| | Faster than the speed of light? No problemo |  |
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Conrad
Number of posts: 5647
Location: Amsterdam, the Netherlands
Registration date: 2007-07-21
| | Subject: Faster than the speed of light? No problemo Sat Apr 04, 2009 7:31 am | |
| It's very simple to have light travel faster than the speed of light: | Quote: | | Reichenbach noticed that the central principle that nothing travels faster than the speed of light is ‘violated’ by certain processes. For example, a spot of light moving along a wall is capable of moving faster than the speed of light. (One needs just a powerful enough light and a wall sufficiently large and sufficiently distant.) |
the solution is to say that the light moving along the superdistant wall is a pseudoprocess and not a causal process.
Another fun fact I learned from my Causality course.
have to get back to writing the damn summary now, but thought I'd share this with you |
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nelle
Number of posts: 628
Registration date: 2009-02-09
| | Subject: Re: Faster than the speed of light? No problemo Sat Apr 04, 2009 7:36 am | |
| I have to share this with my kids. You have no idea how much you have helped with their homework this spring Conrad!  |
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Conrad
Number of posts: 5647
Location: Amsterdam, the Netherlands
Registration date: 2007-07-21
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nelle
Number of posts: 628
Registration date: 2009-02-09
| | Subject: Re: Faster than the speed of light? No problemo Sat Apr 04, 2009 11:26 am | |
|  They are missing their swimsuits though  The last time you "helped" with homework was when you posted the article where the unsuspecting shepherd had found the site of the supposed "garden of eden". Do you remember that? My daughter wrote a paper on it, and got 100% (so thank you very much)! |
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Conrad
Number of posts: 5647
Location: Amsterdam, the Netherlands
Registration date: 2007-07-21
| | Subject: Re: Faster than the speed of light? No problemo Sat Apr 04, 2009 11:44 am | |
| polar bears are funny.
yeah, I remember that article, esp. the great pose of the shepherd in the photo.
anyhoo, if your kids ever wanna write something about Bayes nets and the Causal Markov condition, then lemme know.
damn, how I hate my causality class... |
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SteveL
Number of posts: 260
Location: Toronto
Registration date: 2008-06-04
| | Subject: Re: Faster than the speed of light? No problemo Wed Apr 29, 2009 9:32 am | |
| | Conrad wrote: | It's very simple to have light travel faster than the speed of light:
| Quote: | | Reichenbach noticed that the central principle that nothing travels faster than the speed of light is ‘violated’ by certain processes. For example, a spot of light moving along a wall is capable of moving faster than the speed of light. (One needs just a powerful enough light and a wall sufficiently large and sufficiently distant.) |
the solution is to say that the light moving along the superdistant wall is a pseudoprocess and not a causal process.
Another fun fact I learned from my Causality course.
have to get back to writing the damn summary now, but thought I'd share this with you |
Not sure what the distinction between a pseudoprocess and a causal process is, but light has to travel to the distant wall--which it does at c. Individual photons don't actually move across the surface of the wall at all. |
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Conrad
Number of posts: 5647
Location: Amsterdam, the Netherlands
Registration date: 2007-07-21
| | Subject: Re: Faster than the speed of light? No problemo Wed Apr 29, 2009 11:17 am | |
| | SteveL wrote: | | Conrad wrote: | It's very simple to have light travel faster than the speed of light:
| Quote: | | Reichenbach noticed that the central principle that nothing travels faster than the speed of light is ‘violated’ by certain processes. For example, a spot of light moving along a wall is capable of moving faster than the speed of light. (One needs just a powerful enough light and a wall sufficiently large and sufficiently distant.) |
the solution is to say that the light moving along the superdistant wall is a pseudoprocess and not a causal process.
Another fun fact I learned from my Causality course.
have to get back to writing the damn summary now, but thought I'd share this with you |
Not sure what the distinction between a pseudoprocess and a causal process is, but light has to travel to the distant wall--which it does at c. Individual photons don't actually move across the surface of the wall at all. |
yeah, that's exactly it. That's why it's a pseudo-process: no mark can be transmitted in the process (in a real process the photons would do that). the light spot appears to move along the wall at greater than light speed (appear to who, you ask?) but it's different photons at each point |
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| | Faster than the speed of light? No problemo | |
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