Modern and Theoretical Physics

John Baez just came out with a new edition of This Week's Finds in Mathematical Physics http://math.ucr.edu/home/baez/week235.html If you want to print it out, it is 8 pages on my printer and the first 4 and half pages are about QUANTUM COMPUTING (where they are actually making computerlike things happen in a lab in Canada, which he visited, and they involve quantum effects rather than classical----it sound pretty far out) and then the last 3 or 4 pages of printout are about some of the latest work in QUANTUM GRAVITY I think Baez is one of the most creative people in the business and I think he and his co-workers are hitting top form now. He's a good communic…

Hello. I wonder if someone could answer a question on a particular aspect of lightning? Why do positive streamers appear purple in colour? Thank you

I have a question someone asked me in my time in the military, and though I tried researching it, I am not sure I understood it correctly. Lightnings are "drawn" to anything that dissipates their charge - this is how, as i understand it, you can see a lightning hit sand (there was an occasion i have seen in Discovery Channel once), transforming the sand in its path to glass, and end up touching an underground metal wire-tunnel. Is it possible for a lightning to hit water? If so, what would happen to a fish (or a person, for that matter) that is near it, and how "far" away would a life form (fish or person) should be to be relatively safe? What would dissipate …

http://www.timesonline.co.uk/article/0,,2102-2214707,00.html ===sample=== ...But is string theory true? Peter Woit, a mathematician at Columbia University, has challenged the entire string-theory discipline by proclaiming that its topic is not a genuine theory at all and that many of its exponents do not understand the complex mathematics it employs. String theory, he avers, has become a form of science fiction. Hence his book’s title, Not Even Wrong: an epithet created by Wolfgang Pauli, an irascible early 20th-century German physicist. Pauli had three escalating levels of insult for colleagues he deemed to be talking nonsense: “Wrong!”, “Completely wrong!” and f…

Hi guys I was reading some scifi books, and watching Star trek and was wondering about something. I know that Startrek is fictional, and is MORE fiction than science (please don't start bashing shows here;) ) but I also know that the creators at least TRIED bringing some frictions of truth in their fiction.. They talk a lot about Subspace, and they're not the only show that does that.. Does Subspace really exist? Is it theoretically possible, and.. what.. exactly.. is it? Thanks.. ~moo

Is time a consequence of movement? this thought struck me as i was walking to work yesterday. if the universe was static there would be no need for a fourth coordinate to specify time. although impossible to be static in the quantum realm, theoretically it everything was static would time move foward? and could you tell the difference between the two states?

The Financial Times of London has been described as a prestigous UK newspaper read by many financial movers and shakers. It recently published an article by physicist and science writer Robert Matthews which caused a minor uproar on the physics blogs. Until today, i had seen only a few isolated quotes so I had no idea of what the fuss was about. This morning I found this transcription and also a Matthews website listing professional credentials, peer-reviewed publications and a sample of his writings aimed at popularizing science for general audience. http://www.robertmatthews.org/ http://www.robertmatthews.org/AcadCV.html ===quote=== Nothing Gained in Searc…

The reason that I wasn't posting last week was that I was in California for a conference on supersymmetry, chatting to people like Wilczek and Susskind. Some of the talks have now been put up on the website, and I thought some of them might be of interest to people here: http://susy06.physics.uci.edu/program.html

hello inbetween works cycles at the moment so thought i'd pop in and take a quick look to see what's going on, and propose a strange thought. that is that time is a component of energy, that what we percieve as time is the moment to moment changes in the state of energy that composes matter. also that like matter time has components like wave and particle, being that time exists as individual moments (particle), and in a stream of moments (wave). conjection that in einstein's slowing of time as lightspeed is near, is a resault of the fact that as you approach lightspeed matter is accellerated to the speed of time. time seems slower because you are travel clos…

Now, I remember some time within the last three years that one of my teachers in high school said that the number of atoms in the universe is about 10^? . I've forgotten what the number was. Is there an absolute number of atoms in the universe? I thought atoms decay and split apart. Although I suppose if a fission occurred for every fusion, there would be an absolute number. I'm also curious to know how this giant number could be obtained. I was reading Archimedes' The Sand Reckoner and it reminded me of the day my teacher told us the number of atoms in the universe.

Have now improved my proposal for a single elementary particle to include an explanation of charge and waves. Although not finalised, I would appreciate some constructive critcism of the model as expressed this far. http://elasticity2.tripod.com/interpretation/

I thought I heard once that crystals might be used for memory storage and such? They use crystals on Stargate and such, but aside from New Age junk, are there any qualities of crystals that could make them good for computing? Like crystal motherboards or memory, or crystaline chips? Thanks, LC

I was reading a book the other day and one of the characters was talking about his physics class. He was trying to explain to his friend that physics was cool. but she just wasn't buying it. To get her to realize that it's actually interesting he gave an example of some of the questions. His example was "Say you're traveling at the speed of light in your car, and you turn on the high beams, what happens?" What was said in response to this in the book is unimportant, but it got me thinking. What would happen. If you have any idea at all let me know...and please...and explanation would be nice. ;-)

Did anyone see this on the science channel? What do you guys think about dark matter/dark engergy? From what I've seen at least on the quantum mehcanics board, you guys don't seem to like String Theory too much... I'd really appreciate your input! Thanks, LC

Is size circular ? If physics discovers that A is composed of B, and B of C, this would be a typical reductionist view A -> B -> C. Now imagine that at the planck level C ends up being composed of a smaller A, and the above loop goes on forever. If you were at any given size level you could say A is composed of "a smaller" A and is encolsed within a "larger A". But if the 2 As are identical except for size and the loop goes on forever, then A would really simply be composed of itself. You couldn't distinguish between the larger and smaller, they are relative and an infinite "recursive" like loop. Then an easy way out would be to think of the sizes like points on a c…

I know that when a beam of x-rays strike a crystal (covalent network lattice) that they will be reflected off in layers so that the resulting wavefront is in phase with all other waves. However, i have found 2 equations that are associated with this concept and am not sure which is the correct to use. Theres: {d sin(theta) = n * (lambda)} and {n * (lambda) = 2d sin(theta)} Can u tell me which is the appropriate equation and what the other one would be for. btw. soz for not using symbols, I would if i knew how

Does anyone here "get" NMR? Can you explain J-coupling and NOE's? I get that j-coupling is through bond interactions, but what does that mean? And I get that NOE's are through space interactions, how are they different? And ok, if you can get me that far, can you break down the proton and carbon methods in "simple" language. Any help is appreciated!

From my other post in the General section. Sorry to put it here again but it hasn't gotten any replies and I'd really like to know.... Thanks for understanding

I was wondering if the heat generated by eddy currents (in a theoretical experiment where a wide range of materials were tested) could be measured using an apparatus similar to an induction furnace. I have attached a diagram along with this post to show u what i mean. I was going to measure the heat generated by each metal through a thermometer in water. The water will absorb the heat generated. Can u see any potential weaknesses in this attempt? Will the water always heat up to an excess of 100 degrees? If so, can this be controlled by lowering the voltages applied? (Plz ignore any heat lost to the surroundings.) Thanks for ur help! Prac Diagram.doc

In the gauge field theory photon is represented by a gauge vector field which is massless. But how can we measure the mass of the photon to very small value to convince ourselves that photon is definitely massless? Somebody say that as the universe is just about 13.7 billion years old from the big bang to now, so if we measure the mass of photon through any quantum effects, we will ultimately arrive at a threshold under which we can not push on. In other words, we have no method to measure the absolute zero mass of photon. What are your opinions?

I was wondering if anyone could help clarify this problem I am having. Upon reading a section in a paper, I am a bit stuck as to how this value of the lower bound of the neutrino mass is reached here. I have highlighted the relevent part in the snapshot below: http://img487.imageshack.us/img487/3873/neutrinomass3fk.jpg Is there something missing from this passage, or am I just missing something blindingly obvious? I can't seem to understand how the two squared mass differences coupled with the assumption of hierarchy lead to the quoted value! in case you're curious, the paper is: http://www.arxiv.org/PS_cache/astro-ph/pdf/0407/0407207.pdf tha…

Lee Smolin will be giving public lectures June 14 and 19. I expect the talks to be controversial and relevant to the current debate surrounding unification issues and the status of string theory as science. But the description of the London talk does not explicitly make that connection. That talk is "The Annual Public Lecture" at the London School of Economics CPNSS http://www.lse.ac.uk/collections/CPNSS/events/Conferences/AnnualPublicLecture.htm Anyone who happens to be in London around that time, if interested in science issues, might wish to attend. Prof. Smolin will be introduced by Jeremy Butterfield of All Soul's College-Oxford. From the descripti…

Gravitons... Are there anti-gravitons? Simple question - most is not all particles have anti particles so does one exist in this case or is it the exception to the anti rule? Also is they do exist would that mean you could make an anti-graity device using them Cheers, Ryan Jones

Steven C. Gustafson, 28 May 2006 Conjectures: (1) The measured value of pi changes with time. At the big bang it was 2; now it is smaller than the calculated value of π = 3.14159... starting at about the 121st decimal place. (2) The difference in the measured and calculated values of pi is evident in significant differences in the randomness of the digits of the calculated value of pi before and after about the 121st decimal place. Justification: Consider a circle of circumference 2πr on the surface of a universe of radius R, where all measurements are on the surface. The diameter of this circle measured along the surface is 2θR, where θ = arcsi…

Hi all, I'm not even sure this is the right place to put this thread, I was guessing according to the subject, sorry if I got it wrong, feel free to .. uhm.. relocate me.. I was watching (Again!) The movie "What the @$&^%^#!@ do we know" and there was something there that got me wondering about one of the things said there in particular. In the movie, they showed an experiment done with water and different "moods" -- blessings, curses, words written on pages and such. The water looked different in the microscope in each different canister, even though their initial state was exactly the same. Can that be possible? Is that a working experiment, or just …