Faster than light

[PurpleYouko]

But if they want to get together and compare their observations right next to each other, then at least one of them will have to brake and reverse direction. At that point, it will look to that guy (who is braking and then accelerating) that his twin suddenly grew very old. The simmetry is broken, because they are not in innert systems anymore. Read that website, it does explain the whole thing pretty well and is quite short to go through in 15 minutes smile.gif

But there is no acceleration since they never stop moving or ever come together.

They don't need to. Both frames remain totally unchanged.

They are using a hypothetical, might exist one day, system of instant communication over infinite distance.

The twins paradox is completely different. In that there is acceleration which then kicks in special relativity.

In my case, there is no acceleration whatsoever so general relativity covers it.

 :wacko:  PY  :wacko:

[shvarz]

Well, the whole point of special theory of relativity is that "instanteneous" events are not possible, because no two observes can agree on when a given event occured.  Instanteneous would mean that they did agree.

[PurpleYouko]

So that would make any kind of wormhole travel impossible then.
I understood that instantaneous travel was theoretically possible.

here's another slant on it.

One of my observers goes through a worm hole and comes out in front of the other one.

They pass each other again at the same relative speed but without either one ever undergoing any kind of acceleration.

When they pass this time they should both be older than the other one.

That satisfies all the criteria for the paradox.

 :D  PY  :D

[shvarz]

I doubt special theory of relativity even considers things like wormholes.  Besides, if wormhole moves an object instanteneously in space, it would also move it in time.  So the dude that goes through wormhole will travel in time and may not necessarily be older than his twin.  Maybe going through wormhole will throw him back in time many years.

[PurpleYouko]

You are right that relativity doesn't even consider the existance of worm holes. At least I am pretty sure it doesn't.

I think (though I might be wrong here) that Einstein himself postulated the existence of wormholes.

Wormholes are still a bit of an unknown but I don't think it is inevitable that time travel is also included in wormhole travel.

You have to see though that for my example to happen with no associated shift in time then we would have a REAL paradox that couldn't be reasoned away.

This leaves us with two posible conclusions

1 Einstein was wrong and relativity is bollox.

2 Wormholes are physically impossible.

Take your pick.

 :D  PY  :D

[shvarz]

3) They move you through space and through time.  After all, these two are tightly linked together.

[PurpleYouko]

If relativity is false, it is false in the same way newtonian physics is. It's a special case.

Yes you are probably right here.

There is no doubt that relativity and all the equations that go with it, can be used in all of the situations that we have so far tested it in.  We have never yet even come close to testing it in a situation which could make it fail.

However, it is well known that in certain circumstances, relativity disagrees with quantum mechanics.

It is impossible that both are 100% correct.

Newtonian physics is rather simplistic but serves well enough in every day situations.

Relativity is useful in 99% of circumstances but I have a lot of nagging doubts that when we are able to really test it, we will find it to be a pile of bollox.

Quantum mecahnics make a whole lot more sense and appears to be applicable in a lot more situations.

 :D  PY  :D

[Zelos]

if wormhole exist we have time machines, coz if the 2 ends are moving in a different rate throught time they will be spereted not only in space, but in time 2. if let us say that 1 opening is in a orbit around our sun at a distance of plutos radie. and the other end is close to a neutron star, or moving whit speeds close to light. they will be seperated throught time, and woila, we have a time machine, but we still cant change the past, and if you ask me, relativity and quantum mechanic give as much sense both, sometimes I think relativity givers more

[Botsareus]

hmmm--- Well what happens to an object that is moving near light speed and it Emits light, does this light go slower in one direction (to the abserver moving at near light speed) or not? (Light have to travel at a fixed speeeed)

 :lol: Bau  :lol:

[Zelos]

it moves at the same speed in all directions. if that object is moving ,99C compared to earth we will only see it slow after slithly every second, but for this object the light is moving C metres from it it all directions every second

[shvarz]

It travels at the same speed for all observers.  It has been tested in numerous experiments, and the whole general theory of relativity has been done to incorporate this observation into physics.

I say it's just a bug.  whoever was coding our universe just forgot to apply newtonian physics to light :)

[Botsareus]

"It travels at the same speed for all observers." How is that possible?

Here is another picture:

 --------( L1<----A---->L2 ) ------>

                       B

For A to abserve that the light is traveling the same speed

L1 = speedA - speedoflight
L2 = speedA + speedoflight

For B to abserve that the light is traveling the same speed

L1 = -speedoflight
L2 = speedoflight

Note:

-speedoflight != (speedA - speedoflight)
speedoflight != (speedA + speedoflight)

gg laws, or what?

[PurpleYouko]

So here is another little conundrum.

It is supposed to be impossible for any observer in a box to be able to tell anything about the outside world by means of any experiment that he does that remains entirely inside the box.

He cannot perform any experiment that interacts with anything outside the box in any way.

Supposedly, he cannot ever know how fast the box is moving provided it does not undergo any kind of acceleration.

This is a very well known scientific law that is taught in pretty much every physics class.


This doesn't sit well with relativity.

Think about this scenario.

The observer has a mechanism consiting of a laser that is able to emit a beam of light in a specific direction and at a specific wavelength, and a very narrow detector which is able to detect a photon of the specific wavelength of the laser.
Any change at all in wavelength or trajectory will cause the photon to NOT be detected.

If the observer rotates the mechanism then starts it going, he is going to see diferences if relativity is correct.

If the beam of light is being emited in the direction of travel then the wavelength is going to be blue shifted at the detector.

If the beam of light is being emited opposite to the direction of travel then it will be red shifted. Just like light from distant galaxies is.

if the beam is perpendicular to the direction of travel then it won't ever hit the detector at all since the box (and therefore the detector) will have moved out of the way by the time the beam gets there.
The only way the beam could hit the detector is if the photons are moving with a velocity relative to the laser source rather than at a universal speed.
Remember these photons are being ejected from the laser perpendicular to the direction of travel so they will not be imparted with any forward velocity at all. They will be moving in a straight line from the position that the laser was when they were fired.

So which LAW of physics is right and which is wrong cuz they can't both be right.

 :sly:  PY

[shvarz]

Guys, seriously - read the website that I posted above!  It goes over these questions!

Bots - theory of relativity explains how it is possible.  The whole point of theory is to explain this strage fact.

PY - there is not going to be any change in wavelengths frequency.  For observer in a box everything is going to look as if he were standing still.  Look at the example with the train in the web-site I listed above.  It is a similar idea.

[MightyPenguin]

PY, are you actually a physicist, or one of these crazee internet people who just pretend because their actual lives amount to sod all? I'm beginning to wonder... ;)