Heim-Dröscher space

[Moontanman]

I have been reading about this Hyper drive based on Heim-Dröscher space and I am wondering if it has occurred to anyone else that this would cause a problem with causality. I was always told that no matter how you might try to beat the light speed barrier the main reason it couldn't be done is that anything traveling faster than light would arrive before it left where ever it started from. I always thought this was counterintuitive. It always seemed to me that no matter how fast you traveled the time spent traveling would always be More than zero. For instance if you could travel twice as fast as light you would arrive at the nearest star in two years instead of four but even if you traveled instantaneously you would still never have a travel time of less than zero. I was told this wasn't true that any speed more than light meant you were traveling backward in time. In all the talk about Heim-Dröscher space I haven't heard any mention of this paradox. Has the old faster than time equals backwards in time deal been proved wrong? Or did get I it wrong all along?

 

Michael

[Qfwfq]

I am wondering if it has occurred to anyone else that this would cause a problem with causality.

Of course.

 

I was always told that no matter how you might try to beat the light speed barrier the main reason it couldn't be done is that anything traveling faster than light would arrive before it left where ever it started from.

Actually this is an incorrect way of putting it, all to often heard and misleading.

 

The correct statement is that according to some observers it would be going back in time and according to some its velocity would be infinite. It's a consequence of the Lorentz coordinate transformations.

[ughaibu]

Moontanman: Posted elsewhere by PuGZ: Cherenkov radiation - Wikipedia, the free encyclopedia

[Qfwfq]

Actually that's not relevant, see the first sentence in my sig. It is unfortunate that people are still in the habit of calling c "the speed of light" when meaning the fundamental property of space-time geometry. Light having a reduced speed in materials does not imply a reduction of c.

[ughaibu]

I posted it in response to this, "no matter how you might try to beat the light speed barrier", it seems relevant to me. Also, I have signatures disabled.

[Pyrotex]

...I was always told that no matter how you might try to beat the light speed barrier the main reason it couldn't be done is that anything traveling faster than light would arrive before it left where ever it started from....

Having been through grad courses in Relativity, I do not remember anything like that being said or written. You may be remembering the limerick,

 

There was a young lady of Wight

Who traveled much faster than light.

She set out one day

In a relative way,

And arrived the preceding night.

 

However, as far as I know, the constraint that forbids matter from traveling at or faster than the speed of light has nothing whatsoever to do with backwards "time travel".

[Pyrotex]

By the way, here is a link to an article on Heim-Droscher space and its implications.

[GAHD]

local heim -related links

"heim theory"

"faster than light due in 5 years"

[Jay-qu]

Even if a Heim-Drive could be built I dont think it would go faster than light so to speak.. but you would travel in a region of space where the same rules dont apply. So that you would still be governed by a set of physical priciples, just not ones like our own, I am tempted to say that these laws would not permit backwards time travel - but I would only be guessing in saying so!

[Nootropic]

Apparently, according to Michio Kaku, the founder of string theory and a leading theoretical physicist, there are solutions to Einstein's field equations that due permit time travel. What these solutions are, I have no idea. Off to find them...

[Qfwfq]

Also, I have signatures disabled.

"The velocity of light in vacuo is c, but c isn't just the velocity of light."

 

The trouble is that Einstein, a quite practical fellow, wrote his 1905 paper arguing the matter in a way that gives light a kind of a special status and of course the thorny problem of the time was discussed in terms of light speed. The fact is that any massles particle goes at c and a faster propagation of any cause-effect would lead to paradoxical conclusions, whereas a material medium such as glass or water has an effect that slows light to less than c but without implying a lower limitation on every velocity. Cherenkov radiation does not lead to causality paradox.

 

However, as far as I know, the constraint that forbids matter from traveling at or faster than the speed of light has nothing whatsoever to do with backwards "time travel".

If events A and B are simultaneous according to your coordinates and spatially separated, then according to many other coordinates A is previous to B and vice versa according other coordinates.

 

It is thus paradoxical to consider one of the two events as being the cause of the other, which includes the one being a particle's departure and the other its arrival. Any whatsoever propagation at v > c suffers this difficulty.

[ughaibu]

Qfwfq: Thanks for the further explanation. As I say, I was responding only to a fragment of a sentence, things would probably have been clearer had I also mentioned this sentence fragment, "like saying the light speed barrier will eventually be broken", from post 14 on this thread: http://hypography.com/forums/physics-mathematics/11501-eleven-dimensional-universe-2.html#post176195

Apologies for the confusion.

[Guest Lambus]

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[BenKugler]

From the way i understand it, isnt his theory suggesting that you acualy create your own gravitational field witch allows you to kind of pull the destinations towards you, avoiding traveling back in time.