[Emilio Romero (OP)]

Ok, it gets dark pretty fast....  []

[Ethos]

Ok, it gets dark pretty fast....  []

One unit of Plank time.............5.39124X10^-44 seconds

Nothing is darker than the mind of the suspicious.............Ethos

[Emilio Romero (OP)]

so, there is a speed of light, of darkness, of sound and silence...
 [] [] []

[Don_1]

..... and the UK government have set up speed cameras for the lot!!!

[Fortran]

I measured the speed of darkness last night, it was light for about an hour and a quarter after the sun went down  so I estimate the speed of sdarkness to be around 34mph.

[Emilio Romero (OP)]

great !!
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[LeeE]

It depends upon the type of light that is being switched off.

An incandescent light bulb doesn't cool instantly and if you're not looking directly at the bulb when it's switched off it is sometimes possible to detect that the dimming of the room takes a small but perceptible period of time.

I've also noticed that one of my energy-saver bulbs sometimes flashes quite brightly a few times after it has been switched off.  I suspect this is due to stored charge in the bulb electronics, but I'm not sure about that - there appears to be no faults in the switch and I am happy that it is isolated when the flashes occur.

[Fortran]

Ok time to put you all out of your misery, the speed of 'dark is the same as the speed of light. If the sun instantly dissappeared it would take some 8 min 20 secs before the last (direct) light (from the sun) hit the earth

[Emilio Romero (OP)]

thus the speed of silence is the same as the speed of sound...  []

[Fortran]

thus the speed of silence is the same as the speed of sound...  []

No, it took you a whole 2 hours for you to shut up! lol!

[Emilio Romero (OP)]

touché...

[Yomi]

speed of darkness is same as speed of light

[scalyblue]

Darkness is the absence of light; since it doesn't exist, it can't have a speed.  The light will stop radiating out of the bulb and traverse the room at the speed of light until it hits something, that reflected light will go to your retina to be processed into visual imagry

If you really want to be pendantic about it, your perception of the darkness happens at half the speed of light, plus the response time of your visual cortex.