An Accidental Universe

Tom,

You: "We can observe galaxies moving apart, and we can measure the rate at which the universe expands as changing the scale of the universe -- the whole scale, not just the observer's frame. You're assuming an absolute reference frame that exists only at relative rest."

Me:"I keep pointing out the same scales expanding between galaxies are collapsing into them."

You: "Exactly what do you mean by "scales" in this context?"

That the "changing scale of the universe" is balanced by gravitational contraction, so that "The shape of spacetime is still mostly flat."

You: "Gravity is not a force that contracts anything; gravity is the curvature of spacetime."

The cosmological constant was inserted to balance gravity and keep it from causing the universe to contract. Being a balance to gravity, then presumably it would be an opposite "curvature of spacetime," than gravity. The expansion appears to correlate with a cosmological constant and this term has been used to explain expansion.

How light works is one issue. However, there are two very important facts which then disconnect that from what is usually the 'follow up'. These are:

1 We receive a photon based (ie light) representation of physical existence, ie light is light, physical existence is something else.

2 Einstein has no observational light. He may refer to observers, but there is no light for them to observe with. In other words, the light (which is a ray of, or lightening, or whatever) he uses is actually a conceptual constant against which he then calibrates duration and distance. It is just a constant, it is not observational light. In other words, by conflating physical existence and the photon based representation thereof, he has shifted the time differential which occurs in the timing of the receipt of light by different entities, into being an inherent characteristic of physical existence.

Paul

" ... I can just give up and accept the whole wormholes/blocktime/multiworlds scenario."

You don't have to accept anything, other than that relativity, the special and the general theory, is successfully tested science -- to deny it is not getting you anywhere. The many worlds hypothesis, BTW, is not related to relativity; it is an interpretation of quantum theory. Conjectures of wormholes and blocktime are conclusions *consistent with* relativity, not necessarily true yet not falsified.

If you are going to attack a proposition, John, you should see what you are aiming at. Though shots in the dark may hit something -- they probably won't.

"The cosmological constant was inserted to balance gravity and keep it from causing the universe to contract."

Not exactly. Classical gravity is already "balanced" by G, Newton's gravitational constant. The cosmological constant prescribes a limit that preserves a static, i.e., eternally existing universe, which was the prevailing scientific view before Hubble discovered expansion. The Lambda term was more philosophical (like phlogiston) than theoretical. There in fact, may be a place for such a constant in the classical theory, though we know that its value is very near zero.

"Being a balance to gravity, then presumably it would be an opposite 'curvature of spacetime,' than gravity."

Here's where it is essential to know the mathematics. Your presumption makes no sense -- spacetime can have positive, negative or zero curvature; however, it is nonsensical to suggest an "opposite of curvature." That means absolutely nothing. In fact, consider that special relativity is called "special" because it applies to the special case of uniform (straight line) motion; accelerated (curved) motion is what leads Einstein to the equivalence of gravity and acceleration in curved spacetime.

"The expansion appears to correlate with a cosmological constant and this term has been used to explain expansion."

Not unless it's negative.

John, do you not yet understand how you have been continually "patching up" your ideas to preserve your belief against the weight of facts? You accuse theorists of "patching" when they hypothesize ideas consistent with tested theory. Yet your own patches can't seal gaping holes in your knowledge.

We've wandered far from the topic. Let's try to get back to Andreas Albrecht's startling (to many, not to me) revelation that free choice of random Hamiltonians leads to different cosmological initial conditions. Here's a nonrelativistic hypothesis that if you understand it, might well overthrow those "fantastic" theoretical notions that you believe cannot possibly be right.

What do you think? -- Is Albrecht's model compatible with the conventional big bang cosmology of general relativity? We already know that's compatible with the many worlds hypothesis.

Tom

Hi Kostas,

I'm not sure we mean the thing when we use the term "metaphysics." To find out, and to try and lead the discussion back to the topic, allow me to ask you:

Is Andreas Albrecht's hypothesis metaphysical? Why or why not?

Tom

Tom,

The issue isn't whether Relativity is mathematically accurate, but whether spacetime is a valid physical reason. Spacetime is to Relativity what giant cosmic gear wheels were to epicycles; A physical explanation drawn out of mathematical patterns. Is there something we are missing. I'll post a further response on the cosmology thread Zeeya started recently, later in the day.

As for Albrecht's discovery and any other equations leading to multiworld scenarios, in most other disciplines, there would be a strong tendency to go back and pull apart the math, when the answers start going haywire.

"Spacetime is to Relativity what giant cosmic gear wheels were to epicycles; A physical explanation drawn out of mathematical patterns."

Huh? It's actually a mathematical pattern drawn from physical explanations. Your conclusion (and confusion) comes from not understanding the mathematical structure or its origin.

Tom

I should proofread better. When I said "Is Albrecht's model compatible with the conventional big bang cosmology of general relativity? We already know that's compatible with the many worlds hypothesis ..." I meant to say:

"We already know that it (Albrecht's hypothesis) is compatible with the many worlds hypothesis."

Tom

Tom,

It's not as though I'm the only one questioning spacetime.

While other scientists tread softly around the edges of Einstein's theory, hoping to tweak it into compliance, Barbour and a growing cadre of collaborators see a need for a bold march forward. They aim to demolish the space-time fabric that stands as Einstein's legacy and remap the universe without it.

John,

So to what extent does Julian Barbour agree with your notions?

Tom

Tom,

I can't comment on Albrecht's hypothesis since I don't know it. But I can comment on what I mean by 'metaphysical': "beyond the physical". Thus, 'metaphysics' is knowledge of "what is" beyond our senses.

Why is this relevant to your love/hate relation with "The End of Science"? Because such behavior by physicists and intolerance to diverse views (Joy Christian's for example) is very characteristic of "religious wars". And all religions are metaphysical as they all seek to know "what is" the Universe.

Because such knowledge is fundamentally based on "belief", the truth of such knowledge can only be 'true' if everyone believes in that truth. Thus we get personal attacks, intimidation and persecution of those that think differently. We've seen this movie before!

Read my essay, The Metaphysics of Physics., for more of my thinking on this.

Constantinos

Tom,

The point is that spacetime is conjecture..

I doubt Barbour has any opinions on my views. Any communications I've had with him have concerned his views, of which I see as making the same basic mistake as most other models: By treating time as a measure of sequence, it only emphasizes the static sequence over the underlying dynamic process.

Que horror, disbelief, etc.

doug, Edwin, Paul,

I agree with an accident. Set up some frames of balls and try 1,000bn times to get them to end up at the same space time points. My £10m says you won't do it!

doug. Pass me some CIG. I'm tearing it all out! I think we should distinguish between DEther and distance. (I've just now re-christened ether so it's really the Dark Energy that all current theory relies on). It can now have a local kinetic identity just like matter (so we can now have a QV, Higgs field etc). The problem SR had with it is removed along with the 'absolute' frame AE assumed it needed. Matter and DEther can then move. It can then thin out, but em fluctuations propagate at c locally within it, modulated by the shocks at the 'domain limits'. No violations at all then. Is there anything about that which you find scientifically incorrect? It seems Tom doesn't dare try to handle it as he's seen it's dynamite and may be in denial. I think it's just overindoctrination as I don't have Tom down as an acid tripper! (2 new words in a day!!)

Edwin, Always a lovely breath of fresh air, and some logical sense. Thank you.

Paul, Closing in but no choccies yet. Far simpler ending. Read page 42 2nd para of the current Physics Today Edwin refers to and see if you can think and visualise dynamically. It shows how observer frame matters. It's all about evolution of interaction over non zero time and with media motion.

Best wishes

Peter

Another way of looking at this is to say that until we understand how time works, we'll potentially get nonsense out of any attempt to draw a conclusion from a train of thought like the one Albrecht has pursued. Time is QM is different from time in GR, and we don't know why, or why they're in disagreement in places. We also don't know why we seem to observe a flow of time. Put those together, and it's a lot.

So although Albrecht may have got some real conclusions out of his reasoning, he might also have got nonsense - for some reason that we don't yet understand. We don't know enough to know. The mistake people commonly make is to assume that the framework we have is solid enough to use in this kind of way - they have been told that it is, and underneath they believe it.

Paul,

So essentially he places light at the center and molds a geometric frame around it, a bit like epicycles places the earth at the center and builds a geometric frame around it? His absolute frame isn't spacetime, but light. So the idea of blocktime as "physically real" overlooks this basis?

Anonymousse,

What if we simply do away with time as fundamental and let it emerge as effect, similar to temperature. Then it wouldn't be a vector along which the present moves from past to future, but the changing configuration of what is, that turns future into past. So in QM, it isn't moving along that single external timeline from a determined past into a probabilistic future, but is the occurrence of events collapsing probabilities into actualities. With relativity, it is nothing more than frequency and quite logical that each clock is recording its own rate of change. There is no vector external to the present, because duration is not external to the present. It is the state of the present between the occurrence of events.

We experience it as a sequence of events, but then we still see the sun as rising in the east, moving across the sky and setting in the west.

Hi John,

What if we simply do away with time as fundamental and not let it emerge? What if we have motion in our timeless Universe? What if our clocks only measure durations elapsing?

Kostas,

" ... 'metaphysics' is knowledge of 'what is' beyond our senses."

I suspected that's what you meant. It isn't what I mean, however, nor what science and non-theist philosophy means. There may exist things one cannot sense; short of mystic revelation, though, one cannot have knowledge of them.

Though Aristotle's metaphysics, from which the idea originates, is concerned with 'incorporeal being' that can't be sensed yet exists -- whatever actual knowledge we have of the world is sensuous.

What philosophers call "metaphysical realism" OTOH, allows objective existence of unmeasured (though not unmeasurable) objects.

I find Albrecht's program objective and consistent with metaphysical realism.

Tom

"The point is that spacetime is conjecture."

Only one who doesn't know the fundamentals of relativity could make such a statement. It puts you in the company of Pentcho Valev and others who simply deny the science.

John, I found it startling that you invoked Julian Barbour to support your relativity denial, since his program is the most fundamental relativity research possible.

Tom

Jim,

That's basically what clocks do, but the arrow of time emerges from the non-regularity of action. Otherwise there would be no arrow of time, just cyclical metronomes.

As effect, it's like temperature, color, etc. Given we are a much higher order effect, if they didn't emerge, neither would we. In fact knowledge, being largely based on narrative and cause and effect logic, is emergent from the effect of time. That's one reason why it seems more fundamental than temperature, though the ambient energy of thermodynamics is conceptually more primal than the change of time.