I am getting slightly frustrated trying to explain that time expands. You cannot have a space vacuum expanding without time taking on the same role.

''Gentlemean, the idea of space and time which i wish to develop before you grew from the soil of experimental physics. .. ..

''the provision of equations which the special laws of relativity take on a new form in which the time coordinate plays exactly the same role as the spatial coordinate...''

By Minkowski 1908

Because of this, they are invariant. You cannot say they are seperated, or one has a different nature to the other, because they are identical in the sense that they are one thing. I even showed math this was true.

Therefore, space must expand alongside with time, as spacetime. This is why we say spacetime expands. We never say, space expands alone. I rest the case.

But this doesn't mean that seconds* used to be smaller, does it?

If we think that expansion is only measurable at the larger scales and only measurably affects distances outside of gravity-bound systems and not within them, does that mean that time moves very differently in the voids between the superclusters to how it does within them?


*the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom

What is a second but a man-made calculation? Didn't you know we could have Planck Time clocks?

Yes it does in the same way that a mile used to be shorter.

The deal is to keep light constant ( c ) if space expands then time needs to expand also. If a mile is now mile prime then second needs to have become a second prime.

Remember there is no real space or real time it is all relative to an observer and whatever the situation is of the observer c is constant.

It true that the last few seconds of existence will seem to be longer, something like 20,000 years. This is true.

It's because everything is relative, but a second is still a second.

And there is the crux of the matter! It depends on the conditions you set down before you make your statement, as to how that statement can be interpreted.

Now if you had said conformal time expands with co-moving distance I might have understood you.

It's true that the last few seconds of existence will seem to be longer, something like 20,000 years. This is true.

It's because everything is relative, but a second is still a second.

(sorry) -- doubled that one

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Never attribute to malice what can be adequately explained by ignorance or stupidity.
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Ha! You make a fool of Bad Astronomy. It's clear you're totally retarded with physics.

ATM? Really? Isn't there an elsewhere?

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Never attribute to malice what can be adequately explained by ignorance or stupidity.
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I DID. In the original post. I qoute, yet again,

''Gentlemean, the idea of space and time which i wish to develop before you grew from the soil of experimental physics. .. ..

''the provision of equations which the special laws of relativity take on a new form in which the time coordinate plays exactly the same role as the spatial coordinate...''

By Minkowski 1908

What part of 'playing the same role,' don't you understand?

Plus, just look up spacetime expansion. You very rarely find a source which attributes expansion to space only.

It's quite a flawed system this, a place of physics and astronomy, yet moderators who can't know some basic physics. How is this place to be moderated? Do the mods just roam about and pic something randomly that they think is ATM?

That's a flawed way to behave.

What Minkowski seems to be saying is only that time is a dimension just like the spatial dimensions. No one is disputing this. However, in all the discussions about metric expansion of space-time, it is only expanding along the spatial dimensions, as matt.o already told you here.

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Time expands relative to what?
We can measure the expansion of space, because (despite tommac's protestations) our measuring instruments don't participate in the expansion of the universe, except by moving apart at the galactic-cluster scale and above.
And we can measure differences in clock rates for observers in different locations under SR and GR.
But if time "expanded" for the whole universe, how would we know? Which is, presumably, why we model space expanding using defined, uniform time measurement.

Grant Hutchison

Metric contributions, does not remove the fact that Minkowski spacetime clearly states that time and space are one continuum, therego we say spacetime expands. This should be well known by now.

Why don't you read the rules of the board, if you are still unsure then send a PM to a Mod and ask them.

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I did.

Besides, what's the rules got to do with it? I know the above i know the above isn't ATM.

So it should be the work of a moment for you to provide a reference in which a reputable cosmologist discusses the "expansion of time" as a mainstream concept. And then Jim will take you out of ATM.

Grant Hutchison

What kind of source, because i could name about 10 physicists who when referring to space as spacetime, and that would imply the two must expand.

Claiming an implication is not providing evidence.

I doubt that would suffice, since we seem to be in ATM because of your phrase "time expands". I don't want to second-guess Jim, but since he particularly challenged that phrase, I guess you'd need to find someone reputable who writes specifically about the "expansion of time" as a mainstream concept.

But Jim's the judge of what is satisfactory in that regard, not me.

Grant Hutchison

Implication? It's physical and relative laws.

Gee... don't anyone get physics correcly? Jim has totally ignored what i said, and i'm being bombarded by half correct things.