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 blackcat129
Joined: 7/22/2009
Msg: 1
slowing light downPage 1 of 2    (1, 2)
I have a question about light. If you were to use dimounds and mirrors,dimounds for there refractive quality of slowing light down and mirrors to reflect it accordingly would it be possable to slow a beam of light down enough to observe its movement with the naked eye? Or would it loose to much energy to continue traveling on its electromagnetic wave and the photons just desperse into their sourondings?Just curious.
 nanojeff
Joined: 7/13/2009
Msg: 2
slowing light down
Posted: 7/30/2009 7:53:42 PM
I am not sure on this particular topic, but I think you would be quite interested in Bose-Einstein Condensates wherein, you can "slow down" light speed to approximately 38 miles per hour.
 CoeurDeLion246
Joined: 7/2/2009
Msg: 3
slowing light down
Posted: 7/30/2009 8:16:28 PM
I'm not the most educated physicist, but I'm pretty sure that I can respond to your question. You 'see' by having photons hit your eyes, to put it simply. So the speed of the particles is not relevant to your ability to 'see' them, it's the very mechanics of the process by which you 'see'. Since 'seeing' is simply the process of having photons hit your eyes, you can't 'see' an individual photon no matter what its speed.
 Mister Logic
Joined: 3/5/2009
Msg: 4
slowing light down
Posted: 7/30/2009 8:37:50 PM

If you shine a light at a wall you can bring it to a complete stand still.

Uh... by "it", do you mean the "light", or do you mean the "wall"?

You can't really bring light to a stand still (except if you mean that the photon becomes absorbed by the wall and thereby raises the energy state of one of the atoms in the wall).
 nanojeff
Joined: 7/13/2009
Msg: 5
slowing light down
Posted: 7/30/2009 8:51:39 PM

I'm not the most educated physicist, but I'm pretty sure that I can respond to your question. You 'see' by having photons hit your eyes, to put it simply. So the speed of the particles is not relevant to your ability to 'see' them, it's the very mechanics of the process by which you 'see'. Since 'seeing' is simply the process of having photons hit your eyes, you can't 'see' an individual photon no matter what its speed.


Of course you couldn't visualize an individual photon regardless of its speed. You still have various uncertainty principles to abide by depending upon the nature of the photons you are trying to "see".
 CoeurDeLion246
Joined: 7/2/2009
Msg: 6
slowing light down
Posted: 7/30/2009 8:56:43 PM

Of course you couldn't visualize an individual photon regardless of its speed. You still have various uncertainty principles to abide by depending upon the nature of the photons you are trying to "see".


That's my point. The OP wanted to know about observing photons with the naked eye, hence my statement.
 blackcat129
Joined: 7/22/2009
Msg: 7
slowing light down
Posted: 7/30/2009 9:08:38 PM
no i wanted to know if i could see the stream of photons the light beam that is which consist of billions and billions of photons
 Mister Logic
Joined: 3/5/2009
Msg: 8
slowing light down
Posted: 7/30/2009 9:15:39 PM
i wanted to know if i could see the stream of photons

How do you plan to illuminate them so that they're not dark?
 nanojeff
Joined: 7/13/2009
Msg: 9
slowing light down
Posted: 7/30/2009 9:25:43 PM

no i wanted to know if i could see the stream of photons the light beam that is which consist of billions and billions of photons


You will never see the photons. You can find evidence of their existence by using such techniques as Raman Scattering or Brillouin Scattering.
 DangerInTheDark
Joined: 8/20/2006
Msg: 10
slowing light down
Posted: 7/31/2009 1:19:44 AM
A problem I'm seeing with the thought flow here is, drawing from previous posts, if light is a gestalt created by a mass of photons, and one was able to slow this beam of photons down the a visual speed, how would the light reach one's eyes? I ask this question because in order to view light this way, one would require a vacuum, so as to minimalize the factors affecting the experiment. However, because one wants to see the light, one becomes a factor in the experiment, and one cannot survive in a vacuum. Even a spacesuit type aparatus would not work, as the air within the suit would render the vacuum environment moot point. Another factor contributing to my question is, in this controlled environment, one would want to minimalize the loss of lightmass, or the amount of photons branching off in any direction but that assigned. So, in effect, the experiment would actually have to take place 'in the dark', persay, as the light required by eyes to view the slowed lightmass would corrupt the lightmass. The problem fundamentally lies in a Catch-22: To observe lightmass, we must use light, which requires it's own lightmass. It's like trying to capture a water drop with a river and still have two separate entities.
 bazza1965
Joined: 3/6/2007
Msg: 11
slowing light down
Posted: 7/31/2009 1:23:01 AM
Use Speed Cameras lol
 DangerInTheDark
Joined: 8/20/2006
Msg: 12
slowing light down
Posted: 7/31/2009 1:25:02 AM
As a further point, considering our inability to slow light in the proper environment for viewing, a solution (however farfetched with today's technology) would be to speed up the viewer to near the speed of light. This is, of course, a thought experiment, since as I stated before, our technology base does not support a real experiment of this kind. Were one to reach a speed close to that of light, we would observe the light at its natural speed relative to ours. In other words, were we to move at a rate of speed 20 km/h slower than that of light, we could view it as if it were moving at 20 km/h.
 craig14228
Joined: 7/24/2009
Msg: 13
slowing light down
Posted: 7/31/2009 1:37:53 AM
light travels at c no matter what. The prism does not slow it down, it just breaks it down into separate components based on wavelength. When it leaves the prism, it is still traveling at c. Light always travels at c to any observer. That relativity. You can never slow light down to observe it better.
 abelian
Joined: 1/12/2008
Msg: 14
slowing light down
Posted: 7/31/2009 8:50:02 AM
You always observe light with the naked eye, since that is what your eye responds to.
 JustDukky
Joined: 7/8/2004
Msg: 15
slowing light down
Posted: 7/31/2009 8:54:48 AM
You always observe light with the naked eye, since that is what your eye responds to.

...except on Sunday mornings when I can't get them to open.

Oops...logical flaw in my argument (eye's can't be simultaneously naked and closed)...I blame the booze.
 AwP
Joined: 12/31/2006
Msg: 16
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History
slowing light down
Posted: 7/31/2009 11:14:35 AM
Depending on the properties of whatever substance is being used to slow down light, perhaps it could be done in a large cylinder made of something transparent like glass. As the light creeps along the cylinder, any light that refracts into the sides of the cylinder containing the beam would resume normal speed, allowing you to see how quickly it's moving through the cylinder with the naked eye.
 lyingcheat
Joined: 9/13/2009
Msg: 17
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History
slowing light down
Posted: 1/26/2013 8:17:16 AM
One way of slowing light down is filming it (very short pulses) at very very high speed...


Trillion-frame-per-second video
By using optical equipment in a totally unexpected way, MIT researchers have created an imaging system that makes light look slow.
http://web.mit.edu/newsoffice/2011/trillion-fps-camera-1213.html


http://web.media.mit.edu/~raskar/trillionfps/
http://www.mit.edu/~velten/press/content/
slowing light down
Posted: 1/26/2013 8:07:41 PM
...uh...can I find out what sound sounds like if I slow it down so that it hardly even moves enough to reach my ear? Could I still "hear" it? Am I trying to hear what it sounds like if I make it slower...or what??
 basher2
Joined: 12/11/2007
Msg: 19
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History
slowing light down
Posted: 2/12/2013 9:13:39 PM
The answer is -
sort of.
If you were to pulse a beam of light through a medium that slows light down to speeds that are observable with the naked eye, and ensured that the medium would diffuse or scatter light (kind of like how you can see a laser beam as it passes through smoke, or why the sky is blue), then you would see something somewhat similar to the star wars laser bolts.

However, keep in mind that it is very difficult to see something traveling even as relatively slowly as a bullet. So, to slow down light (300 000 000 meters per second), your index of refraction would have to be 1 million, just to slow it to 300 meters per second. This type of material does not exist. Yet?

The other way to do it would be to make use of some of the things that scientists call "very big". Light traveling through nebula that are light years across should show some of these effects (they tend to be very diffuse, so their indices of refraction would be extremely close to 1).

The key is that you could not see one electron, traveling. You only "see" when the electron hits your eye. You would have to see the electrons that are scattered away from the main beam.

Neat question, though.
 justlookingvt
Joined: 5/8/2010
Msg: 20
slowing light down
Posted: 2/12/2013 9:52:02 PM
Not only can light be slowed down, it can be stopped completely. For information regarding how this is possible, refer to:

http://en.wikipedia.org/wiki/Slow_light

The basic idea is that when light enters a medium (instead of a vacuum), the frequency and amplitude of the wave, light is traveling upon is no longer a pure electromagnetic wave (it becomes a composite wave due to the presence of a medium). This opens the possibility of modifying the composite carrier wave yielding very slow speeds or even stopping light altogether. In the article mentioned above, follow the link to group velocity and particularly the link to phase velocity where the concept of the group velocity of composite waves is nicely explained (see the portion titled "Relation to group velocity, refractive index and transmission speed")
slowing light down
Posted: 2/18/2013 3:37:46 PM
Forgetting about the elements of light which are lost because of the two-way...either -

1- your mirrors are perfect, and the light would just bounce around in there forever.

2- your mirrors aren't perfect...not perfectly clean...and so eventually more and more of the light that hits the not-perfectly-clean parts of the surface therefore transform into heat or whatever, until it just gets dark in there. And probably not so warm though.
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