org/articles/epjc/abs/2021/07/10052_2021_Article_9484/10052_2021_Article_9484.html ). This is a typical case of media blowing things out of proportion. They didn't perform an experiment, just numerical simulations of a different system, and those simulations led them to the Alcubierre metric (that's the mathematical model for a warp drive in relativity). I will not hold my breath that they can actually create a warp drive with this, not even a tiny one.

Peter

[birdguy 3,943]

15 minutes ago, qqwertzde said:

Even the entire energy in the universe wouldn't suffice

Couldn't it encroach into the universe next door to our?

Noel

[dmwalker 604]

1 hour ago, qqwertzde said:

I just had a look at the publication in the European Physical Journal (https://epjc.epj.org/articles/epjc/abs/2021/07/10052_2021_Article_9484/10052_2021_Article_9484.html ). This is a typical case of media blowing things out of proportion. They didn't perform an experiment, just numerical simulations of a different system, and those simulations led them to the Alcubierre metric (that's the mathematical model for a warp drive in relativity). I will not hold my breath that they can actually create a warp drive with this, not even a tiny one.

But the article states:

"Subsequently, a toy model consisting of a 1 m diameter sphere centrally located in a 4 m diameter cylinder was analyzed to show a three-dimensional Casimir energy density that correlates well with the Alcubierre warp metric requirements."

This sounds like something real rather than a theoretical simulation, especially since the next step is to create a tiny nano-scale warp drive craft which they will insert into the warp bubble. 

On reflection, does it mean that the sphere inside the cylinder is real but they don't know if it will actually have the desired characteristics of a warp drive, only that, in theory, it should?

Edited December 8, 2021 by dmwalker

[dmwalker 604]

4 hours ago, birdguy said:

Couldn't it encroach into the universe next door to our?

This reminds me of a Simpsons episode where Homer finds an invisible portal to another universe. He casually discards a paper wrapper by throwing it through the portal and, almost immediately, it is thrown back out with a written message something like "stop throwing garbage into our universe".

On second thoughts it might have been "dimension" rather than "universe". It was a long time ago - season 12, I think.

Edited December 8, 2021 by dmwalker

[scotchegg 4,186]

On 12/8/2021 at 6:21 AM, Jazz said:

I believe Douglas Adams was correct.

Still missing him😢

[Jazz 1,046]

13 minutes ago, scotchegg said:

Still missing him😢

Yes, yes, I think many of us do.

[qqwertz 781]

1 hour ago, dmwalker said:

But the article states:

"Subsequently, a toy model consisting of a 1 m diameter sphere centrally located in a 4 m diameter cylinder was analyzed to show a three-dimensional Casimir energy density that correlates well with the Alcubierre warp metric requirements."

This sounds like something real rather than a theoretical simulation, especially since the next step is to create a tiny nano-scale warp drive craft which they will insert into the warp bubble. 

On reflection, does it mean that the sphere inside the cylinder is real but they don't know if it will actually have the desired characteristics of a warp drive, only that, in theory, it should?

Hmm, you're right, there's more to it than just simulations. However, I stand by my assessment that this will not likely result in a warp drive. In my post above, I criticized some journalists for blowing things out of proportion. That's natural, they sell stories. To some extent, that is also true for scientists. It happens very often that the potential applications of a new idea are described in the most optimistic way possible. What scientists are selling is, more or less, future technology, so you have to make sure that everyone understands just how incredible the potential of your work is. 

But back to the paper. I read "correlates well" as "is not in conflict with". The Casimir effect is a really neat effect, but I daresay that it won't help to create a warp drive. Let me explain what the Casimir effect is.

Consider the string of a guitar, which is clamped at the bridge and the nut of the instrument. Some of you may know that it has harmonics, natural frequencies that are excited when you pluck it. Those harmonics are a direct consequence of the clamping: every note corresponds to a wave that looks like a cosine, and nut and bridge make sure that the wave must have zero amplitude right where nut and bridge are (see https://www.guitarlessonworld.com/lessons/harmonics/ ). What this means is that you can only have waves of a specific wavelength between nut and bridge. On the other hand, an unconfined guitar string could wiggle with any wavelength. 

The same happens with electromagnetic waves: if you set up two metal plates next to each other, they form something like a nut and bridge for those waves: only light (and other forms of electromagnetic waves) with specific wavelengths can fit between the two plates. On the other hand, outside of the two metal plates, light can have any wavelength. What you have accomplished then is that you removed a lot of possible waves between the two plates. That means you have lowered the possible energy in this space, and that creates something that physicists call vacuum energy (since it is an empty space between the plates). Vacuum energy is exactly what you need to create a warp drive.

However, think a bit more about the argument above: I assumed that bridge and nut fix the string exactly at one location in space. In reality, the string will probably move a little across the bridge, and the bridge has a finite width as well. These effects severely limit just how much vacuum energy you can have. 

And that's how I read "correlates well": yes, they get a tiny bit of vacuum energy. However, I would be extremely pessimistic that they will ever get enough energy out of that to create superluminal speed.

 

 

 

[dmwalker 604]

28 minutes ago, qqwertzde said:

However, I would be extremely pessimistic that they will ever get enough energy out of that to create superluminal speed.

So, tiny nano-scale astronauts shouldn't get their hopes up.

[sightseer 895]

@qqwertzde  I don't want to distract you too much from the warp bubble conversation but it occurred to me a bit ago that if the scientists in my original post were able to actually stop light for a period of time and as you say the atoms absorbed the energy then it strikes me as odd that the light would continue on its original trajectory.  Why would it?

[qqwertz 781]

21 minutes ago, sightseer said:

@qqwertzde  I don't want to distract you too much from the warp bubble conversation but it occurred to me a bit ago that if the scientists in my original post were able to actually stop light for a period of time and as you say the atoms absorbed the energy then it strikes me as odd that the light would continue on its original trajectory.  Why would it?

I have to say, you are a very good observer. That is a really good question, and the answer is the reason why I was so impressed by Lene Hau's and other experiments back then. You are right, under normal circumstances light wouldn't keep its original trajectory. Instead, it would be scattered in all directions, like when you shine light on a milky piece of class.

The trick with these really cold atomic gases is that the atoms are moving very slowly, you can think of them as being fixed to their position. The information about the light pulse is imprinted on all the atoms, similarly to a holograph. If you shine another light beam on that holograph, the information can be retrieved and the original light pulse leaves the atomic cloud again. The details are a tiny bit more involved ( https://en.wikipedia.org/wiki/Electromagnetically_induced_transparency ), but that is the main principle. In a normal gas, the atoms quickly move out of place, so that the holograph gets distorted and eventually destroyed.

[martin-w 3,235]

12 hours ago, dmwalker said:

So, tiny nano-scale astronauts shouldn't get their hopes up.

 

I'm just impressed that they think its a genuine warp bubble. 

I will give then only one cat point though, as I don't think it's likely to move us any closer to Captain Archer's fathers warp engine. Which means my love affair with T'pol isn't on the cards any time soon.

 

😺

 

[Ray Proudfoot 8,955]

On 12/8/2021 at 5:53 PM, Rob_Ainscough said:

as you can see the Daleks have access to exotic matter and so does the Doctor. 

Unless it’s at the top of a flight of stairs in which case they’re buggered! 🤣

[martin-w 3,235]

22 minutes ago, Ray Proudfoot said:

Unless it’s at the top of a flight of stairs in which case they’re buggered! 🤣

 

Yes but they got around that ray. They can now hover.

It still freaks me out that Dalek voice even after all these years. 😟

 

 

 

[Ray Proudfoot 8,955]

9 minutes ago, martin-w said:

Yes but they got around that ray. They can now hover.

It still freaks me out that Dalek voice even after all these years. 😟

 

Good old BBC Radiophonic Workshop. That must be the Mk2 version. The one I grew up with definitely couldn’t climb steps.

Very clever person whoever came up with that voice. 👍

[sightseer 895]

I found this.   still thinking about it...quantum computing finally makes more sense but overall its way over my head.

why can't we build quantum batteries that store energy in the same way they can trap light?

Edited December 10, 2021 by sightseer