How fast is the speed of dark?
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Chronos-X said:Can anyone explain what light actually is, and why it can/can't be contained?
And also (though not wanting to take this thread off course anymore) if it's not tangible (cant be touched) why does gravity still affect it?
As for the opening question - Dark is as fast as light.
Dark = absence of light, it takes light 8 minutes to reach us from the sun, therefore if someone came along and 'car jacked' the sun - we wouldnt know about it until 8 minutes later (or something)
Mr Spew said:You also get black, try paints.
Paints and light do not produce the same colour when combined... that's why we have CMYK inks, but RGB lights.
To "project" black, you just stop any light at all from that part of the image.
If you drew a black circle in perminant marker on a transparency and put it in front of a white light, you'd get a black spot on the wall where there is no light.
This is why projectors work best in a dark environment, you'll never get black bits otherwise as they'll always be light from an external source interfering.
EDIT: READ THIS: http://home.att.net/~RTRUSCIO/COLORSYS.htm
laiman said:
They dont, the best a projector can do is not project any light, the best the TFT ones can manage is to black out their TFT panels to stop as much light as possible hitting the screen. CRT (triple gun, red green blue) projectors are the only projectors which can shut off all light where they want to show black, hence why their images look the best
So the black on a projected screen is just the white screen, but dark because you have the lights off and no projected light is hitting it.
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Depends on which way you look at it from...Chronos-X said:Can anyone explain what light actually is, and why it can/can't be contained?
You can think of it either as a wave (more specifically, an oscillating electric and magnetic field, perpendicular to eachother), or you can think of it as discrete quanta of energy, called photons, which is what quantum theory is based on.
As for containing light, that's like trying to contain sound, or a wave in a box of water, it just keeps getting reflected/scattered off surfaces and diminishing in intensity. Since light travels at a constant speed, you can't just hold it in one place, it must always be moving (the exact speed is dependant on the medium).
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Is this right...
when you turn on a light it must take so many milliseconds for the light to reach you as it has a speed.
when you turn the light off there is no delay though and the darkness appears instantly as it has no speed.
???
when you turn on a light it must take so many milliseconds for the light to reach you as it has a speed.
when you turn the light off there is no delay though and the darkness appears instantly as it has no speed.
???
nO}{8 said:when you turn the light off there is no delay though and the darkness appears instantly as it has no speed.
???
The light dissapears at the same speed as it appeared. Stop trying to imagine the dark having speed or even trying to quantify it. There is no dark, just a lack of light.
"Do not try and bend the spoon. That's impossible. Instead, only try to realize the truth. ... There is no spoon. " [/matrix]
If the light stopped being emitted immediately then it would still take the same length of time as the light first reaching you.nO}{8 said:Is this right...
when you turn on a light it must take so many milliseconds for the light to reach you as it has a speed.
when you turn the light off there is no delay though and the darkness appears instantly as it has no speed.
???
Regardless of this, the filament in a lightbulb stays hot, and therefore light, after being turned off for a far longer time than it takes the light to reach you from the bulb anyway so this is the deciding factor in reality.
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reading the thread though.. i dont see what everyone is stuck on...
im sure this has been said but, lets say light is a wave. and when that wave hits ** eyes you see it as light.
so you turn lights on wave is emitted by light bulb. turn light off light bulb stops emitting waves.
im sure this has been said but, lets say light is a wave. and when that wave hits ** eyes you see it as light.
so you turn lights on wave is emitted by light bulb. turn light off light bulb stops emitting waves.
laiman said:
Depends on what projection technology you're talking about. With CRT the electron guns won't fire at that location, so the phosphur won't light up. But with LCD the LCD matrix goes black, shutting off as much light as possible from the light source passing through the panel. More or less.
lol @ speed of dark questions.
Didnt you guys go to school? We see light as it reflects off of things. We see different colours when all other colours in the spectrum are absorbed and the colour we see if reflected. When we see light, we dont see "it", we see the materials its reflecting off. Therefore when the light is switched off, we no longer see anything because there is no light to reflect! Dont try to imagine darkness or the colour black as a 'thing', its the absence of light or absorbtion of the colours in the spectrum respectively.
Didnt you guys go to school? We see light as it reflects off of things. We see different colours when all other colours in the spectrum are absorbed and the colour we see if reflected. When we see light, we dont see "it", we see the materials its reflecting off. Therefore when the light is switched off, we no longer see anything because there is no light to reflect! Dont try to imagine darkness or the colour black as a 'thing', its the absence of light or absorbtion of the colours in the spectrum respectively.