The past few days have been spent preparing a public lecture on the topic of extra dimensions. It’s somewhat difficult to explain the concept of dimensions, period, to the general public, let alone get them thinking about additional ones. Anyway, I’ve poured all my energy the past few days into this and we’ll see how it goes. I gave a dress rehearsal today – talk lasted one hour and the comments lasted 1.5 hours! Given that it was a room full of physicists, each with their own opinions on how to present things, that’s not so surprising.
The talk is Tuesday evening 25 April (7:30 PM, SLAC auditorium), and is part of the SLAC public lecture series. Here’s the cool ad:
Actually, SLAC does a great job on the whole with its public lecture series. The lectures are advertised on the local NPR, the auditorium has been known to overflow, and the lectures have been great. CV readers in the Bay Area should come check us out!
April 25th, 2006 at 7:10 am
Ah let’s see. You and Lisa Randall make two rebels for sure?
Those calculations sound mysterious. Nice intro pictures.
You CV people are sure busy informing society. Good on you all.
April 25th, 2006 at 8:43 am
I like the cool ad. You’re right that “dimensions” are especially hard to explain; not only is the concept intrinsically subtle, but a lot of people already have an image of a new “dimension” as a higher plane or some physically different place parallel to our universe. I find it helps to be really clear about the three dimensions of space that we have (and what it would be like to have two, etc), before saying “and there could be more.”
April 25th, 2006 at 9:36 am
If you want to provide the lay-audience with a fairly concise definition of extra dimensions, I recommend you browse through Chapter#24 of Lisa Randall’s “Warped Passages.” She begins by dividing the definition of dimension into two major classes of meaning: 1) the more rigid (conventional) meaning of dimension and 2) the more flexible (less conventional) meaning of dimension. The more rigid (conventional) meaning of dimension embodies the concept that a “body of dimensions” can be described as being “point-like” in Nature. In contrast, the more flexible (less conventional) meaning of dimension embodies the concept that a “body of dimensions” can be described as being “dual-like” in Nature. While more traditional physics tend to use the more rigid meaning of dimension, string theorists are more apt to use the more flexible meaning of dimensions. However, along with this division in meaning of “dimension”, Randall identifies that an array of ambiguities emerge across the fundamental spectrum of physics. The following is a more conventional example of ambiguities emerging in physics: As one penetrates – using more traditional tools in physics – the Planck scale in quantum mechanics, spacetime (gravity) behaves with extreme ambiguity. In contrast, the following is a less conventional example of ambiguities emerging in physics: As one penetrates – using less traditional tools in physics – into increasingly smaller scales of Matrix Theory, Do-branes (acting like gravitons) behave with extreme ambiguity. Therefore, Randall concludes that spacetime (gravity) is still the mysterious “wild card” in theoretical physics. More specifically, the big picture of spacetime (gravity) is still the huge missing piece of the puzzle in “point-like” models as well as in “dual-like” models in theoretical physics.
April 25th, 2006 at 10:06 am
Way to go: best of luck with the exposition. With so much pop-sci-fi abroad these days, input from a laborer at the coal-face should make a refreshing change
BTW
‘pulic’ is preferable to ‘pubic’, but neither conveys your intent.
April 25th, 2006 at 10:52 am
i wish i lived on the west coast! will you be posting an overview of your lecture? it sounds like a wonderful topic to present, especially for the non-scientific community. best of luck tonight
April 25th, 2006 at 3:53 pm
Ok, so where are the podcasts?! This really ought to be recorded and distributed via iTunes …
April 25th, 2006 at 4:48 pm
More on name.
I had hoped the original reinstated.
April 25th, 2006 at 7:50 pm
A social science professor is one of the regulars in the lunch group I attend on Fridays. A few years ago he asked me (the only math guy in the group), “What is the fifth dimension?” After quipping that it was a seventies singing group, I started to try to give him a real answer, talking about ordered n-tuples and what could be represented with them (including the possibility of additional spatial dimensions we don’t perceive). Then I caught myself, especially because he was getting a bit glassy-eyed:
“Ed, why do you want to know about the fifth dimension?”
“Well, you see, some of my friends are psychic, and they told me that they can communicate on the fifth-dimensional level, so I was wondering what that meant.”
“Oh, that’s easy: It means they’re delusional.”
End of story.
April 25th, 2006 at 8:01 pm
Drat! Family obligations (and grading) will keep me from attending, even though it would be theoretically possible.
Will it be videotaped for the archives? (I know some people …)
April 26th, 2006 at 12:23 am
Dimensions!..Dimensions!..where would we be without them?
The concept of dimensions as stated by Cynthia via Randall hits the nail on the head..which is a pretty good analogy (nail-on-head..Hammer a nail into wood for instance) as to how one can trancend from a visible 3-Dimensional frame (nail external to wood)..to an hidden frame of reference, nail after being hammered into wood equals, nail embedded from view in 3-D frame of reference.
The simplest way to explain the concept of 2-Dimension compacting from 3-Dimension, is to ask a person to lay on the floor,face-up. Next ask the person to try and move, using only points of contact. The movement of the person is constrained, and at the point of contact the persons legs can be moved left or right (remaining in contact with the floor), instigating a Rotational action of the whole persons body.
Whilst a large portion of the persons body is protruding into the volume of space away from the points of contact, surface of the floor and the surface of the body(persons back) interacting with the floor, are interacting along a PLANE surface of 2-D.
The Milkman oil-drop experiment is probably the most intruiging “dimensional” concept.
April 26th, 2006 at 1:04 am
Hi All, the lecture is finished and I can now relax! The auditorium was full and things seemed to go well, lots of questions, etc. The thing was video-taped and my understanding is that it will be put on the web in some form – on the SLAC public lecture series page. Now, for a well deserved glass of wine….
April 26th, 2006 at 5:58 am
Paul Valletta – speaking as a confirmed layperson, I give your “lying on the floor” analogy strong visual merits! This analogy vaguely reminds me of Riemann Surfaces. However, I must admit the concept of the “Milkman Oil-drop Experiment” completely lies outside my realm of extra dimensions.
April 26th, 2006 at 1:32 pm
Cynthia re:”Milkman Oil-drop Experiment” it will come out soon, I am waiting for the right moment
April 26th, 2006 at 2:16 pm
Article was from 2000, so what has progressed in sicnetific thinking?
Hunting for Higher Dimensions
This and more subtle effects of extra dimensions could show up at existing accelerators, such as LEP and the Tevatron at Fermilab, only if the dimensions have scales nearly as big as a millimeter. The powerful LHC will greatly improve the chances for detecting missing energy events and other prominent extradimension effects.
So are the “doom sayers as figures to influence” still going to overide and influence the minds of responsible reporting, had this information not been released to the public? We are in 2006, and what efforts had been thought about to prepare?
A special LHC olympics perhaps.
I won’t even mention Aldeberger here.
So it will be interesting to see what you have reported JoAnne.
April 26th, 2006 at 2:57 pm
Speaking of JoAnne’s “wine glass” (comment#11), Gia Dvali devised a priceless analogue involving a “bottomless martini glass” to explain the Randall-Sundrum scenario of the infinite-dimensions hypothesis. Quoting Dvali (Scientific American, Feb 2004): Imagine pouring gin into a bottomless martini glass whose radius shrinks in inverse proportion to its depth. To fill the glass, a finite amount of gin would suffice. Because of the curvature of the glass, its volume is concentrated near the top. The volume of the extra space is concentrated around our brane. Consequently, a graviton is forced to spend most of its time near the brane. The probability of detecting the graviton quickly diminishes as a function of distance. In quantum jargon, the wave function is peaked at the brane – an effect referred to as localization of gravity. Cheers to JoAnne and her wine glass! Cheers to Gia and his martini glass!
April 29th, 2006 at 8:20 am
I’ve a Ph.D. in engineering but my notion of dimensions is still fuzzy beyond the Enclidean frame.
So I tried to read up on the matter, the first attempt was a book I chanced upon in a used book sale entitled Hyperspace by Michio Kaku written in 1994.
I was struck by what the author wrote in the Preface:
“… the laws of gravity and light seem totally dissimilar…. However, if we add one more dimension, a fifth dimension, to the previous four dimensions of space and time, then the equations governing light and gravity appear to merge together like two pieces of a jigsaw puzle. … In this way, we see that the laws of light and gravity become simpler in five dimensions…. When expressed in dimensions beyond four, however, we have “enough room” to explain the fundamental forces in an elegant, self-contained fashion.”
Part II of the book introduces the ten dimension as the route to the proverbial unification of theory. And somewhere the issue of meaning and purpose of life in the vast universe emerges.
The book closes with an eloquent quote of Stephen Hawking:
“[If] we do discover a complete theory, it should in time by understandable in broad principles by everyone, not just a few scientists. Then we shall all, philosophers, scientists, and just ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason — for then we would know the mind of God.”
Is that what’s all about, knowing God?