Cosmological Redshift and Expansion of Space

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Thomas</i>
<br />what happens then if a light wave is sent out from a distant galaxy in an expanding universe, and half-way through its journey the expansion suddenly stops and turns into a (symmetrically reversed) contraction (so that the size of the universe at reception of the light signal is the same again as at the moment it was sent out)? What would then the redshift be when we observe the light?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Zero. -|Tom|-

How can redshift be viewed as proof the universe is expanding when the rate of expansion is equal to the speed of light? If a galaxy is receeding at the speed of light at all time through time then would the photon even get away from the galaxy at all? Redshift is one of the many data details being tweeked to suit the model.

Hello All

What is space expansion?

Does it actually occur or is it just a mathematical ad hoc idea?

and since it does not occur in gravity bound areas.

I think I'm going around in circles.

again

What is space expansion?

Is it the parts within the space that does the expansion?

Smile and live another day

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Pluto</i>
<br />Hello All

What is space expansion?

Does it actually occur or is it just a mathematical ad hoc idea?

and since it does not occur in gravity bound areas.

I think I'm going around in circles.

again

What is space expansion?

Is it the parts within the space that does the expansion?

Smile and live another day
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

It depends on who you ask. I would say that it is just a conceptually flawed mathematical ad-hoc idea, as space is is not a physical object but essentially <i>nothingness</i>, and nothingness can not expand (and neither be curved).

But even hypothetically accepting the idea of space expansion, the point is that cosmologists claim that within our solar system space has not expanded together with the overall Hubble expansion (as the local space metric is assumed to be determined by the gravitational field of the sun and planets). So if one assumes hypothetically a light signal having bounced back and forth in the solar system between two mirrors for the last few billion years, its wavelength should not have expanded at all, as space has locally not expanded. And it should then also mean that if expanded light waves enter our solar system, they should be shrunk back to the original size, i.e. no redshift should actually be observed at all, contrary to evidence. So this shows that the 'space expansion' model of the redshift is conceptually and logically flawed.

Thomas

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Thomas</i>
<br />it should then also mean that if expanded light waves enter our solar system, they should be shrunk back to the original size, i.e. no redshift should actually be observed at all, contrary to evidence.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">That is definitely not true. Entering, leaving, or being in space that has never expanded has no effect on light. Residing in space that is expanding or shrinking for a very long time will cause the light to do likewise.

So if a lightwave travels through expanding space for billions of years, it gets expanded too (redshifted). If it then enters the solar system, it stays exactly as it was -- redshifted. -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Pluto</i>
<br />What is space expansion?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">That depends on the definition of "space".

Unlike mainstream theorists, who use a methematical definition instead of a physical one, I prefer to stick to the classical physics definition of space being the dimension (a concept) for measuring separation. As such, it is not a material, tangible entity and therefore cannot be expanded or contracted. So the entity that is expanding in the Big Bang theory must be a space-filling medium with some poorly defined properties.

Of course, in these parts, we think the Big Bang has been long since falsified, and that the universe is not even expanding -- as the latest observational results appear to verify conclusively. -|Tom|-