[thechat] Speed of light may have changed recently

John Handelaar john at videoisland.com
Sun Jul 4 08:10:06 CDT 2004

> -----Original Message-----
> From: thechat-bounces at lists.evolt.org
> [mailto:thechat-bounces at lists.evolt.org]On Behalf Of Madhu Menon
> Sent: 03 July 2004 09:58
> To: thechat at lists.evolt.org
> Subject: [thechat] Speed of light may have changed recently
> <quote>
> The speed of light, one of the most sacrosanct of the universal physical
> constants, may have been lower as recently as two billion years ago - and
> not in some far corner of the universe, but right here on Earth.
> </quote>
> Will the physicists on this list please explain the rest of the
> article in
> plain English? My high-school physics is more than a decade old
> and hence,
> rusty. Alan?

IANAP, but

a)  Isn't this old news?  Only the other month we were treated
    to news that some lab had managed to cut the speed of light
    to a relatively leisurely 28 mph

b)  Anyway, it might mean that the 'c' in e=mc^2 isn't as
    constant as assumed

c)  It might also mean that 'c' is indeed a constant, but we've
    not been able to measure its speed *unimpeded* thus far and
    so have no idea what that speed is.  Just as you can slow
    light down by pushing it through, say, glass, it may be that
    light is being slowed down in all cases we can see by whatever
    the stuff is in space between all the bits we can detect.
    If so, it *could* mean that the amount of 'dark matter' out
    there has been getting more dense over time.

d)  There are probably a million other possible explanations as
    well.  These are just the ones which sprung immediately to

And if I'm even remotely in the ballpark don't tell my old physics
teacher because he'd have an aneurysm on the spot.


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