Xref: utzoo sci.misc:838 sci.physics:2908
Path: utzoo!utgpu!water!watmath!clyde!rutgers!umd5!brl-adm!husc6!bbn!gatech!ukma!psuvm.bitnet!ue4
From: UE4@PSUVMA.BITNET (Dan Schultz)
Newsgroups: sci.misc,sci.physics
Subject: Re: differences between sound and light waves?
Keywords: Blumenkraft, Schlagenkraft
Message-ID: <34200UE4@PSUVMA>
Date: 21 Feb 88 20:24:02 GMT
References: <413@prlb2.UUCP> <4110@aw.sei.cmu.edu> <6917@agate.BERKELEY.EDU> <4809@ihlpg.ATT.COM> <1181@microsoft.UUCP>
Organization: Kzin and the Diplomatyx (Chief Cellist)
Lines: 35

In article <1181@microsoft.UUCP>, t-peterw@microsoft.UUCP (Peter Williams) says:
>
>>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
>
>As far as I know the only thing that travels faster than the speed of
>light is the Starship Enterprise. As a high school student, I spent a summer
>working in a reactor. The workers used to laugh because the guides that
>would occasionally come through would say that the blue aura around
>a sample of radioactive cobalt in a bay (ie water bay) was caused by
>EM waves travelling faster than the speed of light in water. I believe
>the real cause of Cherenkov radiation is that the speed of light in the
>emitting medium is greater than that of the water so when the EM
>waves enter the water they release enery (in the form of blue light)
>as they assume the speed of light of the water medium.
>
>Please correct me if I should err.

You are in error.  Cherenkov radiation occures because of nuetrons travelling
in the water faster than light travels in the water.  SR says nothing can
travel faster than light in a vacuume.  Since EM radiation travels slower in
water than a vacuume, particles can move faster than light IN THE MEDIUM.

EM waves moving from a material of one index of refraction to a material of
another index of refraction do not emit other EM waves (or any other enerty)--
they change direction and wavelength.
-------
Daniel B. Schultz

         "A _better_, more _compact_ form of humanity"
                   J. C. Kilgannon.