Jump to content

"Magic technology"


Lo.M
 Share

Recommended Posts

How do we define What Is "Magic Technology"?

What is "magic technology"?

What should be classified as "magic technology"?

Examples of "magic technology":

  • Tachyon Drives

texto alternativo

  • Alcubierre Drives

Ver a imagem de origem

  • Em drive 

imagens? q = tbn: ANd9GcTdhwJILAnCrss0_xqRyxr

 

Edited by Lo.M
Link to comment
Share on other sites

08f11f094bd6aec4b77f0d670eb471bb.jpg

I recall a story from somewhere that involves someone going back in time with an early electronic calculator, the kind with the red LED display. While demonstrating it to the locals, he entered an equation that resulted in the answer "666" being displayed in glowing red numerals and was promptly accused (apprehended? chased? I don't quite recall)) of being a witch.

E: I'd consider a tachyon drive to be imaginary, based on the math....

Edited by StrandedonEarth
Link to comment
Share on other sites

Even if a thing is considered mysterious, the ability to reproduce the effect through an understood mechanism or method makes it, by definition, scientific. 

Which is one of the weirder realizations about Hogwarts School of Witchcraft and Wizardry; in a school all about magic, there area few classes which aren't science. 

The same is conceivably true of almost anything imagined in fiction. Engineering and methodological naturalism mean that all sorts of wonderful ideas will be realized, sooner or later. 

Link to comment
Share on other sites

21 minutes ago, starcaptain said:

Even if a thing is considered mysterious, the ability to reproduce the effect through an understood mechanism or method makes it, by definition, scientific. 

Which is one of the weirder realizations about Hogwarts School of Witchcraft and Wizardry; in a school all about magic, there area few classes which aren't science. 

The same is conceivably true of almost anything imagined in fiction. Engineering and methodological naturalism mean that all sorts of wonderful ideas will be realized, sooner or later. 

I have the same opinion

Link to comment
Share on other sites

43 minutes ago, starcaptain said:

Even if a thing is considered mysterious, the ability to reproduce the effect through an understood mechanism or method makes it, by definition, scientific.

...

Engineering and methodological naturalism mean that all sorts of wonderful ideas will be realized, sooner or later.

And making it "magic" only requires people to not understand it, much like in Dying Earth...

 

Although I'll say that a few things would most likely remain outside the realm of reality, like traveling faster than the speed of light wrt local spacetime, or bending them to our will, or seeing broken glass debris assemble itself back into a glass. Unless if we can prove that many-worlds theory is completely true AND we can actually manipulate them... then get your dices ready folks, we have a lot of probability to go through.

Edited by YNM
Link to comment
Share on other sites

2 hours ago, starcaptain said:

Even if a thing is considered mysterious, the ability to reproduce the effect through an understood mechanism or method makes it, by definition, scientific. 

Which is one of the weirder realizations about Hogwarts School of Witchcraft and Wizardry; in a school all about magic, there area few classes which aren't science. 

The same is conceivably true of almost anything imagined in fiction. Engineering and methodological naturalism mean that all sorts of wonderful ideas will be realized, sooner or later. 

A valid point, now magic is not really magic if you understand how it works and you can modify spells predictable who tend to be true for magic in an video game but not for historical magic. 

For technology its works a lot the same way, I think its plenty of inventions people kind of found by accident and used without knowing how it worked, gunpowder is an obvious one here. 
Yes then it become common the magic went away even if you did not really know why it worked. 

Now say we fond an alien probe with an FTL engine and managed to reproduce the engine but the physic behind it made no sense it would be magic technology. 

Link to comment
Share on other sites

I have an invocation I use every morning to bring forth light:

"Ok Google, set office to 30%"

And one to banish the light at the end of the day:

"Ok Google, turn off bedroom"

If you were not familiar with this technology, you would not have any idea that the small, unobtrusive cylinder hidden on a shelf was in any way related(especially if responses were muted), or that it was dependent on distant computing devices connected via a world wide information network.

 

"magic" technology is all a matter of familiarity.

Link to comment
Share on other sites

1 hour ago, kerbiloid said:

If I hadn't know the Ancient Greek/Roman mythology before, I would never know about a half of planets

Or you wouldn't know them in that name but you'd still know them.

Link to comment
Share on other sites

Alcubierre Drive is a good example to illustrate why all of these "magical" drives really are a bit too magical. Standard way of deriving the warp metric is to say that space-time is flat inside and outside the bubble, with all curvature contained in bubble walls. Problem is, the moment you place something inside the bubble, the space-time is no longer flat due to gravity of that object. This doesn't really cause any problems inside the bubble, but outside, it results in gravitational waves produced whenever the bubble accelerates. Emitted gravitational waves actually compensate for the momentum of the ship, and in effect, you have a graviton drive, which is positively not what you want for warp. Graviton drive is subject to the same efficiency limits as photon drive in linearized case and gets worse at higher energies due to self-interaction. What does it mean for the warp drive? It means that you might as well have a photon drive rocket, and you'll need infinite energy to reach light speed. So forget about FTL.

How do you fix this problem? Well, you need to flatten exterior space-time. That's easy. Well, easy if you have negative energy you need to make a warp bubble in the first place. You just uniformly increase negative energy contribution throughout the bubble, meaning you now have more negative energy than positive energy. In fact, the total mass of ship and the bubble combined needs to be exactly zero to keep exterior space-time flat. A ship in that configuration requires no energy to accelerate, and if you were to match the masses perfectly, would be capable of going superluminal. Of course, there is no known way to match these perfectly, so you'll still be traveling at the light speed at the most, but given that interior time can run arbitrarily slowly, this is still great for interstellar travel. Despite all the problems, warp might still be the answer to how we go to the stars even if we can't beat the light barrier.

That said, lets look at this situation from an alternative perspective. Solving all of the above is a lot of math. Original Alcubierre paper did not include any of these nuances, because this is computationally heavy, and yet, these limitations could have been called out immediately with a bit of thought. Here's why.

You can look at movement of anything through space - flat or warped - as flow of energy. This way, we don't have to distinguish between light, gravity waves, energies in the warp bubble, or the ship itself. If we are talking about general relativity, we do have to consider the entire stress energy tensor, of which energy is just a projection, but the advantage it gives us is that it contains information about momentum as well. More crucially, it's not just a conserved quantity but a conserved current due to symmetries of Minkowski metric.

νTμν = 0

That equation is just a very fancy way of saying that energy and momentum are neither created nor destroyed, and can only flow from one location to another. Moreover, momentum is the flow of energy. Without getting into mathy details, we can apply a generalized version of Divergence Theorem to this.

S nνTμν dS = ⨌VνTμνdV = 0

That's a lot to unpack, but vaguely speaking, if you imagine a boundary around a region of space-time, same amount of stress energy flows into it as out of it in total. So now, let us construct a specific case for a ship preparing to depart.

image.png

So time flows upwards, and one of the spatial directions is across. Picture a hypercylinder in space-time region surrounding the departure event. We can consider ship prior to the departure sitting still in space. As it does so, it moves forward in time, so it "flows" into the cylinder of interest through the bottom face. At this point, the only energy the ship has is its mass energy, so that's the exact amount of stress-energy that enters the cylinder through the bottom face as indicated by the bottom arrow. The exact same ammount must now flow out of the cylinder. If the ship was to remain at rest, all that mass energy would flow out of the top face and the net change would be zero, which is exactly what we expect. However, we are picturing a ship that by some means of propulsion departs this area of space. So the top arrow indicates the flow of stress-energy out through a side wall.

This is where things get exciting. We must still have the total mass-energy of the ship depart, so there is energy flow. But the side-walls of this cylinder are purely spatial boundaries. Flow of energy through a spatial boundary is momentum. So the stress-energy that leaves this cylinder is mass-energy plus some quantity of momentum. But no momentum entered the cylinder. The only way to rectify that and have the total be zero is for something else to depart this cylinder with opposite amount of momentum.

This is why you cannot have propulsion without exhaust. That exhaust can be matter, light, or even gravity waves. But there has to be something emitted that carries away momentum.

The warp drive gets around this by having on board the ship a source of negative energy enough to create the bubble. Because the total energy cannot change, the total mass of a warp-capable ship is precisely zero even before it goes into warp. Because of that, the mass-energy of the bottom arrow is zero, and so the energy and momentum of the top arrow can be zero as well, allowing a warp ship to depart with no exhaust. That, however, leads to other problems. If the net mass of warp-capable ship is zero before the jump, what if something applies a force to it? A slightly more realistic version is a ship whose total mass is just a few grams, allowing it to reach ludicrous speeds on a graviton emission alone once it forms a warp bubble, but such a ship will be strictly sub-light capable.

As for FTL or exhaust-free ships, this principle, unfortunately, puts an very heavy damper on the very idea.

There are other means of going from point A to point B faster than light, like wormholes, but that comes with its own set of caveats and is another long story. I hope that the above is at least somewhat helpful in filtering out impossible magic ideas in propulsion from ones that are simply incredible. Like antimatter beamed core rocket or a wormhole drive. Both of which are still total science fiction for now, but with at least the physics of how it would work being completely clear.

Link to comment
Share on other sites

19 minutes ago, K^2 said:

Without getting into mathy details...

So what do you call this? :lol:

19 minutes ago, K^2 said:

S nνTμν dS = ⨌VνTμνdV = 0

Anyways, supercool, and great explanation! I enjoyed the hypercylinder description; it feels exactly like proving things in geometry. (Hey, I guess it is.) Is there a paper on these issues with the concept? I'd read it.

Link to comment
Share on other sites

19 minutes ago, SOXBLOX said:

So what do you call this?

I call it insignificant amount of math by GR standards. :sticktongue:

19 minutes ago, SOXBLOX said:

Is there a paper on these issues with the concept? I'd read it.

You know? I've never found one that was concise. I'm doing a lot of hand-waving above which just wouldn't do for a proper paper. The original Alcubierre paper is pretty good, because if you understand GR at all, you can follow along. But everything that followed, less so. Most of the work in the field is, "We loaded these parameters into simulation, and this is what we got," and it's just not particularly readable. Part of it is that GR wasn't my primary field, so even my eyes glaze over some of the math. The computational part actually makes more sense to me, but that always goes after very specific cases. Like, how do you reduce total energy needed to create a bubble, etc.

And even with the background, the lightbulb moment for me was when I was trying to work out if a linear gyro was possible. There are a lot of ways to create apparently motionless objects with momentum, like if you have mutually perpendicular electric and magnetic fields, even if they aren't moving, there is net momentum. So it feels like you ought to be able to make an electromagnetic "jar" to hold momentum. But then you keep running into complication after complication that all seem solvable... It reminds me a lot of how if you don't apply conservation principles, it just feels like you ought to be able to build a perpetual motion device with magnets. But just like with magnets, if you actually step back, consider conserved quantities and how they apply to the problem, it's possible to show the fundamental incompatibility between what you are trying to achieve and these conservation principles.

It's not all a total dead end, however. Some interesting questions remain. Like, can you create an empty warp bubble with exactly zero mass? Because even if you can't transport matter inside it, if you can just make a stable warp bubble that travels at FTL speeds, you can use it to send information. Nothing in classical GR or mean field quantum mechanics suggests it to be strictly impossible, but then if it is possible, then so is time travel, technically, which would make things... interesting.

The other avenue is wormholes. There are a lot of new unknowns there, like whether necessary topology can even be found naturally or be created, but also some very familiar restrictions. For example, the only known traversable geometries require negative energy. In general, if you see FTL in GR, expect negative energy somewhere in the mix. But unlike warp, there is no known lower bound on negative energy required. Can we use Casimir Effect to stabilize a wormhole? Maybe! I wouldn't be t any money on it, but nobody found a reason why it would be fundamentally impossible yet.

One thing is for sure. Whatever we come up with will seem like magic, just like Clarke said, but it's not the same thing as saying that anything that looks like magic will be achievable with sufficient technology. Some things really can exist only in realms of imagination.

Link to comment
Share on other sites

2 hours ago, K^2 said:

I call it insignificant amount of math by GR standards. 

*Runs away in panic*

2 hours ago, K^2 said:

Because even if you can't transport matter inside it, if you can just make a stable warp bubble that travels at FTL speeds, you can use it to send information.

That...sounds really cool! Out of curiosity, how would you, assuming this were possible, detect the bubble at the destination? Could it carry a flash of light within it? Or would you have to use something like LIGO, to pick up the distortions?

Edited by SOXBLOX
Link to comment
Share on other sites

12 minutes ago, SOXBLOX said:

Out of curiosity, how would you, assuming this were possible, detect the bubble at the destination? Could it carry a flash of light within it? Or would you have to use something like LIGO, to pick up the distortions?

My guess is that if we have any chance of something like this being stable w.r.t. vacuum, let alone gravitationally, it would have to be tiny enough to benefit from some sort of quantum weirdness. Since it'd have zero net energy and not enough gravitational distortion to detect indirectly, I have no idea how we'd go about detecting it. Otherwise, I'd probably we recommend looking for these on the off chance someone is already using them for long range communication.

Link to comment
Share on other sites

I was under the impression that the objective of the Alcubierre drive was to shrink space in front of the vessel and expand space behind it, so that you are not 'moving' the vessel at all, except perhaps using some chemical thrusters to cross the much shortened distance, or am I thinking of the wrong drive tech?

Link to comment
Share on other sites

12 hours ago, Terwin said:

I was under the impression that the objective of the Alcubierre drive was to shrink space in front of the vessel and expand space behind it, so that you are not 'moving' the vessel at all, except perhaps using some chemical thrusters to cross the much shortened distance, or am I thinking of the wrong drive tech?

I think (under my terrible understanding of GR via friedmann equation) the point @K^2 was making is that if you insert energy somewhere without much energy then you should bring the same energy out of it. This is even true for cosmological purposes I suppose, ie. dark energy to "explain" why the universe is expanding at an accelerated rate...

Link to comment
Share on other sites

This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...