Monday, August 3, 2015

Does Light Always Travel in a Straight Line?

I got a question.  Does light always travel in a straight line?  Well, let me think about that. . . . I would have to say no.  Doesn't a mirror change the direction of light?  Well, yes, but it is reflected in a straight line, too.  Maybe I ought to re-phrase that question to, "can light travel in a curve?"

It seems to be common knowledge that nothing can move faster than light. . . or can it?  Let me pose another question.  Let us assume that I have a very powerful flash light that can shine a spot on the moon that we can see from here.  Now, if I move this flash light back and forth as fast as I can, does the beam of light curve or does it stay perfectly straight?  OK, you say it stays straight?  By flicking my wrist back and forth just as fast as I can so that the spot of light from it on the moon travels back and forth from on side of the moon to the other in just a very small fraction of second.  The speed of light is 670,616,629 miles per hour.  The moon's width is 2,159.2 miles and the average distance from earth is 238,857 miles (since the moon is in an elliptical orbit, it gets a lot closer and a lot further away than that).

I would have to flick my wrist very, very quickly to see the light beam bend.  The spot on the moon would have to move from one side to the other quicker than .0000032 seconds and I am physically not capable of moving my hand anywhere near that fast.  So, I don't believe anything ever will move faster than light (which makes time travel impossible), what do you think?  

16 comments:

  1. Happy anniversary! Just a little bit late, but after 51 years maybe that's okay. About light.... If it bends and turns I wouldn't notice... All I care is that when I turn the switch to ON, let there be light!

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    1. Thanks, and yes, it is OK. The trouble is sometimes when you turn the switch on, nothing happens. Yep, now-a-days, all we have to do is throw a lot of switches and a lot of thing happen.

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  2. I definitely think that the speed of light isn't the limit. We just don't know what the limit is yet. And while I don't know about time travel, I think it will one day be possible to bend space and time so that we can get from one point to another without having to go in a straight line, as we do now. That's how the aliens get here, don'tcha know :-)

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    1. Instead of doing all that research, why not just ask one of those aliens? (grin) Yes, there maybe unseen things that go faster than light. We would not be able to see them, so they would be hard to detect. Scientists are working on that now.

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  3. Just so you will know, light rays do get bent a measurable amount while traveling. Passing a large object like our moon will cause a very small but measurable deflection in the path.

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    1. Yes, I do know that, and by using some huge objects, like galaxies as lenses, they can see what was too far away for just a telescope.

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  4. Light has done funny things in the quantum world.

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    1. Everything does funny things in the quantum world.

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  5. If you are trying to shoot a fish with a bow and arrow,the fish isn't where you see him. Is the light bent? Or just got a kink in it?

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    1. That is an old excuse that bow fisherman use (grin). Actually, the light is bent at a different angle because it travels at a different speed through water than it does through air.

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  6. Way to deep for my shallow mind. You do like to make us think, don't ya?

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    1. I have been told that the older we get, the more we should exercise our minds. But my mind is more like my body, both like to sit and rock in my rocker/recliner. BTW, tried to recline in it once and it flipped over backwards. That just goes to show you that there is a lot in my mind and it makes my head heavy (grin).

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  7. it's time relative? is it linear? can we compare time with how light travels? I want to believe we can time travel. Not certain time travel would be a good idea. Except for Dr. Who....I'm a big fan!!

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    1. Time travel in a phone booth? If I saw a phone booth along the street I would know that I am time traveling. . . back in time. OK, if we can time travel, could we do it in both directions? And of course the old question, if we went back in time and killed our grandparents, would we still exist? And if not, how could we go back and kill our grandparent? I have a lot more questions than I do answers.

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  8. Replies
    1. OK, what? Don't you believe me? I mean, you used the word "if".

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