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Faster than the speed of light?
Posted: 05 July 2008 02:21 PM   [ Ignore ]   [ # 181 ]
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Wouldn’t all the particles somehow end up all going the same speed? And not only that but the out side of the disc would be come infinitely heavy and if you could keep it together it wouldn’t accelerate after the outside got almost to C. I’m trying to visualize what would happen to the disc because if you kept trying to spin it wouldn’t the whole thing become a single ring? Can someone help me calculate how many rpm a 4 inch disc would have to be spinning to hit exactly C?

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Posted: 05 July 2008 02:56 PM   [ Ignore ]   [ # 182 ]
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Come on, that’s a simple calculation.    (C X 60 X 5280 X 12)/(Pi X 4) 

Occam

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Posted: 05 July 2008 03:05 PM   [ Ignore ]   [ # 183 ]
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Yeah i got confused when i divided C/the circumference in miles and had 13 zeros

[ Edited: 05 July 2008 03:19 PM by macro820 ]
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Posted: 05 July 2008 03:19 PM   [ Ignore ]   [ # 184 ]
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Wait a minute.  Any intelligent high schooler should be able to figure that out.  C = 186,000 mi/sec   Multiply that by 60 to get mi/minute.  Multiply it by 5280 to get feet per minute.  Multiply it by 12 to get inches per minute.  You said the diameter of the disk was 4 inches.  Pi X diameter equals circumference.  So, Pi X 4 equals the circumference of the disk in inches.  Divide this into C expressed in inches per minute and you get the RPM.

There’s a difference between being a dumb high schooler and a lazy one.  I’m sure you are far brighter than necessary answer the simple question you posed in your prior post.  So I wasn’t putting you down for being dumb; rather I was surprised that as intelligent as you appear to be, that you begged for help on this calculation.

Occam

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Posted: 05 July 2008 03:24 PM   [ Ignore ]   [ # 185 ]
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Yeah well I am smartish but i have trouble keeping it all straight, while converting all the different units and such especially when i tried to use mph for C instead of /second and put the circumference in miles and i just was using confusing units i guess well thanks sorry i got defensive, don’t see why you focused only on that part of my question though as the other parts are far more interesting

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Posted: 05 July 2008 03:33 PM   [ Ignore ]   [ # 186 ]
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Sorry, as a moderator, I have to read all the posts and feel guilty even taking the time to respond to any.  So, I do the quickies preferentially. 

BTW, you might want to pick up a simple book on dimensional analysis at the local library.  I ran into this by accident my first year of college.  It’s so simple that I was shocked that it never occurred to me, but it is surprisingly powerful in helping keep track of just what you mentioned having trouble with. 

Occam

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Posted: 06 July 2008 01:27 AM   [ Ignore ]   [ # 187 ]
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I found this to be a VERY interesting article… It begun with one of my earliest “science” questions… How fast can information be transmitted by ANY means… I would like to say that as far as the pencil question goes, the answer to me is pretty obvious (would NOT happen due to deformation of the pencil :D) and has been answered many many times in this thread. I have nothing new to add to this matter. But the reason i am posting a reply is this. It is possible to have SOMETHING (clearly not a physical thing) travel faster than light. What do i mean? First let me explain myself. I am aware that nothing with mass can travel (accelerate for some of you) at the speed of light and above. I am aware that information (as we define it) cannot do the same thing. I am not talking about either of these. I am posting the following for an event that not only can hypothetically occur, but one that has been observed many many times before. It is possible to do something that might resemble motion or information delivery at first glance, faster than light. But even though it IS faster that light, it is neither of the two (motion or information).

Assume you have a beacon that is rotating at a constant speed of lets say 2RPS (rotation per second). And its emitting light. Now assume you have a GREAT wall that is half a circle with the beacon as a center, the radius of which is, lets say, 2 light years. We start the beacon, let it reach its maximum speed, turn the light on, leave it revolve a whole 180degrees and shut it of. What we see at the wall’s end is the following. A dot of light that covers the distance of 4π light years (the length of the wall) in 1 second!!!! The dot will appear on the wall a good 2 years AFTER we shut the beacon down but the distance WILL be covered in 1 second FLAT.

I have to make a note here. THIS IS NOT IN CONTRADICTION WITH ANY SCIENTIFIC THEORIES. It is merely a fun mind game that lets you think about what we mean when we say speed limit and what this limit applies to. There is nothing that moves in my example. The motion is an illusion created by our mind as it tries to visualize what is happening. It sees a spiral of photons emitted from the beacon hit the surface of the wall and it perceives it as motion. Thats it.

i always played with this example in my mind when i was a kid and always tried to find a way of transferring information this way faster than light but of course none of them worked. :D:D

And as far as the part where this has been observed… Well we haven’t built a beacon in space and of course we haven’t built a massive wall around it either. What we HAVE observed though is the rotation of pulsars around themselves and they pretty much act as beacons too. :D

[ Edited: 06 July 2008 01:34 AM by kuroSAVVAS ]
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Posted: 06 July 2008 01:42 AM   [ Ignore ]   [ # 188 ]
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come on man think rationally.
who’s gonna sharpen that pencil?

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Posted: 24 July 2008 05:29 PM   [ Ignore ]   [ # 189 ]
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http://www.popsci.com/diy/article/2008-07/quantum-physics-glass

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Posted: 27 October 2008 06:22 AM   [ Ignore ]   [ # 190 ]
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Four men were sitting around a conference room table being interviewed for a job. The interviewer asked, ‘What is the fastest thing you know of?’ The first man replied, ‘A thought. It pops into your head, there’s no forewarning that it’s on the way; it’s just there. A thought is the fastest thing I know of. ‘That’s very good,’ replied the interviewer
‘And now you, sir,’ he asked the second man. ‘Hmmm, let me see….. a blink!,’ said the second man.‘It comes and goes and you don’t know it ever happened. A blink is the fastest thing I know of.’‘Excellent!’, said the interviewer. ‘The blink of an eye. That’s a very popular clich for speed.’
He then turned to the third man who was contemplating his reply. ‘Well, out on my dad’s ranch, you step out of the house andon the wall there is a light switch. When you flip that switch, way across the pasture the light at the barn comes on in an instant. Turning on a light is the fastest thing I can think of.’ The interviewer was very impressed with the third answer and thought he had found his man. ‘It’s hard to beat the speed of light.’, he said.

Turning to the fourth man, a Newfoundlander, he posed the same question.‘After hearing the three previous answers,i t’s obvious to me the fastest thing known is diarrhea,’ said the Newfie. ‘What!’ said the interviewer, stunned by the response ‘Oh, I can explain,’ said the Newfie,‘You see, the other day I wasn’t feeling so well and ran for the bathroom. But, before I could think, blink,or turn on the light, I shit my pants.’

He got the job.

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Posted: 27 October 2008 07:06 AM   [ Ignore ]   [ # 191 ]
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dougsmith - 17 October 2007 07:32 AM

Right. There is no way to transmit information faster than light. This has been drummed into my head by any number of eminent physicists. This is the basic reason not to accept narwhol’s description of the phenomena here.

Just to repeat: we’re talking about moving a rod 93 million miles long and maybe a half-inch in diameter instantaneously, along its entire length. One couldn’t even move a rod half a mile long in this fashion: it would bend elastically close to the initial point of motion, and the bend would create a wave of motion down the rod. Further, the mass and hence inertia of a rod this size would be enormous. Moving one end back and forth would have no effect whatever very far from the point of origin.

Doug and George,I’m no science guy or anything,but Doug I think you are right somewhere in there.It is a cool thought experiment George.It needn’t be muddled with those comments about the heat and stuff.
What about relativity?If George is on the sun,isn’t he in a different time?I don’t know?Is he in the future or the past in relavence to the earth?Yes I understand the 8 min.thing but isn’t there more to it?I don’t know.Explain this to me please.
Is it just simply an impossible scenario?I agree no info can travel faster than light,but with this impossible pencil it makes it possible?

At the point where George starts writing his warning message,aren’t we already in the future,and in the dark so to speak?

[ Edited: 27 October 2008 07:24 AM by VYAZMA ]
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Posted: 27 October 2008 09:11 AM   [ Ignore ]   [ # 192 ]
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Vyazma, everybody is always in the present. It’s just that one person’s present isn’t the same as another person’s present. Whenever you observe somebody else, you are seeing them in the actual present according to you. Don’t get caught up in trying to figure out who’s in the future or in the past—ultimately those calculations mean nothing. Just remember: everybody is always in their own present.

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Posted: 27 March 2009 08:26 AM   [ Ignore ]   [ # 193 ]
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As much as I didn’t like the music in the the Powers of Ten short movie that Doug has posted a link to in another thread ( grin ), it made me realize how different the universe must appear from all these different (size-based) perspectives. If I go back to my OP, where I am sitting on the Sun writing a letter with a pencil that reaches all the way to Earth, and where I now accept that it would have to take longer for the message to reach Earth than the eight minutes it takes light to travel the same distance, I wonder what a giant—who is the size of our solar system—would see. I assume it would not take eight minutes for the light to travel from Sun to Earth from the perspective of the giant. It would be instant; or as “instant” as we perceive light traveling from our computer monitor to our eyes. So what would he see? What would be different? He would probably see me (and everybody else on Earth) to move in a very slow motion, no? Do we then see ants, for example (even though the difference between us and the ants is much smaller than the size difference between us and the imaginary giant), moving slower than they actually do?

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Posted: 27 March 2009 11:15 AM   [ Ignore ]   [ # 194 ]
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Light can exceed the speed of light!

In the most striking of the new experiments a pulse of light that enters a transparent chamber filled with specially prepared cesium gas is pushed to speeds of 300 times the normal speed of light. That is so fast that, under these peculiar circumstances, the main part of the pulse exits the far side of the chamber even before it enters at the near side.

NYTIMES: “light exceeds it’s own speed limit”

Scientist disagree if this is evidence that light can transmit information faster than C.

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Posted: 28 March 2009 03:11 AM   [ Ignore ]   [ # 195 ]
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danlhinz - 27 March 2009 11:15 AM

Light can exceed the speed of light!

In the most striking of the new experiments a pulse of light that enters a transparent chamber filled with specially prepared cesium gas is pushed to speeds of 300 times the normal speed of light. That is so fast that, under these peculiar circumstances, the main part of the pulse exits the far side of the chamber even before it enters at the near side.

NYTIMES: “light exceeds it’s own speed limit”

Scientist disagree if this is evidence that light can transmit information faster than C.

This is from the year 2000; very odd stuff—I wonder if the experiments have been verified and how they are best interpreted. (Often the early press reports are in error).

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