i *think* there is something called a scintilating xray machine or some such
that does something simmilar to this
thy put a whole bunch of electrons into a particle accelerator and run them
up to a moderatly stupid speed then use them to illuminate crystals and the
like.
one of those places where you find scads of lead bricks around the place and
nobody is allowed to use them for normal stuff like holding doors open.

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Omega Software
Sent: Monday, March 08, 2004 7:58 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [OT:] Wet Mars


At 00.42 06/03/2004 +0200, you wrote:
>> Something has always puzzled me about light - if Einstein is right, how
>> can it exhibit Doppler shift?  As I
>
>The energy of a light particle (photon) is h*mu where mu is frequecy in
>Hx. If Einstein is right them E=m*c^2 is constant for the photon in free
>space and then:
>
>        h*mu = m*c^2
>
>But if you move wrt. the origin c is not c-v where v is your speed (or the
>speed of the origin), and:
>
>        h*mu = m*(c-v)^2
>
>Since h, n, c, and v are constants (you are saying you know v, aren't you
>?), the only thing left to change to fix the equation is mu, but mu is the
>frequency. So mu (the frequency, aka 1/wavelength, aka redshift) decreases
>when the observer travels away from the source of light (or the source of
>light travels away from the observer) (remember light energy is a vector
>so vector addition applies between c, the speed of the photon, and v, the
>speed of the source/your speed - that's how you get blueshift, or
>increased frequency - by traveling towards the source).
>
>Peter

Very interesting stuff. By the way, would a stream of electrons moving at
about 1/20th of the speed of light (which if I made my calculations right
means a wavelength of about 500 nM) produce visible, green light, when
approaching an eye or an optical sensor?

If not, why?

Greets,
Andrea

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