Paradox Definition and 1000 Threads

According to relativity of simultaneity, events may not always be simultaneous from both frames of reference. The scenario described above happens due to lorentz length contraction and relativity of simultaneity. Please help me understand where I am getting this concept wrong.

I've come across a paradox I can't resolve. Let's have an isolated system: A gas in a box in a homogeneous gravitational field. When thermodynamic equilibrium is reached, the gas should have an adiabatic temperature gradient (temperature decreases with increasing height). The walls are in...

It was Eric Barber from t'other village, they shave each other, obviously they don't trust anyone else because cutthroat razors.

I met a paradox I am unable to resolve. Here it goes: a special material is placed in thermal contact with 2 reservoirs kept at different temperature. The boundaries of the material that aren't in contact with the reservoirs are thermally insulated. The material being special is able to generate...

In the latest edition of Scientific American, they had an opinion piece titled The Paradox of 1 – 1 + 1 – 1 + 1 – 1 + …. For those with access: https://www.scientificamerican.com/article/1-the-paradox-of-1-1-1-1-1-1/ Scientific American, the once-venerable publication I eagerly awaited every...

I recently revisited Bell's Spaceship Paradox, and I have a few questions about it that I may ask later, but there's one that I can ask now In Bell's Spaceship Paradox, two ships, separated by space, must begin accelerating simultaneously. After learning about simultaneity conventions and the...

Assume it’s extremely bright and sunny outside the tunnel, but very very dark inside the tunnel If you are a passenger riding in the “center” of the train , and the shutting and opening of each door (the tunnel entrance and tunnel exit door) happens very fast and occurs at a point where one...

Brilliant paper https://arxiv.org/abs/2202.04203v2 recently published in Nature Communications (open access) https://www.nature.com/articles/s41467-024-47170-2 resolves and demystifies the Frauchiger-Renner paradox associated with the Wigner friend problem. The resolution of the paradox, in...

suppose the enterprise departs from planet earth on a mission the the other side of the milky way at 90% of the speed of light; since time is dilated while cpt Kirk drinks coffe on planet earth some time passes (let's say 1h). Approaching mars captain Kirk orders dt. Spock to land on Mars with...

Amateur physics enthusiast. I watch a lot of physics explanation videos and one made me think of something. which would later become a paradox that i can't find any other examples of. So if that's the case I feel cool if I came up with one no one has considered before. That being said I know...

User New here but this conundrum is something that occurred to me as I was watching a physics video and I have run out of ways to ask about this. So here I am. Ok first principle. the setup. let's say we have invented a perfect telescope on earth. such that we can resolve any object no matter...

In Aubrey Clayton's book" Bernoulli's Fallacy" which documents the conflict between frequentists and Bayesian interpretations of probability, he describes a problem that was proposed in the 19th century that gives a counterintuitive result. The Problem: "Infer the state of a bag of 3 balls...

Hello, Stephen Hawking's book The Future of The Universe says that matter would have to exceed the minimum speed of 5 times the speed of light to exit a black hole. This means that the matter would have to be transferred to Energy using E=MC^2 but all energy is limited by the speed of light...

I have seen many attempts to rationalise the 'Twins Paradox', but none of the seem satisfactory. They usually use acceleration or asymmetric differences in inertial frame, or other aspects of special relativity that tend to obfuscate the problem/explanation. So proposing an experiment that...

Hello and thank you for welcoming me to your forum! To get started, I would like to give you a little help: In the pattern experiment, when firing the cannon, if part of the momentum reaches the bird, and if another part of the momentum manages to stun the fish, what part of the momentum would...

I would like to propose a relativistic problem that I cannot understand. A car of rest length L travels at close to the speed of light towards a garage, of length L, which also has an opening at the bottom. For a person next to the garage door, the car has a length less than L, due to the...

hi, I am a physics student in grade eleven. I do not have much knowledge of physics but I have a doubt: apart from the maths and the experiments, shouldn't larger masses be attracted to Earth's gravity rather than be attracted the same regardless of mass? if we had a scenario where we have...

Full disclosure: I have asked this question on stackexchange too, but I think I didn't frame my question properly there, which probably led to misunderstandings and complicated answers. Plus some comments there led me to refine the question a bit so I hope it's in a good state now. I am new to...

The ship left Earth at a speed of 0.5c . When the distance between the ship and Earth was 0.25 light year, a terrorist was caught on Earth who said that he had planted a bomb at the time of departure and activated it for 10 months. At that moment, a warning signal was sent from Earth. The...

One person (A) stays on Earth, while another (B) goes on a long journey and returns later. We can calculate the time interval for A and the proper time interval for B. Let's say we get Δt=100y and Δτ'=50y. We then consider a second traveler (C) going on a different journey, departing and...

There are a number n of runners in a race. We know their expected times from start to finish μ(i) and the corresponding standard deviations σ(i). The probability of runner 0 to finish first is given by this integral: It's from here: https://www.untruth.org/~josh/math/normal-min.pdf The 0 is...

Two astronauts A and B are traveling at constant speed, one toward the other. From astronaut A's point of view, his partner B's clock is ticking at a slower rate than his. From astronaut B's point of view, it is his partner A's clock ticking at a slower rate. Does this set up a paradox? Because?

Does the twin paradox hold around a black hole (or maybe less extreme gravitational fields)? In a gravitational fields like that of the Earth it seems to apply. If two particles fall together, with synchronized clocks, and one of them rests on a platform for a while, after which it accelerates...

I understand that the travelling twin (T, say) is subjected to acceleration and deceleration while the stay-at-home twin (S) is in inertial frame all the time. It is this asymmetry which results in the travelling twin aging less than the other, when they two meet up. Since acceleration is the...

I think I broke special relativity…not really but I am clearly over looking something. Imagin a man carrying a pole (like a pole vaulter) running at speed v. The length of the pole = L, so in the frame of the person watching this man run, the length of the pole is observed as L/γ. There is a...

Hi all, I'm a bit nervous about the implications of relativity, not the block universe stuff I can work with that.. What worries me regards planes of simultaneity, when I'm walking away from you my plane of simultaneity will contain you from your past, so the you in my reference frame...

In the image below from the website http://www.mysearch.org.uk/website1/html/250.Twins.html , they try to explain why the two situations are not symmetric, but I don't understand their approach. Even if the website is not giving a sufficient explanation, I would still like to know why the two...

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So I've been trying really hard to understand the theory of relativity at its most basic level lately, and recently I dove down the rabbit hole of the Twin Paradox. This has led me through a series of youtube videos, each one claiming to present a different solution, explain why the other...

Gun with a tachyon bullet paradox if you had a device akin to some kind of ‘gun’, which created tachyons and the fired them, perhaps in a beam or some kind of ‘packet’, when they go faster than the speed of light would go back in time. Lets say the ‘bullet’ or beam, went out into the universe...

I know, I know, yet another Twin Paradox thread. (My apologies if this is already on the Forum somewhere. I found a similar discussion but with no answer to my question. I'd appreciate a link if someone has already given an answer to it.) I'm trying to construct the time elapsed for Stan...

I have a random variable X in range(0,n) where n<1, with a uniform distribution Then the probability of sample space S=n x P(X=x) x<=n which must be 1 Manipulating the equation P(X=x)=1/n >1 Then this violates the fundamental law of probability which says that any probability must be at most 1...

Alice measures the spin, also Bob measures. If we assume that the signals (from Alice to Bob) were sent, they had to be with the speed e.g. 10 c But in another frame of reference Bob first measures, next Alice. Measurement of Alice was cause and was sent back in time, or measurement of Bob was...

Using a simple time clock in the horizontal position you can see the solution to the twin paradox. In this graph the Time clock tics once every half year on earth. 5 years pass on Earth 4 years pass on the spaceship. You don't have to worry about mysterious simultaneity or time jumps...

Alice rests at ##X=L+1## in the inertial frame (T, X). Bob is at rest in the Rindler frame (t, x) at ##x=1## and has the proper acceleration ##\alpha=1##. In the rest frame of Alice, Bob moves from event ##E_1=(-T_2, L+1)## over the distance of ##L## in negative X-direction to event ##(0, 1)##...

I just saw the following clip on youtube It seems that many people are still interested in this topic. Here is the simple clear explanation I came up with, is there any error please ? This means that voltmeter 2 is not measuring the potential difference produced by the charge...

The twin paradox is connected to the special relativity but I wonder simply if one might construct the paradox (or something very similar) based on the Lorentz’ (and FitzGerald) work alone? Several ingredients in the paradox, time dilation and Lorentz contraction, are often mentioned with...

Is the twin paradox settled by saying that any non-straight path between two events (points) in space-time has less proper time that a straight path between the two events? So the twin in the frame which has a longer trajectory between the two pints(curved) will have less elapsed time?

Replace the twins in the twin experiment by identical radioactive samples containing the same starting number ## N_0 ## of atoms. One (A) stays on Earth while the other (B) makes a round trip at high speed. When back the traveling sample is more radioactive because its half-life ## \Delta t1/2...

Applying the Lorentz transformation to velocity and acceleration, we can easily obtain that Aγ3 = α, where A is the acceleration measured by the stationary observer and α is the proper acceleration of the relative moving object. From this point, the equations for a constant accelerated motion...

https://www.popularmechanics.com/science/a41106690/grandfather-paradox-time-travel/ I’ve been studying the self consistency principle, being the idea in time travel that history (the past) must be conserved. When I read about the grandfather paradox it sounded like the same thing. Are these two...

Thinking about Bell's string paradox , I understand that if both spaceships maintain the same and constant proper acceleration, the string breaks because of the non-simultaneity of the acceleration effects at both ends of the string. But I want to introduce and consider a slight and subtle...

In Einstein's twin paradox,the solution comes like this: The twin on the spaceship de-accelerates his spaceship first and then accelerates in the reverse direction.This means his reference frame is not inertial hence he doesn't measure greater time interval as the other twin does...

Assuming that all of my brain states are equally likely to be BBs, and that BBs may exist somewhere outside the event horizon and I won't know about this аnd also the fact that I am either BB or OO, by memorizing 70,000 digits in this way, it is expected that I have increased my chance that I...

Hi Pfs, When Stephen Hawking proposed the idea of black hole information it appeared that information could be lost. it was a problem in GR which is a dererminitic theory. Knowing initial data and Hamiltonian tells you what was and will be. It is not the case in quantum physics. things evolve...

Consider 3 objects, A, B, and C, in relative motion along the x direction. EVENT 1 B passes A while moving at a constant v = 3/5c relative to A. Both clocks set to t = 0. EVENT 2 C passes B when B’s clock reads t = 5 while C is moving at a constant v = 3/5c towards (and relative) to A. C’s...

The Webb telescope images show galaxies that are so far away that it takes ages for their light to reach us, so long that we can see galaxies as they were soon after the big bang. How amazing - but hold on. If we came from the big bang, and nothing travels faster than light, how come we are here...

Not sure to ask here or in Physics/Cosmology. How could life have begun much less evolve (or even planets form) if according to the 2nd Law of Thermodynamics entropy always increases with time?

Hi, I've heard about the EPR paradox as follows: Leave two entangled particles A and B carried by scientists A' and B', with a pair of incompatible properties (eg spin up/down and left/right) in possible Green/Yellow and Blue/Red states. If one measures Yellow state (eg, particle B in spin up...

Hello everyone! I've been studying work and energy, and one problem I have is understanding conservation of mechanical energy. If on a rollercoaster you have two points A and B you expect the mechanical energy at A to be equal to the mechanical energy at point B, makes sense to me; but I started...