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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14 views
What's wrong with this application of Thomas Precession to circular motion velocity measurements?
If you happen to have the Third Edition of Classical Electrodynamics by John David Jackson, turn to section 11.8, as that's where I'm getting all this from. If not, you should still be able to follow ...
5
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0answers
58 views
Why do we identify symmetric 2nd rank tensors with spin-2 particles in string theory?
I am going through Tong's lecture notes on String Theory and came across the following irrep decomposition (Chap 2, p.43) of the bosonic string first excited states:
$$\text{traceless symmetric} ...
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3answers
91 views
Violation of Newton's 3rd law
I'm just expressing my guess.
Let two particles A and B experiences forces $F_1$ and -$F_2$ between them and let guess also there are two observer, one is stationary and other is moving with ...
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1answer
39 views
Relativistic Lagrangian transformations
I need to study the relativistic lagrangian of a free particle.
It's
$\ L= - m c^2 \sqrt[2]{1- \frac{|u|^2}{c^2}} $ I need to study the translation, boost and rotation symmetry. I say it doesn't ...
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1answer
91 views
can be exist the negative mass? [duplicate]
I'm not sure about this but I guess there must be negative masses in the universe because of the symmetry. If the gravity is one of the main forces in nature it must has negatives mass to be able to ...
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3answers
166 views
Energy conserved… or not? Confused!
I am confused. Could someone kindly explain what's going on in this question?
A particle of mass $m$ and charge $e$ moves in the $x,y-$ plane. There is a constant magnetic field $B$ that points in ...
2
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1answer
102 views
How Special Relativity causes magnetism
So my physics teacher assigned us an article about how special relativity causes magnetism in a wire with a current, even with the low drift velocities of electrons in a current.
It seemed that the ...
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0answers
57 views
Relativistic canonical transformation
What is relativistic canonical transformation? I need every piece of information about it.
Does anyone know a reference or an article about relativistic canonical transformation?
For example, in ...
2
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2answers
82 views
Does inertia increase with speed?
I have heard that when the speed of the object increase, the mass of the object also increase. (Why does an object with higher speed gain more (relativistic) mass?)
So inertia which is related to ...
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1answer
26 views
Viewing a reference frame from inside of it?
Can one observe one's own frame of reference without moving out side the frame?
For example, if you are on a train and you throw ball in the air up and down.
When you are on the train (frame 1) you ...
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0answers
35 views
Basic question concerning pure energy and neutrinos [closed]
is the idea of making neutrinos autodisintegrate there self into there basic form which is pure enrgy posibel to ubtain to increase energy in other particles or atoms increasing there sise
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0answers
50 views
Why does an object with higher velocity gain more mass? [closed]
if we inject pure energy into a object capable of moving will it affect the structure of its atoms creating bigger neutrons, electrons and protons making the object increase its size affecting its ...
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2answers
83 views
Einsteins train though experiment. What if the train is moving at the speed of light? (layman Q) [closed]
I understand einstein's train paradox. Where one man on a platform is passed by a man in a traincar, at the moment they meet a flash of light is given off in the middle of the train car. To the man on ...
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1answer
46 views
Speed of Light and Information
Einstein in his thought experiment(?) for the constancy of speed of light in vacuum in all frames reasoned , that if speed of light of vacuum isn't constant than you'll be able to perceive effect ...
0
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1answer
96 views
Neutrinos and Speed of light
Einstein's Special Theory of relativity postulates that the speed of light is same for all frames.
Suppose a neutrino is there moving at the speed of light. Then will that neutrino also be flowing ...
2
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0answers
50 views
How to keep the clock of a spaceship synchronised to the clock of an observer? [duplicate]
I read that the clocks of GPS satellites seem to run slower than the clock of stationary observer, because of their speed (special relativity) and seem to run faster than the clock of stationary ...
6
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3answers
213 views
Why is the Dirac equation not used for calculations?
From what I understand the Dirac equation is supposed to be an improvement on the Schrödinger equation in that it is consistent with relativity theory. Yet all methods I have encountered for doing ...
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1answer
77 views
The definition of Lorentz transformation
I know that the Lorentz transformation, when two frames $\mathcal{S}$ and $\mathcal{S}'$ are in standard configuration (the axes are all parallel to their counterparts in the other inertial frame) is ...
0
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3answers
78 views
Mass in special relativity
I have just got a query about how this equation works if its right.
We have Newtonian Physics saying $F=ma$,
According to the 'Mass in special relativity' the mass changes according to
$$m= ...
13
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1answer
148 views
Is period of rotation relative?
My question is inspired by the following answer by voix to another problem:
"There is a real object with relativistic speed of surface - millisecond pulsar. The swiftest spinning pulsar currently ...
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2answers
112 views
Doubts concerning Wigner's classification
Wigner classified particles in function of the eigenvalues of $P_\mu P^\mu$ and $W_\mu W^\mu$. Then, it can be proved that for massless particles spin values can be only $\pm s_{max}$. But for a ...
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1answer
81 views
Why is this thought experiment flawed: A vast lever rotating faster than the speed of light [duplicate]
If there were a vast lever floating in free space, a rigid body with length greater than the width of a galaxy, made of a hypothetical material that could endure unlimited internal stress, and this ...
1
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1answer
115 views
Why does Lorentz factor not hold for relativistic mass when we apply it to photons? [duplicate]
We know that the photon itself is massless particle $m_0=0$. But we also know, that the mass of the objects does increase with their energy. And we know that under certain circumstances (gravity, ...
10
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2answers
282 views
Does relativistic mass have weight?
If an object was sliding on an infinitely long friction-less floor on Earth with relativistic speeds (ignoring air resistance), would it exert more vertical weight force on the floor than when it's at ...
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2answers
59 views
Limit on velocity in Minkowski Spacetime geometry
Let A be a rocket moving with velocity v.
Then the slope of its worldline in a spacetime diagram is given by c/v.
Since it is a slope, c/v = tan(theta) for some theta > 45 and theta < 90.
Does ...
1
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0answers
43 views
Solving the equation of relativistic motion
How does one solve the tensor differential equation for the relativistic motion of a partilcle of charge $e$ and mass $m$, with 4-momentum $p^a$ and electromagnetic field tensor $F_{ab}$ of a constant ...
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3answers
178 views
There must be free positive charges, moving oppositely to electrons for the wire with current to stay neutral
All popular expositions (e.g. these ones) of relativistic electromagnetism claim univocally that electrons in motion become more dense due to the speed. They teach that Lorentz contraction of charges ...
4
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1answer
99 views
How to understand the emergent special relativity in the superfluid?
The superfluid vacuum theory was proposed to understand some features of the vacuum (aether) from the emergence point of view. Although made up of non-relativistic atoms, the low-energy excitations of ...
7
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3answers
115 views
Do velocity and acceleration time dilation factors add?
For a spinning space station such as in 2001, A Space Odyssey, what would be the time slowing in the perimeter of the spinning space station with respect to the center axis of the station?
The ...
6
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0answers
87 views
Status of experimental searches for tachyons?
Now that the dust has settled on the 2011 superluminal neutrino debacle at OPERA, I'm interested in understanding the current status of experimental searches for neutrinos. Although the OPERA claim ...
4
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3answers
91 views
Bound State of Only Massless Particles? Follows a Time-Like Trajectory?
Is there any way in which a bound state could consist only of massless particles? If yes, would this "atom" of massless particles travel on a light-like trajectory, or would the interaction energy ...
3
votes
3answers
100 views
Reaching the speed of light via quantum mechanical uncertainty?
Suppose you accelerate a body to very near the speed of light $c$ where $v = c - \epsilon$. Although this would take an enormous energy, is it possible the last arbitrarily small velocity needed -- ...
0
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1answer
58 views
Einstein’s Thought Experiment of a Stationary Box and a Photon
1) First of all, let us consider a particle of light, also known as a photon. One of the interesting properties of photons is that they have momentum and yet have no mass. This was established in ...
8
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3answers
85 views
How do we measure the range of distant objects despite relativistic effects?
When we observe astronomical objects like distant galaxies there are several complicating factors for estimating the distance:
Relativistic speed result in length contraction
Relativistic speed ...
3
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2answers
87 views
Are gravitational time dilation and the time dilation in special relativity independent?
There are two kinds of time dilation:
One because the other clock moves fast relative to me (special relativity).
Another one because the other clock is in a stronger gravitational field (general ...
4
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2answers
165 views
What is the Andromeda Paradox?
I have been studying causality (specifically why there is no such thing as a simultaneous instant of time across all observers) recently and I keep hearing references to the Andromeda paradox. Can ...
2
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4answers
256 views
Relativistic origin of magnetic field
There is an explanation in the Wikipedia. Unfortunately the article is quite verbose and doesn't clearly explain why both positive and negative charges vary density even if only one is moving.
It is ...
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2answers
143 views
Relativistic charge density contraction in a closed loop
I have heard that magnetism is a relativistic effect of electricity. The law says that charge is conserved, only distances are shrunk. So, I cannot add more charge to increase density. When we have an ...
2
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1answer
95 views
What is Relativistic Navier-Stokes Equation Through Einstein Notation?
Navier-Stokes equation is non-relativistic, what is relativistic Navier-Stokes equation through Einstein notation?
2
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1answer
55 views
Relativistic Computation?
Is it possible to employ relativity to develop computational technology?
Here is a really basic example:
Build a Computer and Feed it the Problem (say the problem is projected to take 10 years to ...
4
votes
1answer
47 views
Live feed from a Rocket traveling near the speed of light?
Okay, odd question popped up in my physics class today. If a rocket ship is traveling at .99c for 1 year, and is streaming a video at 30 frames/sec to earth, how would the earth feed be affected? ...
1
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2answers
140 views
Doppler shift of radio signals to an accelerating observer
Suppose a man leaves from Earth to a star which is 1000 light years away. He accelerates to a velocity such that the entire trip lasts a year, from the reference frame of the rocket.
Now lets pretend ...
0
votes
3answers
106 views
Stuff can't go at the speed of light - in relation to what? [duplicate]
We all know that stuff can't go faster than the speed of light - it's length becomes negative and all kinds of weird stuff happens.
However, this is in relation to what? If two objects, each moving ...
1
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4answers
174 views
What is the exact mechanism by which time dilates?
What is the exact mechanism by which time dilates for a fast moving object?
Can the time dilation be explained by any theory other than relativity?
3
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1answer
58 views
Rate of spontaneous tachyon emission
It's not possible for an electron to emit or absorb a photon without the presence of a third particle such as an atomic nucleus; without the third particle, it's impossible for such a process to ...
2
votes
1answer
60 views
Faraday tensor, antisymmetric electromagnetic tensor
I want to write $F^{\mu \nu}F_{\mu \nu}$ in terms of $F_{\mu \nu}F^{\mu \nu}$. How to do it?
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1answer
46 views
Organic Proliferation In Terms of Speed [closed]
OK for 5 stars...Dealing with Einsteins theory of special relativity:
Here is the question:
As observed on earth, a certain type of bacterium is known to double in number every 24.0 hours. Two ...
7
votes
1answer
110 views
Cancelling special & general relativistic effects
We know that for a GPS we need to make a correction for both general and special relativity: general relativity predicts that clocks go slower in a higher gravitational field (the clock aboard a GPS ...
2
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2answers
80 views
Faraday tensor, antisymmetric rank two
$F^{\mu \mathcal{V}}$ is defined in
http://www.lecture-notes.co.uk/susskind/special-relativity/lecture-7/relativistic-lorentz-force/
How to show that $F^{\mu \mathcal{V}}$$F_{\mu \mathcal{V}}$, is ...
1
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2answers
81 views
What is the process that gives mass to free relativitic particles?
When a free particle move in space with a known momentum and energy then what is the physical process that gives mass to that free (relativistic) particle?
What is role does the Higgs field in that ...
