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Offline SamanthaLuca

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SpaceTime
« on: 12/09/2008 06:42:05 »
I'm watching the episode "Time Machine" on the show "Naked Science" on NatGeo tonight.

FWIW, I'm 15, my IQ is 177, and I have a great interest in learning more about how and why the universe works.

One thing that struck me in the show was the graphical representation of spacetime (the grid) and their explanation for how light travels.  It's difficult for me to articulate, but I would think that "space" is actually an "ocean" of interconnected particles.  And that such particles are displaced by the presence of planets, stars, etc.  That would explain, to me, why light "bends" around objects; it's really taking a straight path, it's just the path that's distorted.  Does that make any sense?  And if a photon of light travels by leaping from particle to particle, wouldn't it do so in what would appear to be a wave form?

Side question:  I've heard mention that multiple dimensions are involved in resolving M Theory.  Is one of those dimensions "point of perspective"?  Since so many scientific observations are different, depending upon perspective of the viewer, I'm wondering how that's taken into account.

Thanks for sharing any nuggets of knowledge!  ; )




 

Offline graham.d

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SpaceTime
« Reply #1 on: 12/09/2008 11:25:56 »
Samantha, you can try lots of ways to think of space and keep on doing so because nobody knows the "right" way, if there is one. I am not sure about the ocean of interconnected particles idea. The problem is whether you think of space from a quantum theory point of view or from a General Relativity point of view. It is combining these two views into one theory that is part of the great challenge within physics at the moment.

From a GR point of view, light always folllows the shortest distance (in a 4 dimensional, space-time, universe) between two points. This path is known geometrically as a geodesic in the way that great circle routes are geodesics on the earth's surface. Large objects in space distort space-time so that light is seen to bend around these objects. This is also consistant with how a photon (with its mass derived from its energy as it has no rest mass) would behave in a gravitational field. But GR looks at this differently and does not involve the concept of a gravity field at all.

I am unsure about what you mean in your side question. If I understand you, then the answer is no, the multiple dimensions are not really to do with a viewer's perspective, where I think you are referring to relativistic "observers". It is another great challenge to understand the mathematical models that seem to work in particle physics in terms of any sort of visual representation. The mathematical models can produce beautiful structures (in terms of elegance) but these do not actually represent physical reality directly (if there is such a thing - we cannot really visualise multiple dimensions but can only do so by analogy or by reducing all the other dimensions to zero).
 

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SpaceTime
« Reply #1 on: 12/09/2008 11:25:56 »

 

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