Time Travel Possibility: Scottish Scientists Slow Light Speed?

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Discussion Overview

The discussion revolves around the implications of recent research by Scottish scientists who reportedly slowed down the speed of light using a special mask. Participants explore whether this achievement could relate to the feasibility of time travel, questioning the significance of light speed in various contexts, including vacuum and mediums.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant suggests that slowing light could imply a slower speed necessary for time travel, questioning if the speed of light is a fixed number or context-dependent.
  • Another participant clarifies that the speed of light in vacuum (denoted as c) is a constant in relativity, and that light in a medium travels slower, but this does not relate to time travel.
  • Some participants emphasize that the slowing of light does not affect the fundamental principles of relativity or time dilation, noting that the speed of light in vacuum remains unchanged.
  • There is a challenge regarding the interpretation of the research, with one participant asserting that the original claim about light speed being slowed forever is incorrect based on the scientific publication's abstract.
  • Another participant points out that the research demonstrates a specific beam profile that travels slower than plane waves, but this does not alter the established understanding of light speed in relativity.
  • Concerns are raised about the accuracy of popular science articles, with a participant suggesting that the media representation may not fully capture the research's implications.

Areas of Agreement / Disagreement

Participants express disagreement regarding the implications of the research on time travel and the nature of light speed. There is no consensus on how the findings relate to established physics principles.

Contextual Notes

Participants reference a scientific publication and a popular science article, indicating that interpretations may vary based on the source of information. There are unresolved questions about the conditions under which light speed is measured and the implications for time travel.

Auliter
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I've recently read a report about a group of Scottish scientists have managed to slow down the speed of light, not in a certain condition but through a special mask and the particles of light can be forever slowed down. Does that means the speed we need to achieve to make time travel is slower down and make it possible? Or the thing is the light speed we asked to do the time travel is just a certain number and don't really have anything to do with the actual speed of light?
 
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The ##c## that appears in all the equations of relativity is the speed of light in vacuum. Light in a medium generally travels at less than that speed, and it is possible to travel faster than light (but still faster than ##c##) in such a medium - google for "Cerenkov radiation".

However, none of this has much of anything to do with time travel.
 
Nugatory said:
The ##c## that appears in all the equations of relativity is the speed of light in vacuum. Light in a medium generally travels at less than that speed, and it is possible to travel faster than light (but still faster than ##c##) in such a medium - google for "Cerenkov radiation".

However, none of this has much of anything to do with time travel.
Thanks for explanation. But the thing is that the speed of particles of light is slowed down forever which means even in vacuum(not any medium) the speed of light is slower than the original one. You may take a look at the link: http://www.bbc.com/news/uk-scotland-glasgow-west-30944584.
 
Did you read the scientific publication? Of course you didn't. How do I know? Because it says that your claim is wrong in the abstract!

Before you tell us we are all wrong, perhaps you should so a little homework yourself.
 
Vanadium 50 said:
Did you read the scientific publication? Of course you didn't. How do I know? Because it says that your claim is wrong in the abstract!

Before you tell us we are all wrong, perhaps you should so a little homework yourself.
As you said, I didn't. Just get a glance at the BBC news. Thanks for reminding, I may do some search next time beforehand.
 
The c that is relevant for spacetime is the invariant speed that figures in the laws of EM (and all other laws of physics). That a particular photon is put in a state where its detected speed after emerging from a mask into vacuum is slightly slower than c is completely irrelevant to time dilation or any other spacetime phenomena. It is very interesting, but it is really in the category of light in matter going less than c. The researcher's remarkable achievement is to show, without a wavegide, that a non-plane wave reduced to a single quantum has the propagation characteristics of the non-plane wave: that it travels less than c.

Here is the primary reference on this (rather than the pop sci version):

http://arxiv.org/abs/1411.3987

[cross posted with Vanadium 50]
 
They haven't slowed the speed of light in the sense you mean. They've managed to construct a beam profile whose wavefronts travel slower than plane waves do. This isn't particularly exciting - the Gaussian profile they use is a common laser beam profile. What's pretty cool is that they stepped their light source down to emit one photon at a time and still observed the effect.

It doesn't change anything about relativity, or allow time travel. The c used in relativity is the speed of plane waves in vacuum. It might be less misleading to say that these guys made a photon that travels slower than c, rather than that they changed the speed of light.
 
Auliter said:
Thanks for explanation. But the thing is that the speed of particles of light is slowed down forever which means even in vacuum(not any medium) the speed of light is slower than the original one. You may take a look at the link: http://www.bbc.com/news/uk-scotland-glasgow-west-30944584.

That BBC article is a <delicate>less than completely accurate</delicate> description of the actual research to which PAllen has supplied a link.
 
This thread can be closed now.
 

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