0
$\begingroup$

This might be a very naive first thought but I was not able to find any further information if it can be ruled out by some observations or some theories immediately.

Can the increasing mean redshift of galaxies with distance that's usually interpreted as space stretching / expansion also be explained by slower ticking physical processes relative to the currently ticking processes?

This means instead of talking about "expanding space" couldn't increasing physicial process tick speeds be an equivalent at least (or maybe actually mean the same)?

$\endgroup$
0
$\begingroup$

Yes it could.

In reality it is the space itself that the photon travels in that expands, and that stretches the wavelength of the photon. Thus, the frequency of the photon becomes smaller, it becomes redshifted and loses energy.

Now let's try to imagine this another way to see why it could be interpreted as time dilation. Imagine a photon clock that ticks 1 second at the emitter far away. Now let's assume that tick would be measured as exactly 1 second too here on Earth at the moment of emission.

Now as the photon clock itself travels in expanding space, the space between the photon clock's walls expands too, so one tick on the photon clock will seem to take longer as measured here from Earth.

By the time the photon clock reaches Earth, the space between the walls of the photon clock has expanded, and the ticks on the photon clock take much longer then 1 second here on Earth. This means that the photon clock ticks slower, its frequency decreased, because of time dilation.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.