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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On Einstein's original paper: speed of light in different reference frames

On Einstein original paper "On the electrodynamics of moving bodies", on section 2 of the first part (Kinematics), the following thought experiment is described: a rod is imparted constant speed $v$ ...
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Exactly how is the constant measured velocity of light deduced from Maxwell's equation?

For electromagnetic radiation the velocity of propagation is $c = 1/\sqrt{\mu_0 \epsilon_0}$. Since both $\mu_0$ and $\epsilon_0$ do not vary in any inertial frame, then $c$ must be constant in any ...
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Knowledge needed to study and understand general and special relativity theory [duplicate]

Possible Duplicate: What are the prerequisites to studying general relativity? I'am 27 now and i have a burning desire to study math and physics from the ground up and I strongly prefer ...
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High speed and low speed photons

Looking at the discovery of the neutron, and I came across this page: http://www-outreach.phy.cam.ac.uk/camphy/neutron/neutron3_1.htm The animation on the left, talks about low energy photons and ...
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Help Me Gain an Intuitive Understanding of Lorentz Contraction

I'm having a hard time getting an intuitive understanding of Lorentz Contraction. I understand what it is by definition but I don't 'get it.' I'm not a physicist, just an amateur, so sorry if this ...
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Does a photon see a 0-D universe?

For a massless particle the spacetime interval between its point of emission and point of absorption is zero: the two points coincide. From the vantage point of such a particle space-time has reduced ...
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Reflection At Speed of Light

I have looked online to no avail. There is two competing answers and I am curious to know which one is right. Someone asked me this question. If you are traveling at the speed of light can you see ...
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How to measure faster than light electric energy?

According to relativity,nothing can break light barrier.But a recent preprint shows energy transmission of commercial electric power (f=60Hz) is faster than light. (It is not the drift velocity of ...
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Pair production kinematics

In the process $A\rightarrow B+C$ If we know the energy and momentum four vectors of B and C, then how can we find the momentum three vector of A. The particular proces I have in mind is pair ...
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a priori validity of $W=\int Fdx$ in relativity?

There are lots of different ways of arriving at the relativistic relations involving mass, energy, and momentum such as $E=mc^2$ and $m^2=E^2-p^2$ (the latter with $c=1$). One that I've seen in some ...
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Transformation of angles in special relativity

My question is about the problem below Depicted are two space ships (the USS Voyager and the USS Enterprise), each with velocity $v=c/2$ relative to the space station (Babylon 5). At the exact ...
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How does (or can) SR/GR extend to phase space or symplectic manifolds?

I'm asking this question because of an article in New Scientist about a recent preprint by a group including Lee Smolin. I haven't taken the time to comprehend the paper completely. My knowledge of ...
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Must the action be a Lorentz scalar?

Page 580, Chapter 12 in Jackson's 3rd edition text carries the statement: From the first postulate of special relativity the action integral must be a Lorentz scalar because the equations of ...
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Why is time special?

In Special Relativity, the spacetime interval between two events is $s^2 = -(c{\Delta}t)^2+({\Delta}x)^2+({\Delta}y)^2+({\Delta}z)^2$ giving the Minkowski metric $\eta_{\mu\nu}=\text{diag}(-1, 1, 1, ...
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If you make a steel rod from here to Alpha Centauri and move it, will the movement appear there instantly? [duplicate]

Possible Duplicate: Is it possible for information to be transmitted faster than light? imagine this theoretical situation: You have make an extremely long piece of steel (or anything ...
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Does superluminal travel imply travelling back in time?

Is this statement true? You can not travel back in time. If I travel fast enough the clock will start to go backwards, but that does not mean I am traveling back in time. It would only mean that ...
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What exactly is the definition of motion and its relation to Mach's conjecture?

The notion of "movement" seems to be well understood in physics. In fact, I don't recall any physics text-book defining motion. Special relativity theory says that there is no absolute frame of ...
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Deriving the Lorentz Transformation

I have been trying to understand a more or less geometric derivation of the Lorentz transformation, and I'm getting stuck at one spot. The wikipedia article for the Lorentz transformation for frames ...
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Proving that interval preserving transformations are linear

In almost all proofs I've seen of the Lorentz transformations one starts on the assumption that the required transformations are linear. I'm wondering if there is a way to prove the linearity: Prove ...
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The relativity of simultaneity

In his popular book on relativity, in chapter IX, "The relativity of simultaneity", Einstein describes an experiment in which a flash happens simultaneously on A and B, as defined by the fact that an ...
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What conservation law corresponds to Lorentz boosts?

Noether's Theorem is used to related the invariance under certain continuous transformations to conserved currents. A common example is that translations in spacetime correspond to the conservation of ...
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Essential background for QFT study

The preface to Mark Srednicki's "Quantum Field Theory" says that to be prepared for the book, one must recognize and understand the following equations: $$\frac{d\sigma}{d\Omega} = ...
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Does decoherence single out a preferred frame?

Environmentally induced decoherence makes wave function collapse unnecessary. But the environment, usually taken to be some heat bath, introduces a preferred frame. (That in which the total (spatial) ...
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Einstein's postulates <==> Minkowski space. In layman's terms [duplicate]

Possible Duplicate: Einstein's postulates <==> Minkowski space. (In layman's terms) In the spirit of Einstein's arguments using flashes of light, moving trains and mirrors; ...
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Einstein's postulates $\leftrightarrow$ Minkowski space for a Layman

What's the cleanest/quickest way to go between Einstein's postulates [1] of Relativity: Physical laws are the same in all inertial reference frames. Constant speed of light: "... light is always ...
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Relativity in Real Life

I have no formal training at all in relativity. But I was just wondering if our perception of time is altered by different events. Here are some examples I had in mind: If I touch a stove for 10 ...
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Ion Drive Propulsion Top Speed

I would like to know if there is some formula / graph which would provide / show the efficiency of a certain type of propeller in space. Specifically, I'm interested in the acceleration attainable at ...
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Is there a relativistic generalization of the Maxwell-Boltzmann velocity distribution?

The Maxwell-Boltzmann velocity distribution in 3D space is $$ f(v)dv = 4\pi \left(\frac{m}{2\pi k_B T}\right)^{3/2} v^2 \exp\left(-\frac{m v^2}{2k_B T}\right)dv$$ It gives the probability for a ...
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Poincare group vs Galilean group

One can define the Poincare group as the group of isometries of the Minkowski space. Is its Lie algebra given either by the equations 2.4.12 to 2.4.14 (..as also given in this page - ...
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Rotations in space-time

In Landau's Classical Theory of Fields, one finds the statement: Every rotation in the four-dimensional space can be resolved into six rotations, in the planes $xy,zy,xz,tx,ty,tz$ (just as every ...
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Commutation of operators in quantum theory

I have always written the commutation rules of quantum theory as , $[q,p] = i\hbar\delta _{ij}$ But seems that some people write this as, $[q^i,v_j]= \frac{i\hbar}{M}\delta^i _{j}$ (..this is ...
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Time in special relativity and quantum mechanics

The time is treated differently in special relativity and quantum mechanics. What is the exact difference and why relativistic quantum mechanics (Dirac equation etc.) works?
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whats the rate of energy increase required for constant acceleration between 0.0c and 0.99c?

I was wondering how much energy would be required to accelerate 1000kg to 0.99c at 1G. What I don't understand is what the rate of increase of energy is required as velocity increases. I was looking ...
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Non-interchangeability of time-like intervals

I am reading Landau's Volume 2 of the course of theoretical physics. I have a doubt after reading the first few pages of it which I explain below. Landau first defines intervals and on pages 5 and 6 ...
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Why is pseudorapidity defined as $-\log \tan \theta/2$

Why the log? Is it there to make the growth of the function slower? As this is a common experimental observable, it doesn't seem reasonable to take the range from $[0,\infty)$ to $(-\infty,\infty)$ ...
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What does a frame of reference mean in terms of manifolds?

Because of my mathematical background, I've been finding it hard to relate the physics-talk I've been reading, with mathematical objects. In (say special) relativity, we have a Lorentzian manifold, ...
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Speed of light, observed speed while travelling at the speed of light

I was watching Discovery channel the other night, they were telling that time slows down when you travel at a higher speed. This means there is a difference between the actual speed you travel at, and ...
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Show that the electric field E in the system at rest is $E=\frac{Q}{4 \pi \epsilon_0 \sqrt{(x^2+y^2+z^2)^3}} (x,y,z)$ [closed]

A body point charge $Q$ moves in relation to the reference system $\Sigma$ according to the law of motion $x(t)=v_0 t$, $y(t)=0$, $z(t)=0$.
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Where does the minus sign appear from in the metric tensor?

Trying to understand Schutz's AFCIGR, where does the minus sign appear from in the metric tensor? I understand that this expresses the invariance of the spacetime interval. Schutz says (I think) ...
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Double light speed

Let's say we have $2$ participles facing each other and traveling at speed of light Let's say I'm sitting on #$1$ participle so in my point of view #$2$ participle's speed is $c+c=2c$, double light ...
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Tachyon and Photons

Is there a particle called "tachyons" that can travel faster than light? If so, would Einstein's relativity be wrong? According to Einstein no particle can travel faster than light.
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How is energy conserved when a moving charge has false ideas about positions of other charges

An electron is shot towards a target that is negatively charged. While the electron is traveling, the target makes an abrupt move towards the electron. While the information that the target moved is ...
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How large is the universe?

We know that the age of the universe (or, at least the time since the Big Bang) is roughly 13.75 billion years. I have heard that the size of the universe is much larger than what we can see, in other ...
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Difference between timelike and spacelike vectors

Other than one having a positive invariant scalar product and the other a negative one, what are the actual physical differences between these vectors?
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Misunderstanding of Special Relativity

Person A in reference frame A watches person B travel from Star 1 to Star 2 (a distance of d). Of course, from person B's reference frame, he is at rest and is watching Star 2 traveling to him. ...
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Calculating threshold energy of particle reactions

{..everything that follows is in the domain of relativistic kinematics..} Say a particle A collides with a particle B at rest and produces particles C and D. What exactly is the definition of ...
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Spontaneous breaking of Lorentz invariance

Is it possible to spontaneously break Lorentz invariance, i.e., have a Lagrangian that respects LI but a vacuum which does not? If it is possible, why isn't there even the slightest hint of the ...
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Why is travelling around the speed of light a problem?

I don't fully understand what would happen if we could travel at the speed of light. But I saw somewhere here that it would mean events happen out of order. But why is this a problem. It is said that ...
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Could a universe with only massless particles develop life/intelligence? [closed]

Is it impossible for a universe that only contains particles/fields with no rest mass to develop life/intelligence? Assume there is no mechanism to generate a rest mass (Higgs, symmetry breaking, ...
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Special Relativity and time [duplicate]

Possible Duplicate: Question about Time Dilation.. I have a question about special relativity which was bothering me for a while now. I know that as one approaches the speed of light, time ...