i was wondering if there was a speed of darkness…wouldn’t it just be the opposite of light…but everyone tells me it doesn’t exist…well i think it should be discovered…can you help?
another one is why do humans only use at most 10% of their brains and why can’t we figure out how to use more???
RJ
First, you could pick titles more descriptive of the questions you are asking. Cecil rarely visits GQ, so mere mortals have to guess which threads are worth visiting. 
Darkness is simply the absence of light. It has no speed, because nothing spreads it. Photons spread light, and photons have a speed, so we know the speed of light. Darkness is just where there is no light. So asking for the speed of dark makes no sense.
We use 100% of our brains. The 10% myth is a common urban legend, nothing more. Here is a link that should answer your question: http://www.snopes2.com/spoons/fracture/10percnt.htm
Oh, and welcome to the Straight Dope.
And Cecil, indeed, has weighed in on the 10% question: http://www.straightdope.com/classics/a3_028.html