Do electrons accelerating in the presence of a gravitational field radiate due to this acceleration?
30919
A charged particle undergoing an acceleration radiates photons.  Let's consider a charge in a freely falling frame of reference.  In such a frame, the local gravitational field is necessarily zero, and the particle does not accelerate or experience any force. Thus, this charge is free in such a frame. But, a free charge does not emit any photons. There seems to be a paradox. Does a freely falling charge in a gravitational field radiate?
60994
Let's consider it case by case:  Case 1: Charged particle is at rest. It has an electric field around it. No problem. That is its property.  Case 2: Charged particle started moving (it's accelerating). We were told that it starts radiating EM radiation. Why? What happened to it? What made it do this?  Follow up question: Suppose a charged particle is placed in uniform electric field. It accelerates because of electric force it experiences. Then work done by the electric field should not be equal to change in its kinetic energy, right? It should be equal to change in K.E + energy it has radiated in the form of EM Waves. But then, why don't we take energy radiated into consideration when solving problems? (I'm tutoring grade 12 students. I never encountered a problem in which energy radiated is considered.)
113510
Can a free electron with a constant velocity V то move eternally at this rate in the inertial frame? The question arises from the fact that a moving charge creates near its trajectory varying electric and magnetic fields. Whether kinetic energy of electron is spent for it?
85464
I have read that "thanks to conservation of momentum" there is no dipole gravitational radiation. I am confused about this, since I cannot see the difference with e.m. radiation. Is this due to the non-existence of positive and negative gravi-charges? Is this due to the non-linearity of Einstein equations? How the conservation of momentum enters here?  An example of my confusion below  Q: Why I cannot shake a single mass producing dipole gravi-radiation? A: You need another mass to shake it. Q: Isn't it the same with electromagnetism?
33849
I was under the impression that the $1/r^2$ falloff of various forces were because of the way the area of a expanding sphere scales. But that strict $1/r^2$ falloff would only be globally true in a strictly Euclidean geometry, yes? So, if you had an electron and a positron in a warped space due to gravity, wouldn't that $1/r^2$ term in Coulomb's Law end up needing to be adjusted because of the warping of space leading to an increase or decrease in effect due to gravitational lensing or scattering?  I found one related question here:  But it only has one down-voted and unclear answer.
46500
For example an electron radiates when accelerated. So does a positron. But is the radiation emitted by accelerated positronium the sum of the radiation emitted by each separately? If not, why not? If so, does this provide a way of testing whether a given neutral particle is composite? For example, does a neutron bremsstrahlung when decelerated?
14494
Consider the electric field surrounding an electron. The electron moves. A wave propagates at $c$ reflecting the electron's movement. This is an electromagnetic wave. Consider a mass. Classically surrounded by a gravitational field. The mass moves. The field deforms and it propagates at $c$.    Is this not a gravitational wave?  Why do people talk as if only general relativity predicted gravitational waves?
106346
If it is true that an electron can be anywhere in the cosmos at any given time, then is it even theoretically possible that there is only one electron, instead of multiple electrons in the cosmos? If it isn't, I'd appreciate it if someone could point out where I may have misunderstood something as far as the fundamental properties of electrons are concerned.
53458
I understand that electromagnetic fields carry energy, and this energy curves spacetime gravitationally.  That's not my question.  I'm asking if anyone has tried to formulate electromagnetism in such a way that EM charges impart an EM geometry onto spacetime that is only experienced by EM charges.  That is, the EM geometry of spacetime would be a function of charges such that charges themselves produce EM curvature and the motion of charges produces EM torsion, and that charged objects move according to how their charge (electrical or magnetic, positive (N) or negative (S)) experiences that geometry.  For example, a positive electric charge would appear as a "hill" to other pe charges, a "valley" to ne charges, and either a left or a right hand "whirpool" to either nm or sm charges (I'm not immediately sure which would match with which) if it had some velocity.  This formulation would be directly analogous to how energy creates gravitational curvature in spacetime (and if one accepts Einstein-Cartan, gravitational torsion comes from intrinsic angular momentum), and then this resulting geometry is experienced by the energy in that region.  If Einstein is correct about gravity, would it be too much of a stretch to suppose separate metric functions for each of the fundamental forces, considering that they were a single force moments after the big bang?  I'm not currently concerned with the quantum mechanical approach to electromagnetism.  I understand that to be truly fundamental, EM has to be formulated quantum mechanically, but right now I want to limit my question to macroscopic charged objects.
37332
I have read this question:     where Safesphere says in a comment:     Actually, photons themselves don't bend spacetime. Intuitively, this is because photons can't emit gravitons, because, as any massless particles not experiencing time, photons can't decay by emitting anything. The latest theoretical results show that the gravitational field of a photon is not static, but a gravitational wave emanating from the events of the emission and absorption of the photon. Thus the spacetime is bent by the charged particles emitting or absorbing photons, but not by the photons themselves.        where John Rennie says:     as far as I know there has been no experimental evidence that light curves spacetime. We know that if GR is correct it must do, and all the experiments we've done have (so far) confirmed the predictions made by GR, so it seems very likely that light does indeed curve spacetime.   Now this cannot be right. One of them says photons do bend spacetime, since they do have stress-energy, but it is hard to measure it since the energy they carry is little compared to astronomical body's stress-energy. So they do bend spacetime, it is just that it is hard to measure it with our currently available devices.  Now the other one says that photons do not bend spacetime at all. It is only the emitting charge (fermion) that bends spacetime.  Which one is right? Do photons bend spacetime themselves because they do have stress-energy or do they not?
72792
I am sure there is a simple explanation for my confusion, but I am a little puzzled:  We are dealing with two parallel electron cannons that each produces a straight beam of electrons. They are placed at a distance d next to each other, which means there will be a repulsive electrostatic force between the electrons of the two beams. Also, according to the Maxwell equations, every moving electron will produce a magnetic field which then exerts another force on the other beam's moving electrons (similar to the effect that two currents in wires will cause an attractive force between the wires).   However, if we change the reference frame such that we are moving at the same speed alongside the electrons, there will be no magnetic field and no Lorentz Force. We are only left with the electrostatic force.  Do you guys know what might be the fallacy?
105813
So in my textbook, it states that the $E=hf$ equation applies to electrons, and all particles, not just photons.   But in order to prove this, wouldn't these particles need to have zero mass, to satisfy $E=pc$ from Einstein's equation?  In Einstein's theory of relativity $E^2= p^2c^2 + m^2c^4$, we get $E=pc$ because we consider the mass to be zero.   For $E=hf$ to work for other particles, don't we need to assume electrons have zero rest mass?
2304
Gravity causes anything with energy to accelerate toward the source. Black holes, for example, have such strong gravity that they pull in light and don't let any escape. But can acceleration still apply to light? The speed of light is constant, of course, but why are photons affected by gravity yet aren't accelerated by it?  Edit: My main question is why photons aren't affected in the same way as most other particles. I'm perfectly aware that it cannot surpass lightspeed, but I want to know what makes it unaffected by acceleration while other particles are affected.
52898
I have read about an electron making a transition between two energy levels and electromagnatic radiation will be emitted. The problem is how and why e.m radiation is emitted.
39227
For a given black body radiation curve, would the changes to the spectrum resulting from cosmological expansion and those from Doppler effects be distinguishable on the basis of the shapes of the resulting curves alone? Or, put another way, starting from the same spectrum, can both processes produce the same observation (for suitably chosen magnitudes of expansion or velocity)?
106288
We know how to define the , as answered in this question. After watching the Sixty Symbols video about , where the temperature and resulting black body radiation is a crucial element, I wondered how objects made (almost) entirely of neutral particles can radiate electromagnetic waves, since radiation is caused by acceleration of charged particles (at least in classical physics). I can imagine a few possible answers, but I would like the expert's statement:  Neutrons can be excited and radiate when relaxing Neutron stars aren't entirely neutral. The tiny fraction of protons and electrons radiate Neutrons are made up of charged quarks, and the quarks radiate  I believe this question is different from &quot;Are neutron stars transparent&quot; because I'm asking about the generation of black body radiation, not the lack of absorption of any radiation.
52096
In Synchrotrons I think they use microwaves to accelerate the electrons bundles that fly through-how does putting a microwave through a cavity accelerate an electron? I know that the Electric and Magnetic fields could and do have an effect on the electron, but if the radiation is moving parallel to the electron, wouldn't the force be perpendicular? Also, how exactly does the microwave radiation look in the vacuum chamber? Are the two ends constant nodes?