Modern and Theoretical Physics

Planck units like the mass and length come up all over the place in modern physics---they are not the only system, there are other convenient special purpose units, but they are worth getting familiar with. Using the google calculator we can take a kind of almost experimental approach to planck units, explore, build up our concepts, try them out. It is easy---a few posts will show what I mean. So here's a brief tutorial. 1. get to know hbar (Planck's constant) Think of hbar as being the product of amounts of energy and time. Check that by typing things like this into google hbar/minute hbar/year It will give you answers in energy terms----small amounts …

If the Universe started approximately 13.75 billion years ago as theorized by the 'Big Bang' and TIME itself only came into existence at the moment of the Big Bang, then surely this must be 'Universal Time'. Yet Einstein and special relativity shows us that TIME is relative. There is no such thing as universal TIME. This has been experimentally proven. So then how could TIME only have come into existence with the Big Bang, as accepted by many supporters of the Big Bang. If TIME only came into existence with the Big Bang then that time would be universal. The universe would be 13.75 billion years old for us. And if there are aliens living in another galaxy…

Based on humanity's current scientific understanding: If the entire universe, every single planck, even what is now empty space, was somehow converted into a single type of fermion, what would happen? What would happen differently if it were a different kind of fermion? Additionally, what would happen if it were a combination of different fermions, and how would the results differ between combinations? Would it be possible for any conceivable form of life to arise in this new universe? If so, how would the aforementioned variations effect this?

I googled for "define: entropy" and came up with this: "A measure of the disorder in a system." I also entered "entropy" into http://www.dictionary.com and found, among other definitions: "The tendency for all matter and energy in the universe to evolve toward a state of inert uniformity." So if I understand this correctly, entropy is the phenomenon observed when, for instance, an elastic band goes from stretched to slack or a building going from erect to rubble when demolished by means of explosives. Is this correct? If so, what do we call the opposite phenomenon - that is, the building up of physical systems from something simple with uniformly distr…

Hi; Guys, A college student asked the question if a photon has physical volume or geometrical size. Does anyone have a good answer? From the particle point of view, it should have volume/size; from wave point of view, it should not have volume/size. A photon travels from a remote star to the earth (Billion years), does not fall apart during the long journey, it should have certain volume/size.

Does the magnetic field of a wire carrying a current have mass?

Apparently a photon rocket is the most promising engine for interstellar flight. https://en.m.wikipedia.org/wiki/Photon_rocket

I made a thread about this topic on http://www.physicsforums.com/ and some people on there called me a troll, my thread was locked as a result, and then when I tried making another thread, I wasn't able to because someone was messing with my ability to post (probably a mod). When I tried going back I got called a "crackpot" and it said that the ban will "never" be lifted. I spent like an hour making replies to people who posted on my thread and I never got a chance to post them. Anyway, I really needed to vent about that. Now, I'm here for the same reasons I had on there and that is, well, to get different perspectives and maybe even a reality check (as was implie…

Hello friends! I have a question about light. We all know that we see objects because they reflect light into our eyes. But we never see the actual light. So my question is why can't we see light. Or can we in fact see light. If so, how?

Why is it apparent that small things determine how big things work and not vice versa? Why is cause and effect noncommutative with respect to "size". In the sense that CAUSE is due to some physical laws: Quantum fluctuations CAUSE real and virtual particles. Real particles cause leptons, quarks, bosons. Leptons and quarks cause protons, neutrons and electrons. Protons neutrons electrons cause hydrogen helium and carbon atoms. Hydrogen, iron and oxygen cause stars, planets, and water. Stars, planets and water cause galaxies, solar systems, and oceans. Galaxies do not cause stars. Stars do not cause hydrogen. Hydrogen does not cause protons. Prot…

A friend and I were having a debate as to wether this theory holds true: Please try to imagine that you were motionless in free space (relative to whatever....) and you were standing on one end of a plank with your feet firmly secured to the plank, and at the other end of the plank there was a board much like a basketball back board firmly secured to the plank facing you. Please Imagine you had pockets full of good sized rocks, if you were to throw a rock at the back board, you and the plank along with the back board would move in the opposite direction to the rock until the rock hit the back board, then at that point the rock hitting the backboard would cancel out t…

HELP! I've never posted something on this forum before, so I didn't know where to post this... Anyway, does anybody know the effect of temperature on extrinsic (both p-type and n-type) semiconductors, because I can find aboslutely nothing on the internet!!! Thanks

Is there any evidence for the existence of an antiphoton? Or an antimatter version of any of the other force-carrier particles?

I have been looking at the structure of the atom lately and wondered what makes the electron orbit? You would think if a proton is positively charged and a electron is negatively charged that the two would eventually stick together. I realize in theory that the orbiting electron like a planet never lets this happen. But what makes an electron orbit in the first place and when an electron goes from one atom to another how does it automatically orbit in a way that it does not collide with the proton or neutron? I am not interested in theories (there are way to many of them flying around), but in proof + experiments on what is going on. Thanks.

and before anyone complains about this post, I have express permission to post it! here`s how to build your own atomic reactor exploiting the decay principals and it`s physical effects. ALL radioactive isotopes with a high enough decay rate exhibit the physical effect of being several degrees warmer than their ambient temperature, Radium will always be 1 degree C above it`s ambient temp. the principal is simple, put enough radium into a thermos vacuum flask and fill it with boiling water, the water will gradualy get hotter and create steam. that steam may them be used to drive a small fan (turbine) and in turn a that rotation will turn a small generator ( a l…

Think of a body moving as in Newton's first law - in a straight line at a fixed speed say. I have been wondering where is the information for the body to "know" how to move? One could argue that the motion itself is the "information", but that is somewhat unsatisfactory from an information theory point of view. I understand that information theory is being suggested as a possible way of looking at fundamental physics, so my question might be relevant, even though I am only a novice student of theoretical physics.

Well Does infinity exist in nature? I have recently heard blackholes actually slowly die, they somehow radiate energy (I think in gravity waves). Perhaps Black holes (not the event horizon, the "Actual Stuff") has a real size? Also the bigbang seems to suggest our universe isnt endless, Just really really really big. So the universe Does not go for infinity. Theres a Limited Speed, Mass/energy in the universe and Size. If there is a limit on everything there is a limit on complexity. Do we realy know of any instances in which infinity does exist, or have we created the concept?

I don't even know if that termed correctly.. Can a plain piece of " typing" paper " " white paper" held up to a light source reflect visible light frequencies and can these "colors be visually seen by an observer? Ive read: White surfaces are composed of molecules or atoms that don’t absorb any of the visible colors of light. --->"But" those are surfaces not paper, is this correct to compare???

It is Universally accepted that time is the manifestation of the fourth dimension. Even so Have you ever seen a 4-dimensional figure? Can a 3-dimensional figure move without time? Can a 2-dimensional figure move without time? I am proposing that time is not the fourth dimension, but a binding law that all dimensions must obey. Tell me what you think.

Just wondered... If a train is moving alogn at 70mph, and you throw a ball off the back at 70mph...does the ball effectivly 'stop'? Dan

Hello. I'm an aspiring science fiction writer and the type of science I would like to write is "hard sci-fi". That is, I want to create fantastic technologies that obey the laws of physics. I'm just trying to decide if teleportation is one of those things. Let's examine the six possibilities: quantum teleportation, matter/energy conversion, extra dimensions, wormholes, hole teleportation and space warp teleportation. A. Quantum teleportation - has already been accomplished by teleporting a photon's properties, however, not the actual photon itself. For more information, check out the following website: http://www.aip.org/physnews/graphics/html/teleport.…

I learned from my physics class that it is the strong gravity of earth that not only binds us to it but also keeps the moon in orbit... in a similar fashion that the sun by its extremely strong gravity keeps all the rest of the planets (that we know of) in orbit. Ofcourse, centripetal forces are also involved here but what I wanted to know is the energy source for this gravity.. more specifically, the source of energy of earth's gravity. Is it located at the central core of the earth, as some would predict?? what does it look like?? at what rate is the energy being used up (the power, i.e) and, if it goes at this rate, at approx. what point in time will it be totally …

this is a pretty simple concept, look it up on google if u dont know it: basically my question was: if u built a metal suit, wore it, and got hit by thunder, would you be fine? assumin the metal can withstand the current. also are there any conditions, e.g. the metal suit has to be earthed? or does it have to be perfectl smooth, or can there be lumps, bumps, for your head, or where it joins together? and does a car work as faraday's cage if it is hit by ligthening, are the ppl inside fine, would they know about it? would they be electrocuted!?!

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.

This paper by Garrett Lisi, http://arxiv.org/abs/0711.0770, is raising quite a stir in the physics world. Abstract: All fields of the standard model and gravity are unified as an E8 principal bundle connection. A non-compact real form of the E8 Lie algebra has G2 and F4 subalgebras which break down to strong su(3), electroweak su(2) x u(1), gravitational so(3,1), the frame-Higgs, and three generations of fermions related by triality. The interactions and dynamics of these 1-form and Grassmann valued parts of an E8 superconnection are described by the curvature and action over a four dimensional base manifold. Some physics blogs that discuss this paper: http://ba…