An Introduction to Zero-Point Energy

CalPhysics.org ^

[cinFLA]

Just go back and read my posts from last week.

[cinFLA]

But without me how would you justify your posts to your boss?

[_Jim]

How does air "pull"?

Owing to a reduction in 'pressure' above the airfoil as the airfoil moves through the air (and actually, it's a resultant 'push' that occurs from the air *below* the airfoil, but, it is not simply the 'thrust' or a 'push' developed by the prop against the air that produces the resultant *force* ...)

[cinFLA]

and now have apparently added me to the list of conspirators.

I believe it is more correctly stated that you posted to me first.

[sourcery]

Owing to a reduction in 'pressure' above the airfoil as the airfoil moves through the air (and actually, it's a resultant 'push' that occurs from the air *below* the airfoil, but, it is not simply the 'thrust' or a 'push' developed by the prop against the air that produces the resultant *force* ...)

And where does this pressure gradient come from? What does Newton's Third Law of Motion REQUIRE to be the case, given the interactions between the propellor and the air molecules, via which that pressure gradient arises?

[Alamo-Girl]

What do y'all think about the ekpyrotic cosmology? (pdf)

Background for lurkers:

From the CERN Courier

Agreement between the theoretical idea of inflation and experiment is convincing. However, model building is still difficult and seems to require several assumptions and fine-tuning of parameters. This leads to the question of whether there are serious competitors for inflation, for example, in M-theory. This would be desirable since some basic arguments state that de Sitter space-times, which describe an exponentially growing universe, are difficult to implement in supergravity and superstring theories. As Fernando Quevedo of Cambridge discussed, there is a nice way to build inflationary models into brane-world models in string theory in such a way as to trigger the graceful exit from inflation. This leads to a hybrid inflationary scenario being realized in brane-world models. A more radical approach to explaining the flatness and horizon problems - one that really competes with inflation - was introduced by Burt Ovrut from the University of Pennsylvania. Taking its name from a Greek word meaning conflagration, the ekpyrotic universe theory explains the rapid expansion of the early universe as arising from the collision of branes. Through such a collision, a huge amount of energy is almost uniformly and homogeneously deposited on our universe. Despite offering a fascinating and challenging alternative to standard inflation, many aspects of the ekpyrotic universe need further investigation This article contains an interview with Burt Ovrut: The Ekpyrotic Universe - A Collision Before the Big Bang?

A brand new theory about the creation of the universe emerged recently from cosmologists and particle physicists at Princeton University, the University of Pennsylvania and Cambridge, England. The new theory is called the Ekpyrotic Universe, from a Greek word meaning "conflagration" used to describe the universe's creation from a huge fireball that cooled down. Periodically, the Greeks thought, the process could repeat itself.

The new Ekpyrotic theory has grown out of string and super string theory that says there have to be eleven dimensions. We live in the first four of 3-dimensional matter plus time. The 5th dimension is the one in which, the new theory goes, a cataclysmic event took place that ended up creating the universe we are now living in. Dimensions 6 through 11 are like scaffolding behind the scenes upon which our 3-dimensional theater plays out. Dimensions 6 through 11 are also tiny and curled up into little "strings" which are too small to see, but without them the universe could not exist.

String theory says that dimensions 1 through 4 "float," so to speak, in the 5th dimension. The new theory suggests that not only is our universe floating in the 5th dimension, but the 5th dimension can have waves in it just like the ocean. Further, one or more of those 5th dimensional waves can become a soliton - meaning, a wave can form that keeps on going as a wave and does not collapse. If such a 5th dimensional soliton wave should come in contact with a 4-dimensional universe such as ours, what would happen? That's what these cosmologists and mathematicians have been working on. Rather than calling this a universe and the soliton wave a wave, theorists today now refer to large scale mathematical features in different dimensions as "branes." The term originated from discussions about "membranes" between or in different dimensions.

Recently in a meeting at the Space Telescope Science Institute in Maryland, this new theory about the creation of our universe from a 5th dimensional brane slamming into a 4-dimensional matter universe was presented by Princeton astrophysicist, Paul Steinhardt. He worked out the mathematical details over the last year and a half with Princeton graduate student, Justin Khoury; Cambridge, England physicist Neil Turok; and University of Pennsylvania particle physicist and mathematician, Burt Ovrut.

I visited Dr. Ovrut at his Penn Physics Department office this week to talk about this new theory of universe creation from a collision between different dimensions. He began by describing his concept of the 5th dimension.

Phaedrus: this is a bit like your suggestion of the crest of a wave (please read the last link.)

[Right Wing Professor]

Thanks for the ping, but I don't do cosmology either.

[Physicist]

Owing to a reduction in 'pressure' above the airfoil as the airfoil moves through the air (and actually, it's a resultant 'push' that occurs from the air *below* the airfoil,

Now you're talking...

but, it is not simply the 'thrust' or a 'push' developed by the prop against the air that produces the resultant *force* ...)

But yes, that is the same thing. Every action results in an equal and opposite reaction. To say that the propellor pushes against the air is thus mathematically equivalent to saying that the air pushes against the propellor (or the ground against the runner, or the exhaust against the rocket).

One quibble, however: propellor blades do not behave as wings. The pressure difference caused by the difference in camber between the upper and lower surface of the blade is negligible or nonexistent; there is no Bernoulli effect, no aerodynamic lift. The pressure difference arises strictly through angle-of-attack.

[Physicist]

University of Pennsylvania particle physicist and mathematician, Burt Ovrut.

Burt's a good guy. He's more than patient with my stupid questions. And he drives a very cool Alfa Romeo.

[Poohbah]

I did.

You provide no documentation to support your claims.

[tacticalogic]

One quibble, however: propellor blades do not behave as wings. The pressure difference caused by the difference in camber between the upper and lower surface of the blade is negligible or nonexistent; there is no Bernoulli effect, no aerodynamic lift. The pressure difference arises strictly through angle-of-attack.

Is the resultant pressure differential between the front of the propellor and the rear of the propellor due to the blade pushing the air in front backward, displacing it radially, or some of both?

[Phaedrus]

I followed your link on the Cosmological Constant and quickly got way, way over my head. The math and the terminology are quite beyond me. My impression is that there seem to be reasons to believe there is a Cosmological Constant but I have no idea what this means. Perhaps you or someone more knowledgeable could give us the "layman's version"?

[Alamo-Girl]

Thank you so much for your reply!

[Alamo-Girl]

Thank you so much for your reply!

And he drives a very cool Alfa Romeo.

Kewl!

As an overly curious layperson looking for omega=1, it has been my “sense” for a long time that harmonics (or wave phenomenon) must lie at the inception of the physical realm. I was encouraged by the work of this consortium, but their ideas never seemed to get much traction among the peers.

Now, having discovered Burt Ovrut’s ekpyrotic cosmology – and the reaction from his peers - I am ecstatic and very much hopeful the theory will be written in book form for the general public so we can “keep tabs” on it in the years to come.

Sigh ... I wish I were a mouse in your lab.

[Alamo-Girl]

Thank you so much for your post!

Indeed, the meaty stuff in the first link is a tough read. And I’m not aware of a good offering (yet) to fully explore ekpyrotic cosmology without all the math. But there is a great book for the general public on the cosmological constant written by Robert P. Kirshner:

The Extravagant Universe

The book explores the accelerating universe, dark energy --- and therefore, the cosmological constant necessary to arrive at omega=1.

[cinFLA]

How many paid spammers are here on FR touting drug legalization?

[Poohbah]

How many paid spammers are here on FR touting drug legalization?

Maybe you're a little confused.

You're the one saying that there are paid spammers touting drug legalization on FR.

You're the one who has the obligation to identify which screen names they post under and to document those claims. Merely asserting it, as you have done, is not documenting it.

[cinFLA]

My obligation is to identify the source of the money that pays the spammers. That I have done, time and time again.

[Poohbah]

My obligation is to identify the source of the money that pays the spammers.

You have not established that they are, in fact, paid spammers. Your obligation includes posting specific information that identifies the spammers and verifies that they are, in fact, paid by the alleged source or sources of money you identified.

Now, cough up the evidence linking these specific posters to the funding source.

[Doctor Stochastic]

Perhaps we could persuade Senator John Iselin to pass the time by playing some solitare rather than making these accusations.

He didn't even tell us how to get paid.