Black Light
Why don't we have black light? A torch with black light will give a black beam. It will darken the surface of whatever object it strikes. What prevents us from doing this? Or is it not possible at all?
- Hitendra Joshi
- Hitendra Joshi
Labels: SharedPuzzle, thinktank
posted by Rajesh Lal at
2:08 PM
18 Comments:
Black is not within our visible light spectrum because it is not a colour. We can only see black in the absence of light.
-Master Chief
Black is the absence of color
a black light is an oxymoron.
A "black light" used in nite clubs, etc. is really and ultra violet light - not really a "black" light.
Light is a form of energy, a black light, as you suggest, would in fact suck the energy out of things, a feat currently considered to defy the laws of physics. Black lights used in night clubs are not UV lights, as we cannot see those, the are i combination of visible light, what we can see, and a number of other forms of Electromagnetic radiation, including UV.
"Black light" is a misnomer. The bulbs that produce this effect are actually in the violet frequency range, which reflects well on high light reflecting surfaces and not at all on high light absorbing surfaces. Black is not a color, but rather the absence of visible frequencies in the direction your eyes are looking. Scttered light from other nearby sources give different "shades"to what you see as black.
If you want to darken the surface of an object, why don't you just put on some sun glasses? JK
Actually it could be done. Firstly, ay radiation that's outside the visible spectrum could be thought of as bloack light, although (as several commentators have pointed out) this usualy refers to UV radiation. The idea of a torch that you could point at things and darken them is intriguing - theoretically it would be possible to determine the phase and wavelength of each quantum of light energy (photon if you like to think in those terms) and transmit one in antiphase. The result would be a darkening of the object as much of the reflected light is cancelled out. In practice this would be a formidable task - the likes of CERN do this sort of thing on a small scale (a few quanta at a time) but it's well beyond current technology. Not for long though ;-)
Then of course there's Heisenberg's principle (Google this if you feel the need), which tells us that we can't measure quanta beyond a certain accuracy, so darkening rather than blackening an object may be the best that we can do.
Frog Twissell
Quantum Mechanic
we dont have it because we dont need.
I have a black light. It's in my ceiling. The control switch has two positions. Up lights up the room, Down activates the black light, and when I use it, the whole room goes black.
Maybe you have one too. Try it.
Ragknot
LMAO ! Don't try to be funny !
there is no 'light' in darkness...
The Marine's have hi-tech camoflage systems similar to something you might see on Knight Rider or Harry Potter's cloak. Couldn't something like that be used, just 'dim' the outputed light.
we don't have anything "black-holeish" to bend light toward it. as far as i know, extreme gravity is the only thing that can bend light...
u guys are idiots... hes asian... they already have that technology... he just wants to who else in the world is a threat to the asians
sorry... i left out see between to and who sorry for any inconvenience
no im not racist
the only way this could happen is if you use an extreme source of gravity like a black hole, otherwise it is impossible.
as an odd gothic girl once pointed out to me
-White is the absense of color.
-Black is the absense of light.
so therefore if we used black (as a light) then we would not be able to register it on our visible light spectrum.
thank god for that weird girl that was curled up in the corner of the locker room so many years ago...
actually there is something called "black light" it's a light that is part of the UV light spectrum and is highly energetic, but we can not see it because our eyes can not go that far into the spectrum
other people said it also when they were mentioning the electromagnetic spectrum though, just wanted to be a big specific for what "black light" is =)
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