Paradox Definition and 1000 Threads

Consider the following scenario: There is a triplet of persons A, B and C. Person A stays on earth, while person B and C both go onto two different space missions, the directions parallel to each other. Person B travels at 0.45*c, person C at 0.9*c. The space missions are both set to take...

I know that many people here have a very high opinion on the Ballentine's QM textbook. I am also one of them, but one particular subsection of it is (in my opinion) wrong. This is the subsection on the quantum Zeno paradox, or as Ballentine calls it, the "watched pot" paradox in Section 12.2...

Hello, Still puzzled about the twin paradox (one guy stays on the ground, the other goes travelling). If we see the two twins as points in 3D space, the only thing that changes, is the distance between two. That is, the two guys are in totally symmetrical positions, and there should be no...

Suppose there are two electrons which are not moving relative to each other. Then in the reference frame of either electron, there is an electrostatic force pushing the two electrons apart, and they will move apart. However, if an observer is in a reference frame moving relative to the...

When Fermi was asked if he believed in the existence of E.T.s he replied "where are they?" and I think the idea was that if there were E.T.s they should have colonized the galaxy by now. What I am curious about is ... given the fact that the ability to detect earth-like worlds with signatures of...

Nothing much, I have this: I have studied (myself) about this for many days. And I believe that, for some conditions for a complex ψ,ϕ What are those conditions I mentioned about? And which field of study I should go to see?

Okay, I didn't really know where to post this, but whenever I hear about this paradox it is in a conversation relating to physics. Anyway, for those that don't know the paradox, it states that to get to point 'B', one must get halfway there before they can be all the way there. And to get...

I need your help to figure it out if the following thought experiment makes sense. Imagine two points in space at the same distance from Earth, 100 light years. At one point a previously unknown supernova explodes; we observe it’s bright light in the sky for several months, and after that it...

Do you find this argument by this author that SR implies "at least one continuum other than our own spacetime" flawed or reasonable? According to the special theory of relativity, observers stationary relative to one another will measure the time in the rest frame of an entity moving relative...

Okay so everyone is probably familiar with the twin paradox. Basically my question is what would happen if 2 entangled particles somehow underwent a similar scenario? Would they become untangled, or would they remain tangled, and somehow experience time at a different rate then their...

I really can't understand how faster than light travel creates the cause and effect paradox. I have spent many days on internet searching this specific problem but not able to get it. Can some one explain it to me in the easiest way. Another question : i have read many times that...

Hi, Can anyone help me resolve and understand this paradox: e=e^{1+2i\pi} and so e=\left[e^{1+2\pi i}\right]^{1+2\pi i}=e^{1+4\pi i-4\pi^2}=e^{1-4\pi^2} which is obviously fallacious. This paradox is from Roger Penrose Road to Reality and is currently hurting my head. I keep...

The uncertainty principle says that you can't simultaneously measure position and momentum with arbitrary precision. So you can measure one at a time t1 and the other at a time t2 with t2 > t1, thus not measuring both simultaneously, but relativity tell us that there exists a frame of reference...

We think of two very similar scenarios: 1. Two twins are hoovering with their spacecraft s at an earthlike distance A from the Sun and with no velocity with respect to the Sun. Then one of the twins suddenly accelerates to 100 km per second in some direction. He is now the accelerated twin...

We think of two very similar scenarios: 1. Two twins are hoovering with their spacecraft s at an earthlike distance A from the Sun and with no velocity with respect to the Sun. Then one of the twins suddenly accelerates to 100 km per second in some direction. He is now the accelerated twin...

Hi there! My question involves the area of a parallelogram. Now, I know how to prove the commonly used formula (b*h) very easily, however, there is a formula given on Wikipedia as an alternative that states...Given two sides B and C with angle (theta), B*C*sin(theta)=Area of a parallelogram. Now...

I got this problem from one of my favorite webcomics: Paradox occurs on a random day during the year such that it is unexpected which day it is. This precludes paradox day from occurring on December 31st since on December 30th we would know it had to occur the next day. Likewise, since paradox...

Hi, Please consider: At time zero a spaceship takes off from Earth and keeps traveling under constant acceleration. From Earth's perspective, the spaceship's speed keeps increasing but never reaches c. Also from Earth's perspective, the clock on the spaceship keeps slowing down and...

Hello, I was talking with my Physics professor the other day about something I could do in Special Relativity, since I'm only in Physics III and haven't experienced much of it, yet find it very interesting. He mentioned that I could do stuff with the Twin Paradox. Now I know the basic idea...

Interferometrics Cart Imagine that a cart is mounted with two electric motors, connected each to a pulley. Between the pulleys is installed a belt of equidistant holes that always coincide at the same points in relation to the cart. This allows the passage of luminous flux. Like a...

I can't come to a comfortable conclusion which doesn't make positive, negative, real, imaginary, complex, irrational or transcendental numbers seem much different fundamentally. Zeno (to the best of my interpretation) illustrates a large part of my problem with: "If there are many, they...

Twin "Paradox" with no asymmetry Here is another variation of the twin paradox. Suppose we let both twins start their journey from a space station far from any heavenly bodies, so that the whole experiment can be carried out in free space. The twins Jack and John are equipped with identical...

I've thought about something that is a paradox to me. I think I know what would happen in reality but I can't explain why the other option is discarded. Imagine you are an observer that can live "forever". You are over the Earth and looking toward the Sun. For the sake of simplicity, let's...

Everyone knows the situation. The one twin takes off in a rocket, and both twins see the others clock as running slow. Upon the return, its the one who has experienced acceleration that ends up being incorrect. So at some point, the "moving" twins view must show time on his brothers Earth clock...

Bullet-hole "paradox" This is a variant of the so-called "bullet-hole paradox" (the guns can be lasers and the train a spaceship): Two guns are mounted a distance of 40 ns apart (SR unit system) on the embankment beside a railroad track. The barrels of the guns project toward the track so...

Hi, I’ve been teaching myself SR, currently reading Relativity for the Questioning Mind by Daniel F Styer. My math is not great, so I have been avoiding the heavy calculations for now. I will learn those too, but I wanted to understand the concepts first. For the most part I think I have...

I was reading a little bit about the Banach–Tarski theorem. Is this similar to a line segment of length 1 having the same points as a square with side lengths of 1. And then also a cube with sides of length 1. So then I should be able to take a square and pick out all the points and construct a...

can twin paradox be solved,if no, what r the difficulties scientist face to solve it?? or is there a solution on it.

I'm a relative newbie to relativity (no pun intended -- I know you've heard that one too many times), as well as to this forum, so forgive me if this is a dumb question... As I understand it, there is a significant percentage of those that believe that people, spaceships, etc. will never travel...

Before I post this, I want to assure everyone that I am not a conspiracy theorist who doubts Einstein or relativity theory in any aspect. I just don't understand special relativity as well as Id like to and I think having this paradox resolved in my mind will help. The paradoxes that I've...

I've come across an apparent paradox in elementary quantum mechanics, and after a little Googling, haven't found a reference to it. Here goes, The 1-D infinite square well is a classic problem in introductory QM. We find that the position-space eigenfunctions of the Hamiltonian (the "allowed...

Homework Statement Two open-top containers, #1 on the left and #2 on the right, with equal base area A are placed on two scales. The #2 container on the right has an lower diameter twice that of its upper diameter and the height of its lower (larger) diameter is half that of its water height...

The following paradox was put forward by "Fredrik" in a discussion on "time-uncertainity relation"- Lets look at this closely, using position momentum operators and a general quantum state- \langle U|xp - px|U \rangle This can be rewritten as- \sum_{x'}\sum_{x"}\sum_{p'} (\langle...

how is twin paradox resolved in case of no/zero acceleration/deceleration? two twins one on Earth and other on a ship moving at constant velocity (say 80% speed of light). the other twin does not turn around ..thus no acceleration/deceleration. how we resolve the paradox now? twin A will say...

Olbers' paradox states that if the universe is infinite, static and homogeneous then why is the night sky dark. Of course it's been resolved but it brings up an interesting probability question: If we model the universe with a spatial Poisson model (probability that a small element is...

I have attatched my Paradox for the existence of 4,5 and 7 using Brocard's problem . I don't know where i have gone wrong as 4,5,7 exist, surely.

Let us check the derivation of the liar paradox. 1 Sentence 1 is not true. (Assumption 1) (LIAR SENTENCE) 2 Sentence 1 = "Sentence 1 is not true) (True by inspection of 1) (LIAR IDENTITY) 3 "Sentence 1 is not true" is true if and only if sentence 1 is not true (by definition of truth)...

Introduction: (can be skipped) We know the problems around the collapse of the state (specially that we don't know how an outcome is selected from the preferred states). Now thousand of experiments shows us that this strange not unitary transformation of the states occurs when a measurement...

I am confuse at a point that is: I equation P=IV there is an inverse relation between I and V But according to ohm law there is direct relation between I and V. How in in ac Power transmission line 1100 volt cause small current than 220 volt... please solve my this trouble... Everyone...

Hi all. Suppose we have two objects A and B, and suppose we tie a rope R to the objects with the rope R's two edges hooked to a pole or hook on each of the objects. The rope is loosely connected to the hooks on such a way that as objects will move away from each other, then as the rope will...

Hi, I'm new here. This question may already have an answer but I didn't find it. Sorry if there's already one. It's a static version of the twin paradox, without travel and without twins. We have 2 circles C and C' that are superposed. C is fixed, with time t and co-ordinate x along the circle...

i'm trying to conclude on HOW this would be possible... though its a paradox doesn't it seem very possible? in case you don't know what it is its saying movement is immpossible. Example to get from point a to point b you have to go halfway but before you get from point A to A1/2 you have to get...

1. Russell's paradox is: A={x:x∉x} Is A a subset of itself? But my question is: Let there be a set M such that: M={1,2,3,4} The now, one asks if M is a subset of itself. Most probably he would hear a know but, since M={1,2,3,4} and again I write here M={1,2,3,4}, {1,2,3,4} can be...

If observed time approaches 0 at the speed of light, does that mean the distance one travles at the speed of light is infinite? Since speed = distance/time, does this mean that, at the speed of light C= infinity/0 which = 0? There then appears to be no speed at the speed of light. Does this...

So we have covered relativity a couple weeks ago and I've been thinking about the twin paradox. It is when one twin travels on a high speed ship to some distant planet and back. But since all frames of reference are equivalent, each twin measures the other to be younger. My book explained that...

Are the two following hypothetical observations contradictory according to GR? 1. Particles fall towards a black hole but never cross the event horizon 2. After observing this for a few million years, the mass of the black hole is observed to have grown over that few million years. Or...

"The confusion that arises in problems like Example 26.1 lies in the fact that movement is relative: from the point of view of someone in the pendulum’s rest frame, the pendulum is standing still (except, of course, for the swinging motion), whereas to someone in a frame that is moving with...

My question relates to the “Ehrenfest paradox”. I try to grasp it. “In its original formulation as presented by Paul Ehrenfest 1909 in the Physikalische Zeitschrift, it discusses an ideally rigid cylinder that is made to rotate about its axis of symmetry. The radius R as seen in the...

twin paradox alone kills special relativity: the story: A stays on the planet, B round-travels by spaceship; when back, based on spectral relativity, B youngs. analysis: when special relativity is be applied, the property difference between planet and spaceship is never used; so...

[PLAIN]http://www.science27.com/forum/rocketL2.jpg Above the head of observer “A” a mother-ship is moving east 100,000 km/s. and right above the Earth it is launching a small spacecraft moving west with the same speed (100,000 km/s). REFERENCE FRAME A Observer “A” would now (from...