🚀 go-pugleaf

dang...@sound.net wrote:
> 

> 
> A serious answer but wrong (depending on where you are standing).
> From the perspective of the driver the light would travel away from
> the car at the speed of light.  An outside observer would see the car
> as going less than the speed of light (trust me) and the light would
> advance the speed difference between observe car speed and the speed
> of light.
> 

An outside observer would see nothing as by the time the light from
the car reached them the car would have run them down ;)

In all seriousness, when a distant star is travelling towards or
away from the Earth at a small but significant proportion of
the speed of light then the light from it is shifted in frequency
due to the Dopler shift.

So, imagine a car travelling towards an observer with it's
headlights on. It accelerates to the speed of light, remains at
that speed for a short time, then decelerates to a lower speed.
The observer can see the headlights, they suddenly change to
blue then ultra-violet then to x-ray frequencies then to infinite
frequency (zero wavelength) and become undetectable. After a short 
time they turn back to blue, then back to the yellow/white of
incandescent bulbs (assuming that's what they are.)

If the car did not slow down then it would indeed collide with
the observer at the same time as the light from it's headlights.

The driver would not see the lights from his own car as it could
only be seen if reflected back at him and all light travelling
towards the car would be Dopler shifted to infinite frequency.

Barry.

-- 
E-mail: Barry_...@hp.com
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Is this sloppiness caused by ignorance or apathy ? 
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