263 réponses à ce sujet

[CroGamer002]

In that case, most SF's suck.

[Raith Mano]

FTL Travel eh? Well here goes:

FTL Travel can be tackled in a number of ways. To start there are a few of the most easily conceivable types:

Wormhole: A rip through space-time which would allow one to travel outside of the normal range of physics therefore allowing one to move faster than the speed of light, allowing the mass of the object to remain the same while time passes at the same rate at all points throughout the universe. Therefore we do not violate Einsteins theory of special relativity because time will still be a constant for the moving party and for those stationary.

This is all possible because a wormhole violates the physics of relativity and therefore relativity has no effect on what occurs inside of said wormhole.

However, due to a lack of understanding or even the knowledge of a true existence of a wormhole we can only hypothesize on how to create one. We can however assume, with relative safety, that any object the shreds through the standard space-time of the universe and opens in another place violates relative physics due to its inherent nature.

The second, and more probable of the two in my personal opinion, is a true FTL engine that warps the fabric of space-time as you move. Miguel Alcubierre outlined a theory of an engine in 1994 that could propel a ship at FTL speeds, effectively warping the space around the ship where, much like the wormhole, physics is no longer an issue as space-time is being distorted. With the Alcubierre drive a bubble is created around the ship. The ship itself does not move but remains still inside this bubble, while the distortion of space behind and in front of the ship propels the ship itself. The bubble further allows those within it to never feel any inertial effects because within the bubble relativity is still applied and the ship would not appear to be moving at FTL speeds to the occupants. (Outlined in Wikipedia article: http://en.wikipedia....lcubierre_drive).

However, due to our lack of understanding of how to manipulate space-time this is currently only in theory. However there has been speculation that the manipulation of gravity would allow us to bend (not break- breaking is much harder) space-time to our will, therefore allowing the creation of a warp bubble around a ship, allowing this engine to be put into practice.

Issues have been posed to this form of FTL travel though, as many speculate that the ship in the warp bubble, moving at FTL speeds would slammed with high temperatures and Hawking radiation (which is also only theoretical as it is considered the evaporation of a black holes energy and mass. If the black hole can not consume more then it gives off then the hole will eventually dissipate. How you can fight a theoretical FTL drive with a theory that cannot be proven as no ship could ever get close enough to test it is beyond my comprehension, however it is conceivable that thermal radiation [not particularly Hawking radiation] could cause further complications to this theory).

Lastly, a more current investigation into quantum physics is the Higgs boson. The Higgs boson is a particle that, in theory, gives mass its mass. Currently the Large Hadron Collider at CREN is being used to find this particle. In theory, a deeper understanding of this particle, may one day give man the ability to manipulate it through one means or another, much like a mass effect drive in the Mass Effect universe.

Many theories already exist that claim the Higgs boson does not exist which have created many Higgsless models, but still lack the ability to explain mass on the quantum scale.


My apologies if this has already been posted/discussed. These are all only theories and therefore are open to discussion and interpretation. Its been a bit since I've studied physics and quantum physics. No flamings please.

My head hurts now as its been a while since I've studied this. Any questions will be answered shortly.

[jamesp81]

Whatever666343431431654324 wrote...

I *think* that changing one particle does affect the other particle. However, that effect would seem random to the other particle. You wouldn't know that the change is because of the change to the first particle. So they would have to communicate to you that they changed the particle for you to know that the particle was changed.

If you have a collection of particles on either end of the your communications device that you know are entangled to each other, you can just say Up is 1 and Down is 0, thus letting you operate on a binary code system.

[SomeKindaEnigma]

 ^^I think everything you mentioned has pretty much been discussed, but it's a good summary.  I'm especially excited to find out if the Higgs Field/Higgs Boson do exist in the coming experiments of the Large Hadron Collider 

[jamesp81]

KenKenpachi wrote...

King Lenward wrote...

I have not read any of the comment, but simply put....

100 years ago cell phones were scientifically impossible
120 years ago human flight was scientifically impossible
100 years ago space travel was scientifically impossible
ect...

Just sayin....

If I were to go back just 40 years ago and say I could talk to a person in Japan as if they were in the same room they would look me up for public safety.

The only thing thats for sure, is provided we all arn't dead or living like this is mad max, then I'm sure 200 years from now someone with a love of history will pick up a book or what passes for books at that time and remark at how stupid we were. Science has became too...lazy and about being a bigger Thomas Edison than the next guy (IE $$$). No one does any real research into FTL as that would cost money and is beyond out technological capability. Plus its eaiser to say what can't be done than to actully try it.

The reason space exploration has been shelved is because of lack of vision.

The modern scientific establishment guys will stand on a podium and preach a sermon to you about what you can't do and what is impossible.

It will require a visionary to discover what IS possible.  Someone with scientific training but without the establishment mindset.  Visionaries are derided and scorned as fools, so you don't see many of them.

[SomeKindaEnigma]

Again, the problem with quantum entanglement as possibly being used as communication devices is that no information can travel faster than the speed of light. Relatively speaking, it would actually be useful on Earth considering the diameter of the Earth < distance traveled by light in one second, so communications that way can be done in less than a second. If you try to set up communications through entanglement between, for example, the earth and a spacecraft a considerable distance away, obviously you still have to account for a time delay to receive the information from the partner particle.

Modifié par SomeKindaEnigma, 01 avril 2011 - 05:46 .

[jamesp81]

Whatever666343431431654324 wrote...

Mynoot wrote...

armass wrote...

Mynoot wrote...

armass wrote...

Maybe now it's kinda impossible, but who knows if it is still in couple of thousand years

In a couple thousand years, the human race is likely to be extinct.  Hopefully, they can come up with something long before that.

Don't be such a pessimist...

It doesn't take much, given the rate of population growth and the competition for earth's dwindling resources, the poisoning of our habitat in a closed system, I don't think we'll survive a thousand years.  

Actually, the growth of our population is slowing down. They think by the middle of this century that our population may actually start to decline. With a smaller population, we will have fewer resource and pollution problems. If we can ever make solar and biofuel technology economically feasible then suddenly we have infinite energy.

No reason to be pessimistic.

Biofuel technology is a pipe dream.  Believe me on that.  Row crops as a system of energy doesn't supply enough to meet our needs.  Other methods will be required.

[Raith Mano]

SomeKindaEnigma wrote...

Again, the problem with quantum entanglement as possibly being used as communication devices is that no information can travel faster than the speed of light. Relatively speaking, it would actually be useful on Earth considering the diameter of the Earth < distance traveled by light in one second, so communications that way can be done in less than a second. If you try to set up communications through entanglement between, for example, the earth and a spacecraft a considerable distance away, obviously you still have to account for a time delay for the partner particle to actually receive the information.

Well the problem with quantum entanglement is that is has never been tested over vast distances where a delay could be possible, but as far as we currently know what happens to one instantly happens to the other.  It is able to be theorized though that since the particles are linked on a quantum level that said information can be transmitted at FTL speeds.  

Theres just too much we don't have specifics on for it.  However, if it is true, one day teleportations between distance worlds may one day become completely possible and possibly the safest way to travel.

[jamesp81]

SomeKindaEnigma wrote...

 ^^I think everything you mentioned has pretty much been discussed, but it's a good summary.  I'm especially excited to find out if the Higgs Field/Higgs Boson do exist in the coming experiments of the Large Hadron Collider 

Higgs-Boson particles.  Playing with them is all fun and games until you open a portal and an army of Dreen come pouring out......

[Whatever42]

jamesp81 wrote...

Biofuel technology is a pipe dream.  Believe me on that.  Row crops as a system of energy doesn't supply enough to meet our needs.  Other methods will be required.

I was hoping someone would take that bait!

I'm not talking about corn ethenaol. Or even algae. There is simply not enough energy efficiency there (unless we let the algaue fossilize over millions of years and then dig it up, which is what we do!).  The problem is that plants absorb only a small faction of the solar energy that hits it.

However, solar energy is hugely abundent and could solve all our problems. However, current solar technology is also hugely expensive and then we have energy storage problems.

Intead of solving the problem mechanically, what if we could do so biologoically? Bioengineer a plant that absorbed more than 5% of the light that hit it but 25% or 50%? Suddenly we would have near limitless energy and storage would be easy.

Yeah, its fantastical but we'll be working on this problem for decades.

[AlanC9]

jamesp81 wrote...
The reason space exploration has been shelved is because of lack of vision.

The modern scientific establishment guys will stand on a podium and preach a sermon to you about what you can't do and what is impossible.

It will require a visionary to discover what IS possible.  Someone with scientific training but without the establishment mindset.  Visionaries are derided and scorned as fools, so you don't see many of them.

The problem with this logic is that a lot of visionaries are fools.

[jamesp81]

Whatever666343431431654324 wrote...

jamesp81 wrote...

Biofuel technology is a pipe dream.  Believe me on that.  Row crops as a system of energy doesn't supply enough to meet our needs.  Other methods will be required.

I was hoping someone would take that bait!

I'm not talking about corn ethenaol. Or even algae. There is simply not enough energy efficiency there (unless we let the algaue fossilize over millions of years and then dig it up, which is what we do!).  The problem is that plants absorb only a small faction of the solar energy that hits it.

However, solar energy is hugely abundent and could solve all our problems. However, current solar technology is also hugely expensive and then we have energy storage problems.

Intead of solving the problem mechanically, what if we could do so biologoically? Bioengineer a plant that absorbed more than 5% of the light that hit it but 25% or 50%? Suddenly we would have near limitless energy and storage would be easy.

Yeah, its fantastical but we'll be working on this problem for decades.

The problem with that is plants gain most of their actual energy from nutrients in the soil.  The soil itself is insufficient as an energy source.


Solar won't work well for the obvious reasons unless you put the solar collectors in a high polar orbit where they always face the sun, and send the collected energy down to receiving station.

Right now, the only practical solution is nuclear power for large scale, base-load generation (with better flood walls).  For vehicle fuels, some kind of just-in-time on the spot hydrogen production is probably the most practical thing.  Nuclear will be the only real, long term option until someone figures out a way to control a fusion reaction without blowing themselves to hell and gone.

[jamesp81]

AlanC9 wrote...

jamesp81 wrote...
The reason space exploration has been shelved is because of lack of vision.

The modern scientific establishment guys will stand on a podium and preach a sermon to you about what you can't do and what is impossible.

It will require a visionary to discover what IS possible.  Someone with scientific training but without the establishment mindset.  Visionaries are derided and scorned as fools, so you don't see many of them.

The problem with this logic is that a lot of visionaries are fools.

So?

I can guarantee you the science establishment is never going to undertake the task of trying to discover the secret of FTL travel or any other large, ambitious project.  It's not in their mindset.

[Raith Mano]

jamesp81 wrote...

AlanC9 wrote...

jamesp81 wrote...
The reason space exploration has been shelved is because of lack of vision.

The modern scientific establishment guys will stand on a podium and preach a sermon to you about what you can't do and what is impossible.

It will require a visionary to discover what IS possible.  Someone with scientific training but without the establishment mindset.  Visionaries are derided and scorned as fools, so you don't see many of them.

The problem with this logic is that a lot of visionaries are fools.

So?

I can guarantee you the science establishment is never going to undertake the task of trying to discover the secret of FTL travel or any other large, ambitious project.  It's not in their mindset.

Without visonaries we wouldn't have a lot of the amazing tech we have today.  If someone 40 years ago said that it was possible to have a phone so small it could fit in your pocket and have more computing power than all the Appolo rockets combined they would have told you that you were high off your a**.  Visonaries are what keeps the world moving. 

The problem with current federally funded research projects is that they want results they can make money off of, so they're afraid to venture into the unknown.  If you gave a company all the money they could use for the next 15-20 years, we'd be on Mars by 2025 with a large human presence.

Science is only stunted by funding and how much can be made, not imagination and visionaries.

[Phaedon]

IntoTheDarkness wrote...
Or so says the theory of special relativity by Albert Einstein.

A very very old theory which has changed almost fundamentally during the end of the 20th century.

I don't know an expert on physics but:
An object reaching FTL speeds is impossible.

However!

what some physicists refer to as "apparent" or "effective" FTL[1][2][3][4] is the hypothesis that unusually distorted regions of spacetime might permit matter to reach distant locations faster than it would take light in the normal or undistorted spacetime. Although, according to current theories, matter is still required to travel subluminally with respect to the locally distorted spacetime region, apparent FTL is not excluded by general relativity. Examples of apparent FTL proposals are the Alcubierre drive and the traversable wormhole, although the physical plausibility of these solutions is uncertain.

As far as I can tell, mass effect does change the fabric of space and time after all.

And I believe that Hawking supports this theory.

[Gabey5]

science fiction herp derp

[Aurellia]

The statement by the original poster is a simplistic view of relativity theory. There are two interrelated issues.

1 - In naive discussions of this stuff we assume that the topology of the universe as a whole is flat. If our universe is embedded in higher dimensions which various current theories require for other reasons then it is possible that space can be folded onto itself. This is the most common and scientifically "reasonable" way to do FTL travel. You basically create a wormhole. The most obvious forms of wormholes are the result of the rotating and/or charged (Ker and Ker-Newman solutions to the GR equations). See the following articles for some more details

http://en.wikipedia....lack_hole_types

In the section titled "The possibility of time travel" they give a decent explanation of some of the results that can happen when traveling through the middle of a rotating or charged black hole. These kind of black holes have a singularity that is a thin ring.

http://en.wikipedia....ing_singularity

The physics/math of what happens when an object passes through the middle of the ring is an open question. Read the section on Importance to wormhole theory for some info that would relate to mass relays. A mass effect relay is "simply" a device that has a ring singularity in it that can be cross-connected to the ring-singularity of another mass-effect relay.

This is a form of space fold FTL travel. Space fold has been around science fiction in one form or another for a long time. It is one of the most compelling ways to do this because it doesn't create paradoxes like causality violations.

Some science fiction authors play with the embedding space of the universe. They do things similar to if we were all flat-landers living on a plane and the plane was really wrapped like a roll of Saran-wrap then if you could punch through to a higher or lower sheet in the roll you would move instantly from one place to another.

Other authors might put the flat-land on a ball and observe that you can cut off travel time by following the straight line from one point to another on the surface rather than following the geodesic.

If you do this continuously then you get the famous warp drive from Star Trek. With warp drive you are continuously trimming distance off the geodesic by moving partially through the higher dimension in a space with positive curvature.

Finally there are authors that talk about temporarily moving out of space time all together into some other part of the embedding space--hyperspace if you will:)

2 - The Lorentz transformation in SR specifies the basic geometry of flat space time and put simply there is a mathematical singularity at a relative velocity of v=c. If you could somehow get going faster than v=x then you move from the realm of real numbers into complex numbers. I am going to be a little loose with stuff to keep the stuff as simple as possible.

The simple way to see this is to consider the formula m' = m0/sqrt(1-v^2/c^2) when v goes to c m' goes to infinity. But when it exceeds c it goes to a complex number of finite magnitude. If you visualize the surface of this function it turns out that you have singularities (as in mathematical not black holes) at v=c and v=-c. The two ends look kind of like the images on page 7 of the following.

http://krypton.fhda....x_Functions.pdf

Note this is visualizing f(z) = 1/z which looks a little different but it should be good enough to get the idea across here. In that function you have the singularity at z = 0 + 0i. Let's say you are moving from the back to front along the axis. Well, you would run into that singularity. Now it is possible to get around that singularity by drifting slightly to the left or right of it.

So mathematically you can avoid a singularity that lies on an axis by displacing yourself slightly into the other component in a complex number. What this means is if you can add a complex component to your relative velocity then you can travel at a velocity with a real component of c just fine:)

In the case of the Lorentz transformation the real velocity axis would be coming up the back side of the image on page 7 and the complex structure of the function is a little more involved but I hope this demonstrates how it is mathematically possible to get around a singularity in a function.

So to horribly oversimplify, if space-time is defined over the field of complex numbers rather than the field of real numbers and there is a way to add complex perturbations to things like mass, position or velocity then it would be relatively easy to transition from a sub-luminal to a super-luminal state.

Conclusion

Both of these issues touch on the assumptions of the topology and underlying algebraic structures (eg real vs complex vs something else) that underly our universe. As science fiction authors we can creatively modify these assumptions to allow travel over distances faster than light/information can travel.

In many cases writers are exploiting limits or holes in the existing mathematical models of the universe. For example in the case of rotating black-holes the math gives no prescription as to what lies across the plane that lies within the singularity ring.

[Phaedon]

^ Almost cross-post.

[Whatever42]

jamesp81 wrote...

The problem with that is plants gain most of their actual energy from nutrients in the soil.  The soil itself is insufficient as an energy source.


Solar won't work well for the obvious reasons unless you put the solar collectors in a high polar orbit where they always face the sun, and send the collected energy down to receiving station.

Right now, the only practical solution is nuclear power for large scale, base-load generation (with better flood walls).  For vehicle fuels, some kind of just-in-time on the spot hydrogen production is probably the most practical thing.  Nuclear will be the only real, long term option until someone figures out a way to control a fusion reaction without blowing themselves to hell and gone.

Well, I'll disagree with you. There is more than enough solar energy to provide any possible energy needs we have. The problem is to simply make it economical.  Nuclear is an awful solution, its almost an uneconomic as solar and its dangerous.

As for where most plants get their energy from, yes, that's why people are trying to bioengineer better plants. And algae doesn't get most of its energy from the soil, obviously.

[Whatever42]

Ah... more magic wormhole, space-time folding talk. Sorry, for me until someone can verify these mathetical models through verifible, repeatable experiments then its nothing more than fire-breathing unicorns.

[Phaedon]

Whatever666343431431654324 wrote...

Ah... more magic wormhole, space-time folding talk. Sorry, for me until someone can verify these mathetical models through verifible, repeatable experiments then its nothing more than fire-breathing unicorns.

What do you mean?
Doesn't the theory of general relativity prove spacetime?

[Aurellia]

Actually the stuff I wrote and cited is not magic. It is about existing best accepted mathematical models and some consequences of the math and physics. If you go look at the math behind general relativity  and work out the solutions for a rotating black hole you can find it too.  It will stare back at anyone who is willing to do the math.

The general relativity and black hole equations have been verified various degrees through observation and peer review by scientists around the world.   Now you can write off standard science and math as 'magic wormhole ...' talk if you wish but then you are moving away from your original thesis that FTL is scientifically impossible and moving towards your own personal beliefs and biases:)

Where the 'magic' comes in is as writers we can make assumptions about the topology and algebraic structure of the universe. There is nothing wrong with this, that is what science fiction writers do.

Modifié par bioware-sucks, 01 avril 2011 - 07:23 .

[abstractwhiz]

SomeKindaEnigma wrote...

A number of people have said that quantum mechanics has never been proven/verified; I should point out that a LOT of QM is much more than mathematical framework, and has been observed in laboratory experiments. For instance, the Stern-Gerlach experiment, which dealt with spectral decomposition and the deflection of particles in a magnetic field. There's actually plenty of experiments which verified properties and the mathematics put forth by QM, that one was just the first I could think of.

Oh, it's far better than that. The way scientific theories are verified is that one lists out as many of their predictions as possible, and proceeds to check them by experiment or observation. You're basically trying to break the theory. If you do this long enough, and it doesn't fail, there's a good chance your hypothesis is correct, and gets the strong tentative acceptance that goes with the status of scientific 'theory', placing it on par with, say, gravity, or the germ theory of disease.

As far as QM goes, no theory in human history has been so extensively tested. And it has never failed. It's the most verified piece of human knowledge in existence. 

Most of this confusion just comes from the word 'theory' - people hear that and start thinking of theories as random speculation, or interesting sounding ideas that get tossed around in literary fields, or philosophy. There's really no similarity between the two. All you can do in these cases is make arguments for and against, and usually it fails to resolve anything. Scientific theories are an all-or-nothing deal: Make your predictions, run the experiments, and throw the bloody thing out if it fails. 

This is not one of those 'theory fails in real life' things. That is not the sense of theory being used here. That sort of thing has made me facepalm all over this thread. Among other things. Whenever someone says 'just a theory', that's a sure sign that they need to either be educated or, failing that, ignored. <_<

Sorry, but that specific misunderstanding annoys me no end. I don't know why the hell this isn't common knowledge. But then I was mystified when I discovered that people didn't know quantum entanglement was real. 

In any event - here is an old thread on quantum entanglement. I remember this because it was my first post on the BSN. Here's a potted summary. 

QM deals with the states of various entities - I'd say 'particles', but that's not quite true, since actual reality doesn't contain either particles or waves, merely something that we stupidly try to force into looking like that. There are complex-valued probability amplitudes, and...that's it. They sort of look like particles one way, and waves another, but that's not what they are. The actual reality is properly described by the mathematics, not by human intuitions. (Which is why much of this discussion is messed up - I only saw a couple of posters tossing around equations.  Terribly sorry folks, but the secrets of the universe are mathematical. If you dislike math, you may as well give up now. Or move to a universe that behaves differently, but you'd need math to figure out how to do that in the first place...) The actual math of QM describes how to evolve the state of a system over time - or in simple terms, how to take the current state, and figure out the new state that will follow it. 

Now, one thing we can do is build up a composite state of multiple entities, using the tensor product. So if you have two particles, each in some state, you can effectively 'multiply' those states to create a joint state for that two-particle system. This can be extended ad infinitum. You can also go backwards, by factorizing the joint state to get the states of the pieces.

Now, you can apply the transformations in QM to this joint state, and get the new joint state. Sometimes this creates joint states that cannot be factorized. In this situation, the individual states are linked and cannot be treated separately. This is entanglement.

As for FTL, while it is prohibited by relativity, there are solutions to the Einstein field equations that allow for traversable wormholes. You need 'exotic matter' -  matter with negative energy density - to keep the wormhole stable, though. The key point is that there is no prohibition against such matter - we simply don't know how to make it, and it hasn't been observed to occur naturally. So unless a future refinement of our understanding rules it out, there's always that possibility.

Unfortunately, even in such situations, there's still the problem of placing the wormholes in the right places. There's a reasonably hard SF solution used in Orion's Arm, where linelayer ships travel to distant systems the hard way, dropping off one end of a wormhole, leaving the other at home. It takes them decades to centuries to get there, but once the other end is deployed and active, stuff can go back and forth instantaneously.

So if we figured this out, someone would probably still have to spend most of their lives flying to Alpha Centauri to drop off a wormhole. In principle, you could make them go so fast that relativistic time dilation would make them experience only a short time. (From Earth's perspective, they'll still take as long to get there, but they'll age slower.) In practice, traveling that fast is too dangerous, because a single hydrogen atom would strike harder than a bullet. You'd have to carry some sort of ablation shield in front of you to handle the impact - in The Songs of Distant Earth, the ship is essentially carrying a huge iceberg in front. The iceberg takes the impact, and then they replenish it halfway through the trip.

'Nuff said, I think. 

Modifié par abstractwhiz, 01 avril 2011 - 07:31 .