Real-Time Physics

Tom,

Have I ever said I wasn't feeling around in the dark. I suppose I'm just supposed to accept the asymmetry of time as an illusion. Just not there yet.

Regards,

John M

John,

Concluding remarks from my ICCS 2007 paper:

"4.2.4 Complex systems science does not have the advantage of real continuous function calculations that the classical problem has. The generalized problem, however, is the same: design a control that compels a path between two points by least action, least energy. 'Least' in a complex system is not always apparent; it is, however, always present. That is, in fact, what the frozen moment of time that we call 'the present' actually means: the least of all possible moments."

Best,

Tom

Tom,

I know this will get me into trouble, but if the principle of least action was absolute and not just conditional, there would be no action, no reality. The vacuum wouldn't fluctuate. It would be all equilibrium and no punctuation. Flatline on the big heart monitor. Without that force pushing things away from balance in the first place, there would be no need for a tendency to seek the balance back. There would be all now and no then.

Regards,

john M

"There would be all now and no then."

Well, how about that? :-)

Tom,

So why is the 'now' active, if its primary tendency is least action?

Regards,

John M

Tom,

And why does this active, but stationary now even need a beginning or end? Isn't it just the end of one form is the beginning of another and vice versa? Otherwise all action has to stop and there is no path and no resistance, so no path of least resistance or any action, least or otherwise.

Regards,

John M

" ... why does this active, but stationary now even need a beginning or end?"

Bravo, John!

This is the very reason that Einstein inserted the cosmological constant ("my biggest blunder") into his equations. Take it out, and one finds an expanding universe, a quite different physical solution. This is a 4-dimension spacetime expansion, however -- so the universe remains dynamic no matter which point one chooses as the arbitrary beginning. From this, we get the colloquial description of the general relativity model: "finite but unbounded."

Best,

Tom

" ... Isn't it just the end of one form is the beginning of another and vice versa? Otherwise all action has to stop and there is no path and no resistance, so no path of least resistance or any action ..."

Thus, the beauty of Vesselin Petkov's observation that bodies do not resist their motion. I am convinced that many of the Rube-Goldberg-complicated theories of particle physics would fade into obscurity if more simply understood the foundation of classical mechanics.

Tom,

As I originally read it, Einstein inserted the cosmological constant to keep gravity from causing space to collapse to a point, so if we take it out, then wouldn't gravity take over?

Dark energy has been described as the cosmological constant, so presumably it would be an expansion factor.

" so the universe remains dynamic no matter which point one chooses as the arbitrary beginning."

Yet they manage to pin the tail on that donkey at 13.8 billion (earth) years ago. If there is no beginning, how does that get inserted?

If bodies don't resist their motion, how do thermodynamic processes, as well as the change we measure as time, go in reverse?

I'm still leaning toward gravity as a vacuum effect of energy coalescing into mass. The path of least resistance then becomes inward.

Regards,

John M

Tom agreed on "There is one and only one natural point of reference for a natural scale of time: the actual now."

Any objections?

"As I originally read it, Einstein inserted the cosmological constant to keep gravity from causing space to collapse to a point, so if we take it out, then wouldn't gravity take over?"

Holding back gravity doesn't prevent spacetime singularities. The cosmological constant preserves a static universe. Today, cosmologists are again considering a nonzero cosmological constant because of evidence that the universe is not just expanding, but accelerating. All these solutions are consistent with the general theory of relativity.

"If bodies don't resist their motion, how do thermodynamic processes, as well as the change we measure as time, go in reverse?"

We don't measure change as time.

"I'm still leaning toward gravity as a vacuum effect of energy coalescing into mass."

Great. What does that mean?

"The path of least resistance then becomes inward."

Where in the universe is "inward?"

Best,

Tom

Tom,

"Holding back gravity doesn't prevent spacetime singularities.'

It doesn't hold it back, it balances it. Gravity causes space to contract and the primary gravitational features are galaxies. The space in between galaxies appears to expand at a rate that matches the effect of gravity, resulting in apparently flat space.

"We don't measure change as time."

We measure regular cycles as a clock, but would you say the process creating those cycles is not changing from one cycle to the next? Whether it's going from one day to the next, or one tick of a clock to the next, there seems to be some dynamic involved.

"Where in the universe is "inward?""

The gravitational center of attraction.

Regards,

John M

"Gravity causes space to contract ..."

No it doesn't.

"We measure regular cycles as a clock ..."

No we don't. The cycles *are* the clock.

"'Where in the universe is 'inward?'"

The gravitational center of attraction."

Where is the center of the universe?

Tom,

""Gravity causes space to contract ..."

No it doesn't. "

That I do agree with. Space doesn't contract, expand, warp or anything else. Only the physical quantities in it are so dynamic, but since physics treats space as a measure and gravity pulls measurement points together, space gets treated as though it contracts.

" The cycles *are* the clock."

True enough, as well. So if time is what a clock measures, do the cycles go both forward and backward simultaneously, such that time is simply a scalar dimension?

"Where is the center of the universe?'

Yours, or mine? Mine is currently central Baltimore county.

Regards,

John M

"""Gravity causes space to contract ..."

No it doesn't. "

That I do agree with."

Then why did you say otherwise?

"Space doesn't contract, expand, warp or anything else. Only the physical quantities in it are so dynamic, but since physics treats space as a measure and gravity pulls measurement points together, space gets treated as though it contracts."

No it doesn't.

"'The cycles *are* the clock.'

"True enough, as well. So if time is what a clock measures, do the cycles go both forward and backward simultaneously, such that time is simply a scalar dimension?"

What do you mean by simultaneously?

"'Where is the center of the universe?'

"Yours, or mine? Mine is currently central Baltimore county."

Mine is any point I choose. I live in a 4-dimension space.

Best,

Tom

Tom,

"Then why did you say otherwise?"

Language entails a process of constant and often subconscious editing. The proper statement would have been, 'Gravity causes the measure of space to contract.'

"What do you mean by simultaneously?"

Well, if you say time can go either direction, that's not really a scalar, just the vector can point either way. To be a proper scalar, doesn't it have to be 'pushing' in all directions, like pressure, or moving in all directions, like the thermodynamic activity of temperature?

"I live in a 4-dimension space."

Right now, the principle of least action is preventing me from going out and raking leaves, so I apparently only live in three dimensional space.

Regards,

John M

Tom,

You wrote: "Mine [center of the universe] is any point I choose. I live in a 4-dimension space."

Didn't you agree on that the actual moment is the only natural point? You can arbitrarily move in 3D space. However, in reality you are unable to choose the year in which you are living. That's why we should scrutinize Minkowski's spacetime.

Every actual moment is common to all of us, while we do not share the same 3D location.

Genuine relativity means lack of a preferred point of reference. 3D space lacks such point. Elapsed time doesn't; it is an absolute measure.

Regards,

Eckard

"The proper statement would have been, 'Gravity causes the measure of space to contract.'"

Does putting a meter stick upright aside a tree, cause the stick to contract?

"'What do you mean by simultaneously?"

Well, if you say time can go either direction, that's not really a scalar, just the vector can point either way."

How about every direction?

"To be a proper scalar, doesn't it have to be 'pushing' in all directions, like pressure, or moving in all directions, like the thermodynamic activity of temperature?"

It does.

"'I live in a 4-dimension space.'"

Right now, the principle of least action is preventing me from going out and raking leaves, so I apparently only live in three dimensional space."

The principle of least action is not identical to inertia.

"Genuine relativity means lack of a preferred point of reference. 3D space lacks such point. Elapsed time doesn't; it is an absolute measure."

If it were, it would have have an absolute point of reference, contradicting your previous statement.

Only spacetime -- not time alone nor space alone -- is physically real.