Light slows down while travelling through certain mediums, such as extremely dense materials, like diamond. How slow can light be made? Is it at all possible to slow light down to a litteral crawl? Does such light have any special properties, as compared to “normal” light travelling in vacuum?
Diamond isn’t particulary dense. It has a specific gravity of 3.5, which is greater than Aliminium’s 2.7, but less than Iron at 7.9, and way less than Osmium/Iridium at 22.5.
There’s a term “optical density”, but that’s really a bit misleading. Better to talk about refractive index or relative permittivity.
My physics teacher told us that there was a meterial (I don’t remember what it was) that could slow light down to the point where you could walk faster then it. (Of course I’ll have to look for a cite to back this up with).
Here’s a site where they claim they got it down to 38 MPH
Wow. All of this physics talk makes my head spin - it’s absolutely fascinating, but I have a hard time understanding it all.
Desmostylus, I know that diamond isn’t particularily dense compared to other materials, but I chose it because it is a particularily dense transparent medium (to the lay person, who has never heard of alexandrite crystal).
On a related note, one of the more fascinating things that the articles point out (in my opinion) is that regularily opaque materials can be made transparent. I can remember the ads in the comic books that I used to read about “X-ray glasses” that would seemingly do the same thing. I always longed for a pair of those glasses!
Another thing that I found interesting was that light could also be made to travel 310 times faster than c. Could someone explain exactly how this works to me in laymans terms?
Does “slowed down light” have any strange behavioural properties, aside from being really really slow?
Here are a few amusing questions that my brain has come up with:
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If you can actually stop light in certain mediums and conditions, could you (presuming that all conditions were right and that doing so would not disturb the medium or conditions) reach out and hold the “captured” light in your hand?
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I have always wondered about a “strange mystery box”, that was perfectly circular in shape, hollow, and lined with a perfect (in both reflection and curvature) mirror. If you could let light in and close the door to the box fast enough, would you have “trapped” the light inside for all of eternity? (Unless someone opened the box again, in which there would be a brief flash of light and then nothing) I always thought this would be impossible (however very cool), because you could never close the door to the mirrored globe fast enough to prevent the light escaping from the hole it was let in by. However, seeing as scientists have now beeing able to slow light down to a crawl, perhaps my trapped light globe could be possible.