I told you that was psuedoscience. I never said I supported it, please read what I say.
BB shockwave
- Thread starter ULTRA
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I told you that was psuedoscience. I never said I supported it, please read what I say.
Yes, I am inclined to agree. It seems quite fantastic and, frankly, rather dubious. In classical newtonian space I think Einstein is still the daddy.
My sentance never quite developed properly when I read back... I was supposed to say
''It means $$c^2= \frac{1}{\epsilon \mu}$$ changes''
''It means $$c^2= \frac{1}{\epsilon \mu}$$ changes''
Yes thats right, Barrow did some very good work on the subject.
And ultra some of those papers are consistent with relativity, they basically end up modifying one of the other constants in a nutshell... its speculative stuff but its an entertaining read.
Moffat and others have did vsl by a specific type of Lorentz violation.
And ultra some of those papers are consistent with relativity, they basically end up modifying one of the other constants in a nutshell... its speculative stuff but its an entertaining read.
Moffat and others have did vsl by a specific type of Lorentz violation.
Ok. But it could be explained by time dilation according to special relativity. That C is constant, but under certain conditions time is relatively stretched or compressed according to a stationary 3rd party.
This isn't just some kinda test 'cos I'm new here is it?!!
Regards,
ULTRA
This isn't just some kinda test 'cos I'm new here is it?!!
Regards,
ULTRA
lol I once asked the same question, I know what you mean I think but still the problem with that is... stationary compared to what? How do you know if an object isn't moving compared to moving at the same rate you are moving.
I think you are asking how do we know time didn't flow much much faster in the past for all frames of reference. Well to know that you would have to have an absolute frame of reference (and that cannot exist), and it would be the same pretty much as velocity changing. See if time dilation changes or varies, that means velocity also just changed.. its indistinguishable. The only time dilation observations two observers can agree on is gravitational, however if time rates change then they will change the same rate for both observers. Also we know if that happened then gravity would have had to change as well. We could detect a change in gravitational strength, however if everything else was tweaked as well then we couldn't tell.
Its like changing the fine structure constant variables yet still having the same fine structure solution.. no idea how one would even know and yet no idea if it would change any of our understandings or conclusions. Its an area of research though currently. And its also a brain teaser whenever you start wondering about time.
As you say there is nothing "in front" of the expanding universe; therefore it has no leading edge. Or edge of any kind. Even if the universe is finite in size it seems exceedingly unlikely to me that there is a point somewhere where it just ceases to exist. More likely it is closed in some smooth way.
Perhaps though you could say that the present moment is the leading edge of expanding spacetime, in some sense.
I find no empirical evidence either way really, however there is in fact an end to the past light cone so in that regards there is something of an "edge" or boundary for observation. For the purpose of this question we are talking about observation so I found edge applicable.. or end or whatever term you want to describe the limit of our ability to peer into the past.
Most physicists agree on the idea that the universe does not contain a boundary. If you travel far and fast enough, you will eventually reach the point you left. Not only this, but for there to be a boundary, it needs to be a boundary between this and something else, a basic fact of relativity. There cannot be an edge, because there is nothing outside.
Only if omega is greater than 1 and the universe is closed. If it is less than or equal 1 (and currently it is thought to be 1) then it is open or flat, and you don't come back around again.
Well, indeed. But that's a universe devoid of a big bang. That is against mainstream, and against what I thought our topic was all about.
there is nothing outside? Is nothing not something? You see that is speculative even though its a part of relativity, I still am not comfortable in either one because it requires nothing but math, we can't see it or test it.
There is an "edge" to the observable universe, I was merely pointing out if we somehow could see to the very beginning we might see some kind of different spatial structure that may be thought of as a shockwave of sorts.
Anyway I have a big issue with a big bang with no boundary,, infintely small point compared to what?
Quite incorrect.
Don't just say that, tell me why... If not, I have nothing to work with. My statement says that the big bang is current mainstream. I say an eternal universe is not... Explain why you disagree.
I agree, something is nothing, or nothing must be something. But whatever I define as nothing as something, compared to what you beleive as well, does not negate that relativity strictly says that nothing exists outside the universe. We can tackle our own idea's but.... we would need to bring the subject up in psuedoscience.
I think compared in a relative sense. Today the universe has a geometry, but geometry is a low energy condition on the vacuum compared to the initial start up conditions of the big bang. You are right though, interestingly enough. To be small, it's needs some reference to other objects which fail at that level.
Actually, that is a very smart point.
Ironically-enough, I was reading up on some work unrelated really to what we are discussing, but does address the issue of the wave function, and how it cannot be applied to a system outside the universe, because theory does not permit this:
http://arxiv.org/PS_cache/gr-qc/pdf/9812/9812027v1.pdf
''one has to specify some boundary conditions for ψ. In quantum
mechanics, the boundary conditions are determined by the physical setup external
to the system. But since there is nothing external to the universe, it appears that
boundary conditions for the wave function of the universe should be postulated as
an independent physical law.''
http://arxiv.org/PS_cache/gr-qc/pdf/9812/9812027v1.pdf
''one has to specify some boundary conditions for ψ. In quantum
mechanics, the boundary conditions are determined by the physical setup external
to the system. But since there is nothing external to the universe, it appears that
boundary conditions for the wave function of the universe should be postulated as
an independent physical law.''
Ah, I see. There is a misunderstanding at work. The value of omega is the average mass density of the universe. It comes directly from the BB, not the steady state theory.
If omega is greater than 1, it means gravity will overcome expansion, and we'll eventually end up with the Big Crunch. It also means that the universe is closed and unbounded, and as you said, if you could travel in a straight line long enough, you'd come back to your starting point. Geometrically in such a universe, the angles of a triangle add up to more than 180 degrees.
If omega is less than 1, then expansion will continue to accelerate. This would give an open, unbounded universe, in which you would never return to the starting point. Here the angles of a triangle sum to less than 180 degrees.
An omega of 1 gives a flat Euclidian universe, also unbounded, there angles add to exactly 180 degrees.
It appears that omega is indeed 1, which appears wildly improbable, and Inflation Theory explains why it's not improbable, but inevitable.
I agree with the mathematical ratio. What I don't agree with is stating this as if people in acadamia believe our universe is open. The greatest majority agree our universe is closed.