Modern and Theoretical Physics

I was thinking that It would be very beneficial to use air and its properties to build lens or mirror, ofcourse air has a slight refraction rate and if someone can build a tool that strengthen this property and directs the light to a desired position then it is possible to use the solar energy effectively and in a vast area to produce power or reflect the sunlight for cooling an area in the summer. since english is not my native language I put a picture that better describes my ideas, please see and comment on this idea.

Are the higher spatial dimensions there simply to give perpective on each other or is there some other purpose for them?

What Exactly is a Zero Point Field (ZPE)

The new theory explains difficult concepts with mathematical simplicity - it does not require the reader to stretch or convolute their imagination. It tackles the problem of the gravitational interactions between matter and space giving accurate solutions including a mathematical definition for inertia. It employs common sense potential field laws, Maxwellian electromagnetism and a space similar to (though independent of) that postulated by Dirac in his concept of the particle - antiparticle relationship. The reasons for the seemingly anomalous relations between matter and space are arrived at naturally ...no curved space, no 4th dimension It's at; http://www.acadjourna…

what is the latest news on element 118

Every three years there is a big-time world conference on General Relativty and this year it is in Dublin 18-23 July three years ago it was in [edit:correction] South Africa and back in 1998 it was in India so anybody in UK, now is your chance this conference is about every facet of gravity theory and research the gravity wave detectors what observing binary pulsars and other neutron stars tells about gravity all kind of gravity experiments, in space and on ground theories of quantum gravity (john Baez will talk on Loop Quantum Gravity, quantum geometry, and spin foams) here is the website, it has the program of talks, with brief summaries, on …

for those who dont know, perfect motion is when an object which starts moving never stops...... i had always thought this was impossible..... due to air resistance..... how dumb was i??? what happens in space? but then perfect motion is apparently impossible..... why doesnt it work in space??? is it due to the gravity? or just, is it possible? and if it was 'invented', what uses does it have

Any help on this one would be appreciated. A mass of 0.987 Kg of air at 101.3 kPa absolute and a temperature of 15 degrees C is compressed isothermally to a pressure of 500 kPa absolute and a volume of 0.0163 cubic meters. If R for air is 0.287 kJ/Kg K, what will be the work done?

this is a topic that a new member, jana, raised in another thread it really deserves a thread of its own I am hoping jana will provide a tutorial on this that several people besides me can enjoy

I Know how semi-conductors work But I dint know WHY they work. An NPN transistor consists on P-doped silicone sandwiched between two P-doped layers. So assuming that both N layers are the same why are all transistors not bi-polar? Also, all semiconductors have a recovery speed. What determines the recovery speed? How is an ultra-fast diode different than a normal diode? And how do they suddenly fail from overvoltage? Why is voltage so critical?

I have a question about mass-energy conversions in accelerators. I usually think of mass being converted to energy, or vice-versa, as in a cloud/bubble chamber or a nuclear reactor. However, in an accelerator, I was taught that the mass of the particle increases as well as its speed, and by the amount corresponding to E = m.c^2, so that E is its gain in energy and m is its gain in mass. My teacher said that this could happen because work was being done on the particle. Is this correct?

From Simpleton Reaching for the stars Gravity June 21, 2004 Gravitons: Particles responsible for the attraction of all that is matter toward each other. Exchange particle. Clues; How it affects the tide- waters. With out doubt huge amounts of water are lifted to some extend, do to the influence of the moon. How it affects our solar system. The further a planet is from the sun the slower it moves. This seems to be perfectly explained by the laws of universal gravitation. How it affects galactic rotation. We can see that,¨(like in our solar system) the mass of a galaxy is concentrate at the centre. Maybe not as concentrated as in this …

In looking over the Spires Citation Database for physics papers I've noticed a remarkable drop in citations of recent string theory papers. this is for all kinds (string, brane, braneworld cosmology, M-theory) of stringy research. citations by other papers are one possible measure of the quality of research and there has been a surprisingly sharp decline for definiteness I take 'recent' to mean the preprint appeared in the past 4 years so at end 2000 papers appearing in years 1997-2000 are recent. In year 2000 there were 9 stringy research papers that garnered 125+ citations. In year 2003 there were only 4 such papers! And the numbers are telling …

Alright, I've never hidden the fact that I am not a fan of math's so I never saw the need to study Calculus, hence many things in Physics simply go over my head(whooosh) . That is why in many things related to physics, I'm looking for a Cliff-Notes version, especially w/o the use math's or the jargon of Physics. I came across the idea/theory/whatever of Strangelets and it sparked a mild curiosity, so I need your help. Either from what you already know or from the linky below, can you provide an English(no mathematics) summary of what the Strangelets are about? Are they only hypothetical or confirmed(real)? Etc. Be as brief or as detailed as you can or want…

http://arxiv.org/hep-ph/0406197 this recent 10-page paper by Susskind is descriptive of the current situation in string research and may be worth printing off, for anyone interested in stringy theories Naturalness and the Landscape (it appeared yesterday and is available in PDF format at the above link) Although Susskind is highly optimistic and says that a new "paradigm" of string theory has now "emerged from the ashes" of presentday string theory, he does touch on several possible reasons for concern. the business about a new string theory rising from the ashes is on page 1, in the introduction. Susskind is at Stanford, one of the leaders alon…

Thrust of Resisternce when a bus is moving along a horizontal road with increasing speed decreasing speed constant speed

Should seatbelts be fitted for the use of all passengers on buses? List your agruements as to whether it should or should not have seatbelts.

Hi, a Q: if I put a ferromagnetic material inside a coil with current and magnetic field, will the material be accelerated along the coil - like it would be attracted to a magnet pole ? thank you

Unfortunately I don't have a reference, (although I'm sure it would not be hard to find,) I recently read somewhere that temperatures on the moon during it's 'night' can reach minus (-) 150 degrees Celsius. This may seem extremely cold to some, but I don't understand this. If the moon has no atmosphere to keep heat in, then how does it maintain a temperature so high above absolute zero? Would a thermometer show a different temperature if it was hovering a foot off the surface compared to being in contact with the surface? And, if so, would that 'hovering' thermometer be colder? Thanks

According to the Spires HEP database there has been a drop-off in string-related research publication. edit: they havent finished cataloging the 2003 papers so it is not as big a drop-off as it looked like at first In 2002 it was 1677 papers and in 2003 it was down [edit: not clear how much the drop will be] from 1986 to 2002 there was a fairly steady rise in string research output (in the peer-reviewed publications that Spires tracks) and this sudden drop is without precedent. Something like this must have an explanation. What do you suppose the decline in string research could mean? What basic physics issues could it be related to? I…

PLEASE don`t make me have to put this in the Psuedoscience section, it`s a genuine question and I`de like to hear REALISTIC answers, trolls need not apply!!! Wathcing an episode of "Enterprise" there was a situation whereby 2 Enterprises met, seperated by 100 years or such. they were able to interact and touch each other etc... my question is this, WHERE does the extra MASS to create it come from, at 1`st guess you`de assume from ENERGY? well the same question applies, WHERE does all that MASSIVE amount of energy come from to re-create that mass? I`ve been trying to figure it out for weeks, that`s one of the reasons that I don`t beleive a "time machine" can b…

Is there any environment or situation where it is possible to calculate force from ONLY acceleration? I know Force = Mass x Acceleration, but what if you only have any acceleration and deceleration?

here is a simplified calculation of the force between two black holes that someone may have already done at SFN----it may not be new to you but it has an interesting result that connects to Christoph Schiller's "fun with physics" thread Two equal mass BH of the simplest kind (non-rotating electrically neutral), say each with mass M the schwarzschild radius of each is [math]R = \frac{2GM}{c^2}[/math] so naively the closest they could get together is [math]D = 2R = \frac{4GM}{c^2}[/math] and then by newton's law of gravitation the force of attraction between them is [math]F = \frac{GM^2}{D^2}[/math] but [math]D^2 = \frac{16G^2 M^2}{c^4}[…

Does anyone have some QG links they want to recommend as good introductions to the subject, or surveys of current research, or particularly good for explaining one particular line of research? As for a good (popularized) intro to Loop Quantum Gravity there is Lee Smolin's January 2004 Scientific American article called "Atoms of Space and Time". The trouble being that it is not, AFAIK, available free online. here is another good popularly written article by the German science journalist Rudy Vaas http://arxiv.org/abs/physics/0403112 "The Duel: Loops versus Strings" this one is available online. Vaas writes for a German magazine similar to the S…

Peter Woit's blog http://math.columbia.edu/~woit/blog/ reinforces the point that string research should be curtailed because it doesn't qualify as empirical science. The case for cutting funds for string research (until some definite testable predictions can be derived from the theory) was made in Woit's article in the journal "American Scientist", available online, and the earlier article "String Theory: an Evaluation". http://arxiv.org/physics/0102051 It is argued that after a considerable period of waiting (it's been 40 years since the original papers) the theory's many variants still make no definite testable predictions, and therefore one may conclude that …