Thursday, November 19, 2009

When light doesn't travel at the speed of light

Did you know that, when traveling through water, light only moves at about three-quarters "the speed of light" (186,000 miles per second, in a vacuum)? (Telegraph) And when traveling through rubidium cooled nearly to absolute zero, it's moving at 38 mph, and forms "a strange state of matter called Bose-Einstein condensate"? By the way, 38 mph is the slowest we've observed light moving. (For the record, light has been "brought to a complete stop", but that's not "moving", is it?)

And get this. There are conditions where particles can travel faster than the light around it. For example, in nuclear reactors. The result is a beautiful blue glow called "Cherenkov radiation." Pound360 wonders if that explains why Dr. Manhattan is blue?

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.