Speed of Light

Speed of Light
12000 Lunar Orbits/Earth Day

Variable Speed of Light

An observer outside gravitational fields measures the speed of light locally (in his location) at 299792.458 km/s but when he looks towards a black hole he sees the speed of light there to be as slow as a few meters/s. At the same time an observer freefalling into that black hole measures the speed of light locally (in his location) at 299792.458 km/s; when he looks towards the black hole he sees the speed of light there much slower; when he looks away from the black hole he sees the speed of light there much faster. When he looks towar

ds outside gravitational fields he sees the speed of light there a zillion km/s. In 1915 (10 years after Special Relativity) Einstein developed another theory called General Relativity that deals with gravitational fields and according to this latest theory the speed of light appears to vary with the intensity of the gravitational field. Learn More...

Effective Speed of Light

Scientists just confirmed the existence of "Dark Energy", a mysterious repulsive force that acts in opposite to gravity. Scientists today do not know what this "Dark Energy" is but they know that it is causing the entire universe to expand at an increasing rate. This Dark Energy i

s even causing distant galaxies to recede from us faster than our local speed of light. The expansion of the universe is causing light en route to be dragged away from us. This makes observers to see distant inbound light at effective speeds less than 299792.458 km/s and to see distant outbound light at effective speeds greater than 299792.458 km/s. However every non-accelerating observer measures the speed of light locally (in his location) at 299792.458 km/s in any direction. LearnMore...

speed of human brain

speed of human brain

Ask A Scientist©

Computer Science Archive

Brain Speed?

Index Key:   CSI012
Author:      Brian Lintz
Subject:     Brain Speed?
Text:        In terms of megahertz, how fast does the human brain operate?

Response #: 1 of 1
Author:     Psych
Text:       This is a tough question.  A human brain is much faster than a 
super computer at something like visual recognition. It is much slower at math 
than a hand calculator because it is built differently.  Neural Network 
research is starting to look at how the brain works.  One of the big 
differences is that on a typical computer with linear processors, those 
processors do one thing at a time. This allows you to count how much it does 
in a second.  A typical PC has one processor and a lot of memory.  A typical 
brain has billions of processors (neurons) and probably very limited formal 
memory. (See the response to how many bytes in a brain.)