[ExI] Provocative Claim Concerning GR

Lee Corbin lcorbin at rawbw.com
Sat Sep 6 23:54:12 UTC 2008


I claim that photons falling into a gravitational field do not acquire
energy as is commonly thought, nor are they redshifted even an iota,
and that the idea that they do is based upon a simple misunderstanding.

First, suppose that they did, i.e., that their frequencies did increase.
This leads to absurdity as follows.

Experimental situation: We in space are at rest relative to a planet
that has a strong gravitational field (i.e. a planet whose mass has
significantly curved the space near it). We are suffienciently far
away that the effects of this curvature are hardly measurable by
our instruments. We are, for example, 1 million kilometers from
an Earth sized planet.

We now send towards the surface of the planet a beam of photons
at specific frequency nu. At the surface they encounter a mirror
set at 45 degrees to their line of flight, whereupon the photons
travel for five kilometers approximately parallel to the surface of
the planet.  At this point, they strike another mirror also at 45
degrees relative to their flight and are reflected back up towards
us in space. Naturally we measure the received frequency as nu.

Let us suppose, however, that in the five kilometer trip across
the surface of the planet the photons pass many measuring
devices. Now if the actual frequency [1] of the photons had
been blue shifted as they approached the planet so that the
actual frequency with which they passed any measuring station
was not the same as the frequency nu, then we clearly would
have a "build up". For example, if the frequency were now 
faster, as is often claimed, then the number of wave crests
per second would also be somehow greater, and soon 
there would be a surplus of wave crests "bunched up" waiting
to get back up into space. That is, for example, if n wavecrests
are passing the last planetary measuring apparatus per second,
and we back up in space measure some number less than n,
an incredible buildup must be occuring somewhere that would
only become more pronounced over time. Of course, as the
reader has spotted, it is important to remember who is
doing the measurements, and whether their apparati are 
correct.

The correct resolution is as follows. The number of wave crests
really passing any station at any time is constant, because the
photons' frequency remains constant (at nu). What has happened
is that the planet-bound observers are not taking into account
(unless they qualify their remarks) the fact that their time is more 
retarded because they are deeper in a gravitational field. "Yes,"
they should say to themselves, "we measure green photons, but
only because we and our apparatus are so time-retarded. The
photons are really red."

So just because something gets deeper into a gravitational field
does not necessarily mean that it acquires energy. Unlike
ordinary material particles, photons neither speed up nor gain
energy when falling towards massive bodies.

The same goes for so-called red-shifted photons coming from
stars. The photons never had their frequencies shifted! They
simply were emitted by time-retarded physical processes on
or near the star.

In short: No relative motion, no red shift.

Lee

[1] Of course, some would suggest that "actual frequency" be
placed in quotation marks because in the accelerated reference
frames down on  the planet, incorrect observations (i.e..
uncorrected by GR theory) yields numbers too high.




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