## Re: [hackers-il] Travelling very fast with headlights

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• ... http://math.ucr.edu/home/baez/physics/Relativity/SR/velocity.html The short version is that the simple formula that v=v1+v1 doesn t work for relatavistic
Message 1 of 6 , Oct 25, 2005
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On 10/25/05, Chen Shapira <cshapira@...> wrote:

> Any ideas? Perhaps pointers to books or sites that explain the whole thing
> once and for all?

http://math.ucr.edu/home/baez/physics/Relativity/SR/velocity.html

The short version is that the simple formula that v=v1+v1 doesn't work

-- Arik
• ... apt-get install lightspeed http://lightspeed.sourceforge.net/ Not exactly what you asked but this is a nice simulator of many relativistic effects.
Message 2 of 6 , Oct 25, 2005
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On Tue, 2005-10-25 at 22:49 +0200, Chen Shapira wrote:
> Hi Hackers,
>
> I saw the following question in a joke site:
> What happens if you are driving at the speed of light and turn on your
> [snip details]

apt-get install lightspeed
http://lightspeed.sourceforge.net/

Not exactly what you asked but this is a nice simulator of many
relativistic effects.
• ... you won t see the light at all - because in vacuum, there is nothing to reflect this light back to you (it is moving away from you, after all, and faster
Message 3 of 6 , Oct 25, 2005
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On Tue, 25 Oct 2005, Chen Shapira wrote:

> Hi Hackers,
>
> I saw the following question in a joke site:
> What happens if you are driving at the speed of light and turn on your
>
> Well, I'm not sure if you can turn on the headlights when you travel at the
> speed of light, but what if you travel at half the speed of light? Suppose
> that you do this in vacuum.
> How will the light from the headlights look to you (from inside the car)?

you won't see the light at all - because in vacuum, there is nothing to
reflect this light back to you (it is moving away from you, after all, and
faster then you move).

--
guy

"For world domination - press 1,
or dial 0, and please hold, for the creator." -- nob o. dy
• Thanks! This explained things nicely. ... ______________________________________________________________________ This email has been scanned by the MessageLabs
Message 4 of 6 , Oct 25, 2005
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Thanks!

This explained things nicely.

> -----Original Message-----
> From: hackers-il@yahoogroups.com
> [mailto:hackers-il@yahoogroups.com] On Behalf Of Arik Baratz
> Sent: Wednesday, October 26, 2005 12:56 AM
> To: hackers-il@yahoogroups.com
> Subject: Re: [hackers-il] Travelling very fast with headlights
>
> On 10/25/05, Chen Shapira <cshapira@...> wrote:
>
> > Any ideas? Perhaps pointers to books or sites that explain
> the whole
> > thing once and for all?
>
> http://math.ucr.edu/home/baez/physics/Relativity/SR/velocity.html
>
> The short version is that the simple formula that v=v1+v1
> doesn't work for relatavistic speeds. Use the formula in my
>
> -- Arik
>
>
> find a job). Welcome to the Sweet Life.
> http://us.click.yahoo.com/A77XvD/vlQLAA/TtwFAA/saFolB/TM
> --------------------------------------------------------------
> ------~->
>
>