The special theory of relativity describes the motion and dynamics of objects moving at significant fractions of the speed of light.

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What is the 'quantum-developed' or 'relativistic-developed' equation of the electrostatic force?

Quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics that is the first theory where full agreement between quantum mechanics, special relativity and ...
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Special relativity, spacetime, velocity and units

We all know that space and time are the fundamental units, means no mathematical expression can express their relation to other variable fundamentally. But as we know that moving rod has a contracted ...
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How to prove that proper orthochronous Lorentz transformations form a group?

Proper orthochronous Loentz transform are Lorentz transforms that satisfy the conditions (sign convention of Minkowskian metric $+---$) $$\det \Lambda=+1, \qquad \Lambda^0{}_0 \geq +1.$$ How to prove ...
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Time Contraction

This is my first time posting on this site. I am a computer programmer that stumbled across a physics text book and have a question on special relativity. So firstly, I understand that there is no ...
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Electrons faster than speed of light

While looking at some exercises in my physics textbook, I came across the following problem which I thought was quite interesting: It is possible for the electron beam in a television picture tube ...
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The equivalent electric field of a magnetic field

I know that Lorentz force for a charge $q$, with velocity $\vec{v}$ in magnetic field $\vec{B}$ is given by $$\vec{F} =q \vec{v} \times \vec{B}$$ but there will exist a frame of reference where ...
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How does light travel create time travel violating causality?

Saw a question about faster than light travel... I still have the same question though none of the answers offered any resolution for me. It is so summarily assumed by all physicists and commentaries ...
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Could we have assumed the speed of light to be different in different reference frames?

Ptolemy's model of universe assumes that our earth is the static center of universe and everything else move relative to it (ref: The grand design ch:3). This model would give us a consistent picture ...
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Derive $\frac{\mathrm{d}}{\mathrm{d}t}(\gamma m\mathbf{v}) = e\mathbf{E}$ from elementary principles?

It is experimentally known that the equation of motion for a charge $e$ moving in a static electric field $\mathbf{E}$ is given by: $$\frac{\mathrm{d}}{\mathrm{d}t} (\gamma m\mathbf{v}) = ...
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Noether's charge due to lorentz transformation [duplicate]

Possible Duplicate: What conservation law corresponds to Lorentz boosts? For a relativistic free particle, What is the Noether charge generated due to Lorentz transformations? What is ...
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Relativistic momentum

I have been trying to derive why relativistic momentum is defined as $p=\gamma mv$. I set up a collision between 2 same balls ($m_1 = m_2 = m$). Before the collision these two balls travel one ...
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Is there any law that prevents an object with mass to become massless?

I got into a discussion with my physics teacher about the speed of light and I asked What if an object with mass was to lose mass as it gained speed-- would that allow for an object to eventually ...
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Mass-Energy relation

Einstein mass- energy relation states $E=mc^2$. It means if energy of a paricle increases then mass also increases or vice-versa. My question is that what is the actual meaning of the statement ...
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When moving fast Time slows down Vs speeds up

I was watching an old cartoon movie where a scientist makes a gadget, which when bound on the wrist, freezes the movement of the whole world. So, that one may do 100s of things in a single second. ...
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Here's a way to transmit data faster than the speed of light [duplicate]

Possible Duplicate: Is it possible for information to be transmitted faster than light by using a rigid pole? Assume there is a long rod or a string connecting two points separated by a ...
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How realistic is the game “A slower speed of light”?

The game "A slower speed of light" from MIT claims to simulate effects of special relativity: Visual effects of special relativity gradually become apparent to the player, increasing the ...
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What else does the fabric of space-time do?

I know that, the fabric of space is bended so there is a path for another planet to follow to cause gravity I.E. the sun and the earth ( i think) Is htere any othe rthing's the fabric of space-time ...
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Special Relativity & Mirror Reflection

If you move at $5$ $ms^-$$^1$ towards a plane mirror, your reflection moves $10$ $ms^-$$^1$ towards you. But what happens if you're moving much faster, say $0.8c$? Would your reflection move at ...
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Minkowski diagram, hyperbola and invariant quantity of relativity

I have heard of the invariant quantity $\Delta s$ in relativity for which I have stumbled upon an equation $\Delta s^2 = \Delta x^2 - c \Delta t^2$. This reminds me of hyperbola, which has general ...
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Violation of Newton's 3rd law and momentum conservation

Why and when does newtons 3rd law violate in relativistic mechanics? Check this link http://www.animations.physics.unsw.edu.au/jw/Newton.htm.
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Airplane example of special relativity

I'm struggling with an introductory example of special relativity. We haven't done the math yet so I would like an explanation based only on the fact that the speed of light is the same in every ...
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Time dilation $t'=(1-\frac{v}{c})t$ instead of $t'=\frac{1}{\gamma} t$

Suppose we have a train moving. When the origin of train's frame coincides with the origin of observers frame; the the time is set to zero. At that very instant, a photon is emitted from train towards ...
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Testing covariance of an expression?

This is something I've been unsure of for a while but still don't quite get. How does one tell whether an expression (e.g. the Dirac equation) is covariant or not? I get it for a single tensor, but ...
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What is the length of 1 second in meters

If time is treated as a fourth dimension of spacetime, what is relation between length and time units? Or in other words, how can I convert time units to length units, for instance seconds to meters? ...
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“Relativistic Baseball”

On Randall Munroe’s new blog “what if”, he answers the question: “What would happen if you tried to hit a baseball pitched at 90% the speed of light?” http://what-if.xkcd.com/1/ He concludes: ...
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What do I see if I move quickly past a charge surrounded by iron filings?

This might be a straightforward exercise, in which case I apologize. Suppose I surround a charge by iron filings initially oriented in some fixed direction, and I then move past the charge at an ...
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Faster than light due to reference position [duplicate]

Possible Duplicate: Travelling faster than the speed of light Please try to follow and clarify me I've been curious about this for a long time as it seems a bit paradox due to the rule that ...
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What are the mechanics by which Time Dilation and Length Contraction occur?

What are the mechanics of time dilation and length contraction? Going beyond the mathematical equations involving light and the "speed limit of the universe", what is observed is merely a phenomenon ...
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The order of seeing event in different spacetimes

Assume this question: Three events A, B, C are seen by observer O to occur in the order ABC. Another observer O$^\prime$ sees the events to occur in the order CBA. Is it possible that a third ...
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Minkowski diagram and time dilation

After i figured out how to show length contraction in this topic. I tried to use a similar way to show time dilation in Minkowski diagram. Time dilation means that time interval between two events is ...
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Minkowski diagram and length contraction

The length contraction means that an object is the longest in the frame in which it is at rest. Lets assume i have a meter stick with length $\Delta x$ in my rest frame which is $x,ct$ and i want to ...
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Assuming collision , are there fundamental forces associated with absorbtion?

I just learned that strong and weak nuclear forces relate to decay/emission. I know absorbtion depends on Energy levels(QM) and heat(thermodynamics , kinetic energy , entropy) and E = gamma mc^2 ( ...
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Does infinite energy imply Infinite mass (and vice versa)?

If some kind of source was able to supply an infinite amount of energy, does that imply that it also must have an infinite mass? Is the contrary also true?
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Lorentz transformations for sine wave in random direction

Hello i have been struggling to derive Lorentz transformations for a sine wave, which is traveling at random direction. I started by prooving that phase $\phi$ is invariant for relativity and that ...
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Lorentz transformation matrix and its meaning in Minkowski diagram

I have sucessfully derived the Lorentz matrix for the boost in $x$ direction and its inverse. So I know how to get these two matrices: $$ \Lambda = \begin{bmatrix} \gamma & 0 & 0 & ...
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Is the Planck length Lorentz invariant?

The planck length is defined as $l_P = \sqrt{\frac{\hbar G}{c^3}}$. So it is a combination of the constants $c, h, G$ which I believe are all Lorentz invariants. So I think the Planck length should ...
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Time slowing down problem

When someone moves, time slows down for him. Let, a man standing still and another moving very very very fast, this happens for an hour (as measured by the standing man). Time has moved slower for the ...
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What should I call an n>4 dimensional Minkowski metric?

I am manipulating an $nxn$ metric where $n$ is often $> 4$, depending on the model. The $00$ component is always tau*constant, as in the Minkowski metric, but the signs on all components might be ...
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Velocity of electron in electrostatic field. Does radiation matter?

There's a voltage difference of 1000 Volts between two points 2 meters apart. An electron starts at the point of lower potential and is left to travel alone in a straight line until it reaches the ...
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What are relativistic and radiative effects (in quantum simulation)?

I'm reading about Quantum Monte Carlo, and I see that some people are trying to calculate hydrogen and helium energies as accurately as possible. QMC with Green's function or Diffusion QMC seem to be ...
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Definitions: 'locality' vs 'causality'

I'm having trouble unambiguously interpreting many answers here due to the fact that the terms locality and causality are sometimes used interchangeably, while other times seem to mean very different ...
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Is the potential energy in a compressed spring a Lorentz invariant?

The total energy of an object comes from the time part of the four-momentum, and so isn't a Lorentz invariant. On the other hand, is the potential energy of a compressed spring a Lorentz invariant?
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Why Lorentz Transformation in Special Relativity has to be like this?

Basically I think Albert Einstein (A.E.) was trying to find a transformation that: Always transform a constant-velocity movement into a constant-velocity movement. Always transform a ...
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A clock devoid of motion

My understanding is that every clock mechanism we have depends on motion of something w.r.t the observer. From atomic transitions to clockwork gears. So, does this property/constraint makes every ...
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What are $\partial_t$ and $\partial^\mu$?

I'm reading the Wikipedia page for the Dirac equation: $\rho=\phi^*\phi\,$ ...... $J = -\frac{i\hbar}{2m}(\phi^*\nabla\phi - \phi\nabla\phi^*)$ with the conservation of probability ...
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Resolution of twin paradox using Lorentz velocity addition

In the following lecture, starting at minute 29:00 and going further, the professor resolves the Twin Paradox using Lorentz velocity addition. I have a question about this: Isn't the figure given ...
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Explanation of equation that shows a failed approach to relativize Schrodinger equation

I'm reading the Wikipedia page for the Dirac equation: $\rho=\phi^*\phi\,$ ...... $J = -\frac{i\hbar}{2m}(\phi^*\nabla\phi - \phi\nabla\phi^*)$ with the conservation of probability ...
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Rotating hoop in Relativity

What does a rotating hoop, with each point moving at a velocity close to the speed of light, appear like with respect from a stationary observers perspective. For example how does the shape of the ...
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Why Negative Energy States are Bad

The argument is often given that the early attempts of constructing a relativistic theory of quantum mechanics must not have gotten everything right because they led to the necessity of negative ...
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The necessity of the B field

It is fairly easy using basic special relativity to arrive at the conclusion that the magnetic force effect on nearby charges of wires carrying currents on nearby charges is only due to the length ...