Possible matter being Created/Destroyed?

Chronos

Conventional thinking is it has no effect. But, theoretically, it could have increased the size of the solar system by about 40 meters over the last 4.5 billion years - a bit less than expected merely due to radiative loss of solar mass over that same time frame.

Drakkith

How would it cause the solar system to expand if gravity holds us to the Sun? I can understand how galaxies get carried away from each other, but they are not bound.

Ich

What are you referring to?

Naty1

ICH: post #41

Not quite, if I understand your statement: sure, only intergalatic distances have measureable expansion of space. My perspective has so far been, and I may be way off base here, that a locally bound gravitational solar system does not inhibit space itself from expanding. [Unlike, for example, the balloon analogy where ALL space expansion moves massive objects.] In other words, we all agree, I think, that if our solar system were NOT present, it's empty space would expand infinitesimally in that volume; Maybe not by a measureable amount of course. Now we plop in a sun, some planets and moons there...will that stop space from expanding?? Is the presence of mass a glue that ties space together?? I have not so far thought so. [Does more curved space expand 'less' than more flat space??

Ich

Let me quote the FAQ right before the one you quoted:
See what I mean? Expanding space and moving things are (at least locally) different descriptions of the same phenomenon. Just different coordinates. You can't decide which coordinate system is the correct one, as both are valid.

In a patch of empty space, you can easily use coordinates with H=70 km/s/km. Or you can use static coordinates. Both are valid descriptions of - nothing. It makes no difference observationally, so the question is a philosophical one.

Drakkith

Would light passing through an area of space with or without something such as our solar system have it's wavelength stretched a tiny amount? Or how about while moving past or through a large galaxy?

Eimacman

Greetings George Jones:

That is the answer that I needed, I must study this further for my math is not as good as I would like.

Thank you.

Eimacman.

Ich

Depends on the observers you choose. If emitter and receiver are at rest wrt each other, there's no shift. If both are "comoving", i.e. moving away from each other according to the Hubble law, there is redshift, obviously.

In a "static space" description, the first observers don't move, and the second observers move away from each other.
In an "expanding space" description, the second observers don't move, and the first observers have a peculiar velocity that exactly cancels the cosmological redshift.

The results are the same in both descriptions.

Chronos

A photon approaching a gravitational field is blue shifted, as it exits that same gravitational field it is redshifted by exactly the same amount.

Drakkith

Lets say I observe light from a galaxy moving away at exactly redshift z=0.1, and that light happens to go through a galaxy on the way to me. Is the galaxy I am observing the same distance as another galaxy who's redshift is also exactly z=0.1 who's light is not going through another galaxy before reaching me?

Ich

The galaxy introduces some positive curvature, so I'd say that the distance in this direction is a little bit larger. See Shapiro delay.
But I don't see how this pertains to the discussion.

Naty1

ICH

I do see what you mean...now...I think that's the best perspective...Thanks!

Naty1

Found it!!! the 'classic discussion from 2007:

Does Space Expand....[Wallace IS a cosmologist]

http://www.physicsforums.com/showthr...nt+flow&page=2

Chronos

The effect of cosmological expansion on the solar system is negligible. For discussion see http://arxiv.org/pdf/astro-ph/9803097v1.pdf

jimpy

hi Samuel99
it takes a lot of courage for you to post like this.I'm no expert by any means but there are a few issues worth you following up on here.
Firstly,in the case of the expanding accelerating universe then the observations that are made are all historic.
The most recent have just happened here.The rest are history.
So now I'll stick my neck out and we'll see what happens.
I think that the only location that the accelerating expansion of the universe is identifiable(is being the operative word)is here and now.
When we peer into the night sky we have a log of what happened in our yesterdays,right upto the beginning if we accept the idea that "The Big Bang"was an event that actually happened in our yesterdays.
Secondly I don't necessarily understand why 40 metres in 4000 light years is irrelevant.
I haven't been taught that rule.

It all depends on the significance of the variation.
Currently we are discussing here speculative possibilities which have widespread approval in the world of scientists.
The theories involved in your post are amongst the most complex ever advanced by mankind.
One of the first books in English relating to this area is "The Mathematical Theory of Relativity" by an Englishmen called Arthur Eddington" which was published in 1926 and is a second book of his about the theories of Albert Einstein.
It is called "The Mathematical Theory of Relativity"
A very important remark in the introduction to this work is as follows:
(he is discussing determining what length means when we exchange ideas)
"But to catalogue all the precautions and provisos in the operation of determining even so simple a thing as length is a task which we shirk.We might take refuge in the statement that the task though laborious is straightforward,and that the practical physicist knows the whole task without us writing it down for him."
It goes on from here,if you can get the book from your school library you can read the whole thing.It is on page 6 of the introduction.
I am impressed by your spirit,
Jimpy

Ich

There's a discussion of this discussion here.

Chronos

Yes, my apologies, I noticed that after posting the link.