What is the speed of darkness?
373426
Well, since, as stated before, darkness is the absence of light, it travels at the exact speed of light in a given medium. For example, if you turn a light on in a darkened room, it gets bright very quickly (exactly how quickly will depend on the type of light bulb or the colour of the light you use), but when you turn it off, it gets dark at the same rate. Though darkness isn't something that really "travels", what you're measuring is how fast light dissipates, which is at the speed of light!
492088
The speed of sound isn't even close to the speed of light. The speed of sound in air is usually given as 343 meters per second at sea level in air and the speed of light is approximately 3 X 10^8 meters per second (300,000,000 m/s)in a vaccuum.
311698
I'm not sure if this is what you are looking for, but rapidity, in special relativity, is defined as \n\ntanh(rapidity) = v/c,\n\nwhere v is the speed of the particle, and c is speed of light.  For v << c, rapidity ~= v/c; for high v, it may be a more intuitive measure of speed beacuse it ranges from 0..infinity (as opposed to v/c, which is always < 1)
600967
No there is no 'summation' of speeds involved with light.  Light is Electro-Magnetic Energy, although light travels as particles as well as waves.  In this Universe the speed of light is a constant, roughly 186,000 miles-per-second, or 300,000 km/sec or 300 Mega-Metres / sec.  Unless some POWERFUL external force acts upon light, it cannot change speed.  This entails the gravity of black-holes and such. (Not even light can escape from them.)\n\nA vehicle might weigh somewhere in the neighbor-hood of 3,300 lbs. (Approximately 1,500 Kg, for those of you who have not learned to count properly, just yet ...)\nCheck out da' math ...\n\n60mph = 100 kmph = 27.77r mps. \n(1,500 Kg x 27.77r mps) / 9.81 mps = ~ 4,246 N\n\nI doubt, very seriously, that a little over 4,000 Newtons is enough force to even put a dent in the factor of light-speed.  For more info, look-up Einstein's Theory of Realtivity' (Although I believe 90% of it to be short-sighted ancient crap ...)  This subject is covered in it ...\n(umm covered in Einstein's Theory, not copvered in crap .. which err .. is the same thing at times ...
1164047
The speed of light is only defined as a positive number.\n\nThere is no inverse of light speed - no "negative" light speed.\n\nThe speed of "dark" is undefined, since anything times nothing is undefined.  \n\nAll you can do is state how fast light moves out of a location once its source is discontinued.\n\n\nBy the way, saying that "everything has an opposite" is a false statement.\n\n\nHowever, I can see a case for considering that there may actually be a phenomenon of dark spreading at alarming speed, namely the Republican Party.
48947
Darkness is just the absence of light. Darkness is always there. But in theoritical sense, it should be as fast as light  because when the light goes off suddenly, darkness can creep in immediately.\n\nBelow is an interesting thread i found online in an australian website.\n\n"If the speed of light is known, what is the speed of darkness? The two opposing schools of thought that have developed are:\n\n1. Darkness does not move, it is always present, and light is layed on top of it. (As an analogy, consider a table as being darkness, a tablecloth as being light: when you pull the tablecloth off, the table itself (darkness) doesn't move).\n\n2. Darkness moves at the same speed as light, and it meets the laws of motion in that Darkness is the equal and opposite reaction for the action of the movement of light. "\n\nCourtesy:- http://www2.abc.net.au/science/k2/stn-archive1/posts/topic1942.shtm
755656
Light, as we know it, is a rush of photons.  As the photons go along, they would leave a darkness behind the last photon that would follow along at the speed of light.\n\nSince darkness is the absence of light (light would be something like the force acting upon or going through the dark), then by itself, dark has no speed.  It just is.
462491
The speed of light in a vaccum (any space with no matter to interfere) is 299,792,458 metres per second.  Light travels slower through fluids like our atmosphere, and water, and through translucent or transparent matter like lenses.
435346
10% of the speed of light is roughly 1,116,000 mph (186,000 mp/sec * .1 and then mult by 60).\nIt is roughly 1,796,000 kph.
43761
The speed of light in a vacuum is exactly 299,792,458 metres per second (or 1,079,252,848.8 km/h, which is approximately 186,282.397 miles per second, or 670,616,629.4 miles per hour; sometimes roughly 300,000 km per second). This value is denoted by the letter c, reputedly from the Latin celeritas, "speed", and also known as Einstein's constant. Note that this speed is a definition, not a measurement, in that the fundamental SI unit of distance, the metre, is defined in terms of the speed of light: one metre is the distance light travels in a vacuum in 1/299,792,458 of a second. The speed of light through a transparent medium (that is, not in vacuum) is less than c; the ratio of c to this speed is called the refractive index of the medium.
779931
The speed of light in a vacuum is exactly 299,792,458 meters per second (fixed by definition). Although some people speak of the "velocity of light", the word velocity is usually reserved for vector quantities, which have a direction.\n\n\nNothing has a speed greater than the speed of light.\n(except in Science Fiction stories)
53714
Speed of light is 186,282 miles per second\nSpeed of sound is a much slower 761 miles per hour at sea level, although that reduces in higher atmosphere, coming in around just 660 mph at 20,000 feet.
647799
You can't go at the speed of light. It's a theorical limit, so it's unreacheable. Only the light can reach it.\n\nIf C is the speed of light, the fastest you can get is C*0.999999999... (insert as many '9' as you want). When you turn on the headlights, they will be somewhat faster: they'll reach the speed of light.
753670
The speed of light varies depending on the medium the light is traveling through.  In a vacuum however, which is the fastest medium in which light can travel, the speed of light is 299,792,458 m/s.
194843
The speed limit of the universe is the speed of light in a vacuum, nothing with mass can obtain this speed or go any faster.\nIn a vacuum, light will propograte at the speed of light.  In any other medium, light slows down, it does not speed up (your thinking of sound waves that travel faster through denser mediums).\n\nThe inverse of time (unit: second) would be 1/t (or 1/second).  To an average person, this unit wouldnt mean anything, however, you sometimes will see data graphed nothing using time, but the inverse of time on the X axis.  This is done to make the graph easier to understand, since of course, happiness is a straight line.\n\nAny amount of time you can think of can be reduced into a smaller amount. 1 second?...1/2 second.  A nanosecond?...an attosecond (E-18 s).  You can always find a smaller unit, there is no absolute unit of time.
125613
dark doesn't exist, what we measure is the absence of light so there is only the speed of light not dark
157107
Interesting question.  Actually, it may be that 'darkness' is faster than 'light.'  In the universe, there appear to be vast regions of nothingness, like the inside of soap bubbles, that are expanding in volume as fast, or even faster, than the speed of light.  \n\nIt seems like the presense of nothing (or more precisely, the lack of anything at all) has a very weird effect on the 'fabric' of space-time, causing it to expand more rapidly than space which is near to 'stuff.' \n\nThis is called 'zero-point vacuum energy' and plays an important role in modern views of cosmology.