h a l f b a k e r yLoading tagline ....
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
Suppose you want to store energy in empty space rather than a battery. It's easy to think of compacting lots of photons into space. What you need, is either a black hole, or a superreflector.
All modern materials have non-100% reflectance. For example, silver has 98.2% for 550 nm wavelength.
So,
a hypothesis: a material exists with very close to 100% reflectance.
(Similar to superconductivity, and superfluidity.)
If exists, just imagine how light batteries could be....
98.2% - for silver, from here.
http://www.kayelaby...sics/2_5/2_5_9.html
[Inyuki, May 09 2015]
can you permanently capture light?
https://m.reddit.co...ntly_capture_light/
[xaviergisz, May 09 2015]
Total Internal Reflection
http://www.physicsc...Internal-Reflection
Partway to Maxwell's daemon [csea, May 09 2015]
Wikipedia - Reflectance
http://en.wikipedia.org/wiki/Reflectance
[Inyuki, May 10 2015]
Slow light down to 60 km/s
http://news.harvard...999/02.18/light.htm
[AusCan531, May 11 2015]
attenuation in optic fibre
http://upload.wikim...-Zblan_transmit.jpg
from wikipedia [xaviergisz, May 11 2015]
[link]
|
| |
Yeah, I agree, these are big questions, [bigsleep]. Light explosions, among the risks. |
|
| |
But before even having these questions, the biggest one is -- would such material be possible. |
|
| |
A company called Newport makes mirrors with
reflectivity >99.7%, but this is a bit like the
difference between a good conductor and a
superconductor. |
|
| |
Problem is, even with 99.7% reflectivity we get just 100 bounces till we drop to just 74% left. So, if we have mirrors 3 m apart, that would give 0.000001 second to drop from 100% to 74%. (with mirrors 3000km parat you could see something of macroscopic time though) |
|
| |
To sustain for 1 second for mirrors 3 m apart, we'd need reflectivity 99.9999997% to sustain 100000000 bounces till we drop from 100% to 74%. |
|
| |
[bigsleep], very interesting! I wonder, what's the transparency/resistence of fiber optic cables. |
|
| |
Could a geometry be derived within a series of steps
in or graduated indexes to create multiple /
infinite TIR [link] ? |
|
| |
Hmm, [xaviergisz]' link says no. Oh, well... |
|
| |
Maybe, this will be the battery that you have to put a small % of energy into, for a structure and enviroment that can store the light. |
|
| |
If you had a very small black hole, you could just place the
light In orbit, not thought of how to get it out though. |
|
| |
The graph that shows reflectance curve in Wikipedia looks asymptotic to y==100 line. |
|
| |
Seems like the longer the wavelength the higher the reflectance. |
|
| |
I wonder if there's a sweet-spot for some wavelength and material. |
|
| |
It seems like you could see back into the past with this. |
|
| |
Eventually, I'd think the light would heat up the medium and dissipate. |
|
| |
[bigs], the Wikipedia article says TIR can get up to
99.999%, which is four nines short of what's needed
here and many more short of perfect. |
|
| |
If a perfect mirror doesn't exist, you might need
achieve the same thing by letting the light go in a
straight line and bending space. A couple of very tiny
black holes a few mm apart would do the job - just
launch the light into a figure-8 orbit that skirts the
two event horizons. |
|
| |
[bigsleep] Does this mean the exotic materials, once flooded internally to saturation with light, would have novel behaviours? |
|
| |
//To sustain for 1 second for mirrors 3 m apart, we'd need
reflectivity 99.9999997% to sustain 100000000 bounces till
we drop from 100% to 74%// |
|
| |
Only when light travels a full 300,000 km/s If you could
slow it to down to 60 km/s as per the linked article
sustainability increases markedly. |
|
| |
//[MB] Read it again carefully. "Perfect mirrors exist
as TIR// |
|
| |
Ah yes, it seems you are right and I was wrong.
Howevertheless, you're then left with the problem
that the light is travelling through a dense medium
(such as glass or water). I'm not sure how
transparent a material can be, but optical fibres
generally have boosters every few tens of kilometres.
This suggests that light in an optical fibre is
attenuated (presumably by absorbance) by a
significant factor over that sort of distance. |
|
| |
//Some cores are better than others.// |
|
| |
True, and I agree that surface defects probably
account for some of the losses. We need an estimate
of the losses due to absorbance by the glass. |
|
| |
You're assuming that all the losses are reflectance
losses. How much light is lost through absorbance? |
|
| |
//About 50% as I just mentioned. // Wait - I'm
meant to be paying attention? |
|
| |
Don't pay anything!
Does TER work?
A vacuum fibre... |
|
| |
No - the light will bounce back and forth between the
sticky-outy bits of the E and get absorbed. |
|
| |
Is there a limit for the maximum photon density in a defined volume for the natural world? say inside the sun or a black hole. |
|
| |
Send the idea to Elon, Im sure Solar City would like
make their home batteries a bit more flashy and
prestigious. |
|
| |
P.S everyone please buy more Solar panels. II need to
make sure my investments meet their targets this
year. |
|
| |