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## Fridger's Unicorn & "warped extra dimensions"

General physics and astronomy discussions not directly related to Celestia
Topic author
don
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### Fridger's Unicorn & "warped extra dimensions"

Howdy Fridger,

I loved the "Help! My Unicorn run away..." thread in Purgatory.

But, I for one, would really like to hear more about half of your Theoretical Physics department working on warped extra dimensions. Such as:

1) What do you mean by "warped"? Space-time warpage?

2) Why would these extra dimensions have to be "warped"? Would a two-dimensional object/being view our third dimension as being "warped"? Hmmm, I guess it would -- a plane viewing a cube would look pretty warped to itself!

3) Why would they be classified as "extra" dimensions? For example, if the next dimension from our three (excluding time), happens to be an "eternal" dimension (excluding time), then to the beings residing there it *could* theoretically be simply a three dimensional existence to them, just like ours is to us -- no "extra" dimensions involved. If one considers time to not be a dimension unto itself. We have three dimensions, and they have three dimensions. The only "extra" dimension in this case would be time, which we have, and they don't. Would that make us an "extra" dimension to them?

If one considers time to be a dimension, then they could have a fourth dimension in their existence to replace the fourth dimension of time in ours, making both the same number of dimensions -- four. But, this case would then prove that "extra dimensions" do in fact exist.

Personally, I like the thought of an "eternal" dimension (lack of time), because that makes an excellent case for "spirit" or "soul", existing before and after our physical three dimensional existence as human beings.

4) If anti-matter, anti-particles, anti-forces, etc. all exist within our three dimensions, then shouldn't our universe be described as having SIX dimensions -- with the positive items moving forward and the anti/negative items moving backwards through time? In other words, two identical universes, one moving forward and the other (mirror image) moving backward, both in the same Space-Time!

5) If tachyons actually exist (which they do theoretically), could they possibly be objects from another dimension, or inter-dimensional traveling objects, since in OUR universe, they move faster than light, supposedly have mass (if I remember correctly, or I'm thinking of other subluminal particles), AND go right through our existing mass? They appear to defy several laws of physics, but as I recall, they don't really, but I don't remember the reasoning or math.

6) Since we can directly observe other dimensions below us (1-D point, 2-D plane), does this imply that "higher" dimensional "beings/objects" can directly observe us also? We are not able to directly interact with lower dimensional objects, but we can create them, destroy them, and manipulate them to our heart's content. Same with higher dimensional beings? Or would they be able to interact with us, since three dimensions could be considered the lowest possbile interaction level between dimensions? Gives pause for thought (angels, ghosts, etc.)!

Fridger, please don't get too upset at me for asking such "childish" questions of a true professional physicist. I don't have any training as a physicist, but I am an overly-curious human being and ask lots of questions. Thanks for humoring me.

If you were Stephen Hawking, I would ask you if you had considered the thought that black holes might be a doorway to the next dimensional level. Whereby our universe creates matter, which is then converted into energy for them, just like we extract electricity from magnetism (a lower dimension?) here.

Don G.
Last edited by don on 02.09.2003, 11:23, edited 1 time in total.

Topic author
don
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As a follow-up, just a few minutes later ...

It would appear that our three dimensions are either collapsed (infolded) or expanded (unfolded), depending on the starting point.

The collapsed version would start with a cube, infold it upon itself until it is a plane (or line), then infold the plane until it is a point. The expanded version would go from a point, unfolded in all of its possible directions to become a plane, which is then unfolded in all of its possible directions to create a cube.

Thus, to observe the next dimension would require us to either infold a point (before the big bang?), or unfold the cube in all of its possible directions.

All of this, of course, ignores "time".

So, I'm not sure how "warped" or "extra" would fit into this multi-dimensional picture.

-Don G.

t00fri
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### Unicorns and Extra Dimensions...

|
Hi Don and friends of Unicorns and extra dimensions;-),

first of all, as to my 'Unicorn that ran away', I should perhaps add

-- my Unicorn thread was actually redeemed from Purgatory and is
residing since a while in this department;-)
[where it of course belongs to...]

-- people who are more interested in Unicorns that do not run away, have a
good chance of seeing one in clear nights in the sky;-):

Unicorn == Monocerus, the one and only 'stationary' Unicorn...

one is latin one is greek, in each case a familiar asterism...
There was a feature article some time ago about the Unicorn in
Sky&Telescope!

Next to warped extra dimesions and your questions 1) - 6):

(1) The most intuitive way of imagining an extra dimension would be
this. Suppose our 3 space + 1 time = 4 dimensional world would be
drawn for simplicity as a 2 dimensional sheet ( 1 space + 1 time,
say) of infinite size (remember we live in a non-compact
space-time). Let the extra dimension be compact (a circle of radius
R), then forming a cylinder of radius R by wrapping our 'world' around the
circle would be a lower dimensional analogue of our simplest
possible 5 dimensional world. We would of course live on the surface
of the infinite cylinder. Such a simplistic 5-dim space-time represents a
so-called 'factorizable geometry', i.e. the metric (g_mu_nu)
of our four familiar dimensions is independent of the
coordinate describing the 5th dimension!

Things don't have to be that simple, though! Warped space-times are
not of this factorizable type. While more complicated at first,
they have a number of amazing benefits as it turned out....

However, reviewing those in popular terminology would amount to a 1 hour
lecture, I am afraid.

A one-sentence summary would be: In the warped case, there is a real
chance of understanding the longstanding hierarchy problem in
theoretical physics, i.e. the fact that we encounter huge ratios of
(energy) scales without having a clue why this ratio is sooooooo large:

100000000000000000!!

This basic puzzle has been even amplified recently by the
spectacular discovery of a non-vanishing cosmological
constant
or dark energy as it is better termed.

(2) The warping only refers to the extra dimension not to our familiar 4!

(3) 'Extra' = by definition wrto the 4 we know and love...Noone has as
yet contemplated how life would look like in those extra
dims. Let alone spiritual aspects;-)...
In any case, for theoretical physicists, their purpose is usually
quite different from the 4 we live in.

(4) Six dimensions have been quite popular recently, however for
completely different reasons from what you mentioned.

(5) Tachyons might well exist, but they better have no interactions
whatsoever
with any object in our world, otherwise
causality would be inevitably lost. This would be
catastrophic!

For example, girls could become pregnant before their first kiss;-)...

(6) Why would'nt we be able to directly interact with lower
dimensional objects? I can certainly tare that sheet of paper into
'beings'.

Fridger, please don't get too upset at me for asking such "childish" questions of a true professional physicist. I don't have any training as a physicist, but I am an overly-curious human being and ask lots of questions. Thanks for humoring me.

Your questions were not at all "childish", at best expressed sometimes
in a slightly 'unfamiliar' wording. In fact, I enjoy curious people;-)

If you were Stephen Hawking, I would ask you if you had considered the thought that black holes might be a doorway to the next dimensional level. Whereby our universe creates matter, which is then converted into energy for them, just like we extract electricity from magnetism (a lower dimension?) here.

If I was Stephen Hawking I would not be able to answer you,
unfortunately. [I actually know him for many years and had daily overlap with
him at Cambridge/GB a long time ago.]

These things are very controversial, to be serious again.

What is really exciting, however, is that we have a good chance of producing
little black holes in collisions of elementary particles at future accelerators
if the idea of
(large) extra dimensions has some truth in it!

Bye Fridger

PS: For interested people there are two relevant articles in Sky &
Telescope:

1) June 2003: 'Strings, Branes and Extra Dimensions'
2) October 2003: Special Issue: 'The New Cosmology'
This volume was in my mail today and the main article really looks
well written...

Topic author
don
Posts: 1709
Joined: 12.07.2003
With us: 17 years 2 months
Howdy Fridger,

(PS. Guess my reply got kinda long. Sorry 'bout that. I'm just "wired for sound" right now -- meaning "WIDE awake" , even though it's 4:20 am!)

After reading your reply, especially the sentence, "While more complicated at first, they [warped space-times] have a number of amazing benefits as it turned out..." (my highlight, to indicate VERIFIED -- PAST TENSE) ... my brain said, "SAY WHAT???!!!" and I nearly jumped out of my chair! Then I did some further searching on the Web, and for many hours now, I've been simply "blown away" by what I've read.

My last on-line physics update, prior to today, was reading a bit about string theory, which at the time was quite new and controversial; that the existence of black holes had in fact been "verified" and there may be one in the center of the Milky Way; and that most of the calculated mass of the universe is UNaccounted for (80%?), and being called "Dark Matter".

I had no idea that extra dimensions were actually BEING CREATED TODAY, even though they are only one millimeter in size! I also did not realize that there are plans to create Black Holes in future accelerators! It also appears that not only has string theory been accepted, but there are many "types" of strings being theorized (D, S, p, and many others). WOW!

Brane Worlds is totally new to me -- Where our universe could be a mere tabletop, or a molecule in that tabletop, in some other dimension / universe, if I understand it correctly. If this description is correct, it is something that I have personally always wondered about ... the "infinately small to the infinately large" scenario ... in our universe, many XYZs creates an atom, many atoms create a molecule, many molecules create a solid (or liquid, gas, etc.), many solids are combined and then shaped by us, many planets create a galaxy, many galaxies create a universe, many universes create a ???. So, why not consider that our universe is simply a complex molecule that belongs to some other dimension / universe, where it is combined with other molecules of that dimension / universe to form whatever <smile>?

So I must now really thank you for even answering my post, instead of simply telling me to go read the thousands of papers already out there. <smile> I had no idea so much has happened since what, about 1997 or 98? Unbelievable!

With all of this work about extra dimensions already published, what is it that your theory group is doing in the realm of warped extra dimensions?

t00fri wrote:In fact, I enjoy curious people;-)
I am very glad <big smile>!

t00fri wrote:However, reviewing those in popular terminology would amount to a 1 hour lecture, I am afraid.
From what I've just been reading, it appears as though it might take a tad longer than an hour <grin>.

t00fri wrote:A one-sentence summary would be: In the warped case, there is a real chance of understanding the longstanding hierarchy problem in theoretical physics, i.e. the fact that we encounter huge ratios of (energy) scales without having a clue why this ratio is sooooooo large: 100,000,000,000,000,000!!
I'm sure I could look up the "hierarchy problem" but could you give me/us an idea as to where this "energy/scale appears in physics? Like between the size of an atom and the size of a galaxy? Or the energy difference between particle X and particle Y?

t00fri wrote:This basic puzzle has been even amplified recently by the spectacular discovery of a non-vanishing cosmological constant or dark energy as it is better termed.
I've heard of Dark Matter, being described as the yet undiscovered major mass of the universe ... but what is "Dark Energy"? I've not heard of this either?! Man alive, is my mind living in the stone age or what <laughing>???!!! I feel like a kid in nursery school, and only a couple years has gone by since I thought my cosmological knowledge was fairly up-to-date. Sheesh!

Reading the words "Dark Energy" gave me a shiver up my spine. An ex-nuclear physicist (T. E. Bearden) has claimed (and seemingly proven) that it is possible to extract usable energy from the vacuum. He has a working device, called the Motionless Electromagnetic Generator (MEG), a U.S. patent (No. 6,362,718), is seeking funding to scale the device up to a one kv unit, and has published a book titled "Energy from the Vacuum - Concepts & Principles".

Others, such as M. W. Evans, who subscribe to "generally covariant electrodynamics' [such as O(3) electrodynamics (http://www.aias.us/Comments/Background/Background.html)], have mathematically proven *why* this is possible, via curving space-time (http://www.cheniere.org/techpapers/emenergy.pdf).

But now, reading about "Dark Energy", I wonder if the two are possibly connected? Unless Dark Energy is the energy ejected from a Black Hole. But then it should be called Black Energy <smile>.

In reply to "Why would these extra dimensions have to be "warped"?", you wrote...

t00fri wrote:The warping only refers to the extra dimension not to our familiar 4!
Yes, I understand this. But why are you considering / theorizing them to be "warped"? And, warped in what way (as question #1 asked). Your reply was an example of "factorizable geometry", but then you wrote that "Warped space-times are not of this factorizable type." I am assuming that you were addressing these questions with your "1 hour lecture" reply? Darn, no simple answer like "look at it as a hole in space-time" <smile>.

t00fri wrote:(3) 'Extra' = by definition wrto the 4 we know and love...Noone has as yet contemplated how life would look like in those extra dims. Let alone spiritual aspects;-)
Oh, sure they have <grin> -- they're called writers -- of Science Fiction <smile>.

On the serious side, and aside from any specific religion or belief, since so many personal, eye-witness accounts of "spiritual" encounters (angelic, ghostly, and many other forms) have been recorded throughout recorded history, and passed down from one generation to the next in story form before that, not to mention eternity being described as a real place in several religions -- it would seem normal to contemplate the possibility that such a place (universe or dimension) and beings (dwellers of that place) actually exists, and it's inhabitants are able to interact with us in our universe, via whatever means they have (physical, inter-dimensional, mental, whatever).

Along with this sort of contemplation, comes the question, "do we dare open doorways to (create) extra dimensions when we don't even know what is there, let alone what they are, or what opening such a doorway could do to our "known universe?" Who or what organization on our planet could possibly give "permission" to do such a thing? Yes, this question reminds me of the debate over unleashing a fission reaction on our planet to test Einstein's e=mc^2 equation.

t00fri wrote:In any case, for theoretical physicists, their purpose is usually quite different from the 4 we live in.
What do you mean by "their purpose" Fridger? Like the "purpose" of our four is to describe height, width, depth, and time?

t00fri wrote:Six dimensions have been quite popular recently, however for completely different reasons from what you mentioned.
Does that have to do with string theory, and the collapse (compactification?) of 11 dimensions to where we are now? Or do you mean work such as "Dynamical Stability of Six-Dimensional Warped Brane-Worlds" (C.P. Burgessa, James M. Clinea, Neil R. Constableb, Hassan Firouzjahia)?

t00fri wrote:Tachyons might well exist, but they better have no interactions whatsoever with any object in our world, otherwise causality would be inevitably lost. This would be catastrophic!
Maybe I was thinking about neutrinos? Sorry.

t00fri wrote:For example, girls could become pregnant before their first kiss;-)...
Ahhhh, you mean like Christianity's Virgin Mary <smile>?

t00fri wrote:Why would'nt we be able to directly interact with lower dimensional objects? I can certainly tare that sheet of paper into two, can't I?
Yes, you certainly can. What I meant by "direct interaction", was communicating with the object in a two-way conversation. I would consider tearing a piece of paper to be mere "manipulation" (create, manipulate, destroy) of the object. However, if you were to ask the piece of paper a question, and it wrote out a reply (by itself), then I would consider this to be "direct interaction". Sorry for not being clearer.

t00fri wrote:If I was Stephen Hawking I would not be able to answer you, unfortunately. [I actually know him for many years and had daily overlap with him at Cambridge/GB a long time ago.]
I hope it was before his body tried to cheat his mind out of the accomplishments it has produced, and that both of you enjoyed your contact! Through watching the TV specials he has been a part of, and reading his books, I view him as an extraordinary human being (not just an extraordinary physicist) with an unending humor.

t00fri wrote:These things are very controversial, to be serious again.
Of this I have no doubt, and they will remain so until proven or disproven, like every other theory that has ever been submitted to mankind <smile>.

t00fri wrote:What is really exciting, however, is that we have a good chance of producing little black holes in collisions of elementary particles at future accelerators if the idea of (large) extra dimensions has some truth in it!
How does one "produce" a "little" singularity? I can only think of two forms of singularity: the one *at* the time of the Big bang, and Black Holes. The first being of the unfolding type (in my view), and the latter being of the infolding type (explosion / implosion if you will). However, I do recall reading that Black Holes have "stages of life", where they can be active, dormant, or anywhere in-between. Thus, I am assuming (hoping with all the hope I can muster) that the accelerator collision would be creating a dormant Black Hole singularity? And, if it does, what will *keep* it dormant, and/or how would the operators then "dispose" of it, if it doesn't suddenly become active and start sucking in everything within whatever radius of influence it has? It appears that my current behind-the-times knowledge is not sufficient to understand why or how this could possibly be done in a safe manner.

t00fri wrote:PS: For interested people there are two relevant articles in Sky &
Telescope:

1) June 2003: 'Strings, Branes and Extra Dimensions'
2) October 2003: Special Issue: 'The New Cosmology'

Unfortunately, neither is available in their pay-per-article section <sigh>. Back issues cost \$7.95 (US) or \$12.95 (other) and an issue becomes a "back issue" when it's two or three months old (most current back-issue is July, 2003). So, unless you are a current subscriber, or can find a copy of the October issue somewhere, it will be a couple of months before we can order it.

Fridger, can you recommend a few names of people who are considered "experts" in the areas of String Theory, Brane-worlds, Extra Dimensions and other leading-edge topics of physics -- that can be used along with other search criteria when trying to reduce the number of "hits" in specialized search engines (for physics papers)? For example, at arXiv.org e-Print archive (http://www.arxiv.org/), when searching their physics archives for "extra dimensions", ONLY for the year 2003, it returns 174 "hits" (papers) on this topic! So, being able to reduce the number by selecting an author would really help.

Thank you immensely for your reply, Fridger, which has encouraged me to perform a long overdue brain update <smile>. It's 4:20 am here and my mind is still "wired for sound" (wide awake ) with all of this exciting new information. Don't know if I'll even be able to go to sleep <smile>.

Hope you are having a good week!

-Don G.

selden
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Don,

The October issue of S&T that Fridger mentioned is on U.S. newsstands now.
Selden

jamarsa
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It's amazing the discoveries made in the last century in this field. I knew already of the 'Dark Energy' theories (I called it 'Vacuum energy' or 'Zero energy' until now), and I welcome any news related to the structure/knowledge of our medium/reality. But I don't have your expertise to talk about it... only general knowledge.

I'm a fan of good S&F too, and since several of my favourite writers are also researchers , they often write novels based in the new theories they work on.So, I can learn something of them in a fun way...

Last July, during a hiking weekend, I had a interesting meeting (at 1:00 am, around a schnapps bottle ), and we started to talk about quantum physics (in our own layman's terms). I think I specifically talked about the Dark energy issue, because I'm worried about the effects of the current energy sources (specially fossile ones). I was delighted to find that one of them was brother to an spanish expert in quantum mechanics, Gonzalo Muga. Just for curiosity, do you know something about him, Fridger?

http://tp.lc.ehu.es/MUGA/Muga.html

Please, keep on talking. I'm enjoying this too much...

selden
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Javier,

As best I can tell, "dark energy" has nothing whatsoever to do with "zero point energy". I'm sure Fridger can clarify this

Also, the people who are claiming to be able to "extract energy from the vacuum state" are what are known as "confidence artists" or "con men". The individuals involved are fairly well known among the people who keep track of such things. The devices and processes described in the patents are completely bogus. Unfortunately, most patent lawyers know nothing at all about the relevant physics. Equivalent patents for perpetual motion machines have been granted in the past, but eventually have been retracted. You might want to consider subscribing to the "What's New" mailing list, where such topics are mentioned frequently.

The physical basis for the so-called "vacuum energy" is that one can describe some of the observed interactions of subatomic particles in ways which include "virtual particles" and "virtual photons" which exist only for times and distances which are so tiny that one can invoke the Heisenberg uncertainty principle to explain their rather strange properties. The conservation of mass and energy can only be violated when such extremely tiny space-time values are involved. At a macrosocopic level, those violations simply don't happen.

Sorry.
Selden

t00fri
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Don, Jamarsa & Selden,

WOW,

I am very much impressed by the depth and interest I can feel in your feedback! Clearly, I can hardly anymore go explicitly though all of your questions and comments ...

So I have scanned your posts for what I consider particularly interesting/intriguing issues that are perhaps of wider interest. I suggest going through some of them in turn, adding in parentheses the respective names such that you may find yourself here and there. But sometimes it is better for clarity to present various issues in coherence rather than ordered according to the names of the people who have asked...

Here are some topics that I thought would be worth addressing a little more in detail:

-- what is the "hierarchy problem"?
-- meaning and relations of : dark energy, cosmological constant, vacuum energy, zero point energy
--again what is a warped space-time geometry?
--purpose of extra dimensions?
--why are six dimensions fashionable?
--Hawking's state of health
--why we hope to produce little black holes at the next generation of particle accelerators?
--good reviewer names for "strings, branes, extra dimensions, new cosmology..."

If I forgot anything crucial, please let me know, while I am thinking how to present these things in a non-tech and most intuitive manner....

Bye Fridger

t00fri
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### Hierarchy Problem

[Don]: What is the hierarchy problem?

First, we need a couple of general considerations as a warm-up.

1) There is a credo in theoretical physiscs that large dimensionless
numbers never arise accidentally in nature! To make up numerical
coefficients of something that can be measured, there may be a few powers
of Pi=3.1.4159...etc lurking around, but that's about it. So we expect
unknown numerical coefficients always to be naturally "of order
one"
, i.e. between 0.1 and 10, say.

Hence, if huge dimensionless numbers do occur in nature, we are only
satisfied, if we find a physical mechanism that explains this
exceptional numerical enhancement! Not a bad strategy at all!

2) We know four fundamental forces in nature that may well be enough
to account for the "theory of everything (TOE)", notably since their
action has been formulated in a most beautiful mathematical framework,
called "gauge theories". These four forces are (ordered according
to decreasing strength):

-- strong interactions (Quantum Chromodynamics (QCD) binding quarks
into protons, neutrons and pions etc.

-- electromagnetic interactions (Quantum Electrodynamics (QED),
atomic forces...)

-- weak interactions (Quantum flavour dynamics (QFD))

-- gravity

The first three forces have been studied most extensively in our
particle accelerators during the last decades and the so-called "Standard
Model of strong & electro-weak interactions" has celebrated an enormous
success crowned with a Nobel price to its inventors. Nevertheless,
there are many unknown constants in the Standard model and the
forces are NOT unified.

Throughout this success story, gravity has always been ignored with
the argument that in laboratory experiments and at laboratory
energies it is simply negligible (masses are small).

One reason, however, was also that unlike the other three
interactions the theoretical formulation of gravity is persistently
plagued by uncontrollable infinities despite its weakness.

String theory has been acclaimed to be the most promising
candidate (without proof) to account for gravity and the other
forces in a satisfactory manner (TOE?)....Unfortunately, until todate,
string theory has not come forward with a single prediction that
may be falsified experimentally!

Each of the four forces has its characteristic associated energy
scale, i.e. a typical mass of the corresponding particle
spectrum. E.g. the proton mass ~= 938 MeV (MeV = Million electron Volt
= 10^6 eV) would be a characteristic mass for QCD. The weak bosons (W,Z) of
mass ~= 100 GeV (Giga electron Volt = 10^9 eV) for the weak
interactions and the Planck mass ~= 10^19 GeV (determined by
Newton's constant) for gravitation.

So far so good. From these characteristic energy scales of the
various known forces, we then may form dimensionless ratios,
like

Planck Mass/Weak boson mass = 100000000000000000

This huuuuuuuuuuuuuuuuuuuge ratio no theorist would ever want to
explain in terms of factors of Pi! Right?

This is the hierarchy problem.

...And the future is bright...

The spectacular recent baloon experiments measuring the cosmic microwave
background (Boomerang, Wmap) have started off a new aera of
precision cosmological experiments related to gravity
that have provided great clues about the times shortly after the big
bang (300000 years only!), including "inflation", the
geometry of our universe and most importantly:

the existence of dark energy = cosmological constant = vacuum
energy...

to be continued....

Bye Fridger
Last edited by t00fri on 02.09.2003, 22:58, edited 1 time in total.

Topic author
don
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selden wrote:Don,

The October issue of S&T that Fridger mentioned is on U.S. newsstands now.

Thanks Selden. I'll have my wife check in the city since she works there. We live about 50 miles from the nearest magazine rack <smile>.

t00fri
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don wrote:
selden wrote:Don,

The October issue of S&T that Fridger mentioned is on U.S. newsstands now.
Thanks Selden. I'll have my wife check in the city since she works there. We live about 50 miles from the nearest magazine rack <smile>.

;-) America is an amazing country!

Bye Fridger

Topic author
don
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selden wrote:As best I can tell, "dark energy" has nothing whatsoever to do with "zero point energy". I'm sure Fridger can clarify this
And what does Fridger do? Like so many 1950's TV and radio shows ... he left us with a cliff-hanger ...

Fridger wrote:"most importantly:

the existence of dark energy = cosmological constant = vacuum energy...

to be continued....
I LOVE this guy!

selden wrote:Also, the people who are claiming to be able to "extract energy from the vacuum state" are what are known as "confidence artists" or "con men". The individuals involved are fairly well known among the people who keep track of such things. The devices and processes described in the patents are completely bogus.

Maybe, maybe not. Either way, ZPE (Zero Point Energy) certainly isn't any more far-fetched today, than space travel was 50 or 60 years ago, let alone creating extra-dimensions and black holes in a lab.

I merely mentioned it in passing, as I've done some "light reading" on several web sites about it and am certainly no expert on it. That "spine tingler" sentence of Fridgers (mentioning Dark Energy) is what brought it to my mind.

-Don G.

jamarsa
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Hey Fridger, I'm the one who says WOW!! at this opportunity to get information from first hand. I'm honoured to be a listener here.

Curiously, there is an article today in the New York Times about strings theory and current physics issues, including 'dark energy' questions. Could it happen that some of you are also NYT journalists? . I'm going to read it tonight:

http://www.nytimes.com/2003/09/02/science/space/02STRI.html

As for the possible applications, this discussion reminds me of Poul Anderson's 'Starfarers' book, where it talks of a zero-zero engine, 'borrowing' energy from vacuum. Of course, it's entirely hypothetical.
Last edited by jamarsa on 02.09.2003, 21:59, edited 1 time in total.

Christophe
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Here's an article on the string theory and the anthropic principle from the New York Times.

Christophe

Christophe
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You were faster than me on that one Jamarsa!
Christophe

jamarsa
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Location: San Sebastian (Spain)
Christophe wrote: You were faster than me on that one Jamarsa!

Hehe, I bet you have checked slashdot too...

Although I read NYT almost daily (and check the science pages too), so I would have discovered it anyway.

selden
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With us: 18 years
Location: NY, USA
Don,

Perhaps I wasn't clear enough, although you may be writing about possibilities, while I was writing about current events.

The people claiming to be able to provide "zero point energy" sources are known con artists. They've pulled similar scams in the past. I don't know why they aren't in jail, but some people, including the Attourney General of Maine, are doing their best to put them out of business.

WHAT'S NEW Robert L. Park Friday, 25 Apr 03 wrote:2. FREE ELECTRICITY: THE PAIN IN MAINE IS PLAINLY ON THE WANE.
Notorious perpetual motion huckster Dennis Lee, barred from doing
business in the State of Washington last year (WN 4 Oct 02), has
now gotten similar treatment on the other side of the country.
Armed with a report from a physicist familiar with Lee's free
energy scams, the Maine Attorney General filed a Complaint in
Superior Court citing Maine's consumer protection laws. The
Court enjoined Lee from doing business in Maine and required him
to conspicuously state on his website that his products and
services are not for sale in the State of Maine. At its meeting
on April 4, the APS Council adopted a Statement on Perpetual
Motion Machines, deploring "attempts to mislead and defraud the
public based on claims of perpetual motion machines or sources of
unlimited useful energy" http://www.aps.org/statements/03.3.html
Selden

Christophe
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jamarsa wrote:Hehe, I bet you have checked slashdot too...

You're right on, but I did read the article before posting here.
Christophe

t00fri
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[Don, Selden, Jamarsa]
"Dark energy, cosmological constant, vacuum energy, zero point energy"

topic...

1) In quantum physics and specifically quantum field theory, things
appear definitely less deterministic than in classical physics:

Heisenberg's Uncertainty principle and the fact that only
probabilities may be associated to quantum states rather than
certainty like in classical mechanics.

2) The "vacuum state" is by definition the state of lowest energy of a
system. Classically the total energy is the sum of kinetic energy
1/2 m v^2 and potential energy V(x). To minimize it classically, we
would set v=0 and then find the state of lowest potential energy
V_min (x0).

Because the classical ground state completely specifies both the
particle's speed (v=0) and position (at the minimum = x0), it violates
the famous Heisenberg Uncertainty Principle

m dv dx > hbar.

Quantum physics, via the Uncertainty Principle, forces the
particle to spread out both in position and velocity and so causes
it to have an energy somewhat higher than the classical minimum.

The zero point energy (ZPE) is defined as this shift:

E(ZPE) = E(quantum minimum) - E(classical minimum) > 0.

The quantum vacuum state thus has a certain non-vanishing (kinetic)
energy content (that may however not be exploited;-)) due to intrinsic
fluctuations of the quantum fields (particles) according to
quantum uncertainty.

3) Consequently, one may and actually should contemplate about the
vacuum energy (density) associated with gravity!

According to my previous discussion, there is only one huge
associated energy scale, the Planck energy scale, Lambda_P = 10^19
GeV. Thus according to the basic credo, theorists would naturally
expect the vacuum energy density of gravitation to be of order

O(1)* Lambda_P^4 = O(1) 10^76 GeV^4 !!!

a huuuuuuuuuuuuuuuuuuge value or else exactly zero,
e.g. due to some symmetry, like Supersymmetry.

4) The spectacular recent cosmic microwave background experiments
(Boomerang, Wmap) together with the observation of many high
redshift supernovae of (Type Ia) [Perlmutter et al] have provided
convincing evidence that the

gravitational vacuum energy = dark energy = cosmological constant

is different from zero, but so small that again
we have no natural energy scale available that may account for it!

The "hierarchy problem" has an entirely new facet, it is now considerably aggravated!

5) What does this all mean??

Since the Bang, the universe is continuously expanding. Matter
slows the expansion, much as Earth's gravity slows a ball thrown
skyward, and for many decades astronomers pushed their telescopes
to the limit in the expectation of detecting this expected
deceleration
.

What has instead been observed was an

acceleration,

associated with this non-vanishing dark energy!! Spectacular and
most unexpected...

...to be continued...

Bye Fridger

jamarsa
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With us: 17 years 5 months
Location: San Sebastian (Spain)
After reading the NYT article, I have a strange idea rounding my mind...

The article says that it could be possible, in time, that the 'warped' six remaining dimensions would unwarp in time, as result of the loss of energy. It could be that the Big-Bang would be, in fact, the expansion of the first four (and actual) dimensions? Or perhaps they unfolded one at a time (being the first the 'time' one, of course ), thus converting from an one-dimension to 2-dim, 3-dim and so on?

Wild idea, don't you think?