Modern and Theoretical Physics

This question arose in post 17 of http://www.scienceforums.net/forums/showthread.php?t=11414from It was off topic so I'm moving it here. At the center of universe the gravitational potential should be at maximum' date=' the sum of gravity forces is zero.[/quote'] All I really meant was that if you put something at the center of the universe, the net gravitational force on it should be zero, and thus it will remain at rest there. I believe it was Sir Isaac Newton who proved this. In order to prove that at the center of the universe the gravitational potential should be a maximum, you have to use gravitational field theory. If and when Latex is…

First off, I'm not sure if this is the right place to post this topic, but I didn't see an electromagnetic forum. If one exists, then I am blind and i will repost this there. Anywho. For a school physics project I am doing rail guns. I know the basics principals of how they work, and how to build one. The one I will build need only be very small, just big enough to demonstrate that they can work, so my projectile will probably be a penny or something of similar mass. What I am wondering is, what sort of power am I looking at to get this thing moving? I know the more current the better, but how much, and where might I aqquire this? I am considering a car battery, but t…

This came up in a thread a while back but we never go to the end of it... what order does a spark happen in, taking into account dielectric or electric breakdown of air and movement of electrons? Does the air ionise allowing electricity to flow... or... does the electricity flowing cause the air to ionise? Now I know that some of those ionised particles will react, so ozone and nitrates are formed, but do all the ions react or do some remain as ions and what happens to them? Assuming there is standard air conditions, how do you calculate the required voltage or current to make a spark of length x?

Probably not the best use of english, but I couldn't figure out how to describe it better. Now, my idea goes like this (please don't be critical, I haven't done much physics and this is something I sort of just came up with): Everything in the universe is moving relative to some stationary point. This point I will call absolutly stationary. There is probably no reason to find the direction and velocity (relative to say, earth) but would this work? Take a particle and entangle it with another, put it in a spaceship (or whatever) send it off in a direction at a set velocity. Do this thousands of times in many directions around a sphere. After a period of tim…

I know this kind of technology is WAY off in the future, but how viable would it be to use neutrinos for wireless power transmission in, say, 100 years? From a physics standpoint, that is - can power be converted into neutrino rays and back with a high efficiency and little loss? Just wonderin'.

Nuclei, atoms... the Earth and planets, the sun and stars, black holes, solar systems, galaxies... everything is a part of something and everything seems contained in a spherical manner. If the Earth is part of the solar system, the solar system is part of the galaxy and (discounting walls etc..) the galaxy is ultimately part of the universe, who's to say what we call the universe isn't part of something greater?

Dear Folks: I sent youall some of my correspondance involving fusion power a few months ago. A new thread has evolved, the top lightning researcher in the world, Joe Dwyer at FIT, got his Y-ray and X-ray research published in this months Scientific American, http://www.sciam.com/article.cfm...414B7FFE9F Sorry that the Sciam article was a tease, here's the meaty stuff: http://www.lightning.ece.ufl.edu...marays.pdf and according to Clint Seward it supports his lightning models and fusion work at EPS, Electron Power Systems http://www.electronpowersystems.com/ . He proposes applications as varied as home power generation@ .ooo5 cents/KWhr, cars, distrib…

Hello, What do you think about this theory? www.webcom.com/musics/mass.pdf From the definitions of Planck units of length and time is deduced a correspondence between mass and time equal to [tex]m=@'t[/tex], where @' is a constant that has dimension of force. The similarity of this equation with the equation [tex]l=ct[/tex], could allows us to extrapolate a possible physical meaning for this correspondence

Needless to say, it was kindof hard picking a category to post this in... I can envisage a universe with 4 apparent spatial dimensions as far as the physical creation of particles, atoms (or their equivalents) are concerned. I'm sure a type of UBER-exotic biology could even live in such a 'verse where it had to navigate 4 spatial dimensions. But do you think a universe with two apparent spatial dimensions could support life? Could it even support the types of bonds needed to hold atoms (or FLATOMS ) together? Could a two dimensional universe even exist without the third dimension to relate the first two (after all, how could two infinately thin pieces of matte…

This came up from a conversation I was having earlier: Well, classically a force is required to accelerate an object, whereas to maintain a constant speed no net force is required. So when it comes to moving in time, you may say no force is required as you move in time at a constant rate, but is that strictly true? If you take into account time dilation you don't always move through the 4th dimension at a constant rate... So is a force needed for you to move through time? If so what is this force?

The loudness of sound heard when two objects meet together depends on their difference in temperature and state? or the amount of energy transfer?

Hello, I am a GCSE student studying Physics and was wondering if any knowledgable people could explain the alpha scattering experiment to me in plain english.There are a few things I don't understand these are detailed below.. ~Alpha is positive if it was shot at an atom, it would not be repelled because an atom is not charged. Ions are charged ~I have been taught when the alphas are shot at the atom and they come close to the nucleus they change direction and are repelled by the nucleus because positive alpha repel the positive nucleus. How can the nucleus of an atom be charged...atoms are not charged...ions are. I'm sorry if you couldn't understand me. I tend to …

Hi We believe that the universe is expanding or streaching right and does this not mean that our orbit around the sun is being streached. So why is our orbit around the sun gradually not takieing longer.? p.s. sorry if i posted this in the wrong forum im 13 and im only just getitng my head round this.

Another electrodynamics question. You have an infinitely long cylinder made of linear ferromagnetic material of relative permeability Km, and you place it into an initially uniform B field. Let the cylinder axis coincide with the z axis, and let the B field point in the x direction, or y direction. CURL H = 0 What is the B field inside and outside the cylinder? I want to use cylindrical coordinates, define a scalar magnetic potential inside and outside the cylinder, and get the B field this way if possible, but I am not sure if it can be done this way. If there is a better way I am open to that. Thank you

Unlike some of my recent threads, this one is actually a specific problem I need help with. I think the answer is snell's law, but its been years since I have solved it. You can get to Brewster's angle if you keep going. Here is the problem. You have an electromagnetic wave incident upon some surface. There is an incident wave, a transmitted wave, and a reflected wave. The permittivity constant of the one medium is e1 and the permittivity constant of the other medium is e2. Denote the angle of incidence by qi, and the transmitted angle by qt. Using boundary conditions on the electric field E, find a relationship between the angle of inciden…

Hello, can someone please answer this question. sorry if answered before. What key relationships observed in the photoelectric effect led to the belief that light has a particle natuture. and also, is the current model of light a particle or wave one. thank you.

I have read several threads stating time doesn't exist. I want to see how many think it does and how many don't think that it exists.

it occurs to me that since gravitons are particles, they must also act like a wave. with that in mind, shouldn't there be an interference pattern? isn't that an easy way to proof the existance of gravitons? if there is an interference pattern, they exist, if not, then they don't. there must be something wrong with this or it would have already been done. whats up?

I do not know if this fits in this catagory. But, is it possible to teleport any type of matter? I tend to not believe this. With movies such as star trek used teleporting. Sure 24th century. But, how would you be able to break down matter to its simplist form and transport t anywhere. A theory that remains true even today 'matter can not be created or destroyed'. How would you go about moving it at once. Wouldn't you be destroying the matter for an instant then bringing it somewhere else? Or would you just be able to move it atom by atom. You decide.

At research of laws of the nature we actually measure only three parameters – force, length and time. Therefore, it seems rather strange, what for scientists have excluded the unit of measurements of force from the list of the basic units of measurements, and have entered the unit of measurements of mass. Other fact from a series of alogisms concerns to a technique of definition of a unit of measurements of force of electric current. The ampere is defined, as result of interaction of two infinite and parallel conductors with electric current. Such conductors in the nature do not exist. The electric current always is closed and, hence, it has concrete connection with spac…

General relativity and quantum mechanics use a different language toward the universe. Relativity is a mathematical machine which uses tensors (generalization of vectors) and extensive differential geometry (including differential forms, fibre bundles and connections) to explain gravity on the large scale. Quantum mechanics is also a mathematical machine but uses quite different math. QM describes the microscopic universe using linear algebra, fourier analysis, a lot of focus on abstract algebra (especially group theory and lie groups), complex analysis and functional analysis. Geometric algebra (clifford algebra with spinors) can also be used instead of differential…

hi my question is , i know the universe is expanding but by this does that mean that the material the universe or space is made out of (sorry if its sounds stupid im learning) is it actually being streached or is new stuff being made and if it being streached would this not but pressure on the space which is being streached like if you where pulling a elastic band. sorry agian if it sounds stupid its hard for me to explain my question. Thanks

Huygen's wavelets considers every point on a wavefront as a secondary wave emitting source which therefore creates a new wavefront which has propagated away from source. However, there is something wrong, if every point on a wavefront is a secondary wave emitting source why does the new wavefront go backwards (towards the initial emitting source)? Does anybody have a explanation?

hello, kids, what is a hyper cube and i understand wat the first four dimensions are but wat are any other dimensions that can be talked about. like i can comprehend time and space but wat else could ther be. thanks men of earth

Ok, by no means am i an expert at physics or do i really have any experience in atomic theories, but i had an interesting idea one day and i was wondering if i could get some feedback. Gravity. It exists. Lesser than the pull of two magnets yet it keeps the universe in order. Atoms. Building blocks of everything. God's Lincoln Logs. Ok, here is my far out approach to this. The way that the celestial bodies gravitate around each other in huge elipses is VERY similar to that of protons and neutrons orbiting a nucleus. Imagine if humans were 2 billion times bigger. Would the solar systems throughout the universe act and look just like atoms? I am a strong believer in …