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From: msellers@mntgfx.mentor.com (Mike Sellers)
Newsgroups: sci.misc,sci.physics
Subject: Cherenkov radiation (was Re: diffs between sound and light waves?)
Message-ID: <1988Feb18.163235.380@mntgfx.mentor.com>
Date: 19 Feb 88 00:32:30 GMT
References: <413@prlb2.UUCP> <4110@aw.sei.cmu.edu> <6917@agate.BERKELEY.EDU> <4809@ihlpg.ATT.COM>
Organization: Mentor Graphics Corporation, Beaverton Oregon
Lines: 27
Keywords: macroscopic behaviour

In article <4809@ihlpg.ATT.COM>, tan@ihlpg.ATT.COM (Bill Tanenbaum) writes:
> < A stick breaking under foot generates a (sonic) shock wave (chaotic behavior
> < due to parts of the stick moving faster than the speed of sound ?) -- I
> < don't think there is analogous light behaviour in the everyday world
> < (aurora borealis?).
>
> There is analogous light behavior.  It's called Cherenkov radiation.
> It occurs when particles travel through a transparent medium faster
> than the speed of light in that medium.  It occurs in the everyday
> world, but not so as you'd notice.
> -- 
> Bill Tanenbaum - AT&T Bell Labs - Naperville IL  ihnp4!ihlpg!tan

Isn't one instance of this the bluish glow given off by water-bathed
nuclear reactors, or more precisely, by the emitted particles moving
faster than the speed of light in water?  

What is the mechanism behind this?  Particles travelling faster than
c in *any* medium bothers me just a bit ... I mean, what if (physical
non sequitor approaching) we found a meduim wherein the speed of 
light was greater than it is in a vacuum?  What consequences could this
have?

-- 
Mike Sellers                           ...!tektronix!sequent!mntgfx!msellers
Mentor Graphics Corp., EPAD            msellers@mntgfx.MENTOR.COM
"Never confuse motion with action." -- Ben Franklin