Assume we have a box with perfect reflection on the inside. Now we somehow shine a flashlight in there while keeping the box sealed and without putting something in (something like a one-way mirror perhaps?). Assuming that the box has to leaks, could I keep those photons bouncing happily around in there forever? What would happen to them?
I have had Physics 1, so I understand some principles. But please go lightly (sorry about the pun!) on the deep physics terms!
Thanks!
Only if you could get a surface that somehow could reflect 100% of all energy striking it. So far, there isn’t any such surface known, nor is it very likely one will be created. Anything less fine would absorb even a tiny fraction of the light as heat, and would quickly “extinguish” the light.
Even if you did, though, you’d have to make it a perfect vacume. Even a single particle in there would eventually absorb the energy (Or so I would assume).
It would be effectively impossible with current technology, or any technology that is reasonably conceivable. But if it could somehow be done, then you would ‘trap’ the energy as light inside it. When you open it, you’d get a ‘flash’ of light as it all comes out.
(Not a physicist or anything, just well-studied in such things for fictional purposes, but I’m pretty sure that’s all right…)
Yes you can. But you need a mirror that reflects 100%.
I’d just like to reiterate that you’d need a mirror that can reflect 100% of the light. That’s a mirror that can reflect 100%.
Okaaaay, what’s the current reflection quotient of your average mirror then?
How much light does it absorb, and how much is delivered back to the observer??
I imagine that a super-conducting surface would be perfectly reflective (at certain frequencies, anyway).
LMAO!!!
It’s like the very first sentence after the title in the OP was written in freakin’ chinese or something.
This is not a new idea, Dr. Lene Hau at Harvard has actually built a box that will hold light for a half an hour or so. Problem is the heat generated by atoms trapped and travelling at such speeds. You can imagine the explosive posibilities of such a device.
Anyway she has cooled the box to within 1/50 of a degree above absolute zero. It would take absolute zero (theoretically impossible) but, she has slowed the speed of light down to 38mph.
I don’t know for sure if this helps but here you go:
http://dustbunny.physics.indiana.edu/~dzierba/P360/Week13/light/story2.html
So, in response to your question, I would say yes it probably IS possible. Although not nearly as simple as your idea.
If a single particle absorbed a photon, it should re-emit a photon of exactly the same energy in a pretty short amount of time. It shouldn’t cause a problem.
As to mirror, gas lasers use some fantastic mirrors called dielectric mirrors. They are turned to the freqency of light you intend to reflect. They also don’t reflect well at angles not close to 90 degrees to their surface. But, even these mirrors would not be enough. As far as I know, they are the closest thing we have to a perfect (100%) reflective mirror. But even they don’t quite do the trick.
Any interesting thought problem, how do measure how long the light stays bouncing around inside your box? Any device that could sense a photon hitting it is required to detroy/absorb the photon. If you built a perfect light holding box, putting any device in to prove it would necessarily ruin it. The only way I could think to do it would be to bottle up the light and keep it for longer and longer periods before testing. Each time you took a measurement, you would have to “refill” the box with photons. This relates closely to the “invisible eye” thread.
As an aside, people are working on fiber optic replacements that would actually be little optical waveguides built with rolled up dielectric mirror tubes. These should be fairly inexpensive and be able to carry communications for 100’s if not 1000’s of miles without reamplification. 20 miles or so is about the practical limit for conventional fiber optics.
How reflective do the sides need to be? Like, 100%?
Did I somehow miss the boat on something this important? She slowed the speed of light down to 38 mph. What am I missing here?
Granted, it’s been 5 years since I took college physics, but I did take the advanced calculus-based course not the watered down one for Animal Science majors. I recall something about the wave-particle duality of light, something having to do with quanta of light. I never heard anybody tell me that the speed of light could be slowed down. I was under the impression that lightspeed was fixed, and that this in fact was part of the fundamentals of Einstein’s physics. Aren’t we talking about a vacuum here? I suppose a wave’s speed varies when travelling through a medium, I do recall that, but how do you slow down light in a vacuum? Why would cooling it have anything to do with the speed?
More like 100%, I’d say.
Well, yes, OK, 100%, but how close to 100%? I mean, are we talking 100% or something, you know, sort of like 100%?
Well, yes, OK, 100%, but how close to 100%? I mean, are we talking 100% or something, you know, sort of like 100%?
Oh, they’ve slowed it down even further - ]1 mile per hour.
Check some other links here for more technical details. I’d summarize it, but I’m afraid I’d get some crucial scientific point wrong, so I’ll give you the original sources.
One-way glass…
Then you can look in to see if the light is still there 
(Making sure it is 100% reflective inside, of course)
But wouldn’t it have to be 100% reflective?
Why the heck does this question keep coming up? I know that I’ve responded to it myself several times. There have been quite a few responses, so I’ll just note that it’s a heckuva lot easier to capture that photon energy with a sheet of black paper than with a complex mirror arrangement.
…unless that mirror arrangement is 100% reflective.