The Shalimar Treaty

[AngleWyrm]

Sometimes truth is stranger than fiction.

The Shalimar Treaty is a strange treaty about the light-speed barrier, and it's implications on causality. On the surface it is a fictitious peace treaty between Klingon and Federation forces, that backfires. Secondarily, it is between the camps of Einsteinian Special Relativity, and the observers of superluminal events.
http://www.sciencenews.org/articles/20000610/fob7.asp

Mostly, it is about cause and effect, and has as it's theme something from the future-fiction Star Trek drawn into the present-reality to describe a causality paradox.
http://www.ma.utexas.edu/users/clong/newlumin1.html
http://scienceworld.wolfram.com/phys...tyProblem.html

However the arguments used to describe the paradox seem to apply equally well to the sound barrier. Let's say our FTL ship starts at position #1, and broadcasts "A". It travels towards the observer to position #2, where it broadcasts "B", and continues to position #3 where it broadcasts "C". To the observer, the ship arrives first, then it sees "C" then "B" then "A". Apparently backwards in time, and one might even say that it could prophesize the occurance of "A", given that it saw "C" and then "B".



But if we switch the scenario to sound waves, say the craft is using morse code, and traveling at mach 1.1, then what is the difference?
What do you think of this?

[Thermodyne]

Arrggg…………………It’s just Startrek science. The event happens when ever; it is only the observation of said event that would be influenced. Also, Einstein’s limit on the maximum speed that mater can obtain, is based on the theory that mass increases with speed. This foundation of his work has yet to be demonstrated. So everything built upon it is still theory.

Now to add a question of my own. What is the terminal speed of gravity?

[douglas]

Thermodyne said:
Also, Einstein’s limit on the maximum speed that mater can obtain, is based on the theory that mass increases with speed. This foundation of his work has yet to be demonstrated. So everything built upon it is still theory.

On the contrary, particle accelerators have pushed various subatomic particles to very near the speed of light with a resulting increase in mass sufficient to require designing new kinds of particle accelerators (at least of the circular variety) to take the mass increase into account before being able to achieve even higher speeds. The amount of the mass increase corresponded quite well with the predictions of relativity. For a little bit of reference material, go here.

[Slick]

This is what happens when you propose a situation that follows established physics for one part (the propagation of the signals) and makes up jibberish for another part (FTL travel). You can prove anything.

I am not totally discounting that we may one day figure out how to travel faster than light. However, if we do, it will mean that we have to change our ideas about basic physics. If this ever happens, this discussion would have to be done using the new physics, not a bastardization of the current physics. As of right now, we just can't travel FTL. There are some interesting experiments that are going on at the sub-atomic level that may lead to new understandings; but these experiments have so far only yielded results which confirm or are consistent with our current accepted understanding of physics. And our current physics predicts that nothing can travel faster than the speed of light; indeed nothing with mass can even achieve the speed of light.

To some people this is the motivation to discover something new to expand our understanding of how the universe works. I certainly applaud these efforts and hope for their success.

Until we figure it out, or even figure out a theory that can be tested and agrees with observations, FTL travel is currently not possible under our current established theories.

Yes, there are ideas about wormholes, extra-dimensional effects, strings, superstrings and a myriad of other theories that would make FTL travel, time travel and other SciFi concepts possible. Until these theories are reconciled with observations and put into a theory that makes predictions that can be tested, they are just fun things to think about and put into science fiction stories.

That's just my opinion, of course.

[Slick]

Thermodyne said:
Now to add a question of my own. What is the terminal speed of gravity?

"Gravitons" or gravity waves, depending on what property you focus on (similar concept between photons vs light waves) are theorized to travel at the speed of light.

[AngleWyrm]

Our physics predicted nothing could travel faster than the speed of sound. One argument against it was that if you were the target of a supersonic bullet, you would hear the bullet hit, then you would hear the bullet travelling downrange, then you would hear the bang of the bullet leaving the gun; you would witness events going backwards in time, which seemed to present a temporal paradox. This is exactly what happens. The target witnesses the arrival of the bullet, and can even have the time to radio back to the gunner and announce that the firing is still in the target's future (measurable and recordable as such with a tape recorder). But of course the firing is in the gunner's past, so it is meaningless to ask the gunner not to fire.

The best argument against gravity having speed that I've read was by Sir Aurthur Eddington: "If the Sun attracts Jupiter towards its present position S, and Jupiter attracts the Sun towards its present position J, the two forces are in the same line and balance. But if the Sun attracts Jupiter toward its previous position S', and Jupiter attracts the Sun towards its previous position J', when the force of attraction started out to cross the gulf, then the two forces give a couple. This couple will tend to increase the angular momentum of the system, and, acting cumulatively, will soon cause an appreciable change of period, disagreeing with observations if the speed is at all comparable with that of light."

[Slick]

Galileo proved that light moved faster than sound and he probably was't the first to prove it. No modern phyisics predicted that the sound barrier was impossible to break. The term "sound barrier" was coined in the World War II era when countries were trying to make airplanes go faster than sound. They knew it was possible, but were encountering extreme difficulties as they approached the speed of sound. Aerodynamic forces on the airplanes was so great that it caused many failures, crashes and deaths. Hence the term "barrier".

Regarding the question on "terminal speed of gravity". I find it interesting that you quote from the first article that appears in a google search for "speed of gravity" even though it does not represent the vast majority of scientific acceptance; which is that gravity is transmitted at the speed of light. Their pic is nice too. Instantaneous transmission of gravity is correct under Newtonian physics, but not under relativistic physics. If gravity was transmitted instantaneously, I could vibrate a mass to send signals everywhere in the universe instantaneously using gravity as a carrier. This would violate the theory of relativity. The theory of relativity may one day be proven wrong, or I should say incomplete; because its predictions have been observed and verfied many times over and so far it has been shown to be consistent for all observable tests performed. Indeed, NASA has used and does use relativistic physics in its calculations. Even as "slow" (relative to the speed of light) as our Mars missions have travelled, their trajectories were calculated using relativistic physics. If they relied on Newtonian physics, they would be off course. Until the theory of relativity is shown to be wrong, incomplete or it is replaced by a superior theory that more closely agrees with observation and is tested to verify its correctness, I'll consider Einstein to be correct.

[AngleWyrm]

Thanks for clarifying the sound-barrier. That makes much more sense.

I read that article on "speed of gravity" several years ago; that it is now on top of the google search is interesting to me. However discussing credibility of the author avoids the subject material. They called Galileo a worker of black magic when he showed that a grape and a grapefruit fall at the same speed.

Is it true that the calculation of planetary locations must take the force of gravity to be instantaneous?

[Slick]

I don't think so.

Here's the "argument": 'If the sun were to suddenly disappear, it would be unrealistic for the earth to continue to orbit nothing for another 8 minutes.'

I see some problems with this line of thinking:

- First, these same people wouldn't have a problem thinking that the earth would still see the sun for another 8 minutes as the light continued to travel to the earth. But somehow gravity seems different to them. It's probably because we have indisputable proof of the speed of light and the layman can witness its effects. Gravity has yet to be actually measured, which is why I said above that it was theorized to travel at the speed of light (based on principles). Scientists find measuring the speed of gravity acurately very difficult, but they are trying; and the prevailing theory is that it travels at the speed of light under the limits of the theory of relativity. So for some people, no-can-see, no-can-believe. And that's fine with me.

Second, under our current understanding of physics, the sun just can't disappear. So, it's one of those garbage-in-garbage-out arguments. We know of no way to instantaneously remove mass, so of course there is no theory about what happens next.

Last, orbits of planets around the sun are actually ellipses. Also, the sun is actually pulled and moved slightly by each planet. The sun's "orbit" is less than its diameter so it kinda just wobbles a little in response to each planet, but we can measure it. Since our source information (light) travels at the speed of light, we can't see instantaneous effects, if they existed. In a practical sense, the speeds of planets, the sun, the solar system, the galaxy, the local supercluster, etc., are small compared to the speed of light so it limits our accuracy of measurment.

I don't think I am avoiding the subject material. The credibility of the author is certainly important. For every theory out there, there's somebody who is convinced it is wrong and has a counter-theory. Yes, occasionally these people who we consider to be nut-cases sometimes, rarely, are the true geniuses who are actually correct. This doesn't mean that I should believe every counter- or conspiracy- therorist. The process is well established for objectively presenting a new theory, testing it, and adopting it if valid. People with these outlandish theories all claim the same thing: I can't prove it because the scientific community won't grant me any $$$ to use their XXX (equipment, satellite, telescope, collider, reactor, fill in the blank). Most of these guys are just that, nut-cases who are hell bent on trying to get their inane experiments (and their wallets) funded. The scientific community is portrayed by these people as extremely closed-minded, status-quo, establishmental, and rigid. My impression is that this is as far from the truth as possible. The reason why these nut-cases are ignored is because their theories are fundamentally flawed. The last thing the "real" scientists would want is to be on the wrong side of the fence if/when a new correct understanding of the universe is proven. Good theories are tested every single day. Experiments are being done as we "speak" to learn the fundamentals of our universe. That is what the XXX (equipment, satellite, telescope, collider, reactor, fill in the blank) *is* being used for.

[AngleWyrm]

Hypothesis: The effect known as gravity is instantaneous. Null hypothesis: The effect of gravity displays a finite transit delay (presumably comperable to speed of light).

Experiment: If light and gravity both arrive from the sun, then earth's trajectory through space should be a tangent to the center of the observed position of the sun, eight minutes west of current position. On the other hand, if gravity does not travel, then earth's trajectory should be a tangent to the sun's current position, eight minutes east of observed.

Is there a method of measuring earth's current trajectory by ameteur equipment? Could it be plotted via planetary positions or the like?