Re: The world as a photon

[Stephen Speicher <sjs@COMPBIO.CALTECH.EDU>]

On Wed, 5 Mar 2003, James Mackey wrote:

>  One question was, what does the world look like from the frame
>  of a photon ?

In special relativity there is no frame of reference co-moving
with a photon.  It is not possible to construct any set of
coordinates in which the photon is at rest.

(More technically, the spacetime interval between any lightlike
events is zero -- the Minkowski metric is a semi-Riemannian
metric, not positive definite, and the null coordinates are
degenerate.)

> The second question stems from the first.  In relativity I
> recall transforming from one frame of reference to another, and
> requiring that the results be symmetric, i.e. no preferred
> reference frame.  If one of those frames is the frame of a
> photon, is this still true?


See above. You cannot use the Lorentz transformations to
transform to null coordinates, i.e., the Lorentz transformation
also become degenerate.

--
Stephen
sjs@compbio.caltech.edu

Ignorance is just a placeholder for knowledge.

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