Paradox Definition and 1000 Threads

Feynman's "apparent" paradox - Electromagnetism This is the paradox discussed in chapter 17 of "Feynman Lectures on Physics - Vol II" http://www.flickr.com/photos/37453425@N07/3447068420/ Say suppose the battery drains out or somehow you stop the current outta the battery. By...

2. Consider the following objection to STR: “Since time-dilation and length-contraction are reciprocal, STR actually contradicts the frame-invariance of physical age differences, that is, the plain physical facts. For instance, so there can be no ambiguity about “age comparisons”, let us replace...

In the pole and barn paradox, if the observer (person A) closes the both doors simultaneusly (with respect to himself), when he sees the runner's stick (person B) is just inside and keeps it closed forever after that, how will things happen, will the runner be traped or the door will hit the...

an atom goes through a particular nuclear reaction and emits a left-handed and right-handed particle. after the particles have traveled to opposite sides of the universe, if you measure the handedness of one you instantly know the other's which is information moving faster than the speed of...

I know very little about relativity. I have heard that it implies that----- if A and B be two tweens. If A goes in a space trip and then return to B at earth, he will be younger than B. What I am confused is, It must be same thing whether A went away from B in his space trip on the ship or...

Greetings! This is my first post so go easy. I read through the thread addressing the Sci Am article claiming that entanglement violates relativity. The article actually addresses a symptom of a larger issue that exists between QM and SR. I would like to get feedback on this issue as...

This question might rather be posted in Biology but since the information paradox is usually the subject of black hole physics I thought physicists may be better placed to answer it. The fact that information may be lost in black holes is considered a paradox, information is believed to be...

Hello Physics Forums, I am new here and I thank the community for any input I might receive on my physics paradox. To some of you this may not be a paradox and I hope that you may be able to explain to me how this makes sense from all reference points. The paradox follows as such: It has...

I was first introduced to this thought-experiment upon reading Stephen Hawking's A Brief History of Time . Suppose an omnipotent being exists. If it does, it would be able to do anything (by definition!). Therefore, it would be able to produce a rock it couldn't lift. Therefore, it wouldn't be...

this is my 1st post, and its a question that i had developed, most likely out of ignorance, so please save me from my sad paradox. lol Thank you, in advanced. I understand if i where floating in the bulk of space with no visual queues to give me aid in telling me if I were moving, i could...

Please take a look on this paradox. http://knol.google.com/k/alex-belov/paradox-in-classical-mechanic/1xmqm1l0s4ys/3# What do you think?

I read two articles recently and I am wondering if I have the correct interpretation of them. They deal with joint weak measurement and Hardy's paradox. Is the result of the "Direct observation of Hardy's paradox by joint weak measurement with an entangled photon pair" paper indicating...

The idea is as follows: My (imaginary) twin and I were born at the same time, thus just as old. Now, my twin made his own spaceship in the backyard, one day, and decided to go for a ride. It had only room for one person, so I had to stay behind. Now, my twin went out of the Solar System and...

Here is an interesting piece of paradox. We all know Hamiltonian is an energy operator in Quantum Mechanics.The Schrodinger's equation tells that \ H\psi=\ i \hbar\frac{\partial}{\partial\ t}\psi Now,we also know that Hamiltoian is Hermitian.But are we sure that \ i...

Why is the sun's corona temperature around millions of degrees celsius while the sun's surface is about 6000 degrees celsius? Doesn't that defies the laws of thermodynamics?

Correct me if I am wrong, but, if electromagnetism is relative then in a frame where charges have relative motion between the observer, the observer would detect electromagnetic radiation being emitted from the charge, and that to an observer moving alongside the charge at the same speed, no...

http://arxiv.org/abs/0902.3376"

gamma matrix trace Paradox?? Hello, i tried to evaluate this particular little guy: \text{Tr} (\gamma ^0 p_\mu \gamma ^\mu \gamma ^0 q_\nu \gamma ^\nu ) using these identities: \gamma^0 \gamma^0 = I \text{Tr} (\gamma^\mu \gamma^\nu \gamma^\rho \gamma^\sigma) = 4 (g^{\rho \sigma} g^{\mu \nu}...

I understand how the argument goes- let X be the set of all sets which don't contain themselves. If X contains itself, then X is not in X If X doesn't contain itself, then X is X the part i don't understand is, What on Earth does it mean for a set to contain itself? garbage in, garbage...

Paradox? An infinite set having finite volume?? Homework Statement Find the volume, in terms of k, of the solid made from R rotating about the y-axis, if R is defined as the region bounded by e^{-x} and the coordinate axes. 2. The attempt at a solution Obviously, \displaystyle\int^{1}_{0}...

I'm new, and basically just study physics as a hobby. I've yet to understand the mathematics, just the concepts. In studying spacetime contraction, I led myself to a paradox, which would leave someone both dead and alive. Let me explain. Say you were on a spaceship that could travel at light...

Hello Everyone, This is my first post, I didnt see an introduction section to give some of my background. Let me know if there is one somewhere? Anyway, Years ago, I attended a lecture on Zeno's paradox. The paradox basicly says," how many times can I ask you to walk halfway to the...

Homework Statement Assume a rocket ship leaves the Earth in the year 2100. Castor, one of a set of identical twins born in 2080, remains on Earth to work at Mission Control, while the other twin, Pollux, travels in the rocket. Ignore the motion of the Earth relative to the fixed stars. The...

Is there not an inherent paradox in Amelino-Camelia’s DSR (Doubly special relativity)? Every solid piece of matter is the sum of its parts. Put another way, all the building blocks of a meter stick must be less than a meter in length (e.g. the lines dividing centimeters, millimeters, the...

http://www.physorg.com/news151164690.html Lucien Hardy's QM paradox goes back to 1992 or 1993 when he was a grad student at Durham UK. Lundeen and Steinberg's paper was published in Physical Review Letters January 16. They confirm Hardy's paradox, and offer a theoretical explanation or...

If e=mc2 wouldn't that mean I'm in a Xeno's paradox? and What would things be like if e did not equal mc2? ? I understand why it must equal mc2 but can't imagine how things would be if it didn't. and If we watch what's happening in the universe in mega ultra super fast forward wouldn't it...

I'll be giving a small talk to the graduate students of my university on the topic of "counter-examples" and my first counter-example is Russell's paradox. I want to put the theorem in context, but admitedly, I have no idea what I'm talking about when it comes to logic and set theory. I want to...

Marijuana isn't known for being a friend to memory; its short-term effects notoriously impair recall. And although the data is conflicting, some studies link cannabis with memory deficits in those who use excessive doses for long periods of time But new research suggests that one of the active...

Good Hollidays

Homework Statement Find the momentum and energy of photons of light of wavelength 500nm. Usual data of h = 6.63 x 10-34 and c = 3.0 x 108ms-1Homework Equations The Attempt at a Solution > To get momentum, i simply take momentum = h/wavelength = 1.326 x 10-27 kgms-1 > To get energy I use E =...

A paradox?...In STR. A thought experiment; This could take place in a hallway or in space, whichever you prefer. Consider an electron somewhere around the center of your monitor. Now have an observer A at the right of your screen closing the distance between the electron and himself in a...

A car (original length 20 feet) is traveling towards a garage of length 10 feet at speed of 0.8c . Now at such high speed length contraction occurs & contraction factor is 2 , so from garage's frame of reference the car has shrunk to 10 feet & it should fit in the garage where as from the car's...

http://arxiv.org/abs/0901.0640 Horizons and the cosmological constant Krzysztof A. Meissner 6 pages (Submitted on 6 Jan 2009) "A new solution of the Einstein equations for the point mass immersed in the de Sitter Universe is presented. The properties of the metric are very different from both...

In naive set theory, Russell's paradox shows that the "set" S:=\{X:X \in X\} satisfies the weird property S \in S and S\notin S. How does the set theory of Zermelo and Fraenkel get rid of this "paradox"? I.e., which axioms or theorem prohibit S above to be a set? Thank you.

I'm sure this question has been asked thousands of times before, but I can't see how nature determines which twin accelerates (or is subject to a gravitational field) and which one doesn't. People say one twin will feel the acceleration and the other won't, but suppose neither twin had an...

I know that the frame of reference determines that it is the stay-at-home twin who ages faster than the twin traveling at some fraction of light speed. Some years back, an experiment in which one of a pair of synchronized atomic clocks was placed on a commercial airliner and flown around the...

From Olbers' paradox, the night sky is dark because the universe is finite in age, so some stars' light hasn't had time to reach us. BUT, we see the CMB which occurred some 13 billion years ago (14 billion maybe?) So, if light from the cmb has had time to reach us, shouldn't every object's light...

The possible energies of photons is continuous and therefore a photon could have an infinite number of possible numerical values for energy. In contrast all forms of molecular energy are quantized (electronic, rotational, vibrational and translational). Surely the probability of any given photon...

Homework Statement Carmen has just purchased the world's longest stretch lim, which has proper length 30 m. A garage has a proper length of 6.0 m. Carmen concludes that there is no way to fit the limo into the garage. Her buddy Garageman claims that under the right circumstances the limo...

Hi This thought has been in my head for a while and I need to resolve it. If light travels at the speed of light in a vacuum and I am told that it does AND time stops when one is traveling at the speed of light, I am also advised this is true THEN doesn't that mean for light it is...

Resolving the "Twin Paradox" http://mentock.home.mindspring.com/twins.htm I've been trying to follow this unusual explanation to resolve twin paradox, which uses the lorentz relativistic velocity transformation equation to get the speed bob zooms off after Ann at,15/17 C. I can understand...

I have read the sine rule: It states--> sin A/a=sin B/b=sin C/c = 1/2R where R is circumradius. Now, a=2Rsin A b=2Rsin B c=2Rsin C For a triangle R is fixed. In an obtuse angled triangle, the side opposite largest angle is the longest(geomtrically) But the sine of an obtuse angle...

Hi there, here I have this paradox and hope you can explain. There are 2 charged particles, one is moving at speed v, one is stationary. We know the moving charge gives off a magnetic field which can not exert any force onto the other charge because it does not move. Now assume we stay in a...

HI My question is what would the outcome be if the twins started out in 2 ships traveling at uniform .6c relative to Earth and one of them then took her ship and traveled to Earth and back? Which twin would be older?

Reverse Twins paradox ? This may have come up before but I haven't seen it and don't know the answer. What if the twins started out in two ships moving together at relativistically significant velocity relative to earth. One of the twins then simply goes to Earth and back while the other...

I'm trying to make sense of the way time dimension is related to the other 3, the example is twin paradox: Observer 1 is moving away at 0.866c from observer 2, who is standing still, then turns around at a defined point and goes back at the same speed, arriving back to observer 2 position...

can someone help me with this? if i assume that the passengers arrival is uniform, is it still valid?

The classic lighthouse thought experiment leads to a situation in which some "thing" is traveling faster than the speed of light. This is the case because the lighthouse's light beam, if powerful enough, will shine a circle of light on its destination that can travel faster than the speed of...

Homework Statement Identical twins Speedo and Goslo join amigration from the Earth to Planet X. It is 20.0 light years away in a reference frame in which both planets are at rest. The twins, of the same age, depart at the same time on different spacecraft s. Speedo's craft travels steadily at...

The https://www.physicsforums.com/archive/index.php/t-240147.html" occurred to me several years ago when I was still chasing relativity by the tail. I didn't learn that Rietdijk, Putnam, and Penrose had advanced this argument till yesterday. Weird. Anyway there are direct testable consequences...