Where does the energy of a redshifted photon go to?


Can ultracentrifugation (very high gravity) influence time? (continued)

Can a ultracentrifuge be used to test general relativity?


Zero energy universe does not make sense

Is the total energy of the universe zero?


Gravitational radiation from hydrogen atom

Is there a probability that an electron in an atom change its energy level due to emitting gravitational wave?


Is gravity due to the curvature of spacetime?

How does "curved space" explain gravitational attraction?


Quantum Harmonic Oscillator: is it impossible that the particle is at certain points?

Is there actually a 0 probability of finding an electron in an orbital node?


Should we stop saying that nothing can escape the event horizon of a black hole post LIGO?

How does some of the black hole (BH) mass escape the event horizon (EH) of either BH, or the merged EH of two merged BHs?


What is a good introductory book on quantum mechanics?


A question about a proposed "big bounce"

Question regarding the validity of the big bounce


Why does glass/plastic reflect with a dark background

Why does a window become a mirror at night?


Do electrons in a wire, actually jump across two metallic wires twisted together?

tranfser of electrons between two metals and a wire


Where is centre of gravity on a Dyson Sphere?


How much more mass would Jupiter have to accrete to start fusion?


Acceleration in infinite Atwood's machine


How can the diameter of the universe be so big, if nothing can go faster than light?


Why are standing waves produced in an open organ pipe if the medium is same after all?

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


Whether a ball thrown upwards will come back to the same position if we consider the effect of rotation of the earth

Earth moves how much under my feet when I jump?


How can I convert a capacitor circuit to a simpler one?


Paradox - Special Theory of Relativity (edited)


Interaction between charged particles through static electric fields

How is the electostatic field propagated by the vacuum? How does a charge feel the presence of another charge when there is NOTHING between them?


Why can't we run through walls like Harry Potter?

Why doesn't matter pass through other matter if atoms are 99.999% empty space?


Volumetric flow rate as a function of radius of pipe

How does the radius of a pipe affect the rate of flow of fluid?


Question about derivations in Sakurai's Quantum mechanics, section 5.8


What's the best GR book for recreational study?


Why photons are having energy when they are massless?


Does a force propagate instantaneously to move the other side of the box of length one light-year?

What "propagates" a force through the rest of a solid?


The relation between Internal Pressure and flow rate in a balloon

The velocity of the flowing coming out of the balloons?


Why is probability proportional to $ \ e^{-E/kT}$?

Why does the Boltzmann factor $e^{-E/kT}$ seem to imply that lower energies are more likely?


What would the collision of two photons look like?


Question on the stability of the solar system


Are we living in a Universe with 3 time dimensions and 1 spatial dimension?

Intuition for multiple temporal dimensions


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


What does the refractive index depend on?

Why does optical media have different refractive indices?


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


Is a black hole really connecting two parallel universes?

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


Books on quantum mechanics with intuition

What is a good introductory book on quantum mechanics?


Mountain and a feather dropped from same height. Which hits Earth first?

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


Is conservation of energy a set of principles that is inevitable in any 'possible world'?

Why can't energy be created or destroyed?


Connections between classical mechanics and quantum mechanics


Why does ice melting not change the water level in a container?


We don't know when a nucleus will decay. Then how can find its half life?


How can frequency be constant during refraction?

What determines color -- wavelength or frequency?


Does the density of matter increase as we approach the big bang?

What was the density of the universe when it was only the size of our solar system?


Why are we still teaching Newtonian physics if it's "false"?

Did relativity make Newtonian mechanics obsolete?


Work performed by a stationary object in a gravitational field "on Earth"

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


Orbits of binary pulsars. How to calculate?

Create a star system fit to conic equation


Grounded conductor inside a uniform electric field

Confusion with Grounded Conductor: bringing in a point from infinity


Normal reaction - force without acceleration


What keeps mass from turning into energy?


The relationship between the Hubble Constant and cosmological time


Do particle velocities in liquid follow the Maxwell-Boltzmann velocity distribution?

Is there an equation to calculate the average speed of liquid molecules?


Thought experiment: Tethered galaxies - to the extreme

How Does Hubble's Expansion Affect Two Rope-Tied Galaxies?


Does a moving star have a larger gravitational pull?

Does a moving object curve space-time as its velocity increases?


How is dark matter meant to explain the faster than expected rotation of galaxies?

How does dark matter halo outside a galaxy help to explain galaxy rotation curve?


Why do skidding wheels have less traction than non skidding wheels?

Why are there both Static and Kinetic Friction?


Why does space expansion not expand matter?


Can mass be totally converted into energy?


Why Does Thin-Film Interference Manifest Visibly Only on Thin Films?

Is manufacturing roughness really the only reason we don't see optical interference in thick dielectrics like windows?


What causes the light spectrum to appear on oil surface?

What causes multiple colored patches on a wet road?


Why are we not able to move at the speed of light again?

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?


Expanding universe space through matter or matter through space?

What is the meaning of the "expansion of space"?


Exact Relation between voltage and current

The Difference Between voltage and current


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


What is the Earth truly rotating about/revolving around?


Don't Inertial forces obey Newton's third law?

Why does Newton's third law exist even in non-inertial reference frames?


Shouldn't we use a Hamiltonian that doesn't give special treatment to time?

Lagrangian to Hamiltonian in Quantum Field Theory


Greatest and Least Resistance and Current Characteristics of Parallel vs Series circuits


How would we tell antimatter galaxies apart?


Why is there no absolute maximum temperature?


Is the photon first a wave, then a particle?

Are photons electromagnetic waves, quantum waves, or both?


Why does orbiting matter form an accretion disk?

Why do all the planets of the solar system orbit in roughly the same 2D plane?


Kepler's First Law of Planetary Motion: Whats at the other focus?

Significance of the second focus in elliptical orbits


Why do we always see the same side of the Moon?

Why does the Moon face Earth with the same side?


Can we prove that the universe is finite or infinite?


Why don't Moon collide with Earth but revolves due to gravity?

Why doesn't the moon crash into the Earth?


Best resources to self learn, from scratch, mathematics as it appears in physics


Mechanics of a chain climbing out of a jar


Resource recommendation for rotational physics

Recommendations for good Newtonian mechanics and kinematics books


Can water vaporize without reaching 100 degrees celsius?

How does water evaporate if it doesn't boil?


Could tall buildings in very heavily populated cities affect earth's rotation


Do two waves propagating in different directions on the same line induce a standing wave?

Standing waves due to two counter-propagating travelling waves of different amplitude


If I charge 3 capacitors in series, then connect themin parallel, where does the remaining energy go?

Energy dissipated when two charged capacitors are connected in parallel


Perturbation theory in quantum mechanics: assumptions on eigenvectors

Perturbation theory: justifying expansion in terms of eigenstates of the basis Hamiltonian


Classical free fall time to point mass "planet"

The Time That 2 Masses Will Collide Due To Newtonian Gravity


Prove that $\mathbf{E}^2-\mathbf{B}^2$ and $\mathbf{E}\cdot\mathbf{B}$ are the only two independent Lorentz invariant quantities

Fundamental invariants of the electromagnetic field


Determine if Reynolds Number is large or small in classical mechanics.

Is the Reynolds Number well defined for a given system?


Cell phone ring made nearby speaker to create strange noise

Why speaker beeps when a cellphone is kept near it?


What is the origin of elements heavier than iron?


Complete destructive interference of light

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


Youngs experiment - Why only 1 frequency?

Is coherent light required for interference in Young's double slit experiment?


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


What are the effects of a complex refractive index?

Imaginary number for extinction coefficient in complex refractive index


Can Quantum Teleportation be accomplished faster than the speed of light?

Can't quantum teleportation be superluminal some percentage of times?


Do physicists need the idea of 'cause' or 'causation' to do physics?

Is there a notion of causality in physical laws?


Why does friction does not depend upon area of contact?


When is a global symmetry a gauge symmetry?


Cup of water and cup of water with oil on top


Is the Poincaré theorem valid for our universe?

Is Poincare recurrence relevant to our universe?


Does LIGO GW detection methodologically constitute discovery of two specific black holes (as astronomical objects)?

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


Why relativity doesn't rule out Inflation theory?


Is gravitational wave affected by gravitational field

Do gravitational lenses work on gravitational waves?


Time Travel possibility and Paradoxes of The Past

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


Is my expansion of the state $| x \rangle$ correct?

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


Redshift due to a static gravitational field and the conservation of energy

Do photons lose energy due to gravitational redshift? If so, where does the lost energy go?


The Ehrenfest Paradox and Euclidian Assumptions

Euclidean geometry in non-inertial frame


Why do very small balls attached to a tiny spring propel themselves in hardly moving fluids?

Is drag force on an oscillating sphere an effective model for a swimmer?


Position, velocity, acceleration, jolt, and

Physical intuition for higher order derivatives


Does wave interference happen only to same frequency waves?


Could the universe be accurately simulated with an infinitely powerful computer?

Is the universe fundamentally deterministic?


How do we see? Where do the photons disappear?


Is there a reason why the spin of particles is integer or half integer instead of, say, even and odd?


Where is the mistake in the following rationament

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


Confusion regarding the principle of least action in Landau & Lifshitz "The Classical Theory of Fields"


What is the relation between electromagnetic wave and photon?


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


How are gravitational waves exactly produced?


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


Minkowski metric: Why does it look like it does?

Minkowski metric -- why does it follow from the constancy of the speed of light?


Bicycle counter-intuitive: in which direction it will move?


Does waving a magnet around create light?


Entanglement, superposition, and propositional logic

Quantum entanglement vs classical analogy


Can the value of $c$ be calculated from Relativity?

Deriving or justifying fundamental constants


How is the classical twin paradox resolved?


What does the finding of gravitational waves mean for M Theory?

Evidence for quantum gravity from gravitational waves


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


Why can't the outcome of a QM measurement be calculated a-priori?


Why cannot massless particles carry charges?


What is it exactly that conflicts when trying to unify all 4 fundamental forces?

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


Why do physicists believe the "no-hair conjecture" to be true?


Electromagnetic wave and quantum mechanics

What is the relation between electromagnetic wave and photon?


Derivation of the low-energy effective Hamiltonian

Finding the effective Hamiltonian in a certain subspace


What is the physical significance of dot & cross product of vectors? Why is division not defined for vectors?


Is the photon's wave function the same as an electromagnetic wave(light)?


How can we know that all of the results for entangled photons are not chosen when the pair is created?

Quantum entanglement vs classical analogy


When does a singularity start to exist during a black hole formation?


How can the Hubble telescope see the light from galaxies that are millions of light years distant?

How can we see objects that are so far away?


How will the Twin Paradox become, for Time Dilation, if no acceleration was ever involved?


Where do atoms of H and He go when they rise in the atmosphere?


Wanted: simple physical representation of the influence of payload onto car tires

Does car tire pressure change with weight of car load?


Vortex in liquid collects particles in center


Is there any reason for principle of least action to be true?


Why do same/opposite electric charges repel/attract each other, respectively?


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


Why is space a vacuum? Also, why doesn't air from the Earth escape into space?


What will happen if all the population all over the world jumped together at the same time in sea?


What is the difference between weight and mass?


Null geodesic equation with affine parameters

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


modelling the sound wave of a guitar string with an equation

Why do harmonics occur when you pluck a string?


Can a person with bad vision see a blurry picture clearly?

Is it possible to blur an image in such way that a person with sight problems could see it sharp?


Where extra stored energy of Capacitor go ?

A problem of missing energy when charging a second capacitor


Can we reconstruct 1D potentials in QM from the spectrum?

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


Has the speed of gravity been measured experimentally? How?

What is the status of existing measurements of the speed of gravity?


The metric Tensor inside a massive shell

Is spacetime flat inside a spherical shell?


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


Haag's theorem and practical QFT computations


Type of stationary point in Hamilton's principle


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


Why is $C_v$ used in the derivation of the adiabatic equation?


Looking for a calculus based physics book

Recommendations for good Newtonian mechanics and kinematics books


Why do we get results of an inertial frame on an accelerating Earth?

Earth-Centered Inertial (ECI) reference frame as approximate inertial frame of reference


Why is the amplitude of a forced vibration lower above resonance than below?

Physical reason behind having greater amplitude when driving frequency$ < $ natural frequency than that when driving frequency $>$ natural frequency


Under what conditions does the relation $\vec{L} =I \vec{\omega}$ holds good?

Can the direction of angular momentum and angular velocity differ?


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


Optical illusion of car wheels, speeding up

Why do wheels appear to revolve opposite to the direction they are rotating?


Does gravity have a gauge symmetry group?


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

How can standing waves be produced in an open organ pipe if the ends are open?


What is the force that prevents an object in an accelerating inclined plane from rolling/sliding downhill?

How can an accelerating inclined plane prevent a block on it from sliding?


Since the Earth accelerates, does a stationary charge on Earth produce EM waves?

Does a constantly accelerating charged particle emit EM radiation or not?


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


Looking For A Physics Textbook That's not Super Complicated


The effect of gravitational & Coulomb forces on free electrons in a conductor


How to interpret the constraints on Poisson's ratio values, physically?

Limits of Poisson's ratio in isotropic solid


Integrating radial free fall in Newtonian gravity

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


When is spacetime homogenous and isotropic?

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


Definitions of Lagrange points: $L_4$ and $L_5$


What would happen to the Moon if Earth is turned into a black hole?

When a star becomes a black hole, does its gravitational field become stronger?


Why does the visible light spectrum appear to be circular

Why does light of high frequency appear violet?


Why do nearsighted people see better with their glasses *rotated*?


Type of stationary point in Hamilton's principle


Why does the (relativistic) mass of an object increase when its speed approaches that of light?


General relativity, gravity and spacetime curvature

Does the curvature of spacetime theory assume gravity?


Why do particular materials allow particular light waves to pass through them?


Why do we have a galactic and a solar plane


How exactly does time slow down near a black hole?


Confused about length contraction and aberration

What does a sphere moving close to the speed of light look like?


What does 1/k represent regarding Newtons Law of Cooling?


The relation between acceleration and inertial force


Calculating the height objects fall from

Ascertain the height an object has fallen from given force exerted and mass


How do the single photon energy and em-signal energy correlate?

What is the relation between electromagnetic wave and photon?


Initial conditions of the origin of the universe


How does electricity propagate in a conductor?


What is an effective and efficient way to read research papers?

How to learn physics effectively and efficiently


Why should an action in SR be a lorentz scalar?

Does action really have to be Lorentz-invariant in SR?


How concept of spin comes theoretically?


Why do neutrinos propagate in a mass eigenstate?


How can one derive Schrödinger equation?


What is the difference between light and visible light?

Is every electromagnetic radiation considered "light"?


When photons are emitted, do they accelerate to reach the speed of light?


What happened with Hilbert's sixth problem (the axiomatization of physics) after Gödel's work?


What is the formula for determining time dilation (as the object in motion)?

How do I derive the Lorentz contraction from the invariant interval?


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


How does quantum world affect us and why should I care about it?

Canonical everyday-life example of a technology that could not work without humans mastering QM in analogy to the application of GR in GPS?


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


Convert constant of gravitation to days and AUs

Units in gravitational $N$ body simulations


The choice of pivot point in non-equilibrium scenarios

Why if the torque equals zero measured from one point in space it equals zero measured from any other point?


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


why current is same through each resistance connected in series?

Current in series resistors and voltage drop in parallel resistors


Why can we balance our cycles well when it is moving fast?

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


Why is the kilogram the last SI unit which is defined in terms of a physical prototype?

Why do we still not have an exact (constants-based) definition for a kilogram?


What is the difference between ionisation enthalpy and work function?

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


What is the difference between applying force and spending energy?

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


How can the speed of light be independent of the speed of the observer

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


If a black hole was near enough us to be seen by telescope (by eye), if it ate a star, how long would we be seeing the star being eaten?

Can black holes form in a finite amount of time?


What is the process of a photon transforming into an electron and positron?

Why does a photon colliding with an atomic nucleus cause pair production?


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


Are Newton's "laws" of motion laws or definitions of force and mass?


Why don't electrons moving around in a orbit produce electromagnetic waves in their natural state?

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


Why do we assume electromagnetic fields to be doubly differentiable?

Electromagnetic field and continuous and differentiable vector fields


Are there any must read physics books for beginners?


Is the motion of rotation perfectly symmetrical?

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


A ball rolling at the bottom of a spherical bowl

Ball Rolling Down An Inclined Plane - Where does the torque come from?


What is the basic idea of loop quantum gravity?

Give a description of Loop Quantum Gravity your grandmother could understand


What is the intuitive concept of the action of a relativistic point particle?

Trying to understand relativistic action of a massive point particle


Why doesn't position and momentum commute?


Why is oil a better lubricant than water?


How do force carrying particles "give" force?

The exchange of photons gives rise to the electromagnetic force


I heard light was its own antiparticle. What happens if two photons exactly cancel each other out?

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


How does a photon travel the speed of light while it is absorbed in a molecule?

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


Are photons affected by Earth's gravity?


Why do electrons form Cooper pairs below certain temperature?

How does a phonon cause two electrons to attract each other and form a cooper pair?


What is the total observational energy of the universe?

Is the total energy of the universe zero?


If gravitation causes constant acceleration why moon does not fall into earth?

Why doesn't the Moon fall onto the Earth?


Why does matter gather as discs around massive objects?

Why are our planets in the solar system all on the same disc/plane/layer?


Confused about gravitational potential energy

How can we move an object with zero velocity?


Question about torque and center of mass

What point of application of force ensures more acceleration in a rod?


A flying fly inside a sealed box on a scale


Simple pendulum is not so simple as it seems to be?

Would a pendulum swing indefinitely in a frictionless vacuum?


Why does the pitch of a container being filled with water increase?

Why does a container with fluid make different sounds at different fluid levels?


What obstacles does de Broglie's pilot theory have to overcome?

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


How much does the Earth's population affect the force of gravity?

While finding escape velocity, does human mass counts as the mass of Earth?


Does gravity weaken by the square of the distance because the energy is dispersed over the square of the distance

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


Basic understanding of stress tensors in a fluid


Whats the reaction that creates light when I open BreatheRight strips?

Why does separating plastic from a cough drop create flashes?


What is going on in front of and behind a fan?


Relative velocity of two objects travelling at $c$ (or near $c$)

How to derive addition of velocities without the Lorentz transformation?


The force acting on a plate of a parallel capacitor

Attractive force between capacitor plates


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


How much electric charge do electromagnetic waves carry?


Why can't electrons fall into the nucleus?

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


Does a charged particle accelerating in a gravitational field radiate?


Numerical tests of Titius–Bode formula for artificial planetary orbits

Why do the planets' orbital distances fall on an exponential curve?


Is $V= V_1 + V_2$? horrible question but im confused

$V = V_1 + V_2$ confusion? Why is my "proof "incorrect?


Photons from stars--how do they fill in such large angular distances?


Shape of accretion disk surrounding the black hole in Interstellar (film)

What does this depiction of a black hole in the movie Interstellar mean?


A confusion about the proof of $\hat{p}|x\rangle=i\hbar\frac{\partial}{\partial x}|x\rangle,$ using $[\hat{x},\hat{p}]=i\hbar~?$

How to prove $\hat{p}|x\rangle=i\hbar\frac{\partial}{\partial x}|x\rangle$,using $[\hat{x},\hat{p}]=i\hbar$?


What would happen to me if I was in the LHC while it was running?

What would happen if you put your hand in front of the 7 TeV beam at LHC?


bohr-sommerfeld quantiztion condition from semiclasical WKB

Bohr-Sommerfeld quantization condition from the WKB approximation


Learn QM algebraic formulations and interpretations


Commutator between square position and square momentum


Klein-Gordon quantum relativistic equation negative energy

How does QFT interpret the Negative probability problem of the real scalar fields' Klein-Gordon equation?


What's in the empty space between a nucleus and the electrons?

What is in the space between a nucleus of an atom and its electrons?


Trajectory of a photon around a Schwarzschild black hole?


Is the electromagnetic spectrum discrete?


Wormhole time machine and violation of uncertainty?

Is the Uncertainty Principle valid for information about the past?


Does the principle of stationary action always work?

How general is the Lagrangian quantization approach to field theory?


Which book do you recommend to start studying physics for a person who doesn't have any special knowledge about physics?


In what ways does matter behave like a wave?

Is the wave-particle duality a real duality?


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

Is the EmDrive, or "Relativity Drive" possible?


Will an object always fall at an infinite speed in a black hole?

Will free-fall object into black hole exceed speed of light $c$ before hitting black hole surface?


why does the temperature of spray cans always feel cooler than the temperature of the environment?

Why does the gas get cold when I spray it?


How does the Cross section of a toy hovercraft affect on the time that it hovers?

How does the radius of a pipe affect the rate of flow of fluid?


I don't understand why a cavity with a hole is a black body

If a black body is a perfect absorber, why does it emit anything?


How to prove wave nature of large object?


Justifying the notation $\langle x\ |\ \psi\rangle$

Meaning of inner product $\langle \vec{r} | \psi(t)\rangle $


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


Understanding the AdS/CFT Correspondence


Why is propagation of uncertainties quadratic rather than linear?


BINDING ENERGY OR BINDING ENERGY PER NEUCLEON REMAINS CONSTANT


Question on Heisenberg's uncertainty principle

Is the uncertainity principle a practical reality, a theoretical law or a measurement problem?


What's the status of Cosmic Inflation after the BICEP2 debacle?


How can gravitational energy cancel out the rest energy of mass in the universe

Is the total energy of the universe zero?


Basic university textbook without colorful pictures

Recommendations for good Newtonian mechanics and kinematics books


What makes cheese so effective at absorbing microwaves?

Why does pizza cheese seem hotter than the crust?


From Lagrangian of Electromagnetic field to the Lorentz force?

Deriving the Lorentz force from velocity dependent potential


How are electrons wave as well as particles?

Is the wave-particle duality a real duality?


Can kinetic energy in atoms result in emission of all types of EM radiation?


What's the difference between magnetic fields $H$ and $B$?


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


Double Slit Experiment: How do scientists ensure that there's only one photon?


Does length of a hosepipe affect pressure/flow

Does the length of a pipe influences the flow?


What causes the permittivity and permeability of vacuum?


Gravity in 2d space and inverse linear law


What is wrong with particle acceleration based fusion?

Could we use particle colliders as fusion generators?


how come hot bodies emit radiations of several wavelengths?

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


steel pipe with solid core rod resistance to bending

would placing a solid rod inside a hollow pipe increase the ability to resist bending?


Does the gravitational field of the photon create a gravitational wave and a red shift?

Do photons and cosmic rays radiate energy through gravitational waves? If not, why not?


Why does the quarks binding energy add mass to nucleons instead of reducing it?

Quarks in a hadron: where does the mass come from?


Equation to predict the shape of a planet


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


What is the mechanism for atoms absorbing light?

How does an electron absorb or emit light?


Equipartition theorem. Neglecting one rotational degree of freedom

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


What is the mechanism that restricts a body from accelerating past the speed of light?

If rest mass does not change with $v$ then why is infinite energy required to accelerate an object to the speed of light?


Why does paper become translucent when smeared with oil but not (so much) with water?


How to prove that an arbitrary cycle in the PV diagram has an efficiency less or equal than Carnot's Cycle?

Why is the Carnot engine the most efficient?


Maximum spectral radiancy dependency on temperature formula?


If two equal but opposite pulses in a rope coincide, where does the kinetic go?

Why do travelling waves continue after amplitude sum = 0?


Why do we work path integral quantization of bosons and fermions in coherent states?

Why use coherent state path integral? What is its motivation or goal?


The temperature in space is about 3K, however there are almost no atoms in space. How can there be residual heat?


Photoelectric Effect - Dependence of current on frequency


Why do mesons like the J/Psi or Y exist? Shouldn't the quark/anti-quark pair annihilate?


What do we mean by live and neutral wire?

Difference between live and neutral wires


Behaviour of bubbles on the surface of a liquid

Why will two bubbles floating on water surface attract each other?


Why are the elements of the periodic table stable?

How come neutrons in a nucleus don't decay?


Quantum teleportation of atomic states that involve energy

Conservation of energy in quantum teleportation


why does quantumn theory not reconcile itself with general relativity

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


What is a good introductory book on quantum mechanics?


What does the presence of gravitational waves show?

Why is the detection of gravitational waves so significant?


Understanding the basic concepts of quantum mechanics using a model

Quantum entanglement vs classical analogy


How does LIGO remove the effects of environmental noise?


How does LIGO reduce noise below what it is detecting?


Why are the arms of the LIGO interferometer so long?

Why does LIGO have an arm length of few kilometers? Is the distance dependent on Gravitational Wave wavelength?


Acceleration of free particle in Minkowski space!


Is my expansion of the state $| x \rangle$ correct?


LIGO discovery: if the space "time" metric is changed, how is it measured?

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


Could discovered gravitational waves in fact be an aether wind?

Isn't LIGO basically measuring the luminiferous aether?


Other explanation for cosmological redshift?


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?


Hawking radiation and black hole evaporation

Black holes and positive/negative-energy particles


Requesting explanation for why dark matter evidence is not explained by special relativity


Showing $\frac{d^3\underline{k}}{2\omega_{k}(2\pi)^3}$ is Lorentz invariant


Theoretical implications of multidimensional Time

Intuition for multiple temporal dimensions


What symmetry gives you charge conservation?

What is the symmetry which is responsible for preservation/conservation of electrical charges?


What determines color -- wavelength or frequency?


What defines the mass of elementary particle?


When I move while holding a book, why is work done zero?

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


EM Radiations, wavelength and Wein's Law of Displacement

What causes a black-body radiation curve to be continuous?


How does isotropy of free space imply $L(v^2)$ for a free particle?

Deriving the Lagrangian for a free particle


Is it possible that the universe in its entirety is discrete rather than continuous?

Does the Planck scale imply that spacetime is discrete?


Is light electromagnetic waves or quantumn particle waves?

Is the wave-particle duality a real duality?


Quarks are now considered to be fundamentals, but so were atoms some time ago. So the way we see is only limited by our technological advances?

Is everything in the physical world composite?


What is the role of the speed of light in mass-energy equivalency?


How to deduce equations 3.6.15 in Polchinski's string theory book?

A question about the higher-order Weyl variation for the geodesic distance


Perspective and changes in kinetic energy

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


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


Why does a cork float to the side of a glass?


Is anti-matter matter going backwards in time?


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


Good ways for learning and cramming formulas?

How to learn physics effectively and efficiently


Was Einstein wrong when he said nothing can go faster than the speed of light?


How to calculate height of a bouncing ball?

Bouncing ball simulation computer science


Heisenberg's uncertainty principle - Planck's (reduced) constant divided by $2$ or not?

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


Space time curvature due to electric charge or magnetic charges

ALL "forces" as manifestations of properties of space-time


Electric field near surface of a conductor?

Why do surfaces act like barriers for electrons?


How are symmetries defined mathematically?


Why the color of Sun is yellow, red or orange?

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


Why does air circulate on an airfoil --- The Kutta Condition

Why does the air flow faster over the top of an airfoil?


When you twist your glass, the ice stays still

Why does an ice cube not twirl along when twirling a drink glass?


What is the best source to study Classical Mechanics for a Grad Physics student who struggles to solve problems?


What happens to the potential energy of a compressed spring when it dissolves in acid?


Learning about group velocity, phase velocity and particle velocity

What is a good introductory book on quantum mechanics?


electrons in elecrtostatic force(please read specification given below)


Red color has largest wavelenght and violet minimum (in the range of visible light). then why does violet light appears reddish? RED + BLUE = VIOLET

Why does light of high frequency appear violet?


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


The Spinning Log "Perpetual Motion" problem, and my attempt at a solution


What is source of Infrared Radiation from some solid object?

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


Is there a proof from the first principle that the Lagrangian L = T - V?


Where do the bipolar jets of black holes come from?


Why does light reflected on water tends to 'smear' in the vertical direction?

Why does sunset over a body of water cause a path of light stretching towards the horizon?


When light changes medium, does it decelerate, or instantaneously change speed?


How fast does a black hole appear to decay from infalling observer's perspective?

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


Detection of the Electric Charge of a Black Hole


Why is there steam in a hot shower even though the water is not boiling?

How does water evaporate if it doesn't boil?


What is the math knowledge necessary for starting Quantum Mechanics?


Can quantum fluctuation happen outside space-time?

Physical laws prior the big bang (quantum fluctuations)


Torque considered about different points in a system

Why if the torque equals zero measured from one point in space it equals zero measured from any other point?


How do we know that entanglement allows measurement to instantly change the other particle's state?


How does light know which path is fastest?


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


Infinite series of derivatives of position when starting from rest


Is Jefimenko's assertion regarding E and B fields a physical fact?

Do the electric and magnetic components of an electromagnetic wave really generate each other?


Why infrared light waves is visible through camera?

Infrared remote flashes blue light in camera


How can I solve this differential eqution with IVP?

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


How to learn physics effectively and efficiently


Is gravitational attraction increased by relativistic mass as well as rest mass?

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


Exceeding the speed of light using gravity?

Can gravity accelerate an object past the speed of light?


Why does the wave function have to be continuous?


How could the "Big Bang" singularity have actually expanded?

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


Expanding universe - does the Hubble red shift come from gravity?

Is it possible that galaxies' redshift is caused by something else than the expansion of space?


Besides water, which substances are less dense as solids than as liquids?


Is the Higgs boson not responsible for most mass?


Why does a breeze of wind make us feel cooler?

Why does blowing on someone who is wet feel colder than on someone who is dry?


How can I prevent my son building up static on his trampoline?

How to avoid getting shocked by static electricity?


Is there a difference between a postulate and a principle in physics?


Why are alpha particles such a prominent form of radiation and not other types of nucleon arrangement?


How can we deduce the relation $m = \frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}$ between relativistic mass and rest mass in special relativity?

Does the (relativistic) mass change? Why?


why does the phase change when wave reflects from rigid boundary

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


Evidence that the Solar System is expanding like the Universe?

Can the Hubble constant be measured locally?


What is the invariant associated with the symmetry of boosts?

What conservation law corresponds to Lorentz boosts?


Srednicki's Path Integrals: Ground-State to Ground-State Transition Amplitude in the Presence of a Perturbation


Hurdles in creating (close to) infinite images


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


What made us think that Earth moves around the Sun?


What does Lijun Wang's experiment about supraluminal speed of light in a medium mean?


Why does the speed of light $c$ have the value it does?

The origin of the value of speed of light in vacuum


Dense Spherical Black Hole Shell with a Region Inside


Where does the Pauli Repulsive Force come from that counteracts the attraction between atoms and ions?

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


How - The force of a 60 mph crash is not just twice as great as a 30 mph crash; it’s four times as great!

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


What forces are at work causing sand to migrate to the centre of a spinning bucket of water?

Vortex in liquid collects particles in center


On a hot day, when it's cooler outside than in; is it better to put a fan in an open window pointing inwards or outwards?


How can a particle's position be random and uncertain in quantum mechanics if it is already pre-determined in relativity?


In what limit does string theory reproduce general relativity?

How does classical GR concept of space-time emerge from string theory?


Should black holes be considered two-dimensional or three-dimensional?


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


Why do floating water drops form spheres?


If velocity is constant, how can $p = F\cdot v$ be non zero?


Do photons experience every moment in time and position in space simultaneously?

How does a photon experience space and time?


Does Quantum Mechanics assume space and time are continuous?


If light rays obey to the wave equation, why can they be thought as straight lines?


Is there such a thing as "Action at a distance"?


Why don't electromagnetic waves require a medium?


How to visualize the gradient as a one-form?


Are metals more reflective at lower temperatures?

Reflectivity of a glowing-hot metal surface


How to prove that we are living in a 3+1D world?


Effect of redshift on energy conservation


How to compute the speed of a cosmic ray from its energy?

Relativistic speed/energy relation. Is this correct?


What is the gravitational pull if one has as much mass above them as below them?

Would you be weightless at the center of the Earth?


Why is kinetic friction less than static friction?

Why are there both Static and Kinetic Friction?


Why do we use Hermitian operators in QM?


Why is the coefficient of kinetic friction greater than the coefficient of static friction?

Can the coefficient of static friction be less than that of kinetic friction?


Is it really impossible to calculate in advance the result of throwing dice?


How did planets start to spin and do all of them spin in same direction?


How can the unstable particles of the standard model be considered particles in their own right if they immediately decay into stable particles?

What is the essential difference between a resonance and a particle?


How can we see the moon while it's between the Earth and the Sun?


Can very strong gravitational wave collapse into a black hole?

Can colliding gravitational waves create a black hole?


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


HOW is electric field inside a conductor placed in an external field zero?

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


Does the canonical commutation relation fix the form of the momentum operator?


How the speed of light is constant in the universe if it decreases in water and glass and some other objects?

What is the status of massless photons traveling through a medium?


Why does heating eggs not change the State of matter from solid to liquid

Solidification by the application of heat


how is current measured through ammeter?

Conversion of Moving coil galvanometer to ammeter


If current takes the path of least resistance, why do parallel circuits work?

Electricity takes the path of least resistance?


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


How can we assume that reaching the speed of light slows down time?


Does a moving object really shrink due to length contraction?

What is the real meaning of length contraction?


Why don’t photons interact with the Higgs field?


Time dilation in outer space vs in a gravitational field?


What is the difference between the compact U(1) group and non-compact U(1) group?

What is (meant by) a non-compact $U(1)$ Lie group?


Why does a cyclist/motorcyclist bend when making a turn?

Does leaning (banking) help cause turning on a bicycle?


Why a two wheeler is not pulled down by gravity while moving

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


What's wrong with my derivation for the spring constant?

Wrong calculation of work done on a spring, how is it wrong?


Hexadecapole potential using point particles?


Is diamagnetism a static or dynamic effect?


Do different density objects in liquids affect net weight


Why do roads appear wet on hot days? I do not understand

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


Why do non-circular oscillations have angular frequency?

Relation between shm and circular motion


What is meant by the spin of a particle?

What is spin as it relates to subatomic particles?


Explain why we use this formula to calculate total resistance


What is physical significance of product of Inertia?

What's the physical significance of the off-diagonal element in the matrix of moment of inertia


Why does light of high frequency appear violet?


Is the total energy of the universe zero?


The electron: why can't it have both momentum and position

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


Vertical Travelling - Taking Advantage of Earth's Rotation

Sideways motion between a vertical launch from a planet and landing


How did Pauli and Fermi deduce the existence of the neutrino?

Neutron decay and electron anti neutrino $n\to p + e + \bar{\nu}_e$


Why do Oreo crumbs float to a single glob at the very center in a glass of milk?

Why does a cork float to the side of a glass?


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


Why do we use sine/cosines in Simple Harmonic Motion?

How to prove that a motion is Simple Harmonic Motion (SHM)?


Will the background radiation get "dimmer"? If so when will it be "turned off"


What symmetry operation mixes states with different $\ell$ in hydrogen atom?

What symmetry causes the Runge-Lenz vector to be conserved?


How can a particle in a medium ever travel faster than light?

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


Entanglement: Is it possible to prepare and reset probabilities to send information?

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?


Quantum mechanic newbie: why complex amplitudes, why Hilbert space?

What is the physical meaning of a "complete" Hilbert space in QM?


Rotation, cats landing on their feet, and conservation of angular momentum

Effect of the tail of the cat in the falling cat problem


How can things at the event horizon slow down and appear to stop to a remote observer?

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


What is the origin of non-conservative force?

What exactly makes a force conservative?


Resources for applications of Keldysh Green's functions


Effect of introducing magnetic charge on use of vector potential

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


Why does this object periodically turn itself?


Do all the photons have the same energy?

Can someone explain Planck's constant simply?


What would be the requirement to learn matrix mechanics?

Matrix mechanics for those with wave mechanics background


Using Einstein's Relativity: Who is younger?

How is the classical twin paradox resolved?


How does classical GR concept of space-time emerge from string theory?


Projectile motion equations @ very (!) high starting velocity

How to calculate a ballistic trajectory for a suborbital flight?


Transforming a sound wave into a literal light wave. Is it possible?

Why is light produced when an underwater bubble is collapsed with a sound wave?


Why does photon have only two possible eigenvalues of helicity?

Why is the $S_{z} =0$ state forbidden for photons?


How can we compare the ratio of strenghts fundamental forces?

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


Fourier transform in Klein-Gordon equation

Fourier transform standard practice for physics


If magnetic fields are created by moving charges, how do magnets work?

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


What happens to body chemistry at the speed of 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?


Coulomb's Law: why is $k = \dfrac{1}{4\pi\epsilon_0}$

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


Is it possible/correct to describe electromagnetism using curved space(-time)?

Noticing that Newtonian gravity and electrostatics are equivalent, is there also a relationship between the general relativity and electrodynamics?


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

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


Did time exist before the Big Bang and the creation of the universe?


Software to calculate forces between magnets

Where can I find simulation software for electricity and magnets?


Why is gravitational potential energy shared between two particles?

Kinetic energy of the object, but Potential energy of the system: Why is it so?


Is there any way to increase the speed of the blades (air coming out) of my fan?


Would time exist in a universe with only one elementary particle in it?

In a very small static universe with only a particle, does it make sense to talk about time?


Why does my camera's indicator light produce so many reflections off a window?


Interval preserving transformations are linear in special relativity


Do positively charged particles exchange photons?

Deriving the Coulomb force equation from the idea of photon exchange?


Energy doesn't get lost? Basic understanding, please

Kinetic energy conservation in a collision


Eulerian or Lagrangian picture in Fluid mechanics?

Transitioning between Lagrangian and Eulerian fluid variables


Is there a difference in the pace of time between the two cases described below?

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


Can frictional force accelerate (speed up) a body?


Derivative of $T^{\mu \nu}_{\mathrm{mat}}$ in terms of $F^{\mu \nu}$ and $j^\nu$

Show that $\partial_\nu T^{\mu\nu} = - j_\nu F^{\mu\nu}$


Pumping (going faster and faster) on a swing

Can you get a playground to swing from stationary


Why are all light bulbs in a series circuit equally bright?

Why must identical lightbulbs in series have identical voltage drops?


Is Quantum spin greater than $1$ possible?


What are the evidences of the big bang theory?

What has been proved about the big bang, and what has not?


Is mathematical rigour irrelevant in most physics fields?


Do temperature and kinetic energy depend on overall motion?


Momentum measurement of a particle in an infinite well

How can I solve this quantum mechanical "paradox"?


Why isn't Higgs coupling considered a fifth fundamental force?


Is a state with definite momentum possible in presence of an infinite square-well potential?


What will affect the value of Young's modulus?

What factors affect the Young's modulus of elasticity?


Eigenvalues of Lagrangian/action operator?


AC vs DC & why we ended up using AC for power in our homes, etc

Why do we use AC for long distance transmission?


Invariance of lagrangian with $\frac{d}{dt}(f(q,t))$

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


Generalize QFT with gravity by adding metric factor - what's the problem?

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


Gravitational attraction between two kilogram weights

The Time That 2 Masses Will Collide Due To Newtonian Gravity


Trajectory Required to Hit Target with Newtonian Drag

Projectile Motion with air Resistance - Adjust only the Angle to hit a target


Confusion about Dirac notation in quantum mechanics


Why are both LIGO detectors nearly co-aligned?


Why is the direction of a flame is always upward?


Why are the axes in Minkowski diagrams swapped when comparing with diagrams in classical kinematics?

Axis/vector notation in Minkowski diagrams


How much time will it take for an object to fall to the center of the Earth?

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


What happens to gravity in the middle of the earth?


Mathematically-oriented Treatment of General Relativity


How long does it take for a black hole to form for an external observer?


Is there a standard resource that lists all understood particle-particle relationships?


External quality factor of an inductor capacitively coupled to a waveguide

$Q$ factor of parallel RLC circuit in series with a capacitor and resistor


How to know if something is a primitive concept, a law, a definition or a theorem


Explicit solutions to simple one-dimensional fluid flow problems?

Exact Solutions to the Navier-Stokes Equations


Does light color change when refracting?

Does light change color on its way through a window?


Can you lift yourself standing on a wooden block using pulley mounted on block?

Force on rope with accelerating mass on pulley


Is it possible that the LIGO results are anomalies?

Is there absolute proof for gravitational waves?


Textbook on the Geometry of Special Relativity


Quantum entanglement: does it necessarily imply superluminal information transfer?

Why is quantum entanglement considered to be an active link between particles?


Elliptic R-matrix and Yang Baxter solution for XYZ model


Using complex numbers to represent waves

What is the physical significance of the imaginary part when plane waves are represented as $e^{i(kx-\omega t)}$?


Magnetic field of a wire with over 1000 amperes?

Direction of Magnetic force from a current running through a coil of wire


Photons are packets of electromagnetic radiation (wave) what about other particles?

Is the wave-particle duality a real duality?


Does Super Mario physics work in reality?


Relativity and speed of light again - two opposite light sources


If a photon is a boson and has spin 1, shouldn't it have 3 spin orientations since spin 1 is a triplet?

Why does photon have only two possible eigenvalues of helicity?


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?


Because position is relative, is it possible to see a star orbiting a planet?

Could there be a star orbiting around a planet?


Doesn't the Schwarzschild metric combined with Hawking radiation imply that nothing ever gets past the event horizon of a black hole?

Why does Stephen Hawking say black holes don't exist?


Another universe in the other side of a black hole?

Is it mathematically possible for a black hole to be connected to a white hole or a worm hole?


How do moving charges produce magnetic fields?


Propagation of uncertainty - which formula?

Why is propagation of uncertainties quadratic rather than linear?


a question about work needed to move a charge towards another one

How can we move an object with zero velocity?


Which technique is used to measure huge astronomical distances which are in terms of billions of light years?

How do astronomers measure the distance to a star or other celestial object?


Is it better to walk or run when there is rain?


Why does this object periodically turn itself?


What is the motion of quarks inside nucleons?


Why is Earth's gravity stronger at the poles?


Would passing horizontally polarized light through a varying width vertical slit allow you to measure the positional (x) amplitude of light?

Amplitude of an electromagnetic wave containing a single photon


Identify for $f(\infty)+f(-\infty)$ in quantum field theory

S. Weinberg, “The Quantum theory of fields: Foundations” (1995), Eq. (9.2.15)


Resistor circuit that isn't parallel or series


Why do we use Fourier transforms in QFT?

Why use Fourier expansion in Quantum Field Theory?


What is the difference between $|0\rangle $ and $0$?


Why do virtual particles form at black hole horizon?

Black holes and positive/negative-energy particles


Will free-fall object into black hole exceed speed of light $c$ before hitting black hole surface?


How can matter reach the singularity of a black hole if time stops at the event horizon?

Can matter really fall through an event horizon?


Could gravitational waves and electromagnetic waves/light be the same thing?

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


Do photons lose energy due to gravitational redshift? If so, where does the lost energy go?

Have red shifted photons lost energy and where did it go?


How much magnetic field will be required to levitate a human?

How strong of magnetic field would noticibly attract a person?


Can one detect cosmic ray muons with a DSLR camera?

Is it feasible to measure the energy of cosmic ray muons with a consumer Digital Single Lens Reflex camera?


Interpretation of Mass Continuity Equation in MHD


Since Earth spins, would an aircraft travelling opposite to direction of Earth spin take less time?

Does the rotation of the earth dramatically affect airplane flight time?


Why does this resource say that the Schrodinger Equation can be derived?

Is the Schrödinger equation derived or postulated?


Where does the majority of the mass of the usual matter come from?

From which dimensionful constants does proton mass arise?


What causes this pattern in the reflection of a laser on a screen?


Is it possible for a black hole to form for an observer at spatial infinity?

Can black holes form in a finite amount of time?


The distance square in the Newton's law of universal gravitation is really a square?


Problem book in Quantum mechanics with emphasis on physical(ly relevant) problems


How do you change Planck's law from frequency to wavelength?


Conservation of Energy in Different Frames of Reference

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


Difference in velocity of light in change in medium

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


If the observable universe keeps expanding would we eventualy see light 24/7.... clouds permiting?

Will the night sky eventually be bright?


Why does the Sun "shine brighter" some days?

Why is the sun brighter in Australia compared to parts of Asia?


Is the total energy of the universe zero?


What reason(s) exist to suppose that all degeneracy pressures can be overcome in Black-Hole formation?


Electrodynamics and the Lagrangian density

Retrieving Maxwell's equations from the minimum action principle


Why both yellow and purple light could be made by a mix of red, green and blue?

How does light combine to make new colours?


A mathematician who wants to learn particle physics

Mathematician learning theoretical physics


How does a rocket moves upwards to escape Earth's gravity?


Introductory condensed matter physics book

Books for Condensed Matter after Ashcroft/Mermin


Paradox of weight increasing with relative velocity


conservation of energy in orbital motion


Why does a photon have momentum and no mass, yet $p=mv$?

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


Why accelerating charged particles radiate EM waves?

How and why do accelerating charges radiate electromagnetic radiation?


Does rolling without slipping or pure rolling mean friction is not acting?

What role does static friction force play for a rolling object? How can I know what direction it points?


Electric field lines forming closed loops


Is "quantum superposition" just a fancy way of saying that a system is in one state or another with some probabilities?

What's an atomic superstate/superposition, and how is it possible?


Does quantum spin suggest particles have extent?

An electron has no known internal structure, does that imply it has an unknown one?


How fast can video/ transmission waves travel through space?

What will I see if I travelled to a distant planet in 100 times faster than speed of light and look back?


Why do products of nuclear decay have a lower mass than the original nucleus, when the sum of the mass of its nucleons is larger?


Why do electron and proton have the same but opposite electric charge?


Does a photon in vacuum have a rest frame?


Why does the (relativistic) mass of an object increase when its speed approaches that of light?


How is Zeno's Dichotomy Paradox resolved according to physics?

How can an object move from point A to point B?


How come in free fall you feel weightless even though gravity is pulling down on you?


Age of the universe versus absolute time

Doesn't dating the universe violate the concept of spacetime's inseparability?


Why and how does the 'clock rule' of electromagnetism (i.e. current flows clockwise as seen from the south pole of an electromagnet) work?

How do you derive Fleming's left hand rule?


Is it possible that Gravity is a Repulsion phenomenon instead of an attractive "force"?

Can we model gravitation as a repulsive force?


Considering Hawking radiation, can an object ever actually cross event horizon of a black hole?

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


Group and phase velocity - why can the latter be faster than light?

In superluminal phase velocities, what is it that is traveling faster than light?


Does a set of eigenvalues in QM correspond to a random variable in statistics?

Is what statisticians call a "random variable" what physicists call an "observable" in QM?


Comprehensive book on group theory for physicists?


Express Planck's Law for blackbody radiation in terms of frequency


Why isn't the center of the galaxy "younger" than the outer parts?


Backyard experiments to falsify the Flat Earth theory

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


Definition of electric charge and proper explanation


How do I show that $\text{tr}(A^{\dagger} B) = \langle m | A \otimes B |m\rangle $ for general matrices $A$ and $B$?

Uhlmann's Theorem: proof of $\text{tr}(A^{\dagger} B) = \langle m | A \otimes B |m\rangle $


Is there any material that does not return/reflect light?


Why is the gravitational constant.. constant?

Is the gravitational constant $G$ a fundamental universal constant?


Black holes and positive/negative-energy particles


Use of fission products for electricity generation


Rigorous Mathematical Proof of the Uncertainty Principle from First Principles

Heisenberg Uncertainty Principle scientific proof


Why does general relativity need space to be continuous?

In GR, why should the spacetime manifold be differentiable?


Can the Hubble constant be measured locally?


Why does space expansion not expand matter?


Why do we prefer "Lagrangian and Hamiltonian mechanics " over the newtonian mechanics?


Trouble understanding Landau & Lifshitz writing about Lagrangians and Galilean Relativity

Deriving the Lagrangian for a free particle


Why are galaxies flat since it's an unstable configuration in 3d?


Experimental evidence of a fourth spatial dimension?


Spin, orbital angular momentum and total angular momentum


What is the scientific reason for the inclination of earth's rotation axis?


Why aren't we all moving at the speed of light relative to photons?

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?


How far can a sub-light-speed particle travel? And how fast will it arrive?

How far can something travel in a straight line?


According to some theories space is constantly expanding but at what granularity?


Can we use the planets and Sun to fling out a craft at relativistic speeds?


Why do two bodies of different masses fall at the same rate (in the absence of air resistance)?


Why Earth is considered to be an inertial frame?

Earth-Centered Inertial (ECI) reference frame as approximate inertial frame of reference


Gravitational force: Is the gravitational force dependent on the nature of the medium present in between the two masses?

Why is there no permittivity-type constant for gravitation?


Concentration and manipulation of magnetic fields

Can magnetic fields be redirected and focused at one point?


Dipole Moment (spherical/arbitrary charge density)

Radially symmetric charge distribution (dipole moment)


How can I best independently study physical cosmology?


Work done by Friction. Can it be positive or zero?


When two equally opposite charges placed then which type of motion will carried out b/w them?


Gravitational effect at different depths in the earth


Relativistic Commutation relation for momentum and position

Is there a time operator in quantum mechanics?


Difference between first newton's law and second newton's law ?


Why do tidal forces not violate conservation of energy?

When a planet is heated through gravitational pull, where is the energy taken from?


Flotation of a body which is submersed into a incompressible fluid using Archimedes principal

Basic buoyancy question: Man in a boat with a stone


In what physical situation would the correlation of two spins be useful?


Trying to understand why energy must be quantized/discrete

Discreteness of set of energy eigenvalues


Book recommendations for fluid dynamics self-study


Time dilation (special and general relativity)

Cancelling special & general relativistic effects


Expectation value of momentum in any bound state

Expectation of momentum in the bound state


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


Why do Calabi-Yau manifolds crop up in string theory, and what their most useful and suggestive form?

Why (in relatively non-technical terms) are Calabi-Yau manifolds favored for compactified dimensions in string theory?


Where is the force of gravity fueled from?


Do we have proof that the universe is finite?


Lagrangian mechanics vs Hamiltonian mechanics

What exactly are Hamiltonian Mechanics (and Lagrangian mechanics)


Textbook on group theory to be able to start QFT

Comprehensive book on group theory for physicists?


Is the total energy of the universe zero?


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


Have red shifted photons lost energy and where did it go?

Redshifting of Light and the expansion of the universe


Does quantum mechanics conserve information after a measurement?

Is there conservation of information during quantum measurement?


Second law of Thermodynamics: Why is it only "almost" always true that entropy is non-decreasing?

Chance of objects going against greater entropy?


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


Time as a Hermitian operator in quantum mechanics


Double slit experiment - how to see an electron going through a slit?

Is Dr Quantum's Double Slit Experiment video scientifically accurate?


Do spacelike singularities really exist in quantum gravity?

Do singularities have a "real" as opposed to mathematical or idealized existence?


What software programs are used to draw Mechanics, Electricity & Magnetism, Waves, Thermodynamics, Optics & Modern Physics diagrams?

What software programs are used to draw physics diagrams, and what are their relative merits?


Gravitational waves detection, any news?

Is there a good chance that gravitational waves will be detected in the next years?


What is the current science on entropic gravity?


Has anyone actually "seen" entanglement?

How do we know that entanglement allows measurement to instantly change the other particle's state?


Is two cars colliding at 50mph the same as one car colliding into a wall at 100 mph?


Eq. (2.4.7) of Weinberg, "Lectures on QM" from eq. (2.4.6)


What is a good introductory book on quantum mechanics?


Condensed matter physics for mathematicians

Mathematical rigorous introduction to solid state physics


The exchange of photons gives rise to the electromagnetic force

Deriving the Coulomb force equation from the idea of photon exchange?


Why does space expansion not expand matter?


Theories that Relate Gravity, Electricity, and Magnetism

Noticing that Newtonian gravity and electrostatics are equivalent, is there also a relationship between the general relativity and electrodynamics?


What are the factors affecting transparency and color of a substance


Maximum friction force for a wheel to be able to roll

Can we know when rolling occurs without slipping?


Is the ground state closest to the uncertainty relation?

Do stationary states with higher energy necessarily have higher position-momentum uncertainty?


What happens to the energy of photons when two light waves with plane wavefront interferes destructively?

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


Why are we still living if matter and anti-matter annihilate each other?

How come the universe is made of matter and not antimatter?


It seems wrong to find the mass using weight alone when using chemical compounds

What is the difference between weight and mass?


If earth generates magnetic field does it attract metal?

Are metals more heavy due to the Earth's magnetic field?


How can we differentiate between matter and antimatter?

How would one detect antihydrogen in the universe?


What does negative absolute temperature mean?


Will the night sky eventually be bright?


Why doesn't this perpetual motion machine work?

Why doesn't this magnetic perpetual motion machine work?


Cancelling special & general relativistic effects


Do quantum physics apply universally at all scales?

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


How can a photon exist on its own without a mass?

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


Are the electric charges of an electron and a proton equal or approximately equal?

Why do electron and proton have the same but opposite electric charge?


Tangential acceleration in circular motion?


Recommendation of papers, or reading materials on ${\cal N}=2$, ${\cal N}=4$ supersymmetry


What is $\Delta t$ in the time-energy uncertainty principle?


Is there a simple explanation for the fact that the Lorentz transformation must be linear?

Interval preserving transformations are linear in special relativity


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


Is the observable universe growing or shrinking?

Maximum size of the observable universe?


Recommendation for contra-variant and contra-variant vectors in the context of special relativity

Textbook on the Geometry of Special Relativity


Why does paper become translucent when smeared with oil but not (so much) with water?


A confusion on Radiations emitted from a body

Acceleration of electric charges and radiation


How can physics claim that information cannot be destroyed?


What is the difference between diffraction and interference of light?

Why is it difficult to differentiate between interference and diffraction?


Why is Coulomb's law is an inverse square law?

Does Coulomb's Law, with Gauss's Law, imply the existence of only three spatial dimensions?


Is it possible for a substance to be lighter than air in a liquid state?

Is it possible to have a Gas heavier than a liquid?


Are scientists missing the point with distant cosmic objects, or is it just me?


Why do heated bodies produce continuous spectra?

What causes a black-body radiation curve to be continuous?


Understanding "natural variables" of the thermodynamic potentials using the example of the ideal gas


Why must nuclei contain both protons and neutrons?

Why don't neutrons cluster on their own?


How much Sun is expected to curve spacetime?

How to measure the curvature of the space-time?


Disproving an Operator Identity; Completing a Set of Rotationally Invariant Operators


Is the Universe being dragged into a singularity rather than expanding?


Shape of tank for which water level falls at constant velocity


Learning General Relativity from a mathematical and physical point of view


How do virtual photons exist without violating conservation of energy?

Why don't virtual particles violate conservation of mass/energy?


Is red-shift a violation of the conservation of energy?

Redshifting of Light and the expansion of the universe


Deriving Potential Energy Density for Longitudinally Vibrating String

Potential energy of an infinitesimal length of elastic rod


Prove that time for planet to fall into the Sun equals $\left( \frac { 1 }{ 4\sqrt { 2 } } \right)$ of the planet's period


Is the speed of light the speed limit or does light just happen to travel at the maximum speed?

What is so special about speed of light in vacuum?


Is general relativity a background dependent theory in five dimensions?

Can general relativity be explained by equations describing a fabric of space embedded in a flat 5-dimensional Minkowski space?


What will happen if one reach the boundary of the Universe?


Is space expanding equally in every direction?


Quantum Entanglement- why are we so suprised?

Quantum Entanglement - What's the big deal?


Do the virtual particles have any mathematical meaning in vacuum in absense of real quanta?

Do virtual particles actually physically exist?


Why does light follow the Fermat's principle of least time?

How is Fermat's least time principle proven?


Why is the Principle of Superposition true in EM? Does it hold more generally?


On the evolution of the universe that currently has no definitive answer to how it is evolving and at what rate:

According to Hubble's Law, how can the expansion of the Universe be accelerating?


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


Why can't a real scalar couple to the electromagnetic field?


How exactly does wave theory of light fail to explain blackbody radiation?


Conservation Laws and time-reversal symmetry

Is there something similar to Noether's theorem for discrete symmetries?


Is the interference quantum mechanical superposition the same as entanglement?

Can Quantum Entanglement and Quantum Superposition be considered the same phenomenon?


Difference between a light wave in space and a wave in a pond

What's the difference between mechanical and electromagnetic waves?


Cross product and the right hand rule - what is the intuition behind it?

What is the physical significance of dot & cross product of vectors? Why is division not defined for vectors?


Are black holes an infinite source of energy?

Why does a black hole have a finite mass?


The significance of the pressure term within the momentum-energy tensor

Intuitive understanding of the elements in the stress-energy tensor


Path integrals and Weyl ordering in Peskin and Schroeder

Why path integral approach may suffer from operator ordering problem?


Can Lagrangian be thought of as a metric?


Would you be able to see yourself in a mirror in front of you as you two are in a room traveling at the speed of light?

reflection at speed of light when both mirror and viewer is travelling at the speed of light


Can anything other than recessional motion cause a redshift?

Other explanation for cosmological redshift?


Travelling at a relative speed greater than the speed of 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?


What Happens to electrons after Alpha Decay and Nuclear Fission?


Influence of spacetime curvature on electromagnetic wave propagation

Coulomb's Law in the presence of a strong gravitational field


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


Action-Reaction pair in case of rocket accelerating in space

What is a rocket engine thrusting against in space?


Does EPR permit information to travel faster than light?

Quantum entanglement faster than speed of light?


Compound microscope vs astronomical telescope


Why does the magnitude squared of the wave function give us the probability density?


We Don't NEED Quantum Gravity because Gravity isn't Even A Force!

What are the reasons to expect that gravity should be quantized?


What is the significance of the "squared" in $E =mc^2$?

What is the meaning of speed of light $c$ in $E=mc^2$?


If you fall in a black hole, when do you go past the event horizon?

Can matter really fall through an event horizon?


Why does aluminium foil spark in the microwave?

Why do metal objects in microwaves spark?


At what point does force stop translating an object and start purely rotating it?

Do objects rotate around the torque vector or its center?


Magnetic field and electric field induce one another forever

Induced magnetic field produces electric field and vice versa forever!


A roadmap for learning standard model of particle physics

A No-Nonsense Introduction to Quantum Field Theory


What exactly is "displacement" and "velocity"?

What is displacement? Position relative to a reference point or change of position


Calculating impact velocity and time with non-uniform acceleration

Kinematics with non constant acceleration


Effect of sun turning into a black hole on earth

If the Sun were to suddenly become a black hole of the same mass, what would the orbital periods of the planets be?


What is the physical significane of Complex Time Evolution in EM Waves?

What does the complex electric field show?


Why does the wind direction vary locally?


Why can't we stand on fluid surface if newton's third law is applicable

If Newton's third law is true, why can we sink in sand?


Derivation of Euler's equations for rigid body rotation


What is the physical significance of dot & cross product of vectors? Why is division not defined for vectors?


Contracting Indices in General relativity


Is absolute zero possible in a complete vacuum?

Why is absolute zero considered to be asymptotical? Wouldn't regions such as massive gaps between galaxy clusters have temperatures of absolute zero?


What does Bell's Theorem really violate?

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


Representations of a symmetry group: what is actually being represented?

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


Caldeira-Leggett dissipation model: Call for Help!

Caldeira-Leggett Dissipation: frequency shift due to bath coupling


How do we know distance to; size of merging black holes?

How were the solar masses and distance of the GW150914 merger event calculated from the signal?


How two charges of different magnitude can exert equal force

How do varying static point charges exert the same force on each other?


Griffiths's take on degenerate perturbation theory

Why are the zeroth order terms in degenerate perturbation theory the eigenstates of the perturbing Hamiltonian?


Where does stuff "sucked" up by a black hole go?

What happens to light and mass in the center of a black hole?


Does the ground beneath a levitating object change due to the rotation of the earth?

Why does the atmosphere rotate along with the earth?


How far would I have to go to see a fully rounded Earth?

How far into space does one have to travel to see the entire sphere of earth?


Recommendation request for a book explaining string theory to a common idiot (me)

What is a good non-technical introduction to theories of everything?


Interpretation of the nature of light in quantum mechanics

What is the relation between electromagnetic wave and photon?


Lagrangians, Hamiltonians and the Legendre Transform

Why are Hamiltonian Mechanics well-defined?


How to define system boundaries for Pauli exclusion principle?

Pauli principle for particles very far apart from each other


Are there substances that could only exist in one state of matter or at least not all of them?

Why does matter exist in 3 states (liquids, solid, gas)?


Is the wave-particle duality a real duality?


What kind of energy/force do astronauts experience away from the earth 's atmosphere/beyond?


Relationship between electromagnetic wave and photon


Conserved Quantities And Lagrangian Mechanics

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


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


How to prove useful property of logarithm of generating functional in QFT?


Earth moves how much under my feet when I jump?


If I have a rod,made of some metal,what experiment should I perform to check whether or not the mass is evenly distributed in the rod?

How can I determine whether the mass of an object is evenly distributed?


Why the reference for kilogram has to be round in the Avogadro Project?

Why is the prospective new kilogram standard a sphere?


How is the expansion of space itself explained in LQG?


How to calculate a planet's tangential velocity moving in an elliptic orbit?

Velocity of an satellite in an elliptical orbit


Can time period for pendulum be negative?

Use of negative frequency for the sake of simplifying mathematics?


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


Invariance of canonical Hamiltonian equation when adding the total time derivative of a function of $q_i$ and $t$ to the Lagrangian


Resistor circuit that isn't parallel or series


Quantum uncertainty affecting classical object?

Probability, quantum physics, and why (can't it/does it) apply to macroscale events?


Is the following proof of the "cancellation of dots" correct?

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


Are the 3 generations of matter somehow connected to 3 dimensions of space?

Why are there 4 Dimensions and 4 Fundamental Forces?


Moment of Inertia of a Ring about an axis inclined at $\frac {\pi}{4} $ radians with normal to plane of ring


Is a unit coupling coefficient for mutual inductance (so $M=\sqrt{L_1L_2}$) compatible with different self-inductances $L_1\neq L_2$?

How do I show for an ideal transformer $M^2=L_1L_2$?


Why is pressure in a liquid the same in all directions?


What does $t_0$ mean in constant acceleration equations?


Does a photon not having a reference frame result in logical inconsistency?

Does a photon in vacuum have a rest frame?


How are the photon and electron entangled in this situation?


Does third law of motion apply to light or EM waves?

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


if somehow we could survive in black hole would we survive the end of universe as time inside black hole would stop and would be infinite?

What will the universe look like for anyone falling into a black hole?


Vector spaces for the irreducible representations of the Lorentz Group


Physical reason why the wavelength defines the minimum sized opening an electromagnetic wave can pass through?


Why do denser things sink? Detailed justification needed


Is there any evidence of black holes existing?


Is the there a unique correspondence between the potential and bound state wave functions?

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


If the friction coefficients depend on the object's property, why do they change in sliding & rolling, despite the object being same?

Why are there both Static and Kinetic Friction?


Are electrons really elementary particles?

References on the non-compositeness of the known elementary particles


Could we recognize our galaxy by looking at it from a different place in the universe?

Are all galaxies we see really our Milky Way? Any possibility?


Why buoyant force equals weight of fluid displaced?


Spinning a rope when hanging, what is the curve?


Calculating effective capacitance of a circuit


Why do photons and gluons not interact with the Higgs field?

Why don’t photons interact with the Higgs field?


If photons have a wave particle duality would gravitons have a wave particle duality?

Does wave-particle duality exist for gravitational waves?


Radially symmetric charge distribution (dipole moment)


How is electric field instantaneously generated inside a conductor connected across two terminals of a battery?

How does electricity propagate in a conductor?


Effect of a photon on curvature of spacetime

Does a photon exert a gravitational pull?


Why can't electrostatically accelerated deuterium beams neutralized by electrons produce net energy fusion?

Could we use particle colliders as fusion generators?


Do we have the potential technology to harness the energy the Earth is constantly giving us?

Can we get energy from the Earth's rotation?


Interpretation of $\langle \phi | A | \psi \rangle$

Meaning of $\int \phi^\dagger \hat A \psi \:\mathrm dx$


How is the classical twin paradox resolved?


Gyroscopic precession force translated 90 degrees?

What determines the direction of precession of a gyroscope?


What would be pure energy ?An example of pure energy?

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


Book recommendation for self study of General relativity


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?


Where does the energy go if a ball hits the ground WITHOUT bouncing?

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


Energy conservation Hamiltonian dependency

Example where Hamiltonian $H \neq T+V=E$, but $E=T+V$ is conserved


Why do i see more steam coming out from the vessel containing water after i turned off the stove?

Why is there more steam after a pot of water *stops* boiling?


Many-worlds interpretation (MWI) and conservation of energy

Many-worlds: Where does the energy come from?


Photons from stars--how do they fill in such large angular distances?


Magnetic Forces and Junkyard Magnets: What's Going On?

How can magnets be used to pick up pieces of metal when the force from a magnetic field does no work?


Mass converted to energy in a common fire?


Mathematical proof of an electron can't absorb a photon

Can a free particle absorb/emit photons?


Why does a rolling thunder always starts with a high pitch and ends with a deep, low sound?


How do we know that light is made up of electric and magnetic fields?

What is the experimental evidence that light is an electromagnetic wave?


Why is the speed of light not 3 x $10^{8}$ m/s, or why not a round figure for the meter

Why is the speed of light defined as 299792458 m/s?


What force keeps electrons in their orbitals and not collapse into the positively charged nucleus?

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


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

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


Where does the earths magnetic field originate

Why does Earth behave like Natural Bar Magnet?


Why doesn't an electron's charge rip the electron apart?

If like charges repel, why doesn't a charge break itself apart?


What happens to wheels of a car moving near speed of light?

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


How do electrons choose their way through nodes?

How do electrons know which path to take in a circuit?


Where does all the energy in the universe come from?

Is the total energy of the universe zero?


How come the cosmological constant supports the idea of dark energy existing?

What are the differences between dark energy and a cosmological constant?


How is sun's atmosphere (corona) hotter than the surface itself?

How does the sun's surface conduct thermal energy from the convective zone to the corona?


Travelling backwards in time - is it possible?

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


Showing the annihilation of an electron-positron pair

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


Relativistic speed/energy relation. Is this correct?


Significance of $i$ in the Schrödinger equation

Where does the $i$ come from in the Schrödinger equation?


What happens to a white dwarf star if it has mass higher than the Chandrashekhar limit?

Why does a star beyond a certain mass limit (Chandrasekhar limit) only become a black hole?


Why can we cycle faster than we can run?

What makes running so much less energy-efficient than bicycling?


New coordinates in terms of old from Jacobian-- Software?


Do lower dimensional objects actually exist?

If I squeeze something really hard, will it ever become two-dimensional?


Is the world we are living in discretized?


Einsteins idea about solving the ether problem


What are Quarks made of and will they ever decay to this?


Will an un-scattered photon go to the edge of the universe?

What happens when a photon reaches the "edge" of the universe?


Hawking Radiation: Couldn't virtual particles make black holes more massive?

Black holes and positive/negative-energy particles


When you are standing in a running train if you jump means will you be in same place or will you be in front or back?

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


Difference between irreversibility and entropy?


What is the effect of water 'climbing' over a cup via a wet string?

Capillary action and conservation of energy


How to read this state in quantum physics?

What do term symbols with a half-integer "$L$" like $^3[3/2]_{1/2}$ mean?


Can we prove Conservation of Angular Momentum without assuming internal forces are central?

Why is conservation of angular momentum considered a law?


Gravitational field strength inside the Earth

Would you be weightless at the center of the Earth?


Quantum Stat-Mech Proof of an Inequality for the Partition Function


Problem in Solving an Equation in Quantum Mechanics

Doubt in a certain equation of a research paper


What is a good book for quantum mechanics and quantum computation?


Energy Stored In A Capacitor (Slowly Moving Parallel Plates Together)

What happens to capacitor’s charge when the plates are moved further apart?


Eigenvalues of Angular Momentum in Quantum Mechanics

Why is orbital angular momentum quantized according to $I= \hbar \sqrt{\ell(\ell+1)}$?


Electromagnetic interaction physical interpretation

If both radio waves and gamma rays can travel through walls


Is time dilation a mechanical slowdown only?


Why is this not a violation of parity invarance for EM


Problem-solving approach to Classical Mechanics

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


Do time dilation tests prove that it exists or that atomic clocks are faulty?

How can we be sure about the constancy of atomic clocks as in the Hafele and Keating time dilation test?


How did Rayleigh and Jeans apply the Equipartition of Energy in determining the energy distribution of blackbody - radiation?

How exactly does applying the Equipartition Theorem to radiation leads to UV catastrophe?


Is a Rubbia thorium reactor safer than other modern reactor types?


Why are generalized positions and generalized velocities considered as independent of each other?

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


Can lightning be used to solve NP-complete problems?


How can a quasar be 29 billion light-years away from Earth if Big Bang happened only 13.8 billion years ago?


Photons in expanding space: how is energy conserved?


Laws of Atomic Theory - how is this possible?

What sets a "Law" apart from a "Rule" or a "Principle"?


Distribution of Dark Matter around galaxies

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


Can the time direction of wave function collapse be reversed?

On the nature of the collapse of the wave function


Elementary explanation for motion of a gyroscope

Without using rotational mechanics, why does a gyroscope precess the direction it does?


Why does space expansion not expand matter?


Commuting operators with no eigenstates in common: infinite potential well

Conservation of momentum in infinite square well


Do black holes have a moment of inertia?


How does the diameter of an open ended tube affect the frequency?

Does the frequency of a organ pipe changes with its diameter? Explain


Experimental limit on Newtonian mechanics not to depend on third derivative

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


Why is the potential drop zero across a wire of zero resistance?

Why is the voltage drop across an ideal wire zero?


What exactly is the color charge in QCD?


Matter waves? what does de Broglie mean?


Photoelectric effect:- Reduction of wavelength increases current?

Photoelectric Effect - Dependence of current on frequency


Observation effect in double slit experiment

What is an observer in quantum mechanics?


How do I get the position at time $t$, if acceleration depends on position?

Calculating gravity when taking into account the change of gravitational force


How to extract the masses from LIGO strain data?

How were the solar masses and distance of the GW150914 merger event calculated from the signal?


Why are there only two charges - positive and negative? Why not more or less?

Can a third type of electrical charge exist?


Why does a body always rotate about its center of mass?

Do objects rotate around the torque vector or its center?


Is Kirchoff's Voltage law valid in inductive circuits?

Application of Kirchhoff's laws in circuits with inductors


Why does a plastic comb attracts tiny bits of paper if it is an insulator?

Why does the comb attract the pieces of papers if they're neutral?


What does it mean by "the age or our universe"?


Flat Earth Horizon vs Spherical Earth Horizon

How far into space does one have to travel to see the entire sphere of earth?


Starting a fire with a lens without the sun


How friction between water and ice creates distribute charge in the cloud?

What causes charge buildup in a cloud before a lightning storm?


In circular motion is the angular velocity vector always perpendicular to centripetal acceleration?

In circular motion of a particle is the velocity of particle always perpendicular to the centripetal acceleration?


Why are there specifically 10, 11, or 26 dimensions in string theory?

Why does string theory require 9 dimensions of space and one dimension of time?


Is it possible to formulate the Schrödinger equation in a manner that excludes imaginary numbers?


Where do electrons in electricity come from?


Reconciling Two Contradictory results of Time Dilation

What is the proper way to explain the twin paradox?


What's the reference frame for displacement when calculating work?

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


What is the proof for kinetic energy $= mv^2/2$?

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


Why the centre of Newton's rings is dark?


Explaining to an 8-year-old why nothing can travel faster than light


Can black holes form in a finite amount of time?


Special terms related to escape velocity

In what direction should you throw a 1 kg uniform sphere in order to put it into lower Earth orbit?


Size of Visible Universe: Why now ~50Bly instead of 15?


Do virtual particles pop in and out of existence in the space just outside the nucleus?

Do virtual particles actually physically exist?


Different masses in free fall towards a massive body

Why do two bodies of different masses fall at the same rate (in the absence of air resistance)?


Why do we study the projective representations of SO(3) in the context of the theory of angular momentum?


Do I use kinetic energy or momentum to figure out the final velocity?

When to use Conservation of Energy vs Conservation of Momentum


Gravitationally bound systems and cosmological expansion?

Can the Hubble constant be measured locally?


How can the energy eigenkets and position eigenkets of a quantum system both be complete?

Hilbert space of harmonic oscillator: Countable vs uncountable?


Virtual Photon in Electron Scattering Feynman diagram

Energy conservation of Virtual Particles - Quantum Fluctuation?