What happens to electromagnetic field when crossing event horizon

What do you feel when crossing the event horizon?


How to prove the fact that ANY motion of body is superposition of translational and rotational motion of and about centre of mass respectively?

How is Chasles' Theorem, that any rigid displacement can be produced by translating along a line and then rotating about the same line, true?


Does the (relativistic) mass change? Why?


Einstein equation $E=mc^2$: Does it mean an object without mass does not have energy?


How is a pseudo-Euclidean metric superior to Minkowski's complex metric?

Minkowski's complex Euclidean space vs. the real pseudo-Euclidean version


How do the sides of a conical container supports the fluid it holds?

Does the weight of fluid in a conical container act entirely on the base?


How is the size of the particles is determined?


A question regarding specific heat capacity


What is the temperature of a single proton?

Can a single molecule have a temperature?


Was the singularity at Big Bang perfectly uniform and if so, why did the universe lose its uniformity?


Why aren't we more heavier at midnight than at noon on the earth's surface?

Are we slightly lighter during the day and slightly heavier at night, owing to the force of the Sun's gravity?


Why is the gravitational force always attractive?


Quantum mechanics and gender of unborn baby

Is my baby's gender an example of Schrodinger's cat?


Why does tension not do work in this spool reel problem?


How do I determine the energy of a wavefunction after computing a numerical solution?

Numerical solution to Schrödinger equation - eigenvalues


Will a pure rolling cylinder stop on a rough surface?


How much work can a force on a spring do? (Why are two methods wrong?)


Would time speed up on an object you're moving towards?

Would approaching a distant star at near the speed of light unfold its entire history in "fast-forward"?


What happens if you push a lot of (ideal) balls that are perfectly aligned?

Is it possible for information to be transmitted faster than light by using a rigid pole?


How are billion-year half-lives approximated?

How do we know that some radioactive materials have a half life of millions or even billions of years?


Calculating the drag force provided by a laminar flow

Terminal velocity of a steel ball in water


Does entanglement not immediately contradict the theory of special relativity?


Atoms In Space - More Specifically Helium


Are there any other pairs similar to virtual and normal photons?

What makes a Feynman diagram real or virtual?


How does gravitational time dilation work in artificial gravity made by rotating a cylinder?

Can a ultracentrifuge be used to test general relativity?


Why is there no change in speed of a charged particle in a uniform perpendicular magnetic field?

Is there an intuitive explanation for why Lorentz force is perpendicular to a particle's velocity and the magnetic field?


Gravity anomaly in Lacnov, Slovakia: Gravity ashamed


With respect to what does time itself change?

understanding time: Is time simply the rate change?


If I touch an object, am I touching the atoms on its surface?

What does it mean for two objects to "touch"?


What is the simplest possible experiment that proves that there are atoms?


Gravitational boson violating relativity


Can dark energy be converted into energy source?


Does laser beam expand along distance or not?


Why don't non-Hermitian operators with all real-eigenvalues correspond to observables?

Why do we use Hermitian operators in QM?


Are virtual exchange particles real or just mathematical?

Do virtual particles actually physically exist?


Why the moon doesn't fall down to earth?

How does Newtonian mechanics explain why orbiting objects do not fall to the object they are orbiting?


Why isn't energy stored in a capacitor equal to just $QV$ when it is fully charged?

Why does a $1/2$ appear in this simple capacitor equation?


If electromagnetic waves can be generated by oscillation of a coil why can't light?

Radio antenna producing waves in the visible spectrum


Are all forces explained in terms of curved spacetime?

Can all fundamental forces be fictitious forces?


Do particles in a black hole stay in constant orbit?

Why are orbits around black holes stable?


Why don't electromagnetic waves require a medium?


If nothing can escape a black hole, where does Hawking radiation come from?

From where (in space-time) does Hawking radiation originate?


Time it takes for a single unit of movement


Difference between $\Delta$, $d$ and $\delta$


Rotational/spin degrees of freedom for a monoatomic gas in free space

Why do we ignore rotational energy in monatomic gases?


Length of time interval for an atom in excited state to drop to lower energy level

How long does it take for an excited electron to return to ground state?


Stationary waves on a laminar liquid flow near collision with a surface


Math needed for undergrad Statistical Mechanics/Thermal Physics

How should a physics student study mathematics?


Is the Higgs particle the final one predicted by the Standard Model?


Is uncertainty principle a technical difficulty in measurement?

Is the uncertainty principle just saying something about what an observer can know or is it a fundamental property of nature?


Isn't the uncertainty principle just non-fundamental limitations in our current technology that could be removed in a more advanced civilization?


Why does separating plastic from a cough drop create flashes?


What distinguishes the particles we chose as matter from their antimatter equivalent?

Identification of particles and anti-particles


Could two different bases of a Hilbert space have different cardinality?

Hilbert space of a free particle: Countable or Uncountable?


Why not formulate Quantum Mechanics using Lagrangians?

Why not use the Lagrangian, instead of the Hamiltonian, in nonrelativistic QM?


Why do (most) metals cause problems in a microwave oven? Which metals (if any) don't?

Why do metal objects in microwaves spark?


Time dilation as an observer in special relativity


In an absence of gravity, does time flow faster or slower than on Earth?

How much faster would a Clock without gravity run?


Why can't the units of work and torque be interchanged?


What is the maximum possible frequency and wavelength?

What is the minimum wavelength of electromagnetic radiation?


Maxwell demon : how can the demon move the door without doing any work ?


Why does holding something up cost energy while no work is being done?


How did Newton find the relationship between force, mass and acceleration?


Is there a way I can prevent static electricty buildup from shocking me?

How to avoid getting shocked by static electricity?


About the geodesics in general relativity

Why do objects follow geodesics in spacetime?


What exactly means "is a singlet under $SU(N)$"

What does "the ${\bf N}$ of a group" mean?


What is the world's biggest Schrodinger cat?


Did physicists solve the grandfather paradox?

Is time travel possible? Is it possible to go back in time?


How do we know the Earth orbits around the Sun and not the other way around?

Why do we say that the Earth moves around the Sun?


Dependence of Force as a function of Distance?

Force inversely proportional to the squared distance


Why is Planck mass much larger than the smallest mass that we actually know about?

Planck mass is about the mass of one eyebrow hair


Why is the speed of light considered as a fundamental constant if its speed changes with medium resulting in refraction?

What do physicists mean when they say "speed of light"?


If I lift a box vertically, why is the work I do equal to the distance I lift it times the force of gravity on the box?

What exactly is $F$ in $W = \int_{a}^{b} F dx$?


Light clock with mirrors on a moving train

I am confused about the idea that the speed of light is independent of the speed of the source of light


Work done by kinetic friction on a block modelled as a system

What is the significance of the sign of work done? Does it affect internal energy also?


Why does the early universe look so big in a telescope?


What is the relationship between the absolute nature of the speed of light and the indeterminate nature of Heisenberg’s uncertainty principle?

Calculate the uncertainty in velocity of electron


Why specifically does FTL violate causality?

What are some scenarios where FTL information transfer would violate causality?


Rigorous underpinnings of infinitesimals in physics


Constancy of $c$ from Maxwell's Equations

Deriving the speed of the propagation of a change in the Electromagnetic Field from Maxwell's Equations


How does terminal velocity affect the weight of a closed system?


Is the curvature of spacetime in General Relativity instantaneous?


Does the cosmological constant represent anti-gravity?

Why does dark energy produce positive space-time curvature?


How nuking the poles of Mars would create an atmosphere?

Using nuclear devices to terraform Mars: Elon Musk's nuclear proposal?


How can an electron have angular momentum when it doesn't orbit the nucleus?

What's is the origin of Orbital Angular Momentum of electrons in atoms?


Deriving Euler-Lagrange for Electrodynamics Lagrangian

Derivation of Maxwell's equations from field tensor lagrangian


Energy Conservation during Constructive Interference


Why the outer shell in the cylindrical capacitor doesn't contribute to the field of the capacitor?

Electric Field from charged sphere within another charged sphere does not reinforce?


What is the frequency of the vertical and horizontal movement for small displacements?

Understanding transverse oscillation in 1 mass, 2 spring systems


"We certainly cannot have observers in the same reference frame disagree on whether clocks are synchronized or not"-is this true?

Can Special Relativity hold even without motion?


Want to prove a differentiation based formula for propagated uncertainty


Why is the power of $T$ to the fourth in Stefan's law? Any particular reason?

Intuitive reason for the $T^4$ term in Stefan Boltzmann law


Why does a person in a satellite revolving the earth feel weightlessness?


Galilean invariance of the free schroedinger equation

Galilean invariance of the Schrodinger equation


Why does silver lose its magnetic moment?


Cosmic gravitational background and its temperature

Is there a Cosmic Gravitational Background Radiation (CGBR)?


How do quantum fluctuations make up vacuum energy?

Are vacuum fluctuations really happening all the time?


Can we prove that all possible symmetries of a system were found?

Is there a systematic way to obtain all conserved quantities of a system?


Picking a guitar string of fixed length to get any nth harmonic, is it possible?


Is this actually how gravity is illustrated?

Is the popular explanation given for gravity in General Relativity misleading?


How to calculate a wheel's linear velocity if there is slipping


Symmetrical twin paradox in a closed universe


Good books for understanding Lagrangian formulation of classical fields?

Any good resources for Lagrangian and Hamiltonian Dynamics?


What forces are involved in bending a freekick like that?

What causes a soccer ball to follow a curved path?


Why is my shadow deformed and not the shadow of the ceiling?

Why do shadows from the sun join each other when near enough?


How can gravitational waves be detected when spacetime bends the instruments?

LIGO flawed by the identical expansion of laser wavelength and arms in presence of a gravitational wave?


How does gravity affect different bodies?


Is anti-gravity (i.e. repulsive gravity) possible in theoretical physics?


Is it possible that there are still gravitational waves of the big bang?


LASERS: How do we get all the emitted photons of equal wavelength & equal phase?

Why is the photon emitted in the same direction as incoming radiation in Laser?


To which extent is general relativity a gauge theory?


Why do we think Spin is angular momentum as opposed to some other quantity?

Spin, orbital angular momentum and total angular momentum


Why does the road look like it's wet on hot days?


How can gravitational waves dissipate the energy carried by them?

Where does gravitational waves' energy go?


Why is average velocity the midpoint of initial and final velocity under constant acceleration?


Is there a truly stationary frame of reference? (part deux)


What´s the physical foundation of the assumption that the curvature of spacetime can be quantised?


Why isn't a Photon justified in concluding that it is at rest and everything else is moving past it at c?

Does a photon in vacuum have a rest frame?


How would we estimate, ahead of time, "the chances" of LIGO spotting black holes colliding in the period that it has been operating?

What was the rate of Black Hole - Black Hole mergers expected to be detected by LIGO prior to GW150914?


What actually is the event that we think we have detected with gravitational waves?

Are the LIGO observations proof of a black hole merger, and what happened to the black holes?


Why can't we say that moon attracts the earth?


What are some of the best Physics resources online?


Why do fundamental particles have charge?

Why, fundamentally, are particles charged?


Why is Gauss's law used to compute electric field only for infinitely large objects in my physics textbook?

Why we cannot use Gauss's Law to find the Electric Field of a finite-length charged wire?


Lorentz transformation for timelike and spacelike points

A question about causality and Quantum Field Theory from improper Lorentz transformation


Why no interference among waves in white light

Why don't waves with different wavelengths interfere with each other in white-light?


What would happen if a charge could travel at $c$?


Action and reaction forces during collision

Given Newton's third law, why are things capable of moving?


Does the laws of gravitation apply to two energies as well?

Does everything with mass or energy have a gravitational pull?


How can there be weight without movement?


What longest time ever was achieved at holding light in a closed volume?


Are E and B fields synchronous in light waves?

Electric and Magnetic field's phase difference shift in linearly polarized electromagnetic waves


What is actually the characteristic length in fluid dynamics description?


How did Einstein come the conclusion that nothing can travel faster than the light in vacuum?

Special Relativity, 2nd Postulate -- Why?


Is friction really independent of surface area?

Is friction a function of surface area? What is the microscopic workings of friction?


How does a massive photon arise in the Condensed Matter Analogue of the Higgs Mechanism?

How come a photon acts like it has mass in a superconducting field?


why does a person feel weightless during free fall?

Why does a free-falling body experience no force despite accelerating?


Book Recommendation for Lagrangian and Hamiltonian Mechanics

Any good resources for Lagrangian and Hamiltonian Dynamics?


Do we have any idea why Planck's constant has the value it has?

Why do universal constants have the values they do?


How does quantum foam at small distance scales conflict with general relativity?

What are the Conflicting Predictions of General Relativity & Quantum Mechanics?


What's the difference between work in thermodynamics and mechanics?


Difference between reflection and re émission of light


What does "causally connected" or "causes" really mean?


How Einstein thought experiment clock works in quantum world?

Is the Planck length the smallest length that exists in the universe or is it the smallest length that can be observed?


Twin Paradox in case of two twins that don't meet


Why is it physically impossible to heat something higher than Planck's Temperature (absolute hot)

Why is there no absolute maximum temperature?


Can gravitational waves escape from inside of black holes?


Proving a relation with Four-velocity tensor

Transforming an equation to the co-vector version


Does the speed of light vary depending on what it travels through?

What is the mechanism behind the slowdown of light/photons in a transparent medium?


Do greenhouse gasses make the world habitable?


Is it possible for more than two particles to be entangled in a quantum way?


How can Bernoullis be solved without Vectors

Define Pressure at A point. Why is it a Scalar?


Acceleration of a container in thermodynamics

Would the temperature of a gas change when accelerated in a train?


Why is the gravitational force $10^{38}$ times smaller than the strong nuclear force?

Why is gravity weak at the quantum level?


Parallel Universe Moving Backwards in time

What happens at the interface between two universes with opposite thermodynamic arrows of time?


How possible is it that the Large Hadron Collider (LHC) on its second try, could disrupt the gravity of Earth?

Are there experiments that are banned from being done at the LHC?


Why isn't dark matter just ordinary matter?


Practical Book on Hamiltonian and Lagrangians?

Any good resources for Lagrangian and Hamiltonian Dynamics?


Resistor circuit that isn't parallel or series


Why would spacetime curvature cause gravity?


When we catch a falling object, where does its kinetic energy go?

if a body is stopped by means other than friction, where does energy go?


What are some good physics websites for learning in general?


How fast is Earth moving through the universe?


Are wave functions real physical objects?


Is the wave-particle duality a real duality?


What did Feynman mean by "gravity itself is a pseudo force"?


Does the Earth actually rotate around the sun?

Why do we say that the Earth moves around the Sun?


How does the Hawking Radiation mechanism cause a black hole to lose its mass?

What is Hawking radiation and how does it cause a black hole to evaporate?


Why can't we produce visible light from a radio transmitter?

Radio antenna producing waves in the visible spectrum


"And God said......and there was light." What does these equations mean?

What is the meaning of this "let there be light" joke?


A sees B's clock running slow and B sees A's clock running slow?

How is the classical twin paradox resolved?


What is the half-life threshold for an isotope to be considered stable?


Given Newton's third law, why are things capable of moving?


What is the mechanism behind the slowdown of light/photons in a transparent medium?


Why are electromagnetic waves not able to pass through a hole with a diameter smaller than the wavelength?


Number of planks required to stop the bullet


Could we obtain free electrical energy from the Earth's magnetic field?

Can the Earth's magnetic field be used to generate electricity?


Is there any potential associated with magnetism


How is it that the cross product of two vectors is always perpendicular to the given vectors?

Meaning of the direction of the cross product


Active noise cancellation technology measurements

Maximum delay for effective active noise cancelling?


Are photons electromagnetic waves, quantum waves, or both?

Is the wave-particle duality a real duality?


Does the weight of a computer go up as information is added to it?

Is a hard drive heavier when it is full?


Confused about time dilation/length contraction

Does the sign of $\Delta x$ matter in this time dilation calculation?


How to construct an isomorphism between the Complexified Special Linear Lie Group and the Special Unitary Group?

What's the relationship between $SL(2,\mathbb{C})$, $SU(2)\times SU(2)$ and $SO(1,3)$?


If I'm floating in space and I turn on a flashlight, will I accelerate?


Why $\vec F=m\vec a$ instead of $\vec F=m\vec v$?

Why force $F$ is $ma$ but not $md$ or $mv$? How can I observe and understand "force" in real life?


Conservation of energy (or lack thereof) in Doppler cooling

When lasers are used to cool atoms or ions, etc where does the heat go?


What should a physics undergrad aspiring to be a string theorist learn before grad school?


Why is speed/position relative but acceleration not?


Why does water not spill out of a cup when the cup is upside down on a smooth surface?

Atmospheric pressure experiment using a cup with a fluid to hold a glass plate


post selection and instantaneous communication

EPR-type experiments and faster-than-light communication using interference effects as signaling mechanism


Basic maths theories for good understanding of the standard model

Mathematical background for Quantum Mechanics


Why the electric field inside a conductor is zero?

Can a conductor run out of electrons to cancel external electric fields?


Why exactly is it that light cannot escape a black hole?


What is the shape of a rope hanging from two ends?

Shape of a string/chain/cable/rope/wire?


Universe Expansion as an absolute time reference


Wikipedia's derivation of torque related to angular acceleration

Derivation of Euler's equations for rigid body rotation


Popular depictions of electromagnetic wave: is there an error?


how does different colour wavelength intefere?

Colors from a computer vs. colors from visible spectrum of sunlight


Why fundamentally does classical mechanics lead to second order dynamics?

Why are differential equations for fields in physics of order two?


Is it possible for information to be transmitted faster than light by using a rigid pole?


Why electron-positron annihilation releases two gamma photons?

Why can't a single photon produce an electron-positron pair?


What causes the rainbows with beautiful forms by shining white light on a cd?

Why does a CD work as a diffraction grating even with light from a light bulb?


How is the age of the universe theorized?

How has the age of the Universe been derived from the observations made by the Planck mission?


Relationship between Magnetic Field and Electric Field along with velocity and kinetic energy

Finding net magnetic and electric force on charged particle


How to combine measurement error with statistic error


How to determine the components of a velocity vector undergoing a central force

Distribution of orbital velocities in a disk galaxy for N-body simulation?


Why is the total energy of an electron in an atom negative?

Negative energy levels in the diagram for a hydrogen atom


Non-hermitian hamiltonians and symmetry properties of $\partial_t$

Why can't $ i\hbar\frac{\partial}{\partial t}$ be considered the Hamiltonian operator?


Why don't planets radiate in orbit like a charged particle?

Why do planets not radiate EM waves in their orbits?


If the angular momentum is conserved in a system whose moment of inertia is increased, it's kinetic energy decreases

What is happening to rotational kinetic energy when moment of inertia is changed?


Are increases in Planck's constant and the speed of light operationally distinguishable?

Is it possible to speak about changes in a physical constant which is not dimensionless?


Is there a strict proof of the statement that a reversible process is always quasi-static?


Does string theory require continuous spacetime?


Why are magnetic fields a consequence of special relativity?

Does special relativity make magnetic fields irrelevant?


Why does foam build up when boiling food with the lid closed?

Cooking pasta: why does adding a lid lead to overflow?


Where can I learn the rules of representation decompositions?

Comprehensive book on group theory for physicists?


How is it possible that SI units allow us to write $F=ma$ without an extra constant?

How do we know that $F = ma$, not $F = k \cdot ma$


What is the microscopic equation to calculate sound speed in an ideal gas?

Simple explanation of relation between speed of sound and r.m.s. speed?


Could somebody survive a fall by jumping off an object shortly before impacting?

Would it help if you jump inside a free falling elevator?


According to Newton's Second Law, why is $F = \Delta p/\Delta t$ rather than just $F \propto Δp / Δt$?


Why does a fabric become darker when is wet?


Is there a physical reason for level repulsion and avoided crossings?


Why do we write $t$ as $ct$ in special relativity?

Why do we set $x^0 = ct$ instead of $x^0 = t$?


Can you detect light that is never going to reach you?


Does a ski racer with a larger mass have an advantage?


$g=GM/r^2$; $M=$mass of Earth. So in center $r=0$, so $g$ should be infinity


Trouble with geometric proof of gravitational force inside a sphere

Gravitational field intensity inside a hollow sphere


Do our eyes act as observers at the quantum level?

What is an observer in quantum mechanics?


How does air neutralize charged objects?


If I'm floating in space and I turn on a flashlight, will I accelerate?


Independence of generalised coordinates and momenta in Hamiltonian mechanics

Equivalence between Hamiltonian and Lagrangian Mechanics


proof for $\langle q| p \rangle = e^{ipq}$


Why are black holes called singularities?

Why singularity in a black hole, and not just "very dense"?


Do the entropy of the universe and third law of thermodynamics conflict?

How can it be that the beginning universe had a high temperature and a low entropy at the same time?


Why do electrons occupy the space around nuclei, and not collide with them?


How to develop the static and kinetic friction formula?

Why is the equation for friction so simple?


Lorentz transformation in "On the Electrodynamics of Moving Bodies"?

Confusion I have regarding Einstein's 1905 derivation of LT


Is it possible that photons lose a small amount of energy over time to become redshifted instead of being redshifted because of an expanding universe?


Can the newly discovered mass of the neutrino explain in part, the missing matter

How do we know Dark Matter isn't simply Neutrinos?


Does my interstellar pole thought experiment violate casualty?

Is it possible for information to be transmitted faster than light by using a rigid pole?


Why does the Lorentz transformation have to be a linear transformation?

Are Lorentz transformations linear transformations?


how do photons move with respect to EM (I'd like to picture wave magnitudes frame by frame)

What is the relation between electromagnetic wave and photon?


Isn't the uncertainty principle just non-fundamental limitations in our current technology that could be removed in a more advanced civilization?


Is the change in orbital of an electron the only way a photon is created


Calculating collapse factor in the crater equation


"FTL" Communication with Quantum Entanglement?

Quantum entanglement as practical method of superluminal communication


Doubts regarding Einstein's 1905 derivation of mass-energy equivalence

What's the purpose of the arbitary additive constants in Einstein's Inertia of Energy Paper?


The universe is said to have begun as a singularity, but how do we know nothing else existed?


Quantum made easy: so what *is* quantum mechanics all about?


Does the Planck scale imply that spacetime is discrete?


How would wormhole-based FTL violate causality?


Math and Theoretical Physics Topics & Textbook for Self-Study


Bathroom photons from the edge at the universe

How is it possible that we see light from shortly after the big bang?


Can water pressure ever be high enough to trap gas bubbles or keep them from surfacing?


Why do we seek to preserve gauge symmetries after quantization?


In calculating work done by a constant force over a constant distance, why doesn't the subject's initial velocity matter?

Why does the amount of energy transferred depend on distance rather than time?


Why are eigenfunctions which correspond to discrete/continuous eigenvalue spectra guaranteed to be normalizable/non-normalizable?


Recommendations for good Newtonian mechanics and kinematics books


Why is a $\pi$ phase added on reflection and why do things change with absorption?

Phase shift of 180 degrees of transversal wave on reflection from denser medium


According to Newton's third law, why don't Action and Reaction make equilibrium?

Given Newton's third law, why are things capable of moving?


Warning: Gruesome. Which one cuts faster? Guillotine with a slanted blade or with a flat blade?

Why does Guillotine have of 45 degreed blade rather than the one parallel to the ground?


Calculating the age of the Universe now and 30 billion years from now

Universe Expansion as an absolute time reference


How big should a lens of a telescope be so we can see the American flag on the Moon from the Earth's surface?

Observing lunar lander and footprints on the moon?


Law of reversibility of light and total internal reflection

Does light reflect if incident at exactly the critical angle?


How to derive the equation in my question?


Where should a physicist go to learn chemistry?


What state is fire? Solid, Liquid or Gas or Plasma?


Wien's displacement law in frequency domain


Gravitational time dilation at the earth's center


Newtonian gravity equation in a 2 dimensional world

Gravity force strength in 1D, 2D, 3D and higher spatial dimensions


Why does the amount of energy transferred depend on distance rather than time?


Studying physics at undergraduate level: Prerequisites


If there is no gravity, does that mean there's no mass as well?

What truly is mass, and is there a direct way to measure it?


About the complex nature of the wave function?


Is uncertainty principle a technical difficulty in measurement?

Isn't the uncertainty principle just non-fundamental limitations in our current technology that could be removed in a more advanced civilization?


How does an electric field come inside a conducting wire inside the circuit?

What happens when we connect a metal wire between the 2 poles of a battery?


Is the expanding of the universe also a cause which can induce gravitational waves from mass?

Is the sensitivity of the LIGO sensitive enough to measure the "expansion of the universe"? What specifically is the numerical ratio of effects?


How did LIGO scientists determine the source of the gravitational waves they detected?

Are the LIGO observations proof of a black hole merger, and what happened to the black holes?


Why do objects appear smaller when viewed from a distance?

Why do objects appear smaller when farther away?


Are gravitational waves dissipated and what is the mechanism?

Where does gravitational waves' energy go?


How to calculate the buoyant force on a balloon at different altitudes


Is there any issue/concern for a slight wavelength shift of the laser light in the LIGO experiments?

LIGO flawed by the identical expansion of laser wavelength and arms in presence of a gravitational wave?


Could LIGO discovery be due to e.g. earthquakes or have a terrestrial source?

Is there absolute proof for gravitational waves?


What is the likelihood of ever discovering the graviton?


Why and how is the speed of light in vacuum constant, i.e., independent of reference frame?


Now that gravitational waves have been discovered, what does their particle version look like?

What is the difference between gravitons and gravitational waves?


Recommendation on ADM mass and Bondi mass


What is the effect of gravitational waves on time?


Is it possible to prove that planets should be approximately spherical using the calculus of variations?


How does total internal reflection cause sparkling of diamonds?


Is the universe fundamentally deterministic?


Is it accurate to say that nothing can travel faster than $c$ in a GR context, where more space can be created?

What does general relativity say about the relative velocities of objects that are far away from one another?


How can light appear to spread in mainly a few rays (e.g: 2,4)?


Validity of naively computing the de Broglie wavelength of a macroscopic object


Surreal Trajectories in Bohmian Mechanics

Does recent paper show Bohmian mechanics is correct?


Can a photon be captured in a grid space representation at a fractional Planck position?

Does the Planck scale imply that spacetime is discrete?


How is it that distortions in space can be measured as distances?

LIGO flawed by the identical expansion of laser wavelength and arms in presence of a gravitational wave?


How much light is necessary to form a black hole

Can a black hole be formed by electromagnetic radiation?


How were gravitational waves discovered?


Why can an electric field escape from a black hole?

Detection of the Electric Charge of a Black Hole


Why is this result wrong for finding speed of a neutron in relation to deBroglie wavelength

$\lambda=\frac{2h}{p}$ instead of $\lambda=\frac{h}{p}$?


Proof of angular frequency in damped oscillator

Finding the steady state solution of a damped oscillator


Finding the work done by friction when sliding on parabola

How do I find work done by friction over a curve represented by a polynomial?


Is there a database for experimental evidence of different physical theories? If not, how to find up-to-date information?

A reference request for real world experimental data


Can someone explain how water from a garden hose can propagate in a sine/cosine wave?


How large does an air gap have to be to allow for heat transfer by convection?

At what gap width between two plates does convection not occur?


A modern approach to gauge theories; book reference


What mathematics shows that time goes backwards when going faster than C?

How does faster than light travel violate causality?


Could quark star becomes a neutron star?

How big of a neutron star would be needed to form a quark star inside of it?


Why is a paraboloid surface formed with a rotated liquid?


Does an object rotate around its COM when no torque is given?

Do objects rotate around the torque vector or its center?


Why is there a controversy on whether mass increases with speed?


Equivalece of the geodesic equation and the continuity equation for the energy-momentum tensor


What is "quantization"? Give one example


Why won't a tight cable ever be fully straight?

Why can't a rope be pulled completely straight?


Does time dilation make travelling close to the speed of light redundant?

How long would it take me to travel to a distant star?


What is the spatial representation of a momentum eigenstate and why?

What does the Canonical Commutation Relation (CCR) tell me about the overlap between Position and Momentum bases?


How do we decide the direction of angular velocity vector?

How to define orbital angular momentum in other than three dimensions?


How can centripetal acceleration not change speed?

Why normal acceleration doesn't bring a change in speed?


Why does your reflection suddenly turn upside down while slowly walking away from a curved mirror?


Evolution principle of the physical laws


How (if at all) can the neutron-proton ratio of stable atoms be explained under the nuclear shell model?

What makes the number of neutrons the number of proton similar?


Rigid body dynamics: Ideal rod with 2 masses

If I push or hit an object in space will it rotate or move along a straight line?


Why doesn't the Sun appear green to our eyes?


What is the probability that gravitation wave detections were coincidental errors?

Meaning of $5.1\sigma$ significance with regards to GW150914


Does a force have to be maintained during a distance to do work?


Is it possible to project an image into the eye which appears to be on a focal plane above source, and is larger?

Is it (theoretically) physically possible to project an image into thin air?


What happens if a body jumps in the Moon?

Earth moves how much under my feet when I jump?


How wide does a wall of ice need to be to stay in place?


Do electrons jump from terminal-to-terminal in the vacuum of space?


What would happen to a teaspoon of neutron star material if released on Earth?


Why is the atmosphere transparent in the visible spectrum?


Plausibility of black hole in center of galaxy (apparent paradox?)

Is there a black hole in the centre of the Milky Way?


Why does the weak interaction not conserve the flavour quantum number?


How can the speed of light change in the medium when we know that it is always equal to $c$?

What really causes light/photons to appear slower in media?


A question about the propagation of uncertainties


How are the classical and quantum picture of electromagnetic radiation related?

What is the relation between electromagnetic wave and photon?


Why doesn't the entropy increase when two similar gases mix with each other?


How does one determine ladder operators systematically?


Why are $E$ and $B$ fields not redundant?


How did we arrive that kinetic energy $KE = \frac{1}2 mv^2 $?

Why does kinetic energy increase quadratically, not linearly, with speed?


are photons are being exceptional in case of mass?

How can a photon have no mass and still travel at the speed of light?


Malus Law in Michelson Morley experiment


Electric charge neutrality of the Universe: evidences and theories


Is the speed of propagation of Einstein's gravitational waves unique?


How does latent heat of fusion/vaporization/sublimation of water change with pressure?

What is the effect of an increase in pressure on latent heat of vaporization?


Two balls A and B of the same size are dropped from the same point.


Why Electric current is considered fundamental quantity

Why is the ampere a base unit and not the coulomb?


$C_v$ for polytropic process having equation $PV^{x}=k$

Formula for molar specific heat capacity in polytropic process


Expansion of space vs movement within space


Does the expanding universe prove the theory of relativity wrong?


Why the action of a relativistic point particle is considered to be negative?

Why Lagrangian is negative number for a relativistic massive point particle?


Effect of relativity on observers of two different inertial frames observing an event taking place very far away


Reason for audio speaker diaphragm shape


How do we normalize a Dirac delta function position space wave function?

Don't understand the integral over the square of the Dirac delta function


Why do electric field lines never intersect?

Why can two (or more) electric field lines never cross?


Can we tell the difference types of recession?


Why would a photon striking an electron "make both recoil"?

If photons have no mass, how can they have momentum?


What are the alternative explanations for the indirect evidence of gravitational waves?

Is there any alternative theory that gets rid of gravitational waves, yet fits all data?


What does it mean for a particle to have spin of 2?

What is spin as it relates to subatomic particles?


Flow of alternating current in an ac circuit

In an alternating current, do electrons flow from the source to the device?


Do the same equations of motion imply the same Lagrangians?

Proof that total derivative is the only function that can be added to Lagrangian without changing the EOM


Using formula for work with distance of 0m

Why does holding something up cost energy while no work is being done?


A question based on the paper 'ON THE ELECTRODYNAMICS OF MOVING BODIES'

Does a photon instantaneously gain $c$ speed when emitted from an electron?


Why isn't dark matter just ordinary matter?


Does a magnetic field do work on an intrinsic magnetic dipole?


What exactly is NASA's proposed mechanism for "propellantless" "EM Drive" propulsion?

What are the proposed theoretical explanations for the EmDrive?


What would be suggested books for beginners to Zeeman Effect and Quantum Physics?

What is a good introductory book on quantum mechanics?


Substitution $\partial_\mu \to D_\mu \equiv \partial_\mu + ieA_\mu$ allows the introduction of electromagnetic interactions


Is energy content of a system different depending on the observer?


Lagrangians with higher derivatives than Klein-Gordon

Why are there only derivatives to the first order in the Lagrangian?


Rotation systems. Problem interpreting an equation


Quantum mechanics,and how the law $ΔxΔp≥ℏ/2$ explains the paradox regarding atoms

Why is the nucleus so small and why is the atom 99.999% empty space?


Can we add two singularities and make a single singularity?


Angular Velocity at different points on a rigid body

Why is angular velocity of any point about any other point of a rigid body always the same?


Why is the speed of light in vacuum constant?

How can I explain the scientific basis of the constant speed of light to a $c$-decay proponent?


Why does the action have to be hermitian?


Calculations with operators - Proof: Equation of Operators


Any real life demonstrations of radioactive decay?

Can nuclear transmutation be observed in real time?


Observer looking out through the window of a train

Why does one get an illusion as moon following him?


Can neutrinos really travel faster than the speed of light?


Photons have no mass. So, why does $E = pc$ hold?

If photons have no mass, how can they have momentum?


What are the units for rate of movement through time?


Does light escape from highly dense bodies

If you shoot a light beam behind the event horizon of a black hole, what happens to the light?


Online course on theoretical electrodynamics

Video lectures on graduate level Classical Electrodynamics


Is the concept of space-time curvature a recursive one?

Does the curvature of spacetime theory assume gravity?


Is there experimental evidence that massless particles such as photons attract massive objects?


Deriving Feynman rules from Renormalized Lagrangian

Why are derivatives in interaction terms treated differently from derivatives in the kinetic term?


torque on a body without any supporting point


Prerequisites for Griffiths electrodynamics

What does it take to understand Maxwell's equations?


What would happen in a collision of an antimatter singularty and a matter singularity?

What happens when a "matter-black-hole" and an "anti-matter-black-hole" collide?


Photon speed going from $0$ to $c$ initially?


Will we feel the gravity of a star 10 light years away for the next 10 years if, somehow, it vanishes today from its position?


With redshift, energy is lost. Where does it go?

Photons in expanding space: how is energy conserved?


Does gravity act in the centre of the Earth?

If it was possible to dig a hole that went from one side of the Earth to the other...


Why do we say that the Earth moves around the Sun?


Position vs Time Function for a Falling Object Without Assumption of Constant Acceleration

Radial fall in a Newtonian gravitational field


In quantum mechanics, why position and momentum are related by Fourier Transformation (only)?

Intuitive explanation of why momentum is the Fourier transform variable of position?


Photoelectric Effect, Why can't two quanta interact with an electron at the same time?


If lead's electron configuration ends with 6p$^2$, shouldn't it be paramagnetic?


How does heat actually stay kept in the carbon molecules in the atmosphere?

How does carbon dioxide or water vapour absorb thermal infra red radiation from the sun?


How does gamma ray emission make an atom more stable?


Why does a helium filled balloon move forward in a car when the car is accelerating?


how come electric field is o but current is there?

Is there no electric field inside a conductor?


Why do we see the sun as being yellow, if it is actually white?

How can sunlight be white , but pictures of the sun be orange?


Where does the extra mass come from if an object approches speed of light?

Why is there a controversy on whether mass increases with speed?


Producing free energy using perpetual motion

What prevents this magnetic perpetuum mobile from working?


Best books for learning quantum mechanics from scratch?


Could we travel faster than the speed of light in a medium, but slower than the speed of light in vacuum?

What happens if light/particles exceeded the speed of light for a particular medium?


Does all visible light pass through the atmosphere?

Can someone explain to me the concept of atmosphere opacity?


Do new universes form on the other side of black holes?


Can black holes form in a finite amount of time?


Is 0 of anything the same as 0 of any other thing?


What is the solution to Newton's bucket problem?

How does a spinning object "know" that it is spinning?


Missing elements? Electron shell filling after argon

Why do electrons not fully fill up all the orbitals sequentially?


I'm too mathematic minded, which textbooks will suit me better?


Why does the density matrix $\rho$ obey a wrong-signed Heisenberg equation of motion?


Would an object floating in a spinning cylinder in empty space be pushed toward the wall of the cylinder?

Why would a spinning space station create a centrifugal force on an astronaut rather than simply spinning around him/her?


Mössbauer rotor time dilation test. Why rotating clock dilates?

Can a ultracentrifuge be used to test general relativity?


pattern of moving electrons in wire under AC


Why does a bullet not shatter a window glass but a stone does?

Can a bullet shot through a glass make a clean hole?


Do photons experience time and if so how?

How does a photon experience space and time?


Why is the energy of Gamma and Alpha radiation discrete while the energy of Beta radiation is not?

Why is the spectrum of the $\beta$-decay continuous?


Why don't two pieces of matter stick together?

Why don't metals bond when touched together?


Relation between energy-time uncertainty principle and virtual particles

Energy conservation of Virtual Particles - Quantum Fluctuation?


Why is an object pushed when you push it?

Given Newton's third law, why are things capable of moving?


Conceptual difference between Hamiltonian and Lagrangian formulation

Why not use the Lagrangian, instead of the Hamiltonian, in nonrelativistic QM?


Why is the potential always quadratic in nature?

Why is the harmonic oscillator so important?


Why does a helium filled balloon move forward in a car when the car is accelerating?


Where does the energy go when you stretch a rubber band?

Why does holding something up cost energy while no work is being done?


Are these two writings of Planck's Law the same thing?


What would the collision of two photons look like?


Why does the moon appear white/grayish and the sun yellow?

Why is moonlight less colourful than yellow light?


Why should physical theories always have a Lagrangian formalism?

How do I show that there exists variational/action principle for a given classical system?


Why can't it work? Perpetual motion machine

Why doesn't this perpetual motion machine using the buoyant force work?


How can black holes be observed to grow?

How can anything ever fall into a black hole as seen from an outside observer?


Why toilet paper is softer in moist air?

Why is paper more frangible when it is wet?


What are some books that introduce me to advanced physics concepts?


Can measuring the refraction index in an object measure the strength of the quantum gravity between atoms of the object?

What is the mechanism behind the slowdown of light/photons in a transparent medium?


How would you describe what the affine parameter is in layman's terms?

What is the physical meaning of the affine parameter for null geodesic?


Do other people's mass count when measuring the attraction of the earth on me?

Does not the mass of those living on the Earth add on to the mass of the Earth or is it too negligible to be cared for?


How does an object in vacuum loose its temperature?

What are the various physical mechanisms for energy transfer to the photon during blackbody emission?


Determine resultant velocity of an elastic particle-particle collision in 3d space


How to calculate the average of a set of measurements with uncertainties?

How do you find the uncertainty of a weighted average?


Does a field have any physical meaning or significance?


Can I calculate the size of a real object by just looking at the picture taken by a Camera?


Can we observe a star collapse into a black hole?

Black hole formation as seen by a distant observer


What would happen if you split an antimatter nucleus?

Can Antimatter undergo nuclear fission/fusion?


Why does dark energy seem to push things apart?

How does dark energy allow the universes expansion to accelerate?


What is the cause of the surface tension of the liquids?

Why is surface tension parallel to the interface?


How many dimensions does a singularity have?

Is a black hole singularity a single point?


Why are tidal forces pointing away from the Moon?

Does Earth really have two high-tide bulges on opposite sides?


Prerequisites and introduction to string theory


What really happens when matter and antimatter combine?

What is "pure energy" in matter-antimatter annihilation made of?


Dipping a Dyson Ring below the event horizon

Fighting a black hole: Could a strong spherical shell inside an event horizon resist falling in to the singularity?


A flying fly inside a sealed box on a scale


Calculate age of the Universe at 7 billion and 28 billion years old

Calculating the age of the Universe now and 30 billion years from now


Is the 74.2km/sec per megaparsec accidental?

Hubble time, the age of the Universe and expansion rate


Is a collision with an immovable object equal to a head-on collision?

Train crash: are these situations alike?


Why does a bicycle (without any support of stand) falls down being at rest, but not under motion?

Why doesn't a bike/bicycle fall if going with a high speed?


How functions become operators in quantum mechanics?

Why do we use operators in quantum mechanics?


Why does this perpetuum mobile not work?(Gases and Densities)

Why doesn't this perpetual motion machine using the buoyant force work?


Why does cornstarch and water mixed together become solid when put under stress?

Why do non-Newtonian fluids go hard when having a sudden force exerted on them?


Landau's derivation of a free particle's kinetic energy- expansion of a function?


Is the trajectory of the Moon around the Earth stable?

Why does the moon drift away from earth?


Is the universe immediately dependent upon the past?


Are free electrons in a metal really free


How many worlds does the world split into in the Many Worlds Interpretation?

Many-worlds: how often is the split how many are the universes? (And how do you model this mathematically.)


Does influence on gravity increase with mass when velocities approach the speed of light?

If a mass moves close to the speed of light, does it turn into a black hole?


What is the speed photons coming out from headlights of a car running 100 km/h?

If I am travelling on a car at around 60 km/h, and I shine a light, does that mean that the light is travelling faster than the speed of light?


Why does time reversibility imply equilibrium in a thermodynamic system?

Intuitively, why is a reversible process one in which the system is always at equilibrium?


Noether's current expression in Peskin and Schroeder


Explain reflection laws at the atomic level


Why do we say that the Earth moves around the Sun?


Applications of low-dimensional topology to physics

Applications of Algebraic Topology to physics


Quantum teleportation - the alternative to destroying atoms


A Basic Question about Gravity, Inertia or Momentum or something along those lines


Do Photons interfere when it passes through a slit (one)?

How can a single slit diffraction produce an interference pattern?


Why can light (photons) bends in a curve through space without mass?

Explain how (or if) a box full of photons would weigh more due to massless photons


How can laser interferometry be used to measure path difference smaller than wavelength of laser light?


How do I derive geodesic equation using variational principle?

Geodesics equations via variational principle


Does a similar concept like centrifugal force exist for the whole universe?

What if the universe is rotating as a whole?


Friction and surface area. How friction does not depend on surface area?

Does the contact area affect friction forces?


Why is particle superposition still part of quantum mechanics?

How is it possible that quantum phenomenons (e.g. superposition) are possible when all quantum particles are being constantly observed?


How is the classical twin paradox resolved?


What would happen if I were to fall into a massive hollow planet?


Recommended books for advanced undergraduate electrodynamics


Is this a correct demonstration for why elements above untriseptium cannot exist?


If all motion is relative, how does light have a finite speed?


Why does the Sun's (or other stars') nuclear reaction not use up all its "fuel" immediately?


Why is there a temperature gradient on Earth?


Intuitive explanation of the half in the $\frac{1}{2}at^2$ distance equation?

Why there is a $\frac{1}{2}$ in the distance formula $d=\frac{1}{2}at^2$?


A block floating on water is pushed inside until it touches the bottom. Will the block come back?

Why doesn't hydrostatic pressure glue objects to the seafloor?


How to find out whether a transformation is a canonical transformation?


Can we obtain interference pattern with single electron/photon in Young's double slit experiment?


How far do we need to be removed from the earth to show the curvature with a viewing angle between 42 and 48 degrees?

objects distorted by the earths curvature


Would time freeze if you could travel at the speed of light?


Why is the contribution of a path in Feynmans path integral formalism $\sim e^{(i/\hbar)S[x(t)]}$?


Positron-electron annihilation - can more than two photons be created?


How do black holes form without violating the uncertainty principle?

Do black holes violate the uncertainty principle?


Why do the satellites revolves on a circular path around a planet at orbital velocity?


While jumping in a high speed train why we fall on same place?

Will a ball thrown straight up in a train land in same spot (in real world)?


What is the reason behind why energy must always be conserved, apart from observation?

Why can't energy be created or destroyed?


Where does gravity get's its energy from?

How gravity can give energy for unlimited time?


If electron carries negative charge, why bother looking for it's electric dipole moment?


Why does cancellation of dots $\frac{\partial \dot{\mathbf{r}}_i}{\partial \dot{q}_j} = \frac{\partial \mathbf{r}_i}{\partial q_j}$ work?


Is a purely white light made up of an equal amount of all wavelengths of light in the visible spectrum?


Why does space expansion not expand matter?


What is time, does it flow, and if so what defines its direction?


Stress tensor: forces on the other three faces of the infinitesimal cube

Why is 3D stress tensor acting only on three surfaces?


Does the notion of "rate of a clock" have an absolute meaning in relativity theory?

Is there a device that could measure the speed of time?


Relativistic speed and quantum entanglement

Is quantum entanglement affected by time dilation?


How can we actually prove that photon is its own antiparticle?


Identification of particles and anti-particles


What does the Kretschmann scalar really tell us about the geometry of spacetime?


Direction of tension force and restoring force

Is there a general rule for determining the direction of tension force?


Speed of light in vacuum - is it really a constant and what is the accurate value?

Has the speed of light changed over time?


What is behind the definitions of work and energy?


Does positive charge absorb electromagnetic radiations?


Does light really slow down when moving through a transparent medium?

What is the mechanism behind the slowdown of light/photons in a transparent medium?


More detail on why pressure increases at the bottom of a column of gas


Why is a bound electron less massive than its free counterpart?


Why isn't perpetual motion possible, even though we are so technologically advanced?


Self-study book for dynamical systems theory?

What are some of the best books on complex systems and emergence?


How do electrons move in a lightning strike?

If air cannot conduct electricity, how can lightning happen?


What decides that "it (mass energy) " is going to become mass or energy?

What keeps mass from turning into energy?


With respect to what we are saying space is homogeneous or space-time is isotropic?

What is meant when it is said that the universe is homogeneous and isotropic?


Speed of Dark experiment, does it *really* travel faster than light?


Is hole in semiconductor really positive?

What are "electron holes" in semiconductors?


Do photons gravitationally attracts one another?

Do two beams of light attract each other in general theory of relativity?


Why no Top Physicists Work on Bohmian Mechanics?

What is wrong with the De Broglie–Bohm theory a.k.a "Causal Interpretation" of quantum theory?


Have we proven that higher dimensions exist?

Experimental evidence of a fourth spatial dimension?


What would be physics of a star totally consisting of electrons?

Can there be Electron and/or Proton Stars?


Gauss's Law for a Uniformly Charged Solid Sphere

How do we make symmetry assumptions rigorous?


Tension when two connected blocks are pulled in opposite directions

Why I think tension should be twice the force in a tug of war


Prerequisites and introduction to string theory


How to get the accurate relativistic momentum form for photons?

If photons have no mass, how can they have momentum?


Did cosmological natural selection get a reprieve?

Smolin on Cosmological selection and neutron stars


Can we use quantum entanglement as a way to send information or data?

Quantum entanglement: does it necessarily imply superluminal information transfer?


Which Mechanics book is the best for beginner in math major?


Why can't helicopters reach mount everest?


Why is charge not taken as a fundamental unit?

Why is the ampere a base unit and not the coulomb?


Are all means of heating equally efficient?

Is everything 100% efficient at heating?


Calculating size/weight of the base of a banner to withstand wind load

How much wind does it take to tip a sign over?


Symmetry factor of $n$-point one-loop diagram


Commutation relation of a operator with Hamiltonian


What happens if the earth stops rotating?

If the earth would stop spinning, what would happen?


How does water evaporate if it doesn't boil?


Are gravitational waves transverse or longitudinal waves, or do they have unique/unknown properties?

Are gravitational waves longitudinal or transverse?


Euler equation with single state variables

Calculate Euler equations of fluid dynamics without division?


Why does the Moon face Earth with the same side?


How is the equation of motion on an ellipse derived?


How do photons know they can or can't excite electrons in atoms?


Light and Gravity - bending of light around a massive body

Why can light (photons) bends in a curve through space without mass?


Why is the gravitational force always attractive?


How much time passed for the passenger traveling with at speed-of-light spaceship?

How long would it take me to travel to a distant star?


Driving car with (almost) the speed of the light and switch the headlights on

If I am travelling on a car at around 60 km/h, and I shine a light, does that mean that the light is travelling faster than the speed of light?


Why aren't all photons virtual particles even in the "vacuum" of empty space?


Help explain how direction change relates to acceleration

How can an object's instantaneous speed be zero and it's instantaneous acceleration be nonzero?


Did Hubble consider gravitational redshift?

Why is "gravitational" red-shift neglected in galaxy and galaxy cluster scales?


Can we use the linear momentum of photon to create thrust

Rocket propelled by a giant monochromatic laser


Why don't electromagnetic waves need vacuum to move?

How do electromagnetic waves travel in a vacuum?


Initial particle configuration of a spiral galaxy for $N$-Body simulation

Distribution of orbital velocities in a disk galaxy for N-body simulation?


Rotating rod - Why can't it reach the speed of light?

Rotate a long bar in space and get close to (or even beyond) the speed of light $c$


How can current flow in an ideal wire if all of its points are at the same potential?

How electric currents can flow between 2 points at the same potential?


Commutation relations $[\phi(x), \phi^\dagger (y)]=-i \Delta(x,y)$ for spacelike separations $(x-y)^2<0$

A question about causality and Quantum Field Theory from improper Lorentz transformation


Period of a pendulum on a train at relativistic speeds as observed by 2 different observers

A simple pendulum moving at a relativistic speed - how does the period change?


What is the magnetic field inside hollow ball of magnets?


Is the boiling point of water really 100°C? If so, how come water evaporates at lower temperatures?

How does water evaporate if it doesn't boil?


Force on different points on a body not passing through the centre of mass


Amount of energy required to keep 1 kg object above the ground?

Why does holding something up cost energy while no work is being done?


What is the kinetic energy of a number of discrete particles and question related to Thermodynamics


Raman vs Fluorescence, scattering vs absorption, classical vs quantum

What is the difference between Raman scattering and fluorescence?


Does a particle falling into a black hole ever reach the center?

Does any particle ever reach any singularity inside the black hole?


Resource recommendation for a thorough coverage of rotational mechanics (especially gyroscopes)

Recommendations for good Newtonian mechanics and kinematics books


Do we need to add the sign before the unknown value in the mirror formula?

Deep confusion with conventions and signs in geometric optics


Is it possible to have a rate of change of acceleration?


Is there an equation for the strong nuclear force?


How is Newtonian gravity derived from the converse of shell theorem?


Is the wave-particle duality a real duality?


Is the Moon in a "Freefall" Around the Earth?

Why doesn't the Moon fall onto the Earth?


Confusion regarding fundamental particles

Why do physicists think that the electron is an elementary particle?


We know that the protons in a nucleus are positively charged. So why does the nucleus stay intact?


Can we give particle with no mass, mass?

What if we could give photons some mass?


How does light speed up after coming out of a glass slab?


Why does hot water freezes faster than normal water?

What is the status of Mpemba effect investigations?


Can we estimate the size of a neutron star based on direct observation?


Wouldn't a photon disappear because of length contraction?

Calculating length contraction at speed $c$ (not near it)


Is there a limit in angular speed in special relativity?

Rotate a long bar in space and get close to (or even beyond) the speed of light $c$


Does the general theory of relativity imply time dilation across the whole universe?


Heuristic derivation of Schrodinger equation


Proving that force satisfies the laws of vector addition


What happens to a radar signal when it meets with a superconductor?


how does it come that atmospheric pressure does not cut off blood flow in blood vessels?

Why does the aorta spray blood when atmospheric pressure is higher than blood pressure?


Renormalization group equation: physical meaning of energy scale

What is precisely the energy scale of a process?


Why are parallel spins energetically favorable for nucleons?

Why doesn't the deuterium nucleus have spin $0$?


If a wormhole connects between ground and sky, does an object require extra energy to pass through it?

How does conservation work in wormholes?


What does it mean to say exchange "force" is not really a force?

Nature of the quantum degeneracy pressure


Where does the energy that release when bond is formed between two atoms come from?

The exact mechanism of energy release durning bond formation on the atomic level


What leads to the existence of critical temperature?


Where does the extra kinetic energy come from in a gravitational slingshot?


What happens when a photon hits a mirror?


Does the universe expand in every direction evenly?

Is space expanding equally in every direction?


Gravity will bend light. But will bent/curved light create gravity?

Does a photon exert a gravitational pull?


How does gravity affect light although it's massless?


What cosmic event would have to occur for us to notice gravitational waves in everyday life?

How close would you have to be to the merger of two black holes, for the effects of gravitational waves to be detected without instruments?


Universe as a black hole - how did everything escape?


Time dilation of a body A with respect to B

How is the classical twin paradox resolved?


What is the method of attraction between two sheets of material with a fluid in between


Why does a soda bottle foam or froth when dropped?

Why are coke bottles that much fizzier if you shake them?


Why is kinetic energy defined as $(1/2)m v^2$?

Why is there a $\frac 1 2$ in $\frac 1 2 mv^2$?


Is everything 100% efficient at heating?


Do charges attractions cause time dilation?

Why is spacetime curved by mass but not charge?


Can the density of quarks be more than density of black hole?

How can super massive black holes have a lower density than water?


Why is there no charge in a capacitor connected to one battery pole?

Is a capacitor in an open circuit charged?


Expansion of the Universe: is new space(time?) being created or does it just get stretched?


How does electron gets negative charge and proton gets positive charge?

Why do electrons, according to my textbook, exist forever?


Force responsible for increasing a spiraling object's tangential velocity

How can tangential acceleration from a radial force be explained?


When everything follows strict laws in the universe, where does probability come from?

Is the universe fundamentally deterministic?


Time coordinate inside black hole horizon

The arrow of time and the cosmology of a black hole interior


How does an electron manage to constantly revolve around the nucleus of an atom forever?

Why don't electrons crash into the nuclei they "orbit"?


How does a frame of reference work in relativity?

How is the classical twin paradox resolved?


How does friction help the car to move forward?


How we see laser light if it travels in a straight path?

What makes some laser beams visible and other laser beams invisible?


Where does the dark energy of space expansion come from?

Energy conservation in General Relativity


Is It Possible To Move The Earth In A Direction?


Trouble with Landau & Lifshitz's expansion of the Lagrangian with respect to $\epsilon$ and $v$

Landau's derivation of a free particle's kinetic energy- expansion of a function?


If photons have no (rest) mass, why would black holes attract light?


Reference request: Relation between $Sp(N)$, $Spin(N) $, $SU(N)$ groups and physics

Comprehensive book on group theory for physicists?


Which one is good for starters in QM? Principles of Quantum mechanics by Dirac or by Shankar?

What is a good introductory book on quantum mechanics?


What is the frequency of a single photon?


How to solve this rotational mechanics problem?

$F=ma$ contest problem on angular momentum


Why is there a magnetic field around a magnet if there are no charges moving?


Consider a horizontal surface with or without friction. Ideally, will a wheel rolling without slipping roll forever in both cases?


Why is surface tension parallel to the interface?


When a color LCD/LED display is off it is black, when on it is colored. What color to light is an LCD/LED display


Will any massless particle/object in the vacuum of space always travel at the speed of light?

Do all massless particles (e.g. photon, graviton, gluon) necessarily have the same speed $c$?


If you could ride an elevator through the earth

If it was possible to dig a hole that went from one side of the Earth to the other...


Why does $\frac{1}{4\pi}$ appear in many formulas?

Why is there a factor of $4\pi$ in certain force equations?


Concerning a previous possible tachyon observation?


Does the unit of Inertia include radians?


Does a photon exert a gravitational pull?


Would it matter if the Earth rotated clockwise?


Why does Principle for least action hold for classical fields

How general is the Lagrangian quantization approach to field theory?


If 'pure energy' is photons, and energy is conserved, how can matter and antimatter (electrons and positrons) annihilate into photons and vice-versa?

What is "pure energy" in matter-antimatter annihilation made of?


Can a value of "length, in meters" be attributed to a pair of ends which are rigid (but not at rest) to each other?

If two ends were a certain "length" apart were they therefore at rest (or at least rigid) to each other?


Why light can't go faster then 300 000 km/s? What prevents it?

Why and how is the speed of light in vacuum constant, i.e., independent of reference frame?


What areas of physics depend on the sum $1 + 2 + 3 + 4 + 5 + 6+ 7+\ldots= -1/12$?

Critical Dimension of Bosonic Strings and Regularization of $\sum_{n=1}^\infty n$


Speed of different em radiation in a medium

Why do prisms work (why is refraction frequency dependent)?


What's the proof that the polarization occur s to the electric field of the light?

Why doesn't the magnetic field polarize when polarizing light?


If photons don't have mass, how can they accelerate objects?

If photons have no mass, how can they have momentum?


Colors from a computer vs. colors from visible spectrum of sunlight


Send a signal from Earth to a planet billion light years away instantly

Is it possible for information to be transmitted faster than light by using a rigid pole?


Is the potential energy of molecules related to its temperature?

Do ideal gases at zero Kelvin have potential energy?


Good Source to Understand Angular Momentum

Angular Momentum of a rigid, extended object: When we see a rotating object, is the state of rotation is totally relative?


Which textbook of differential geometry will introduce conformal transformation?

Reading list and book recommendation on Conformal Field Theory


Why is a coherent state an eigenfunction to the annihilation operator?

How are the definitions of a coherent state equivalent?


Can 'Backradiation' warm its own source?

Colder surface radiates to warmer surface


relation between Schrodinger equation and wave equation

How is the Schroedinger equation a wave equation?


Finding charge (electromagnetism course)

Calculate force of electric charges "suspended" by strings


Advice on beginning self-learning physics from scratch


Is the popular explanation given for gravity in General Relativity misleading?

Does the curvature of spacetime theory assume gravity?


Is it degeneracy pressure rather than electrostatic repulsion that stops us falling through the floor?

How can I stand on the ground? EM or/and Pauli?


Is the car/wall comparison valid for speeds close to $c$?

What is the relative speed of two near-light speed particles headed towards each other?


How can flux be the number of electric field lines normal to a surface?

Why does the density of electric field lines make sense, if there is a field line through every point?


How to calculate the resistance (conductance) between two contacts embedded into a 3D object?

Resistance between two points in an infinite metal sphere/cube


What are the orbits of satellites; circular or elliptical?


What degrees of freedom (other than polarization) of a photon can be used to store quantum information?


Fermi's yield estimation of the Trinity Test

How did Enrico Fermi calculate the classical Fermi Problem?


Does this analogy with matter and energy hold?

Possibility of making dark energy equivalent with dark matter


Cosmological constant in General Relativity

What are the calculations for Vacuum Energy?


Minimal possible energy to make calculation

Is it necessary to consume energy to perform computation?


What is the kernel for a double slit experiment?

How to arrive on the diffraction pattern for the double slit experiment using path integrals for the Gaussian slit case?


In path integrals, why is phase defined the way it is?

Why is the contribution of a path in Feynmans path integral formalism $\sim e^{(i/\hbar)S[x(t)]}$?


How does the maximum kinetic energy of an ejected electron affect what happen to it after being ejected?


What's the evidence supporting 1 singular Big Bang?


If planet orbits are in the shape of an ellipse and the sun is at one focus, what is at the other focus?

Significance of the second focus in elliptical orbits


Problems of General Relativity on small and large scales


Complex Space Time - Mathematical Foundations


How does "curved space" explain gravitational attraction?

Why would spacetime curvature cause gravity?


Is there any evidence to suggest that subatomic particles have 3D physiscal size?

What is the mass density distribution of an electron?


Has string theory predicted any experimently verified results?

Does string theory provide quantitative experimental predictions?


Electromagnetic fields vs electromagnetic radiation


Does quantum chromodynamics imply continuous space?

Does Quantum Mechanics assume space and time are continuous?


Feynman's question on the mathematical machinery underlying nature

Feynman's infinite amount of logic for one tiny bit of space


Why doesn't a bike/bicycle fall if going with a high speed?


Dielectric liquid sucked up between two cylinders with a voltage difference


What determines whether a unit is a base unit?

Why is the meter considered a basic SI unit if its definition depends on the second?


Symmetrical twin paradox in a closed universe


If I cut a string, will its length be rational or irrational?

Is it possible for a physical object to have an irrational length?


Rotation About Axis of Diatomic Molecule

In counting degrees of freedom of a linear molecule, why is rotation about the axis not counted?


Uncertainty principle in quantum entangled states

Why can't we use entanglement to defy Heisenberg's Uncertainty Principle?


Can electromagnetic radiation (i.e. photons) produce gravity?

Does a photon exert a gravitational pull?


How does the momentum operator act on state kets?


Does a photon in vacuum have a rest frame?


Why electron clouds in atoms don't radiate?

Where did Schrödinger solve the radiating problem of Bohr's model?


Are there any naturally occurring perfect circles?


Why doesn't mass of bob affect time period?


What is the difference between center of mass and center of gravity?


Do airplane wings use difference in pressure to generate lift or conservation of momentum?


Why this perpetuum mobile can't be possible?

Why doesn't this perpetual motion machine using magnets work?


Why doesn't the Higgs give mass to neutrino?

Do neutrinos not couple to the Higgs field?


Conservation of energy of a rotating body


What causes a whirlpool to form in a bathtub?

Why there's a whirl when you drain the bathtub?


Why don't electrons crash into the nuclei they "orbit"?


Is the gravity between objects other than celestials observable?

Can the effects of a person's mass upon the local gravitational field be detected and measured remotely?


Apparent energy loss due to acceleration

Where does the extra kinetic energy of the rocket come from?


Is the electromagnetic force responsible for contact forces?

How can I stand on the ground? EM or/and Pauli?


Why is movement the consequence of a force and not the other way around?

What, if anything, makes forces the "cause" and acceleration the "effect"?


Is it possible for a photon to be at rest?

Does a photon in vacuum have a rest frame?


Is it possible for a planet to be made entirely of water (even it's core)?

Could there be a body of water the size of a planet?


What is the total energy of the Universe?

Is the total energy of the universe zero?


Static friction greater than kinetic friction

Why are there both Static and Kinetic Friction?


What are the Conflicting Predictions of General Relativity & Quantum Mechanics?

A list of inconveniences between quantum mechanics and (general) relativity?


Energy of a system of particles in a reference frame

Is the change in kinetic energy of a particle frame independent?


How can a Lagrangian determine how its fields transform?

Does the lagrangian contain all the information about the representations of the fields in QFT?


Why Do We Say That the Electric Forces Are Stronger Than the Gravitational Forces?

What does it mean to say "Gravity is the weakest of the forces"?


Can statistical mechanics explain the second law completely?

How do you prove the second law of thermodynamics from statistical mechanics?


In an alternating current, do electrons flow from the source to the device?


Why does adding red light with blue light give purple light?

How does light combine to make new colours?


Electric dipole moment(EDM) underlying physics

What is the mass density distribution of an electron?


Are bubbles in ice at a lower or higher pressure than atmospheric pressure?


Why must a singularity form inside a black hole?


How to discover the $F = m\cdot a$ equation from scratch?


Virtual photon description of B and E fields


If the universe is expanding then why does the distance between Sun and the Earth is not expanding?

Why does space expansion not expand matter?


Cosmic Expansion - Why aren't we ripped off yet?


What would an observer see if he/she flew toward a clock at relativistic speeds?


Partial derivatives in Lagrangian formalism

Calculus of variations -- how does it make sense to vary the position and the velocity independently?


Kinematics question - Newton's Law of Motion


Is acceleration quadratic or linear outside of a gravity field?

Why does kinetic energy increase quadratically, not linearly, with speed?


Traveling between two planets at rest to one another

How is the classical twin paradox resolved?


Idea is to make an equipment like torch, which should emit darkness.. Is it possible?


We know that the protons in a nucleus are positively charged. So why does the nucleus stay intact?


Is the converse of Noether's first theorem true: Every conservation law has a symmetry?


Physics books covering classic mechanics

Which Mechanics book is the best for beginner in math major?


Why air above airplane's wing moves faster?


can silence happens when 2 sound waves destroy each other

What happens to the energy when waves perfectly cancel each other?


Force as change in momentum vs. change in velocity


Why is gravity weak at the quantum level?


Virtual photons, what makes them virtual?


I would like to know, what would happen if a primordial black hole mass of Earth, would impact with the Earth

What would the effect be of a small black hole colliding with the earth?


Doesn't quantum uncertainty disprove string theory?

Is there a heuristic explanation for the derivation of Heisenbergs Uncertainty Principle from String Theory?


Is it possible to reconstruct the Hamiltonian from knowledge of its ground state wave function?

In quantum mechanics, given certain energy spectrum can one generate the corresponding potential?


Why does solid turn to liquid deep in the Earth?


Why does one particle in Hawking radiation have negative energy?

Black holes and positive/negative-energy particles


Any good electricity and magnetism books for highschool students?

Electrodynamics textbooks that emphasize applications


Can this relativistic hack allow one to see beyond an event horizon, in principle, else why not?

How much energy does a photon need to form a black hole?


What is the importance of torque direction?


What kind of effect would cosmic expansion have on planetary motion or keplerian orbit?

Would order 1AU metric expansion of space begin if the solar system were not inside a galaxy?


The ability to squint and focus - what is it called and is it used in optics?

Pinhole camera: How "How to See Without Your Glasses" works?


Why can the y and z-components of spin be measured simultaneously?

Why only 1 component of angular momentum?


Did the universe really start with a single point?


What is the gravitational field inside a hollow spherical cavity embedded in a solid sphere?

Gravitational field intensity inside a hollow sphere


What is the program of quantum field theory? What is its derivation?

Is "quantizing" a field different from "quantizing" a particle?


Heated and cooled air effects on combustion

Are internal combustion engines more efficient on cold days?


Non-singlet and singlet flavor combination

What exactly means "is a singlet under $SU(N)$"


Is the magnetic field zero inside an ideal conductor carrying a current?


Does infalling matter ever cross the event horizon?

Can black holes form in a finite amount of time?


What is the Difference between Lorentz Invariant and Lorentz Covariant?

Definitions and usage of Covariant, Form-invariant & Invariant?


What is the simplest way to prove the Earth is round?


What is the physics behind these balancing forks?

Physics behind a match performing a trick on center of mass


Why can't we feel acceleration under free fall?

Why don't we feel the subtle speed change of Earth's elliptical orbit?


Does a "capacitor" for light exist, which could filter out flickering?


How to explain implicit time dependence to someone?

What is the difference between implicit, explicit, and total time dependence, e.g. $\frac{\partial \rho}{\partial t}$ and $\frac{d \rho} {dt}$?


Why do we perceive a mixture of blue and yellow paint as green?

Why does adding red light with blue light give purple light?


Calculating the force required to lift a weight with a screw


How to imagine the electromagnetic waves?

What is the relation between electromagnetic wave and photon?


Nature of spacetime 4-vector and tangent space?


Why doesn't the Moon fall onto the Earth?


How much gravity (and/or magnetic field) would a space ship need to generate to hold an atmosphere around it?

Can low-gravity planets sustain a breathable atmosphere?


Why are heavy elements used in nuclear power plants?

Why do only heavy radioactive elements perform fission?


Proof of the Gauss's law for gravity without divergence

Intuitive explanation of the inverse square power $\frac{1}{r^2}$ in Newton's law of gravity


Particle accelerators reaching light speed

Accelerating particles to speeds infinitesimally close to the speed of light?


How exactly are the relative strengths of gravity and electromagnetism quantified?

What does it mean to say "Gravity is the weakest of the forces"?


Theoretical Possibility of "Opposite" Gravitational Mass?


Could we send a man safely to the Moon in a rocket without knowledge of general relativity?


Special relativity and black hole paradox

Can a black hole form due to Lorentz contraction?


Work, Energy & Power - Body slides down a hemisphere


What the live streaming of a time traveler will look like?


is the expansion of the universe observable at a smaller scale?

Can the Hubble constant be measured locally?


What does singularity mean in the context of black holes?

Why must a singularity form inside a black hole?


Quantum Entanglement - What's the big deal?


What evidence is there of the existence of quarks?

Can quarks be considered real and elementary?


Why time slows only for moving object and not stationary observer? How the "stationary" & "moving" are decided?

How is the classical twin paradox resolved?


Free space propagator: reconciling two results

Free Particle Path Integral Matsubara Frequency


If I aimed two identical lasers at a screen, what would the interference pattern look like?

Is it possible to observe interference from 2 independent optical lasers?


Why does water pouring from a glass sometimes travel down the side of the glass?


Doesn't this LED created by MIT violate the second law of thermodynamics?


Why does a window become a mirror at night?


Can a solid object inside the black hole event horizon avoid the singularity?

Solid objects inside the event horizon - can they remain "solid"?


If steady current flows in a metallic conductor of non uniform cross section area then why is current constant?

Why does current density changes but not current?


Why does the sky change color? Why is the sky blue during the day, red during sunrise/set and black during the night?


Why can't the entropy of an isolated system decrease?

Chance of objects going against greater entropy?


Calculating Dark enegy, dark matter and the rest

How do scientists calculate the percentage of dark energy in the universe?


Why is it necessary to use the imaginary number in QM?


Electrons moving faster than light and backward in time?


Why does breaking Bell's inequality rule out all local hidden variables theories?

What combinations of realism, non-locality, and contextuality are ruled out in quantum theory?


What is/might be the basic component that makes up elementary particles?

What are the strings in string theory made of?


How can orbitals be oriented if the nucleus is symmetrical?

Where do symmetries in atomic orbitals come from?


Radiation of visible light from LC circuit

Can an LC oscillator be used to generate visible light?


Electrons fly on certain orbits around nucleus. why do not they radiate waves and crash to the nucleus?

Why don't electrons crash into the nuclei they "orbit"?


Is "The curl of the gradient of any scalar field is identically zero" contradictory to Faraday's Law?

How is the curl of the electric field possible?


Kepler problem in time: how do two gravitationally attracted particles move?

Don't heavier objects actually fall faster because they exert their own gravity?


What is the reason for this pattern of noise in electric kettles?


Producing photons with same frequency, different amplitude wave

Amplitude of an electromagnetic wave containing a single photon


Are there any theories out there that explain this time travel paradox

Is time travel possible? Is it possible to go back in time?


Why Are Even and Odd Regge Trajectories Degenerate?

Why are the even and odd Regge trajectories degenerate?


Magnetic monopole and electromagnetic field quantization procedure

Does existence of magnetic monopole break covariant form of Maxwell’s equations for potentials?


Electric field in a parallel plate capacitor

Field between the plates of a parallel plate capacitor using Gauss's Law


Why does work equal force times distance?


How is it possible for a standing wave to exist in a tube with both sides open?

Reflection of sound waves from the open end of an organ pipe & relationship b/w nodes & pressure


Calculating the charge density of a capacitor with one plate tilted


What is the difference between work function and the ionization energy?

What's the difference between the work function and ionisation energy?


Does gravity travel at the speed of light?


What are the reasons for making the mole a base SI unit?

Why is the mol a fundamental physical quantity?


Why is the mole/"amount of substance" a dimensional quantity?


"The mass of the proton is $1.672\,621\,637(83) \times 10^{-27}\:\mathrm{kg}$" - please, how does the error work for this?


What is the relation between electromagnetic wave and photon?


The energy of a photon and gravitational red shift


Why does the light side of the moon appear not to line up correctly with the evening sun?


How to observe Newton's third law violation?

Apparent Violation of Newton's $3^{\text{rd}}$ Law and the Conservation of Momentum (and Angular Momentum) For a Pair of Charged Particles


Can we make a force which can oppose earth gravity?

Is it theoretically possible to shield gravitational fields or waves?


What is the formula for determine heating produce by a lens?


Is it possible to determine the outcome of any impact knowing only the ratio of masses?


Apparent depth and virtual image position

Real and apparent depth not looking perpendicular to the interface


What is the correct formula for gravitational time dilation for a satellite in a circular orbit?


Using Lagrangian mechanics instead of Newtonian mechanics

What is the difference between Newtonian and Lagrangian mechanics in a nutshell?


Interval preserving transformations are linear in special relativity


How can we travel back to time if we go with a speed $>> c$?

How does faster than light travel violate causality?


Why doesn't air below a falling object balance its weight?

Given Newton's third law, why are things capable of moving?


During a turn, do the rear wheels necessarily trace out the same arcs as the front wheels?


How to derive addition of velocities without the Lorentz transformation?


light is allowed to pass through transparent objects?


Do Ampère's and the the Biot-Savart law give different answers for the magnetic field of a circular loop?

What is the difference between Biot-Savart law and Ampere's law?


Why does blowing on hot coffee cool it down?


Is the uncertainty principle a property of elementary particles or a result of our measurement tools?


Is the universe fundamentally deterministic?


How does the curvature of spacetime induce gravitational attraction?


Do GR and SR have to be considered together to determine time dilation?

Is gravitational time dilation different from other forms of time dilation?


Why don't we consider jerk in physics classes?

Why are there only derivatives to the first order in the Lagrangian?


Does spacetime have a "preferred" speed/metric?

What is so special about speed of light in vacuum?


How do we know there are dimensions above the third?


Cause behind bending of light in refraction

Why does electromagnetic refraction happen?


Deriving the expectation of $[\hat X,\hat H]$


When do I apply Significant figures in physics calculations?


Prereqs for The Geometry of Physics by Frankel


How are the Lagrange equation and Feynmann path integral related?

Classical limit of the path integral formulation of quantum mechanics


What is charge actually? How to define it?


Linear Algebra For Physicists (Book Recommendations)


Limits of Poisson's ratio in isotropic solid


Was the mass of the universe the same when it first began as it is now?

Given that matter cannot escape a black hole, how did the big bang produce the universe we see today?


Computer simulation of Schrödinger equation

Does there exist a free good molecule / atom simulation software?


What happens to the acceleration of a body undergoing constant force?

Is kinetic energy a relative quantity? Will it make inconsistent equations when applying it to the conservation of energy equations?


If an object moved 5 meters in a second, how can its velocity be 10 m/s?

Why do these two ways of understanding constant acceleration give different results?


Heat energy in special theory of relativity

Is temperature a Lorentz invariant in relativity?


Two observers moving opposite to each other will see each other moving at speeds greater than light?

If I run along the aisle of a bus traveling at (almost) the speed of light, can I travel faster than the speed of light?


Is cold dark matter made of Higgs bosons?


Different formulas for calculating power

How do I calculate the power consumed by a lightbulb?


Is temperature of a single molecule defined?

Can a single molecule have a temperature?


Have we ever seen an atom? If not, how do we know they exists?


What is so special about speed of light in vacuum?


What does "the ${\bf N}$ of a group" mean?


Can someone recommend good resources to self study physics please?


How would it be to look at the sky if the earth were near the edge of the universe?


Is the Earth negatively or positively charged?


Analytic solution for angle of minimum deviation?


Differences in the behaviour of pinching a garden hose and closing a tap


How to sail downwind faster than the wind?


Why would an electron in an orbit be accelerating continuously and would thus radiate away its energy and fall into the nucleus in a classical model?

Why do electrons around nucleus radiate light according to classical physics


What happens to the bar magnet field when it breaks?

Why does it seem like a broken magnet's poles flip?


Why will an accelerated electron emit a photon?

Why do accelerating electrons emit radiation?


Reducing the Tsunami impact using Nuclear bombs


Collision Between Two Particles: Writing the Mass As A Function of The Angle


If it takes infinitely long for someone to fall in a black hole, wouldn't it evaporate first?

Does any particle ever reach any singularity inside the black hole?


Why is the formulation of M(embrane) theory so hard?

Why one-dimensional strings, but not higher-dimensional shells/membranes?


Two synchronised clocks accelerated perpendicular to Earth's gravitational field

Which clock is the fastest inside an accelerating body?


Is it plausible for spacetime to be shaped something like a torus?

What is known about the topological structure of spacetime?


Does Earth really have two high-tide bulges on opposite sides?


Black hole entropy versus entropy of normal matter

Why is black hole entropy not an extensive quantity?


Centre of gravity vs centre of mass for a pyramid mounted on a cube, all sides of length $l$

What is the difference between center of mass and center of gravity?


Why do you need debroglie wavelength less than nucleus diameter to probe a nucleus via deflection?


Issues with the chain rule in derivatives in chiral perturbation theory

Derivative of the product of operators and Derivative of exponential


Convert an equation for acceleration into one for velocity

How to get distance when acceleration is not constant?


What constitutes an observation/measurement in QM?


Is electric charge truly conserved for bosonic matter?


Why isn't the time-derivative considered an operator in quantum mechanics?

Why can't $ i\hbar\frac{\partial}{\partial t}$ be considered the Hamiltonian operator?


If light travels along null-like geodesics, does that mean it remains at the same point on a spacetime manifold?

Why doesn't $ds^2 = 0$ imply two distinct points $p$ and $p'$ on a manifold are the same point?


Faster-Than-Light Communication using Entangled Photons

The choice of measurement basis on one half of an entangled state affects the other half. Can this be used to communicate faster than light?


Pulley system: how can tensions be equal throughout a entire rope if the weights on opposite ends are different?

Tension in an Atwoods machine conceptual?


Why doesn't the moon crash into the Earth?

Why doesn't the Moon fall onto the Earth?


Both Eigenvalues and Operators are "Observables"?

Does every hermitian operator represent a measurable quantity?


Are we slightly lighter during the day and slightly heavier at night, owing to the force of the Sun's gravity?


Why Can a Skydiver Hit the Ground and Be Killed?

High speed does not kill. Does acceleration do it ? or jerk?


How does a shadow appear to break the speed of light?

Is it really possible to break the speed of light by flicking your wrist with a laser pointer?


What makes neutron heavier than a proton?

What's with the very slightly larger mass of the neutron compared to the proton?


How does an electron spin through 720 degrees for it's marked side to come back to view?


What would be gravity in one spatial dimension?

General relativity (gravitation) in time and one spatial dimension


Is there an EMF in a conductor moving at constant speed across the uniform magnetic field

Moving conductors in magnetic fields: is there electric field or not?


Why does the refractive index depend on wavelength?

Why do prisms work (why is refraction frequency dependent)?


What is time, does it flow, and if so what defines its direction?


Number of points where gravitational field due to $N$ point-masses vanishes

Is there always an equilibrium point in space for gravity?


Explanation that air drag is proportional to speed or square speed?


What is the required prerequisite knowledge of QM, for starting QFT?


Exchange particles-real or just mathetical constructs?


How can we consider charge to be continuous?

Why are continuum fluid mechanics accurate when constituents are discrete objects of finite size?


Why does dark matter form a halo, Unlike normal matter?

If dark matter only interacts with gravity, why doesn't it all clump together in a single point?


What about continuity of Space and possible discreteness of Time?


Charged pion decay and spin conservation

Angular momentum conservation in pion decay?


Representation of the Lorentz group from representation of its Lie algebra

From irreducible representations of the Lorentz algebra to irreducible representations of the Lorentz group


Is the amount of energy in the universe a finite quantity Joules?

Is the total energy of the universe zero?


Light, is it a photon or electronic magnetic radiation?

What is the relation between electromagnetic wave and photon?


Can a submerged place in the sea have huge air pockets?


The General Relativity from String Theory Point of View

In what limit does string theory reproduce general relativity?


Does juggling balls reduce the total weight of the juggler and balls?


What is the phase difference of the oscillations of the two prongs of a tuning fork?


Why do electrons occupy the space around nuclei, and not collide with them?


Can we say an isolated molecule has/is at some Temperature?

Can a single molecule have a temperature?


Planck length implies lattice structure of space?


Gravity in the center of a hollow neutron star

Is spacetime flat inside a spherical shell?


Relativistic time dilation / length contraction

Can a ultracentrifuge be used to test general relativity?


Do mankind and manmade activities/constructions have any effect on the rotation of the Earth?


Representation Theory in a Nutshell for Physicists?

Comprehensive book on group theory for physicists?


In which direction do gravitons travel? Do they originate from mass or are they collected by masses?


How does an electron jump from one lobe to another of the same hourglass-shaped $2p_x$-orbital?

How does the electron jump across "gaps" in its orbital?


Why do physicists believe that there exist magnetic monopoles?


What is the difference between the blackness of a Black Hole and the blackness of a Black Body?

Is there a substance that doesn't reflect OR absorb light from the visible light spectrum?


Confusion regarding factor 2 in uncertainty principle

Factor 2 in Heisenberg Uncertainty Principle: Which formula is correct?


How is it possible that pair production results in the decrease in a black holes energy?

Black holes and positive/negative-energy particles