Questions tagged [special-relativity]

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

Filter by
Sorted by
Tagged with
1
vote
0answers
19 views

Is there a special relativity approximation of gravity?

The Newtonian approximation of gravity is $\frac{GmM}{r^2}$. General relativity is the accurate model of gravity. But does special relativity by itself provide any update to Newtonian gravity? I think ...
0
votes
2answers
21 views

What happens with the number of protons inside a wire in movement?

In Special Relativity we solve the problem of the moving wire with an electrical current saying the protons inside the wire have a higher density: hence the wire is not neutral anymore (and we ...
2
votes
4answers
107 views

Why is special relativity unable to describe gravity?

The equivalence principle states that there is no difference between an accelerated frame of reference and the acceleration from a gravitational field. Since special relativity is able to describe ...
2
votes
2answers
65 views

Doesn't relativistic mass increase mean increased energy released when matter is turned to energy?

If there were an interstellar spacecraft being propelled by gamma rays from electron/positron annihilation, they say it would get harder to keep accelerating it the closer it got to the speed of light ...
2
votes
0answers
37 views

Mass as a coupling and mass as a Casimir operator

In Poincare group, we consider mass as a Casimir of the group. Hence it is a constant in various frames (I do not mean old fashion Lorentz transformation). But, in the quantum field theory mass is the ...
-2
votes
4answers
113 views

I think it sounds dumb. Did special relativity already possess quantum field theory?

Because when we look at the way Dirac got his equation he factored out the energy momentum relation in special relativity effectively and at a certain point he noted that there was that the factoring ...
1
vote
1answer
59 views

Relativistic velocity addition - algebraic structure?

The relativistic velocity addition $\oplus$ for 3-velocities $\bf{u}$ can be constructed from Lorentz boosts $\Lambda$ acting on 4-velocities $u$ $$ u \to u^\prime = \Lambda(v) \, u \implies \bf{u}^\...
-7
votes
0answers
62 views

Why can't we go faster than light? Is this speculation physical or mathematical? [closed]

Good morning all, According to the equation of relativity for a macroscopic object to go at the speed of light it needs infinite energy $ E=\frac{mc ^ 2}{\sqrt{1-v ^ 2 / c ^ 2}} $ with E the energy ...
-1
votes
0answers
34 views

Is probability conserved in Dirac's original formulation of relativistic QM?

In non-relativistic quantum mechanics, the normal condition for position eigenstates is $$\langle y|x\rangle=\delta(y-x).$$ However, this condition is not Lorentz-invariant. I have never seen a ...
0
votes
0answers
7 views

Lunar Reconnaissance Observer 1-way data use

I'm performing a Relativity study on 1-way light transmission, and I'm trying to use NASA Lunar Reconnaissance Observer (LRO) mission data as in https://www.nasa.gov/mission_pages/LRO/main/index.html. ...
12
votes
3answers
832 views

How do Rindler coordinates fit into special relativity?

It is often said that special relativity doesn't handle acceleration since you general relativity for that. If I understand correctly this is incorrect just with some caveats. Rindler coordinates are ...
-4
votes
1answer
49 views

Particle moving almost at the speed of light

I have been wondering for a while. Is it possible that when a body or a particle moves close to the speed of light, it interacts more with the Higgs boson? If so does that explain why moving at the ...
-3
votes
0answers
33 views

Lorentz Transformation and metric in tensor notation [closed]

Show that $$ g_{\mu\rho}g^{\rho\nu} = \delta_\nu^\mu = \begin{cases} 1\ , & \text{when } \nu = \mu\\ 0\ , & \text{otherwise} \end{cases} $$ here the $g$ is metric.
0
votes
2answers
47 views

Would time dilation make it impossible to accurately convert between calendars across the galaxy?

A hypothetical signal is emitted from a known exoplanet thousands of light years away. The signal marks the occurrence of an epoch-worthy event on that planet, and we (the receivers) want to know ...
1
vote
1answer
19 views

Magnetic field in the moving inertial and noninertial reference frame

Is there any generic way to calculate magnetic field in the moving inertial and noninertial reference frame? For example, there is the Earth magnetic field, we can assume it is uniform permanent field....
0
votes
0answers
22 views

Four momentum product [closed]

Can you please help me to understand how to get $p_1 . p_2$? I could not understand what happen to $T^2$ or MT, ET terms in $p_1 . p_2$? Thanks in advance.
-1
votes
1answer
61 views

Longitudinal and transverse mass

Then, it was pointed out by Thomson and Searle that this electromagnetic mass also increases with velocity. This was further elaborated by Hendrik Lorentz (1899, 1904) in the framework of Lorentz ...
1
vote
1answer
22 views

Difference between relativistic and non-relativistic classical equations of electron

Both in classical (non-relativistic) electromagnetism and in relativity the equation of motion of an electron in electromagnetic field is $$ \frac{d\mathbb{p}}{dt}= e(\mathbb{E}+\frac{\mathbb{v}}{c}\...
3
votes
1answer
40 views

Collision of hypothetical Tachyon with normal particle?

If we are dealing in one dimension, what will happen if a hypothetical particle Tachyon (pure imaginary rest mass, $v>c$ and real momentum & total relativistic energy)? Will it interact with ...
0
votes
0answers
26 views

What are the Research Areas and Topics in Modern Physics for Bachelor's Students? [closed]

Research areas can be experimental, theoretical or computational using some software till now I know the basics of Matlab,Mathematica & Python.
1
vote
0answers
28 views

Energy and momentum conservation laws in special relativity

In special relativity the energy of a material point is defined $$E= \frac{m_0}{\sqrt{1-v^2/c^2}}c^2,$$ and the momentum is defined by $$\mathbb{p}= \frac{m_0}{\sqrt{1-v^2/c^2}}\mathbb{v},$$ where $\...
1
vote
0answers
27 views

Problem in solving a question related to Lorentz transformation [closed]

Let $(x, t)$ and $(x', t')$ be the coordinate system used by the observers $O$ and $O'$. Let O' move with velocity v=Bc along their common positive x axis. If X+=x+ct and X-=x-ct are the linear ...
1
vote
3answers
38 views

Pair production in vacuum

So , everywhere I have looked for pair production it is stated that it cannnot happen in vacuum . Most proofs I have seen for that , state that the conservation of energy and momentum cannot be true ...
0
votes
1answer
49 views

Ladder Paradox and Understanding Space-time Diagrams

With the given details, An observer $O$ at rest relative to the garage with measured length $L_g$= 6.10 m. The garage is equipped with doors that can open or close instantaneously at a chosen time. ...
-6
votes
0answers
65 views

Do coherent waves USE Time while decoherent/localized waves HAVE Time? [closed]

Could Time have States? Is there universal Time for coherent waves to use? When an object HAS Time, does it age? Don't physical objects require Time to exist? Is time swapping from being coherent, ...
0
votes
0answers
20 views

Change in area of a disk near black hole?

I know that the length contraction can be determined by the formula: $L\sqrt{1-\frac{2GM}{Rc^2}}$ But how can we calculate the decrement in area due to the black hole?? Suppose we have a disc of area ...
1
vote
0answers
39 views

Curvature of hypersurface in flat spacetime

Can we have a hypersurface in flat spacetime whose curvature is non zero? If yes, then what is the physical significance of that? I think there can be a hypersurface in flat spacetime with non zero ...
3
votes
0answers
82 views
+50

Expansion in flat spacetime

I have been studying Raychaudhuri equation and focusing theorem related to it. Focusing theorem says that if the strong energy condition is satisfied and rotation tensor vanishes $\omega_{ab}$=0 then ...
2
votes
2answers
91 views

Effect of velocity on gravitational force

If I am aboard a spacecraft and have with me two identical metal spheres having rest mass $= m$, what happens to the gravitational force between these two spheres as the space craft velocity ...
2
votes
2answers
109 views

Does an observer inside of an accelerated frame experience tidal force?

Thanks to Andrew Steane and Pulsar in this topic I understood that in a frame with constant proper acceleration, each hyperbola in $T-X$ diagram demonstrates a constant position while each line ...
1
vote
5answers
158 views

Hafele–Keating plane paradox

As many of you have probably known there was a famous Hafele–Keating experiment, which was about a plane traveling the globe in order to prove predictions of special relativity and general relativity. ...
0
votes
0answers
38 views

Help me select a thesis topic in high energy physics [closed]

i have come up on many topics which require high level of knowledge in physics to write thesis about. but since iam a masters student i want to write a dissertation on topic of high energy physics. i ...
0
votes
0answers
26 views

Infinite dimensional representation of generators of the Lorentz group

I was reading Schwichtenberg's "Physics from Symmetry 2nd Edition". In Section 3.7.11, there is the discussion on the infinite dimensional representations. If we consider a transformation of ...
1
vote
1answer
64 views

Explicit calculation, non-relativistic limit of $p^2-m^2$ in L. Ryder p.189

This could be related to this question or Eq. (18) p.12 but at the moment I am just very pragamatically in need of an basic explicit calculation to understand the paragraph between (6.36) and (6.37) p....
3
votes
1answer
55 views

Simultaneous Lorentz and Galilean invariance

The introduction of the Lorentz transformation is usually motivated by the Galilean failure when it comes to Maxwell's equations. Are there physical systems that exhibit both Lorentz and Galileo ...
0
votes
0answers
12 views

Threshold energy in relativistic collision: Frame choice matters for finding initial speed of proton? Conservation of energy alone doesn't work?

The situation is a proton colliding with a stationary proton with enough energy to create a pion. I know the typical way to do these problems is to use the center of mass frame, but I wanted to try it ...
-2
votes
0answers
16 views

If a clock is placed on the center of a rotating body and one in the surface will it any difference on time? [duplicate]

If we place a clock on the center of a rotating body and the other clock in the surface of the body, clearly the speed of serface clock is greater than the center clock but but the clock is static ...
1
vote
1answer
22 views

Is there a rotation of the polarization plane in rotating refractive media?

Since there is a transverse Fresnel–Fizeau effect according to Jones, R. V. (1972). "'Fresnel Aether Drag' in a Transversely Moving Medium". Proceedings of the Royal Society A. 328 (1574): ...
0
votes
0answers
44 views

Lorentz algebra structure in Hilbert space vs Vector space representation “must have the same commutation relations”

I'm following the Srednicki book, Ch. 2 The definitions are: Small Lorentz transformation on Minkowski space, so $S^{\mu \nu}$ forms the vector representation of the Lorentz group $$ \Lambda^\rho_{\;\;...
0
votes
1answer
64 views

Is there an analogue to 'length' in time, in SR?

It seems to me that the notion of 'length' (in 1 spatial dimension, I define the length of a body in a certain referential to be the maximal spatial gap of two of its points at the same time) has no ...
3
votes
0answers
64 views

Lorentz transformation of the Electromagnetic field

Consider an inertial system $\mathcal{O}$ and a Lorentz boosted system $\mathcal{O}'$, moving with a velocity $\vec{v}$ with respect to $\mathcal{O}$. Then we have expressions for the electromagnetic ...
0
votes
1answer
40 views

Lorentz transformation of a trajectory

I am having trouble understanding how to apply the Lorentz transformation to a particle trajectory. Suppose we have a body moving in one dimension in one frame where the position is given by $x(t) = f(...
-1
votes
3answers
102 views

How did scientists come to know what to do with $E=mc^2$? [closed]

When Albert Einstein proposed his famous equation $E=mc^2$ for rest mass he never said anything it's about about breaking the nucleus. Then how did scientists come to know what this mean? But again ...
-3
votes
0answers
31 views

Which expression for kinetic energy is correct in relativistic QM? [duplicate]

Usually the expression for Kinetic energy is taken as $$T = E-mc^2 = (1/\sqrt{1-v^2/c^2}-1)mc^2.$$ However, it can also be taken as $$T = (mv^2)/2*\sqrt{1-v^2/c^2}$$ which is half the potential ...
1
vote
0answers
31 views

Different versions of mass during early years of special relativity [migrated]

My question is basically about four different versions of mass from the early years of special relativity when the concept of relativistic mass was acceptable. I'd appreciate it if you try to keep ...
0
votes
0answers
62 views

Could a device witnessing the Free Will Theorem be handheld?

After watching Conway's lectures on free will, I realized that I wanted a device akin to a Magic 8-Ball®, but rather than being influenced by the cosmos, it would be free of surrounding influences. Is ...
-5
votes
1answer
74 views

Is the speed of light not infinite? [closed]

The speed of light C is equal to 299 792 458 m/s at this speed it would take me 3.03 minutes to get to mars at the closest orbit but if I was going the speed of light would I not be at mars instantly ^...
1
vote
1answer
88 views

Momentum in special relativity

I have been trying to understand absorption of a photon by a massive object, specifically the transfer of momentum and kinetic energy between the two. Starting from energy-momentum relation $E^2 = p^...
2
votes
4answers
109 views

Am I understanding the equivalence principle correctly?

So Einstein stated that gravity and acceleration are the same things in a local reference frame (please correct me if I misstated that). Here is what I think I understand and want you to verify if it ...
0
votes
0answers
21 views

Confused with proper times in accelerated system of reference

Im told in an exercise that Alice gets in a spaceship and from a the base's inertial reference frame her worldline is: $x^0 = ct$ and: $$x^1 = L \left(1-\cos\left(\frac{t}{T}\right)\right)$$ In the ...

1
2 3 4 5
188