I keep thinking about the whole expanding universe thing and this board has really help me sort out some bad logic on my part but just when i think that I kind of understand some things I realize that I have a bunch of other questions that I dont. I really want to understand why the expansion of the universe is taken as mainstream. During my last phase of questioning myself I came up with these questions:

1) When we discuss that the universe is expanding, are we talking about mass moving away from mass or that absolute space is getting larger? If the universe is expanding or at points has expanded at speeds faster than the speed of light I assume we would have to assume the latter.

2) If the universe is exanding ... does that also mean that time is contracting? Basically if we are talking about the time-space expansion if space is expanding I believe time would have to contract or would it also need to expand?

3) If we ( on the earth ) we either permanently or temporarily being effected by an increasing gravitational field wouldnt that compress our time and space making galaxies appear further away ( well they really are further away relative to us ). If our time was slowing and our distance was being compacted, wouldnt in effect, relative to us, make the universe expand? Would that also cause light to redshift as it enters our deeper gravitational well?

4) In fact could our localized space be shrinking, making the universe appear like it is growing? Could this cause redshifts?

5) Since we have only started to understand GTR for less than 100 years ( which is nothing in terms of the age of the universe ) is there a possibility that our position in the galaxy or some other cyclical force has brought us into an increased gravitational state, temporarily ???

Hubble's observations in ~1929 and subsequent refinements thereto. Hubble himself was not quick to conclude these observations implied the universe was expanding, but most everyone else did.

The latter, although I don't know if you should throw that word "absolute" in there.

Don't forget that when talking about relativity, you have to specify relative to what?

Yeah, but then why would more distant objects be redshifted more?

But that's quite a while in terms of a scientific theory. You would be surprised how many times GTR has been tested and how well it is understood.

No, unless you can identify a mass that would create such a huge gravitational field.

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1) Relative to everything? If the universe is expanding, and we are not shrinking, thus making the universe expand, then the universe would have to be expanding relative to everything. The question is, is time-space expanding? If so is it expanding relative to everything? This is what I have a hard time believing in.

2) The distant objects would be redshifted more because of distance needed to travel. As we sink into a well all distances are further. Thus making very distant objects further away.

3) The same could also be true about the world being flat and that planets and stars rotating around the earth. How many years was that theory taken as absolute truth.

4) A black hole? , The center of our galaxy, or our galaxy as a whole?, the things that make galaxies move?

The universe is expanding, and everything contained in the universe is moving relative to everything else. Not necesserily at the same speeds. This is because inflation left large area's of the universe expanding at different speeds, as strange as this sounds. Space and time is certainly expanding. If it isn't, then we need a better explanation to why things are moving about in a static vacuum.

There is also no center to the universe Tommac.

How is time expanding?

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Well, space and time are invariant systems, meaning that they are somehow the same thing. So if space expands, so must any notion of time.

In a word, no. I know of no part of mainstream science that says this. If you want to speculate about time expanding, take it to ATM.

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You're very good at running your mouth off, and by the quality of your arguements, you don't know any relativistic concepts correctly.

It won't go to ATM, because it is well known that space and time are a continuum. They are the same thing.

I can show math that proves this.

That is a dreadful attempt at an analogy. In ancient times people believed the Earth to be flat because it looks that way locally, and our early ancestors had not yet learned to do the observations that would indicate otherwise. Aristotle and his fellow Greek scholars inferred that our planet was spherical and were able to estimate its size pretty closely.

It is true that space and time can be considered as part of a single construct aka space-time continuum. But they are separate, distinct dimensions. Expansion in the dimensions of space does NOT automatically imply expansion in the dimension of time.

If you have math to "prove" this, sure, show it... in ATM.

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Oh so math is against the mainstream now. I hope i am not the only one who notices your trolling.

The math such as Cartesian Products, and Lorentz Boosts prooves that time and space are a single fabric. But you'd argue this as well wouldn't you?

Special Relativity

1. Special Relativity and Flat Spacetime involve deep understanding into the spacetime interval — the metric — spacetime diagrams — vectors — the tangent space — dual vectors — tensors — tensor products — the Levi-Civita tensor —electromagnetism — Lorentz transformations — differential forms — worldlines — proper time — energy-momentum vector — energy momentum tensor — perfect fluids — energy-momentum conservation index manipulation, and more.

In these relativistic principles, we need to know some concepts.

Minkowski’s flat vector spacetime is best used in physics today. It is given as (-, -, -, +) or (+,+,+,-) and with a matrix of, and in special conditions, can be written as (0,0,0,0) in zero-dimensions:

…..1000
…..0100
N=0010
…..0001-

The following equations are called ‘’Cartesian’’ coordinated systems, and they describe the distance between two points:

s^2 = (∆x)^2 + (∆y)^2

In a rotated system, we twist coordinates around in space, and we find them as a geometry of distance. The new coordinates are given as:

s^2 = (∆x′)^2 + (∆y′)^2

Being almost identical math, they are easy to remember. In this case, we say that distance is an invariant of these equations. More interesting is that we learn that time is also an invariant of space.

Because of this, we can therefore find the following equation describing a spacetime interval:

s^2 = −(c∆t)^2 + (∆x)^2 + (∆y)^2 + (∆z)^2

Where (t, x, y and z) are the coordinates of spacetime, because we can rotate space, and find a corresponding value with time, and this is why we say that space and time are one thing. All these equations lead to many more equations, just as Lorentz Boosts which derive from the mathematics described by Galileo, and his coordinates are given through the variables:

x' = x − vt
y' = y
z' = z
t' = t

We therefore give the spacetime metric a 4x4 matrix. Time coordinates are found as being invariant to the system. We then have the formula,

s^2 =n_μ_v∆x^u∆x^v

We can simplify the transformation in spacetime into a more arbitrary equation,

x^u → x^u ’ = x^u + a^u

Where aμ is a set of four fixed numbers. Translations leave the differences ∆xμ unchanged, so it is not remarkable that the interval is unchanged. The only other kind of linear transformation is to multiply xμ by a (spacetime-independent) matrix:

x_μv’ = Lamba^u’_v x^v

Occams Ghost you are painfully close to another suspension with your rude post above. Tone it down.

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Sorry

But to be fair, he started it.

No, he has been questioning your rather off topic claims. Since I signed in and started reading, I am questioning them too.

Emmm... no. I do recall him continually trying to bring what i say down by saying i should move off to ATM. This is insulting, when i am talking about things totally mainstream.

Hence my original post ''The universe is expanding, and everything contained in the universe is moving relative to everything else. Not necesserily at the same speeds. This is because inflation left large area's of the universe expanding at different speeds, as strange as this sounds. Space and time is certainly expanding. If it isn't, then we need a better explanation to why things are moving about in a static vacuum.

There is also no center to the universe Tommac.''

You will find answered Tommacs questions in post 3.