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Old September 20 2012, 07:29 PM   #61
gturner
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

Manticore wrote: View Post
gturner wrote: View Post
Manticore wrote: View Post
Again, you're talking about the Twin Paradox, which is only applicable to General Relativity. Newtype is talking about Special Relativity. :bitch:

So fricken annoying to see the two so constantly conflated, which is why I despise the twin paradox.
No, the twin paradox comes from special relativity, which had no trouble explaining that the twins wouldn't be the same age, just trouble explaining why A should be older B instead of B older than A, if there wasn't a preferred reference frame, which special relativity said there wasn't. That's why it was called a paradox.

As I recall, Einstein had largely resolved it around 1910, before general relativity, by distinguishing btween the non-accelerated reference frame and the accelerated one, which initially would also seem to be relative (which one is accelerating? Wouldn't it depend on your point of view?), but only one twin feels like he's pulling some serious G's somewhere along the way, leading to the importance of the non-accelerated reference frame's proper time, etc.
But for the twins paradox to occur, one has to change your inertial frame of reference, which is the domain of general relativity. Otherwise, one twin sees the other as aging more slowly, and vice versa.
But the paradox is only a paradox under special relativity, which couldn't initially explain why one reference frame would be prefered over the other, accept by noting that one of the twins underwent acceleration (that was bouncing around somewhere near 1910). That brought up the question of why an acceleration should matter, and given that acceleration and gravity are the same thing to the twin (he can't tell which is which inside a sealed box), gravity must be doing something weird to time, too, leading to general relativity.

The twins paradox isn't a paradox under general relativity because it explained why it occured (thus no longer a paradox), but the fact that the twins clocks don't match was apparent in special relativity, where it of course created a paradox (all reference frames are not equal - but they are - except they're not - damn).

The interesting thing about this new warp drive is that the twins paradox doesn't occur because their clocks stay the same. Both twins stay in a non-accelerating inertial reference frame the whole time. There's no time-dilation for either of them, just a seperation of distance (along with the doppler effect of moving relative to the transmission speed of a whatever they use to send signals back and forth).

Whenever they meet up, their clocks will still be in sync.
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Old September 20 2012, 07:30 PM   #62
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

...then why were we arguing again? It seems like we were saying the same thing in different ways.
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Old September 20 2012, 07:31 PM   #63
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

gturner wrote: View Post
newtype_alpha wrote: View Post
I can't speak for Einstein or Hawking, but the MATH doesn't lie, and the underlying logic is pretty clear on this matter. If we're flying towards each other, we will both look at each other and we will be able to say the same three things: "You're moving towards me, you have more energy than me, and time is moving slower for you."
I think that's backwards. If we're moving toward each other we're both blue shifted, not red shifted.
Doppler shift is immaterial. The speed of light is still constant in both reference frames, and time dilation is a consequence of this.

Although, I admit it's been so long since I actually did the equations that I can't remember anymore if a positive or negative integer for velocity would actually make a difference. I remember thinking that it should, and being told by someone smarter than me that it wouldn't, but that same person suddenly went on to explain how the GPS system is more proof of special relativity.

I'll probably sit down and play with the numbers later tonight, just to be sure.
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Old September 20 2012, 07:55 PM   #64
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

gturner wrote: View Post
But the paradox is only a paradox under special relativity, which couldn't initially explain why one reference frame would be prefered over the other, accept by noting that one of the twins underwent acceleration (that was bouncing around somewhere near 1910). That brought up the question of why an acceleration should matter, and given that acceleration and gravity are the same thing to the twin (he can't tell which is which inside a sealed box), gravity must be doing something weird to time, too, leading to general relativity.
The trouble with this is General Relativity never formalized the MECHANISM involved. While gravitational time dilation can be inferred by the behavior of light (e.g. light still moves at C even when it's coming from a neutron star) that still wouldn't apply to the acceleration of a spacecraft, since even while accelerating it is still transitioning between inertial reference frames as parts of the ship collide with other parts of the ship and experience velocity changes (impulse and inertia).

Gravity is a special case in GR because, because it's an example of a constantly moving frame of reference (as opposed to movement BETWEEN frames). A rotating reference frame (a space station, for example) is sometimes said to be non-inertial as well, but in this case only locally (.e.g if you fall off the wheel you are immediately in an inertial frame in which the space station is rotating).

The interesting thing about this new warp drive is that the twins paradox doesn't occur because their clocks stay the same. Both twins stay in a non-accelerating inertial reference frame the whole time.
But that's just it: a warp drive is using an accelerated reference frame by definition. Strictly speaking, it's a situation in which the ship has created a stationary reference frame that it itself in motion in an arbitrary direction. This is similar to gravity -- a reference frame that is constantly moving towards the center of mass -- and should have some similar implications for time dilation.

The thing is, gravitational time dilation is only a consequence of the fact that light retains its native velocity regardless of acceleration, and time dilation should persist because the gravitational field never STOPS accelerating and the Earthbound twin never enters an inertial one. I'm trying to think whether this would actually be true of a warp drive, since in that case the drive can be SHUT OFF and the ship reenters an inertial frame anyway.

It's probably worth keeping in mind that photons only ARRIVE at their target at the speed of light; GR allows that from the transmitter to the receiver, over a distance of one light second, the photon can do whatever the hell it wants -- slow down, speed up, change directions, go into orbit around a black hole, move backwards, do some jumping jacks, double its energy or halve its energy etc -- but it will always reach you exactly one second after it leaves the transmitter. In a way, even gravitational time dilation is only apparent, but it only seems not to be because you can never create a situation where you wouldn't observe it.
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Old September 20 2012, 07:56 PM   #65
gturner
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

^ Yeah, I think we might be talking about two slightly different things. Special relativity is usually concerned with two people in constant relative motion, where all observers think everybody else's clock is slow (and you also get into Lorentz contraction and other effects), but other odd things show up when the relative motion is altered to form a closed path, but closing the path required applied forces to alter the motion.

I'm not sure if this new drive would involved just normal doppler effects or what are termed relativistic doppler effects, and how the idea of a non-accelerating reference frame that accelerates (space-time contracting in front, expanding in back) alters the situation. I'm sure the original articles on the earlier conception of this drive system should cover it in some detail, or at least the discussions about the earlier (high-power requirement) drive system.

Sounds like we might have to do lots of digging to get our mental models straightened out.
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Old September 24 2012, 05:20 PM   #66
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

So, if a real warp-ship looks like this:
http://orbitalvector.com/FTL/Interdi...ge_IDDrive.jpg

...then would a real shuttlecraft for it, look like this:
http://tommytoy.typepad.com/.a/6a013...bf26970c-800wi

???
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Old September 24 2012, 06:14 PM   #67
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

^No, to follow trek design. the shuttle should evoke the ship it's based on. Your joke fails.
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Old September 24 2012, 09:43 PM   #68
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

Has anyone pointed out the obvious yet? That thought is more feasible than warp drive.
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Old September 24 2012, 10:13 PM   #69
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

Deckerd wrote: View Post
Has anyone pointed out the obvious yet? That thought is more feasible than warp drive.
If it is more feasible, why haven't we experienced any examples of it?
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Old September 25 2012, 02:37 PM   #70
Robert Maxwell
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

I love how something that depends on a fanciful form of matter is considered "feasible."
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Old September 25 2012, 05:39 PM   #71
Rowan Sjet
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

It's not fanciful, it's Dilithium!
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Old September 25 2012, 09:39 PM   #72
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

Robert Maxwell wrote: View Post
I love how something that depends on a fanciful form of matter is considered "feasible."
1000 × 0 is 1000 times bigger than 0.

I think... My calculator is giving me a weird division by zero error for some reason, so I can't verify it.
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Old September 25 2012, 10:17 PM   #73
gturner
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

Exotic matter is entirely feasible, like adding elements to the periodic table. Like any infrastructure expansion project, you just make the physicists wear bright orange safety vests over their lab coats and pay them union wage scales. Then, presto, they make a new form of matter (over budget, of course).
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Old September 28 2012, 11:42 PM   #74
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

larryman wrote: View Post
So, if a real warp-ship looks like this:
http://orbitalvector.com/FTL/Interdi...ge_IDDrive.jpg

...then would a real shuttlecraft for it, look like this:
http://tommytoy.typepad.com/.a/6a013...bf26970c-800wi

???
No. Ironically, the warp spaceship might be more doable than having an all payload craft--the shuttlecraft hover and land with no reaction mass. I was looking at the the small test stand using a laser and wondered if this might be helpful, and then I looked at this: http://arxiv.org/abs/1207.7030

Some of you may be familiar with Aridas Sophia's idea or early jeffries/Declaration type ringships passing through a ring type superimpeller as he calls it.

http://s112.photobucket.com/albums/n...arison-2-1.jpg
http://s112.photobucket.com/albums/n...t=Tankenka.jpg
http://www.trekbbs.com/showthread.php?p=2548299

Then I recalled a possible mission to the deep space solar foci http://www.tsgc.utexas.edu/archive/design/foci/

You go far enough out--and you are in a focal line.

I wonder if something similar might be had in terms of powering a warp line with line of sight travel from one star to another. I don't think the warp ship could generate its own effect. If it can--it might be launched from a chemical rocket--deploy, and be rather like New Horizons. Travel at 10 X c and Alpha Centauri is 21 weeks away? Six month Mars mission time? You need a big dish to receive here tho'

Then too, I remember my book The Science in Science Fiction. In short what it says is this. If you saw it on saturday morning cartoons--it won't work.

Sorry.
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Old September 29 2012, 08:22 PM   #75
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Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

I'm thinking that real warp travel if we ever have it will use beamed energy propulsion.

Now wait, you say--the beam can only travel at lightspeed. True enough--but an intersection point between two beams?

An example take a solar system wide Marquee sign. You have a wide array of lights. Each vertical bank of vertically stacked lights is about 1 AU apart from the next bank. Now if you have one bank of lights turn on after they 'see' the previous bank of lights turn off--well, there's your light delay. Now, if one bank of lights is pre-programmed to turn on right after after the previous one turns off--that's fine.

From a distance, you have a pattern of 'off' lights that races across the array at FTL speeds--even thought the light from each bank is only at c.

Patterns, like warps, can be most any speed: http://cosmoquest.org/forum/archive/...p/t-97480.html

Now IIRC, the small perturbation they want to create--a mini warp--uses a laser beam. But what if you use two beams and have the intersection point be where the warp ship enters--and rides a warp along an intersection point. So you fire the laser beams ahead of time before adjusting the beam intersection point.

Now I was reading about deep space mission to the solar foci. After a time, you don't get a focal point--but a focal line.

These two techniques might be useful in some way:
http://arxiv.org/abs/1207.7030
http://arxiv.org/abs/1207.6780

Maybe if one could cloak the mass of the craft's Higgs field--it could then ride the intersection point perhaps:
http://www.trekbbs.com/showthread.php?t=181216&page=2

Aridas own ring shaped impeller/subspace catapault/gateway station design may also play a part in bootstrapping outward.

The warp ship is going to eat power, and I seem to remember hearing that a craft cannot generate its own warp bubble--so there are problems:
http://www.universetoday.com/93882/w...ller-downside/
But that does seem to release a lot of energy too--but first, you have to have that energy...

Aridas own ring shaped impeller/subspace catapault/gateway station design may also play a part in bootstrapping outward.

In other words, I don't think you can have a ship turn on it's own warp drive and go where it wants. You are going to have to have some in-space infrastructure--and a lot of it--Babylon % gate style I would think.

http://www.trekbbs.com/showpost.php?...9&postcount=74
http://news.discovery.com/space/how-...ve-120924.html
http://www.futureincredible.com/2011...-science-fact/

Take a look at this: http://www.space.com/2129-research-w...yperdrive.html
Felber's "analysis found that a mass moving faster than 57.7 percent of the speed of light will gravitationally repel other masses lying within a narrow "antigravity beam" in front of it. The closer a mass gets to the speed of light, the stronger this antigravity beam becomes. Thus, the forward antigravity field of a suitably heavy and fast mass might be used to propel a payload from rest to relativistic speeds."

You might need a run and go to enter the warp?

Maybe warp messaging can come first
For any intersteller com--you are probably going to need a huge dish:
http://cosmoquest.org/forum/showthre...s-Link-Design?

There is just no way around lobbing tons of massive infrastructure to space. We are going to have to get used to that.

Last edited by publiusr; September 29 2012 at 08:32 PM.
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