Faster than light

[Skoteinos]

Imagine a wormhole that goes to a planet 2 million light years away. On Earth we see it as it was 2 million years ago. You step in the wormhole and you are there. 2 million years have passed for you in an instant and you see it as it is now relative to Earth. You look back at Earth and you see it as it was 2 million years before. You jump in another wormhole and your back on Earth in the present. You travelled faster than the speed of light 4 million light years in minutes and yet only minutes have passed on Earth.

Intuitively faster than the speed of light has no effect relative to your departure point but sub-light does' date=' or am I wrong.

Just aman[/quote']

 

Reason you see it as 2 million years back ( or whatever distance/time is required) is because the photons traveling the distance take that long, hence the photons 2 million years ago are finally reaching us, that doesn't mean thats the time over there, its present there, we just don't see it yet (in a sense of excluding other variables changing time's characteristics), A wormhole doesn't make you travel 2 mil light years instantly, on the contrary, it makes you travel 0 distance instantly, through a dimension that hooks the two positions in 3d space through 4d (or however many required) space. Hence the speed of light is not disturbed. And your not traveling through time (if planets are at rest relative to each other, ignore cosmic expansion and such), the wonders of worm holes.

[mattd]

I'm exceptionally naive on this subject, but find it nonetheless fascinating as hell.

 

Regarding tachyons:

 

If tachyons theoretically are traveling "backwards" in time, and if we were ever able to detect and maybe study these theoretical objects, wouldn't we be able to detect certain things from our own future by some sort of forensic examination? Kinda like archeologists, but futurologists?

 

Sounds weird, I know...

[cyeokpeng]

Another possibility of a system faster than the speed of light. We know from our observable radius of the universe to be defined by the Hubble's radius.

Hubble radius = speed of light c/Hubble's constant.

That means that if there are galaxies further away than the Hubble's radius (should be since we know from the Big Bang theory that our universe is still expanding), the galaxies should be travelling away from us faster than the speed of light. How do we explain this phenomenon? Does this violate Einstein's postulate?

[cyeokpeng]

Another possibility of a system faster than the speed of light. We know from our observable radius of the universe to be defined by the Hubble's radius.

Hubble radius = speed of light c/Hubble's constant.

That means that if there are galaxies further away than the Hubble's radius (should be since we know from the Big Bang theory that our universe is still expanding), the galaxies should be travelling away from us faster than the speed of light. How do we explain this phenomenon? Does this violate Einstein's postulate?

[Severian]

the galaxies should be travelling away from us faster than the speed of light. How do we explain this phenomenon? Does this violate Einstein's postulate?

 

Presumably they aren't anymore. The are thought to be outside of our horizon because of inflation in the early universe - a period where the universe grew exponentially. There is no contradiction in this because there was no information flow - it was the fabric of space-time itself which was stretching. Einstein's postulate is only saying that information should not move faster than c.

[Severian]

the galaxies should be travelling away from us faster than the speed of light. How do we explain this phenomenon? Does this violate Einstein's postulate?

 

Presumably they aren't anymore. The are thought to be outside of our horizon because of inflation in the early universe - a period where the universe grew exponentially. There is no contradiction in this because there was no information flow - it was the fabric of space-time itself which was stretching. Einstein's postulate is only saying that information should not move faster than c.

[cyeokpeng]

What about light that is swept past like the lighthouse effect, observed at a very very far distance away? Ideally, if we can observe the sweeping of light in an arc at increasing distance from the light source, the observed speed of sweeping action will increase until the observed speed is faster than the speed of light. From what I know, light rays does not possess finite rigidity and hence it will not bend inwards due to limiting rigidity of the light path. Real objects will appear bent if the same experiment is done using a long object instead of light rays.

[cyeokpeng]

What about light that is swept past like the lighthouse effect, observed at a very very far distance away? Ideally, if we can observe the sweeping of light in an arc at increasing distance from the light source, the observed speed of sweeping action will increase until the observed speed is faster than the speed of light. From what I know, light rays does not possess finite rigidity and hence it will not bend inwards due to limiting rigidity of the light path. Real objects will appear bent if the same experiment is done using a long object instead of light rays.

[swansont]

What about light that is swept past like the lighthouse effect, observed at a very very far distance away? Ideally, if we can observe the sweeping of light in an arc at increasing distance from the light source, the observed speed of sweeping action will increase until the observed speed is faster than the speed of light. From what I know, light rays does not possess finite rigidity and hence it will not bend inwards due to limiting rigidity of the light path. Real objects will appear bent if the same experiment is done using a long object instead of light rays.

 

No object, or information, moves faster than c in that scenario. Relativity doesn't preclude two event from happening at times separated by less than d/c, it only precludes causal events from happening under those conditions.

[swansont]

What about light that is swept past like the lighthouse effect, observed at a very very far distance away? Ideally, if we can observe the sweeping of light in an arc at increasing distance from the light source, the observed speed of sweeping action will increase until the observed speed is faster than the speed of light. From what I know, light rays does not possess finite rigidity and hence it will not bend inwards due to limiting rigidity of the light path. Real objects will appear bent if the same experiment is done using a long object instead of light rays.

 

No object, or information, moves faster than c in that scenario. Relativity doesn't preclude two event from happening at times separated by less than d/c, it only precludes causal events from happening under those conditions.