Posted on 06/09/2003 6:11:13 AM PDT by andy224
Bull! Causality means something. The fact that disconnection from causality has been invoked is by nature admitting a problem with inflation and relativity.
Peter Higgs, Professor (Emeritus) of theoretical physics at Edinburgh University
Age: 60
Educated: Cotham Grammar School, Bristol, and King's College London.
Claim to fame: Predicted the Higgs bosun particle in the Sixties,
Avast ye swabbies!
Fine. Go ahead and explain what you mean by a disconnection from causality as it relates to Relativity and Inflation.
I'm not the one invoking causality to explain away the problem. However, it is essentially saying you can attain or exceed the velocity of light as long as you can't "measure"(detect) it.
If you aren't invoking causality, who is?
Who or what is "it" in your second sentence?
Oh, indeed! What do you think it means?
The fact that disconnection from causality has been invoked is by nature admitting a problem with inflation and relativity.
Well, I don't know what "disconnection from causality" means, but are you trying to say that the math doesn't work out?
Here--->Inflation
This is a very remarkable behavior. It means that two points that are initially in causal contact (d < dH) will expand so rapidly that they will eventually be causally disconnected. Put another way, two points in space whose relative velocity due to expansion is less than the speed of light will eventually be flying apart from each other at greater than the speed of light! Note that there is absolutely no violation of the principles of relativity. Relative velocities v > c are allowed in general relativity as long as the observers are sufficiently separated in space.
That to me, means that things can go faster than light, you just can't "see" them.
Causality is defined in the link---> (d < dH). The distance between 2 points is less than the light horizon. It is obvious that the horizon expands at the speed of light. Therefore, if an object is at a distance less than that horizon(within the light cone of the other object) at any time it must travel faster than the horizon's velocity to be greater than the horizon(outside the light cone); that is, from this (d < dH) to this (d > dH).(it must do so while within the horizon--the superluminal velocity). Explicitly, if a distance grew(separated) 1 mm in 10-33 seconds, it would have to "travel" at least 1030 m/s during some portion of the growth. The speed of light is somewhat slower than that.
All of this using a given Universal Time Zone, a specified absolute T.(Hey, I'm not the one specifying T, it's the inflation guys and their timeline.)
Causality means that causes always precede effects. Do you understand why d < dH is equivalent?
It is obvious that the horizon expands at the speed of light.
As a matter of fact, during inflation the horizon shrinks.
Isn't that the problem?(things move outside the horizon)
I'm not mincing words, I'm stating exactly what happens. How does the horizon shrink? Does light change speed? Does light go backwards? A light cone has a definite shape. It is a cone, not a coke bottle.
The Hubble parameter--the temporal curvature of the universe--changes. As space stretches faster and faster, the distance over which the accumulated Hubble expansion exceeds the speed of light gets smaller and smaller. For example, if the Hubble constant suddenly became 300,000,000 s-1, then you couldn't see any objects farther away than one meter, by virtue of the fact that anything beyond that would have a speed greater than c relative to you. Any light that happened to be in transit from any more distant object at the time of the phase transition would be redshifted away to invisibility.
Imagine you're driving in a long line of cars. You can see cars that are a certain distance away. As you drive, you start to go around a gentle curve, and you lose sight of some of the most distant cars. The curve gets tighter, and you lose more cars still. Then, you go around a very tight curve, and you can only see one car ahead of you.
What happened? Did those other cars suddenly zoom away? Did you go backwards? Did it suddenly get foggy?
The analogy isn't quite perfect, because the car example is based on spatial curvature rather than on temporal curvature, but it conveys the correct idea that the temporary loss of contact is a geometrical thing.
Now, how again would this lead to effects preceding causes?
Well, inflation flattens rather than steepens curvature. And things still have to travel faster than light to not been seen "after" they have been seen.
Inflation flattens spatial curvature. Read again what I wrote.
And things still have to travel faster than light to not been seen "after" they have been seen.
That's perfectly acceptable. As long as it doesn't lead to effects preceding causes, it doesn't violate the principle of relativity.
I did read your post and we are speaking of space. Velocities happen in space. Now what determines time? Is it completely fictional? What is time at A and how does it relate to time at B?
"It" doesn't violate causality since we can't see "it" and you are fudging with "time", whatever that is, in the situation describing inflation.
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