Why do two blurry shadows, when brought close to each other, appear to "bulge" and merge?

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


Does special relativity's kinematic time dilation have a physical effect on matter, and how can you test this?


Are gaussian integrals also valid for complex constants?

Gaussian integral with imaginary coefficients and Wick rotation


How does the spacetime curvature cause an object to attract towards the ground?

Why would spacetime curvature cause gravity?


Is there a limit to $\frac{d^nx}{dt^n}$?

Upper limits for jerk and higher derivatives in physics


Does material (density) affect falling rate of objects?

Why do heavier objects fall faster in air?


Why do shadows seems to "unite" before the object does


What exactly causes the normal force and how is it related to friction?

How is frictional force dependent on normal reaction?


Ball thrown faster than terminal velocity

If starting speed is faster than terminal velocity then what?


Can these different Lagrangians lead to the same equation of motions?

What does a Lagrangian of the form $L=m^2\dot x^4 +U(x)\dot x^2 -W(x)$ represent?


Mean value of $[x,p]$ on an eigenstate of $x$

What's wrong with this derivation that $i\hbar = 0$?


A mathematical step done by Schrödinger in his solution to the hydrogen atom I need clarification on

How can one derive Schrödinger equation?


Will the weight further increase while going inside the Earth?


The "Satellite Paradox": Twin paradox in orbiting satellites


What's special about the $T-V = H- 2V =2 T- H$, which the least action principle extremizes?

Why should an action integral be stationary? On what basis did Hamilton state this principle?


Why do photons have spin of 1 when they have no mass?

What is spin as it relates to subatomic particles?


Is the theory of electromagnetism very incomplete in physical interpretation?

Can all fundamental forces be fictitious forces?


$\text{div} \ \vec{F} = \vec{0}$ for a conservative force?

Divergence of $\frac{ \hat {\bf r}}{r^2} \equiv \frac{{\bf r}}{r^3}$, what is the 'paradox'?


How are neutrinos massless? Could they or at least some of their forms be a potential candidate for Dark matter?

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


What is wrong with this calculation of work done by an agent bringing a unit mass from infinity into a gravitational field?


If application of force does not result in spatial movement, has work been done?

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


Higher-order Weyl dependence of geodesic distance

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


Why do all heavier gases in the atmosphere not settle down to the surface?

Why does the composition of the air does not change with altitude?


If energy is neither created nor destroyed, where is the extra space coming from?


Device or material that is (near) 100% transparent from one side and (near) 100% reflective from the other side?

Light "diode" and 2nd law of thermodynamics


Hydrostatic pressure in different Tank shapes

Varying pressure in container with aperture


Why we don't work physically when we don't make something move?


How can a horse pull a cart, given Newton’s third law?

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


Is the electromagnetic force responsible for contact forces?


Charge is relativistic invariant. What does it mean?

How can we prove charge invariance under Lorentz Transformation?


What do you mean by frequency of SHM and how is it related to angle covered in a UCM?

The meaning of "Angular frequency" of a spring that behaves as a simple harmonic oscilator


Does the canonical commutation relation give a unique solution for the momentum operator?

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


How can wind feel colder than normal air if it has more energy?


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


Is 1 Joule the work done to lift ~100g through a distance of 1m?

A few questions about the concept of work


Why is there no tangential acceleration in uniform circular motion?

tangential acceleration for uniform circular motion


Does Action in Classical Mechanics have a Interpretation?


What do we actually mean by parallel rays when talking about reflection from a concave mirror?

What does it mean to say image is formed at infinity?


Moment of inertia and centre of masses of continuous bodies

Moment of inertia: why $\mathrm{dI}=r^2\mathrm{dm}$ instead of $\mathrm{dI}=m\mathrm{dr^2}$?


Understanding the Fermi level and the Fermi-Dirac distribution


Why is there an inconsistency between the gauge transformation of the classical canonical momentum and the momentum operator in quantum mechanics?

Why is the "canonical momentum" for the Dirac equation not defined in terms of the "gauge covariant derivative"?


Why is $dE = C_V dT$ for an ideal gas, even when the process is not constant volume?


Why is Cosmic Microwave Background Radiation attributed to the Big Bang?

What evidence do we have that CMB is the result of the Big bang?


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


Why can we multiply different units but not add them?

Why can we only add or subtract things of the same dimension (meters/second, newtons, etc)?


Which waves are produced during tuning fork vibration?

What sort of waves are produced by tuning forks? Is it transverse, longitudinal or both?


Should physical solution to Schrödinger eq. always be real in one dimencional space?

When Eigenfunctions/Wavefunctions are real?


Why is the Dirac mass term Hermitian if Grassmann-valued fields anticommute?


Can Hydrogen Fusion via CNO Cycle Occur in First Generation Stars


In the case of a ball swinging in circular motion on a rope, w/out gravity or air resistance, what is the force pulling outward on the rope?

What is the cause of centripetal/centrifugal force?


Direction of the current and the electrons

Why is the charge naming convention wrong?


Dynamics of Event Horizons between head-on colliding non-rotating black holes

Black hole collision and the event horizon


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


What happens if you dump antimatter into a black hole?

What happens when anti-matter falls into a black hole?


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


Why is sound reflected and not transmitted through a wall?


How does the electron know to "release" the photon at the same angle at which it got absorbed?

Explain reflection laws at the atomic level


Will a piece of ice, floating on water in a beaker, rise or fall when I add oil on top of water?

Buoyant force when object is between two liquids


Can gravity be quantized in a way that doesn't require a particle?

Why quantising gravity necessarily give us gravitons?


Star formation after big bang doesn't violate entropy?

How does the formation of a solar system not break the second law of thermodynamics?


As anyone attempted to show that QM and GR cannot be unified?

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


Why is a temperature gradient set up in a heated rod?


Why the book falls faster than a feather, dropped from the same height?

Why do heavier objects fall faster in air?


Is space itself expanding or is it just momentum from the Big Bang carrying things apart?


Is my analogy on Hawking Radiation correct?

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


Does a helicopter that simply hovers remain in the same spot on earth?

Why does the atmosphere rotate along with the earth?


Is there a layman's way of telling when someone can see into your room?


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


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


Is it possible to maintain the electric current permanently?

How can I put a permanent current into a superconducting loop?


Why is the relationship between force and acceleration linear?

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


Heisenberg's Uncertainty Principle : How is particle position determined more accurately with shorter wavelengths?

Wavelength of light too long to measure electron position in double-slit experiment?


Why are squares, square-roots, and second-order differentials, common in natural laws, but not cubes, cube-roots, and higher order effects?

Why do most formulas in physics have integer and rational exponents?


What methods are used to measure an objects temperature in kelvin? And what is the Rankine scale?

Why is a degree Celsius exactly the same as a Kelvin?


How did Planck arrive at the idea that energy is quantized?


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

What's the difference between centre of mass & centre of gravity for massive bodies?


A doubt on Christoffel symbols: to be a tensor, or not to be, what's the answer to that question?

Why aren't Christoffel symbols tensors? - asked from a fibre bundle perspective


Does modulating a laser source change its color?

If turning a perfectly monochromatic laser on for a finite time gives a frequency spread, where did the other frequency photons come from?


Kinetic Energy of Electrons vs Current in the Photoelectric Effect

Saturation current in photoelectric effect


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


Why is change in Gibbs free energy not always zero? ($q = T \Delta S$)

Why is Gibbs Free Energy not equal to 0? Its definition itself makes it 0


Charge on outer part of infinite parallel capacitor

Why are the two outer charge densities on a system of parallel charged plates identical?


Can we increase the potential of a charge/mass by keeping many charges/masses next to it?

Dilemma in Theory of Superposition of Electric potential


Intensity and Young's Double slit experiment

Why does interference pattern remain constant?


Second law of Newton for variable mass systems


Just another confusion on Fermi level and Fermi energy


If I'm moving at half the speed of light $c/2$, and another object with $c/2$ in the opposite direction, will I move with 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?


Are there any experiments going related to gravitational shielding?

Is it theoretically possible to shield gravitational fields or waves?


Is the speed of light constant relative to the observer?

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


How to calculate the effective resistance of this circuit

Resistor circuit that isn't parallel or series


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


Is the electronic structure of an atom with two or more electrons solvable analytically?

Why can't the Schrödinger equation be solved exactly for multi-electron atoms? Does some solution exist even in principle?


High School Physics Question on Work and Energy


Confusion about the dimension of a Hilbert Space in Quantum Mechanics

Hilbert space of harmonic oscillator: Countable vs uncountable?


Interpretation of the azimuthal quantum number

Why are the higher angular momentum states of a hydrogen atom closer to the nucleus?


Can the circulation around a wing be predicted (roughly) without the help of a computer?

Generation of lift and uniqueness for 2D Laplace equation around body


Is It Possible to Express all fundamental forces in the form of generalized potentials?

How general is the Lagrangian quantization approach to field theory?


Does a filament of lamp still have resistance when no current flows, and if yes, why?

How is resistance defined when there is no current?


Why do we consider Lagrangian densities in field theory (as opposed to Lagrangians as in point mechanics)?


Application of Lagrange Multipliers in action principle

Hamilton's principle with semiholonomic constraints in Goldstein


Does velocity or acceleration cause time dilation?


Different answers for the same problem, Einstein's relativity vs Newton's gravity

Does a charged particle accelerating in a gravitational field radiate?


Why does power increase as a constant force accelerates a body?

What is force? How does a constant force output a nonconstant power?


Why is normal ordering a valid operation?


Eigenstate of position operator after collapse of the wave-function

Are eigenstates of the position operator continuous?


Am I seeing a particle orbiting a Morris-Thorne Wormhole?


Why image gets formed when light rays intersect?

Why is an image formed when two light rays coming from an object intercept?


Determining equations of motions of a system from its Euler-Lagrange equation where the latter contains two arbritrary functions

What does a Lagrangian of the form $L=m^2\dot x^4 +U(x)\dot x^2 -W(x)$ represent?


Can you use this method to measure the speed of light in one direction?

Is there any way to measure the one-way speed of light?


Is a superconductor really a super conductor?


Algebraic uncertainty principle and the particle on a ring

Why doesn't the uncertainty principle contradict the existence of definite-angular momentum states?


If gravitational waves travel at the speed of light, how can they escape black holes?


Can there be a multiple dimension of time?


Newtonian mechanics in higher dimensions

Gravity in other than 3 spatial dimensions and stable orbits


Why is it that when you break a brick it hurts less than when you don't break the brick?


Do vacuum bubbles exist in theories with normal ordered Hamiltonian?

Calculating Green's function from Dyson's series without normal ordering


Does classical electrodynamics break momentum conservation in some cases?

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


Reducing degrees of freedom of a system described by an equation

Procedure for reducing the degrees of freedom of an arbitrary system


Why does the conversion of mass to energy have anything to do with the speed of light?

What was Albert Einstein's proof for $E=mc^2$?


When the hamiltonian isn't equal to energy?

When does Hamiltonian equals to energy of the system?


Proof of contracting Christoffel Symbol Identity

Contracted Christoffel symbol in BSSN formulation


Number of Possible Frequencies in Visible Spectum

Is the electromagnetic spectrum discrete?


Would a buoyant force still act if the object is placed at the bottom the fluid(without any gap for the fluid to enter)?

How does the buoyant force on a cube at the bottom of a tank of water manifest itself?


How does the Earth have enough gravity to hold on to its atmosphere?


Bound states of the $V(x)=\pm \delta'^{(n)}(x)$ potential?


Eigenstates and eigenvalues of the operator $xp+ px$

What is the spectrum of $\hat x \hat p + \hat p \hat x$?


Does having a minimum length in space violate Lorentz invariance?

Does the Planck scale imply that spacetime is discrete?


Can the expansion of the Universe be faster than the speed of light?


If there is no absolute time, how can we say the Big Bang was 13.8 billion years ago?


Why do we need extra force to pull an upside down mug out of a bucket?

Why is it so difficult to pull an immersed mug out of the water?


Is my visualization of a photon correct?


Does Hawking radiation never happen because a black hole takes an infinite time to form?

Can black holes form in a finite amount of time?


Can string theory explain why the charge of the positron and of the proton are equal?

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


What is the origin of elements heavier than iron?


As space expands, does this not imply that time also expands?

Does time expand with space? (or contract)


Why the relation $H=B/\mu_0$ makes sense?

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


Why does a dielectric slab move inside the capacitor?


How can I check if a given force (in vector form) is conservative or not?

What causes a force field to be "non-conservative?"


Off-diagonal elements of the inertia tensor and its eigenvalues

What is the physical significance of the off-diagonal moment of inertia matrix elements?


How does an antiparticle respond to a gravitational field?

Does antimatter curve spacetime in the opposite direction as matter?


What will be the effect on the water level?


How do we see an object fall into a Black hole in gravitational waves?

So Black Holes Actually Merge! In 1/5th of a Second - How?


Why does blowing air through pursed lips make the air cooler than if we exhale through wide open mouth?

Why does the air we blow/exhale out from our mouths change from hot to cold depending on the size of the opening we make with our mouth?


Does an accelerated electron (due to gravitation) emitts e.m. radiation?

Does a charged particle accelerating in a gravitational field radiate?


Since infalling objects appear to "freeze" on the event horizon of a black hole, does that nullify the blackhole information paradox?

Where is the black hole information paradox?


Does the existence of magnetic field follow from special relativity and invariant of electric charges?

Does special relativity make magnetic fields irrelevant?


Will time exist in heat of the universe?

Would time still exist after Heat Death of the Unverse?


Lagrange with Higher Derivatives (Ostrogradsky instability)

What is an intuitive way of understanding Ostrogradsky instability?


Warp drive small scale experiments "proof of concept"


What does the Big Bang and theortical physics predict about the matter and antimatter?

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


Spontaneous Symmetry Breaking vs Addition of 'Mass terms' by hand

What goes wrong if we add a mass term for gauge bosons without the Higgs mechanism?


Can we go from equations of motion back to Lagrangian?

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


Question on the statement of Noether's theorem


Some books and tutorials for a beginner?


Derivation of Fermat's Principle from the Least Action Principle

How are classical optics phenomena explained in QED (Snell's law)?


When an electron tunnels through a barrier, where would it be found when measured?

Can a particle be physically observed inside a quantum barrier?


How can gravity be describe as a carried on gravitons if light is affected by gravity but no effect on gravity?

Does a photon exert a gravitational pull?


How does a photon transform into two particles

How does gamma-gamma pair production really work?


Why are nuclides with an even number of protons and neutrons more stable?

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


Does a bulb offer still offer resistance even after it gets fused?

Does a filament of lamp still have resistance when no current flows, and if yes, why?


The Heisenberg Uncertainty Principle and the 1D particle in a box

Heisenberg Uncertainty Principle Applied to an infinite square well


Why voltage is same across parallel circuit if it is work done per unit charge?

Why does voltage remains same over Parallel Circuit


What is a periodic function that can calculate daylight hours of any given city at any given day?

Hours of light per day based on latitude/longitude formula


Why speed of light is same in all reference frames?

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


Calculating work done or energy expended difference in two biomechanics examples

How much more net energy do I use walking up hill?


Why does a hot bulb filament emit photons?


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


Work and energy - explanation of definition


Are there any real ways at least in theory to manipulate quantum vacuum for propulsion or energy generation?

Can energy be taken out of the QFT vacuum?


Can you change the wavelength of light keeping frequency constant and can you do the opposite as well?

Why does wavelength change as light enters a different medium?


Why don't we define time derivative of acceleration?

Why don't we consider jerk in physics classes?


Can light travel slower than the maximum?


Why can we parameterize a null geodesic such that its velocity is four-momentum?

General relativity: For massless particles, is the momentum and velocity 4-vectors equal?


Young slits, mirrors and interference patterns

When light reflects off a mirror, does the wave function collapse?


Does gravity follow law of conservation of energy?


Can Quantum Entangled particles convey information faster than speed of light?

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?


A book on special special relativity covering covariant and contravariant tensors

Textbook on the Geometry of Special Relativity


What if Force was not Mass times Acceleration?


Why do quantum tunneling consume energy, if not then why it must pay back borrowed energy quickly?


Is time a mathematical entity or there is any demostration of its existence?


What causes the 'backspin' while sliding a pencil along a table?

Why does a ping pong ball change direction when I spin it on a table?


How is it possible that unrolling scotch tape in a vacuum causes X-rays?


Book on tetrads formalism and tetradic formulation of General Relativity

Resource Recommendations: General relativity, local tetrads and particle physics


What creates the physical difference in ageing when travelling close to the speed of light?

What is the proper way to explain the twin paradox?


Does black hole formation contradict the Pauli exclusion principle?


Schwarzschild Radius of the Universe Part 2


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


What causes the magnetic field around a wire?

How do moving charges produce magnetic fields?


How can we relate the idea of flux with electric field


What force creates the reflected wave in a string attached to a rod?

Wave reflection and open end boundary condition intuition


Integral version of Ampere's law: why current outside the surface does not contribute to $\oint B\cdot d\ell$?


Bending timespace fabric model: does it explain gravity by another gravity?

Better explanation of the common general relativity illustration (stretched sheet of fabric)


Does modifying the geodesic Lagrangian $L$ with a smooth function $f(L)$ give the same geodesic curves as solutions?

Geodesic Equation from variation: Is the squared lagrangian equivalent?


Can a third type of electrical charge exist?


What does it mean to say the CMBR has a “temperature”?

What is meant by the temperature of the CMB?


Why do I feel a force from a non-accelerating punch?


Self-Adjoint Operators in Stone-Von Neumann Theorem

Why do we use Hermitian operators in QM?


Do physicists accept true randomness in nature?

Is the universe fundamentally deterministic?


If car is going with constant velocity, and hits a man, will the man experience force?


Can Gauss Law for any arbitary closed surface be derived from Coulomb's Law?

How is Gauss' Law (integral form) arrived at from Coulomb's Law, and how is the differential form arrived at from that?


Why does increasing voltage increase current?

Given Ohm's law, how can current increase if voltage increases, given fixed resistance?


What force an observer attached to a reference measures?

Force equations for a particle in a non-inertial frame of reference


Is there a way to calculate frequency of visible white light?


At very high speeds, why don't many things become black holes due to increase in mass and reduction in volume?

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


Is the Hamiltonian fully defined by a quantum state (vector)?

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


Why is mass an invariant in Special Relativity?

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


Calculating magnetic field of solenoid (displacement current)

Electric field created from time varying current in solenoid


Why doesn't the work done by atmosphere contribute to increase in internal energy of gas?


How did J.J. Thompson decide that the electron was negative charge?

Why is the charge naming convention wrong?


Cosmic Microwave background radiation and the spectrum

What is meant by the temperature of the CMB?


Why don't the satiltes fall into the earth?

Why doesn't the Moon fall onto the Earth?


Why are we still considering gravity as one of four fundamental forces?

Why do we still need to think of gravity as a force?


How to account for direction of wave propagation in the wave function?

How to determine the direction of a wave propagation?


Better explanation of the common general relativity illustration (stretched sheet of fabric)


Looking for a Basic ( or "for Dummies" ) Explanation of the Lagrangian - Hamiltonian Relationship. ( Mathematician )

Equivalence between Hamiltonian and Lagrangian Mechanics


Is E=hf applicable for all types of particle?

Why can we apply the $E=hf$ equation for electrons?


Expected momentum ground state electron in $\rm H$ atom

Using the uncertainty principle to estimate the ground state energy of hydrogen


Why not consider rate of change of acceleration?

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


Implications of the delayed choice quantum eraser experiment

Why doesn't delayed choice quantum eraser experiment imply retrocausality?


Could the world be represented as binary?

Can we simulate the whole universe in computer?


Why can't we use conservation of mechanical energy here?

Why isn't energy conserved in this collision problem?


What is the advantage of using imaginary units for time in the Minkowski Space rather than regular euclidian space as Lorentz used?


What is more fundamntal? Fields, the excitations of which are particles, or particles, from which fields are formed?

What is more fundamental, fields or particles?


Why is $f\in C_{\infty}=\{f\in C(\mathbb{R})\mid \lim_{R\to\infty} \sup_{∣∣x∣∣>R} ∣f(x)∣=0\}$

$f\in L^1(\mathbb{R}) \cap C^1(\mathbb{R})$ and $f'\in L^1(\mathbb{R})$


Conceptual understanding of deviation of light ray and change of speed in the phenomenon of refraction

Looking for the actual reason of refraction explained precisely without analogies


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


Why does Newton's Third Law actually work?


Why does radians disappear in equation $\tau = I\alpha$


Why does light bend during refraction and is there any conceptual understanding as to why?


How to generate a general $2 \times 2$ unitary matrix by repeated application of the matrices $e^{i \sigma_x t}$ and $e^{ i \sigma_z t }$?

Equivalent Rotation using Baker-Campbell-Hausdorff relation


Why time dilation does not contradict relativity


Why isn't force $\vec{F}=m \vec{v}$ instead of $\vec{F}=m \vec{a}$?

Why force $F$ is equal to $ma$ and not $mv$?


Is blackbody radiation due to electrons transitioning from higher levels to a lower level?

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


Black Holes - behaviour of masses perpendicular to accretion disk

Why does orbiting matter form an accretion disk?


Does a rest charge on the surface of the earth emit radiation

Does an classical charge that is stationary in a gravitational field radiate?


Can we create black holes in modern particle accelerators?

Can black holes be created on a miniature scale?


Can we use light slingshotting behind a blackhole as a cosmic mirror to our past?


What's the difference between burning a book and throwing it into a black hole

Why is the information paradox restricted to black holes?


Best astrophysics textbook if I hold a PhD in nuclear engineering

What are good books for graduates/undergraduates in Astrophysics?


Lorentz Transformation - Derivation of $\beta$


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


Is $F = G\dfrac{{m_1}{m_2}}{r^2}$ really true?


Does matter turning into energy, or vice versa, violate the Law of Conservation?

What keeps mass from turning into energy?


Why is gravity still considered a fundamental force?

If gravity isn't a force, then why do we learn in school that it is?


How can the Hamilton-Jacobi equation represent the motion of a particle as a wave?

How do you get quantum Hamilton-Jacobi equation from Schrödinger equation?


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


Why is frequency a fundamental property of waves?

Why doesn't the frequency of light change during refraction?


Can the signs of charge of electron and proton be reversed?

If electrons were positive and protons were negative, would life be different?


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


Does a superconductor have exactly zero resistance?

Is a superconductor really a super conductor?


How do we know that a wave of light has electric field?

Have we directly observed the electric component to EM waves?


Why exactly does a material reflect/absorb/refract light?

Why do some materials reflect (metals) and other materials reflect and refract (glass) from the quantum perspective?


Does it make an essential difference for SR or GR if the speed of light had a different but finite value?

The origin of the value of speed of light in vacuum


Can we entangle three or more particles between each other?

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


Is it known what the necessary and sufficient conditions are for the existence of a "3+1 split" (by means of a foliation) of a (Lorentzian) manifold?


Force-carrying particles for electrostatic force

Using photons to explain electrostatic force


What does it actually mean for an electron to be excited?

Electron shells in atoms: What causes them to exist as they do?


What apparatus do physicists use to hold a photon and for how long?


Why does frictional force cause a car to move? Also, is friction a reaction force?


Will the kinetic energy and potential energy of a wave on a string be maximum or minimum in its mean position?

In wave motion of a string both kinetic energy and potential energy are minimum at $y=y_\text{max}$ then why does the string come down again?


Galilean invariance of a subset of Maxwell equations


Why can gravitational potential energy be expressed both as $mgh$ and $-GMm/r$?

Near Earth vs Newtonian gravitational potential


Cross product of the quantum mechanical operators $\textbf{p}$ and $\textbf{A}$


How did friction generates heat? Why rolling friction is less?


Does a photon in vacuum have a rest frame?


Recommendations for beginner - intermediate quantum mechanics books


How to propagate uncertainty to $\tan(x)$?


Understanding rationale behind choice of certain mathematical structures in QM

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


The Sun bends planets' trajectory and speeds up it towards the perihelion; does it both actions with light?


Why does conservation of angular momentum explain why planet orbits lie in a plane?

How do we know that the motion of the particle in an central force field lies on a plane?


Blowing air on fire gives me two different results

Why does a candle blow out when we blow on it? Our breath is 16% oxygen and only 4% CO2


Why do lines in atomic spectra have thickness? (Bohr's Model)


Why is the tension at the bottom of a rope hanging from a ceiling zero?

What holds up the lowest point of a rope following a catenary curve?


How can someone mathematically prove that a spherical wave equation solution cannot be a electromagnetic wave?

Why is dipole the simplest source in electrodynamics?


Please why am I thinking wrong? Relativity problem

Relativity problem: Finding the minimum separation between Bob and Alice


Is the spectrum of visible light infinitely divisible?

Is there an infinite amount of wavelengths of light? Is the EM spectrum continuous?


Why doesn't physics like infinity (or does it)?


How to find the canonical equations of the series RLC circuit?

How to find the canonical equations of the RLC circuit


Why isn't tension in a tug-of-war twice the balance's reading?

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


Is their any proof that space is filled with virtual particles or can they only be emitted by atomic nuclei and electrons?

Do virtual particles actually physically exist?


Why we take Schrodinger equation as a complex quantity? Why wavefunction is a complex quantity?

About the complex nature of the wave function?


Why don't I see infinite images with parallel mirrors?

Are infinite reflections between two mirrors really infinite?


What did Freeman Dyson mean when he said this?


How does light interference explain colour mixing?

What determines whether colors you can't see are visible or not?


Lagrangian for relativistic massless point particle


Particle in a box momentum wavefunction?

Value of momentum of a particle in 1D box prepared in a particular state?


Dipole moment in the Optical Interaction Hamiltonian

Why the dipole interaction term in the Hamiltonian has all diagonal elements to be zero in the energy eigenbasis?


Pressure of 2 immiscible liquids of diffrent density in a u tube


Why are thermodynamic potentials minimised?


Why do we 'jump' when we push the ground?

Why does Newton's Third Law actually work?


Who wins the race between an astronaut falling towards a black hole and the event horizon shrinking due to Hawking radiation?

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


Confusion on the wave aspect of matter: physical meaning of the de Broglie relations?


Why can't an electron absorb multiple photons?

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


Finding speed of mass m attached with two inextensible strings

Why is velocity of the mass $v/ \cos θ $? Why not $2v \cos θ$?


How fast can the Earth rotate without people on the equater falling off and how long would the day last with this speed?

How fast would the Earth need to spin for us to feel weightless?


Pauli exclusion principle: why does it imply that $Z\approx N$ in stable nuclides with $A<40$?

Stable Nuclei - Deviation from equal protons and neutrons


How to calculate spatial distance in space-time?


There is something I don't understand in the answer of the following question


If I attach a u-shaped pipe with a fan blowing into it to a cart, will the cart move? if so, in which direction?


Net Work Done When Lifting an Object at a constant speed

Work done when lifting an object at constant speed


Where will two point mass collide due to gravitation?

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


Recommend some advanced books on the standard model?

Books for particle physics and the Standard Model


Leibniz Rule for Covariant Derivative Question


Can spacetime be curved even in absence of any source?

Physical meaning of non-trivial solutions of vacuum Einstein's field equations


How can we see black holes form and gain mass if nothing can cross a horizon (when viewed from our reference frame)?

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


What force pulls the simple electromagnetic train?

How does this "simple" electric train work?


We know a human cannot run on water, but could a much stronger and faster animal?

How fast would someone have to run to run over water?


Why do symplectic form need to be closed in classical mechanics?

Why closed in the definition of a symplectic structure?


How refractive index is related to speed of light in mediums?

Why Does Snell's Law use Sine Instead of Angle Values?


The correct expression of the Euler-Lagrange equation in Field Theory

Is the shorthand $ \partial_{\mu} $ strictly a partial derivative in field theory?


Show the Christoffel symbol satisfy this condition

A helpful proof in contracting the Christoffel symbol?


Why does the air flowing above the aerofoil moves faster than the air flowing below the aerofoil?

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


How can a capacitor discharge if there is no field outside?


What is an observer in quantum mechanics?


In general relativity, what makes an object released in a gravitational field START to fall?

How does "curved space" explain gravitational attraction?


Why doesn't friction depend upon area of contact?


What do off-diagonals in density matrix represent?

Does a physical interpretation of density matrix cross-terms exist?


Using particle physics math model to simulate simplest life

Can we fully simulate molecular physics?


Is the incident photon in a mirror, the same one that reflects?

During reflection does the emitted photon have same properties?


If light is considered a wave, then what exactly is a photon?


Why do we feel weightless on zero G planes?

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


Why does the gravitational field for certain configurations, at certain points in space, diverge to infinity?


Why the dust on the wing cannot be cleaned by air flow?

Why does dust stick to rotating fan propeller?


Natural and man-made nuclear transitions


Does an electromagnet have a magnetism limit?


Statistical tension between two measurements


Foundations of conservation of 4-momentum in special relativity

How can I prove that the four-momentum of relativity is conserved like in classical mechanics?


What is the actual uncertainty principle formula?

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


Are diagrams describing the warping of space misleading?

Better explanation of the common general relativity illustration (stretched sheet of fabric)


Potential difference across a zero resistance wire


Why do things move from Higher potential level to lower potential

Why does Flow always occur from Higher Potential to Lower Potential?


Current flows without any potential difference


If the magnetic force doesn't do work then what does it?

What is the mechanism by which magnetic fields do work?


Is it possible for $\beta$ be negative in Boltzmann probability distributions?

Prove that negative absolute temperatures are actually hotter than positive absolute temperatures


What causes the charges in conductor to move towards lower potential terminal of cell


Special Relativity metric and imaginary sentence


Why does the trend of gravitational field of Earth is like this ( the graph below)?


Help at dismissing a time dilation "paradox"


if the result of a measurement has to be an eigenvalue of the Hamiltonian, what is the theoretical reason for line broadening?

What is the meaning of natural line broadening?


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


Work done by moving up an inclined plane


Application of Heisenberg's uncertainty principle on photons


Why do supermassive black holes have a much lower density then smaller ones?

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


Why does Newton's Third Law actually work?


The "contradiction" in special relativity


If I had an initial upwards velocity and thrusted upwards to exactly counter-act gravity at all times, would I eventually escape Earth's gravity?


Isometric embedding of embedding of Schwarzchild metric

Isometric embedding of Schwarzchild metric in $\mathbb{R}^4$


Can a quasiclassical electron wave packet in elliptic orbit be formed from bound hydrogen-like eigenstates?


Is the Lie algebra of $SL(2,C)$ isomorphic to the Lie algebra of Lorentz group?

How do I construct the $SU(2)$ representation of the Lorentz Group using $SU(2)\times SU(2)\sim SO(3,1)$ ?


Can One-Way Speed of Light be Instantaneous?


What happens to the force and other quantities in cases like the force of gravity between two bodies once they collide and become one single body?

Singularity in Newton's gravitational law


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


How do I find the approximate surface area of a chicken?

How do I experimentally measure the surface area of a rock?


Could the antimatter from the Big Bang have gone in the opposite direction in time?

Could the missing antimatter lie outside the observable universe?


If we can see the light reflected off objects, why can't we "see" light?

Why can't we see light travelling from point A to B?


If incoming photons increase the mass and gravity of a black hole are they then some kind of source of gravity?

Does a photon exert a gravitational pull?


Assumption while deriving Time Independent Schrödinger equation

Time dependent Schrödinger equation with time independent potential and separation of variables


Can the charge of $d$, $s$ and $b$ quarks be thought of as unitary charge?

Is it a coincidence that quarks have exactly -1/3 or 2/3 the electron's charge?


Validity of Euler-Lagrange Equation in Quantum Theory

Why does the classical path give the dominant contribution in the path integral?


Does it make sense to define an angular velocity four-vector in special relativity? If it does, how would it be?

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


What is the relation between a object and the height of the water splash?


Conversion between pressure in PSI and velocity


What are the best books on general relativity for beginners?


Does a single photon have a wavelength or not?

What exactly is meant by the wavelength of a photon?


What happens in Neutrino-antineutrino annihilation?


Do anti-parallel photons affect each other gravitationally?

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


How could light from a TV screen refract when viewed through a helmet's transparent visor?

Why do everyday plastic items interfere with light polarizers?


What is an example of a transparent matter with refractive index less than 1?

Medium with refractive index less than unity?


Electric arc and electric spark differences?

What is the difference between electric spark and electric arc?


Is temperature a Lorentz invariant in relativity?


Is there one photon per wavelength of light?

What is the relation between electromagnetic wave and photon?


Has the gravitational interaction of antimatter ever been examined experimentally?


How do we move forward in space without air or atmosphere?

What is a rocket engine thrusting against in space?


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


First Law of Motion, Gravitational acceleration and Law of Conservation of Energy

How does escape velocity relate to energy and speed?


Partial derivative of position in respect to velocity

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


Since measurement collapses wavefunction and everything is constantly interacting, how does uncollapsed wavefunction exist?

Why aren't particles constantly "measured" by the whole universe?


About estimating the age of the universe


Weight of liquid with something swimming on it


How to find the inverse metric in this case?


How does light know which path is fastest?


Is an electron completely determined by its mass?

Fundamental particles identical or just differences very small?


Deriving Length contraction without time dilation?

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


This a question in context to rolling friction

How can the contact point of rolling body have zero velocity?


Relation between slit width and intensity of light in Young's double slit experiment

How is the width of a slit related to the intensity of light passing through it?


Why is oil a better lubricant than water?


How did Rutherford conclude that most of the mass (as well as the positive charge) was concentrated in the nucleus?


Quantum Entanglement and transfer of time information, is it possible?

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?


Does drift velocity depend upon cross sectional area of the conductor? If yes then how?


Can a four-divergence be added pure Yang-Mills Lagrangian to alter the action?

Do an action and its Euler-Lagrange equations have the same symmetries?


Adding a total time derivative to a Lagrangian

When can we add a total time derivative of $f(q, \dot{q}, t)$ to a Lagrangian?


Solution to any classical mechanics problem

Is there any physics that cannot be expressed in terms of Lagrange equations?


If photon is massless, then how can it interact with gravity?


Possible impact of antimatter on space-time?

Does antimatter curve spacetime in the opposite direction as matter?


Why we don't consider these incident rays while drawing a ray diagram?


Does energy do anything else other than work?


Why does increasing voltage result in a decrease in current and not rather a decrease in power?

Why the current decreases with increase in voltage in transmission lines? But according to Ohm's law current should increase with Voltage


What will be the variation in potential in a zero resistance wire connected to a battery?

Potential difference across a zero resistance wire


As the temperature increases,the resistivity of conductor also increases why?

Temperature dependence of resistivity in metals


Is the force which throws a body on a rotating disk outwards centrifugal force?


External force dependent on velocity on a Lagrangian

Velocity-Dependent Potential and Helmholtz Identities


Invariance of Lagrangian under Poincaré group transformations implies covariant Lagrange equations?

Invariance of action $\Rightarrow$ covariance of field equations?


If you live in a two-dimensional world, would it be possible to explain the angular momentum?

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


Having trouble in a statement made in sakurai modern qm

Having trouble with a statement in sakurai modern qm


Is the exchange of momentum between two interacting objects always the same?

Deriving Newton's Third Law from homogeneity of Space


Using the time-independent Shrödinger equation to model photons

Are the Maxwell equations a correct description of the wave character of photons?


How do we know from representation theory that a massless spin-1 particle has only two polarizations?

Counting degrees of freedom of gauge bosons


How does high velocity cause low pressure?


What causes highly compacted matter to collapse into a black hole?

Neutron degeneracy pressure and the Schwarzschild radius


Different energies for particle in a box from $0$ to $L$ and $-L/2$ to $L/2$

Solving TISE for particle in the box for Infinite square well


Why don't hovercrafts move West relative to the Earth

Why does the atmosphere rotate along with the earth?


Do non-vanishing boundaries conditions necessarily force a discrete/quantized set of solutions for the Schrödinger Equation?

Discreteness of set of energy eigenvalues


Why do particles and antiparticles annihilate?

Mechanism of pair production and annihilation of matter


Why do elements want to mimic Nobel gasses so much?

What is the quantum mechanical explanation of the octet rule?


What is the highest possible energy of a photon?

Are there any theoretical limits on the energy of a photon?


Electron ejecting from surface while photoelectric effect


Question regarding (i), on page 31 of Dirac Principles of QM

How to prove that if the expectation value of $A$ in any state is real, then $A$ is Hermitian?


How do we know that heat is a differential form?


Visualisation tool for different speeds?

Web utility for viewing $x$-$t$, $v$-$t$, and $a$-$t$ graphs


Why does $n \lambda = 2 \pi r$ cause a standing wave in a circle?

In De Broglie's Explanation for Bohr's Quantization Condition, why do we not use 2πr = n λ/2, why do we use 2πr = n λ?


How does the formation of a solar system not break the second law of thermodynamics?


Lower spin than one half? Spin other than whole/half integer?

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


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


March 2021 CERN discovery? What would be the properties of the new particle/force from decaying bottom (beauty) quarks?


Why is a large cavity with a small hole at constant temperature approximated as a black body?

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


Conmutator of $[x, f(p)]$ on quantum mechanics

How to derive $[x_i, F(\vec p)] = i \hbar \frac {\partial F(\vec p)}{\partial p_i}$


On work done by motion of objects in elliptic orbits


Why can we not observe Faddeev-Popov ghost fields?

Why Faddeev-Popov ghost cannot exist in external line?


In the kinematic equations $\vec{v}^2 = \vec{v}_0^2 + 2\vec{a}\cdot \Delta \vec{x}$, what does squaring a vector mean?

Asking the vector form of the equation about velocity


What are the physics definitions for time and energy?

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


What is the physical meaning of commuting in quantum mechanics?

What is the physical meaning of commutators in quantum mechanics?


Behaviour of water as pressure increases to infinity

Water behaviour under theoretical near-infinite pressure conditions


These two operators commute...but their eigenvectors aren't all the same. Why?


Why is phase space volume of a energy surface proportional to probability of a microstate of that energy?

When is the ergodic hypothesis reasonable?


Determining loss of intensity in a slow neutron beam after passing through a metal plate

Calculation of number density from material density


What is light, a wave or a particle or A wave-particle?

What do we see while watching light? Waves or particles?


Why massless particles have less number of possible polarisations than massive ones?

Polarization vectors of massive and massless particles


Under which representation (and how exactly) transforms the given bispinor?

How does the Lorentz group act on a 4-vector in the spinor-helicity formalism $p_{\alpha\dot{\alpha}}$?


If the universe is infinite, then how can we tell it's expanding?


de Broglie wavelength for particles with mass

Where does de Broglie wavelength $\lambda=h/p$ for massive particles come from?


Why is it not possible for equipotential surfaces to intersect in this case?

Why is electric field zero where equipotential surfaces intersect?


Why is it problematic to regard the Lorentz group as ${\rm SO}(4, \mathbb{C})$?

Special relativity and imaginary coefficient of the time coordinate


Why is there a field in a circuit when connects two ends of wire to positive and negative terminal of the battery?

Why is there an electric field in a wire even though it is a conductor?


Calculating ellipse graph of an orbit only with velocity

Predicting orbital trajectory of an object


A free particle moving faster than light?

Does quantum mechanics allow faster than light (FTL) travel?


How can net potential energy for a charged particle be 0 but still have a net electric field

How can the electric potential be zero at a point where the electric field isn't, if that field can give a test charge kinetic energy?


If $B_1,B_2$ and $B_2,B_3$ are MUBs, can we conclude that either $B_1,B_3$ are MUBs, or they have equivalent Hadamard matrices?


Are ultra-cold neutrinos an option for cold dark matter?

Why are neutrinos ruled out as a major (or even sole) component of dark matter?


Why do we believe space and time are intertwined? What is the idea behind it? And how do we arrive at this conclusion?


Calculus shouldn't work for describing physics


Why does pressure decreases in the direction of acceleration?

Pressure difference along horizontal in accelerated fluids


How does electric field propogate in a wire?

I don't understand what we really mean by voltage drop


What maintains constant voltage in a battery?


What Lagrangian counterterms might be needed in a $\phi^ 6$ theory in 3D?


A top on a string from the perspective of forces

Gyroscope's motion explained by internal forces


Having trouble with a statement in sakurai modern qm

Can't Prove formula from Sakurai's Modern QM @ Perturbation Theory


One-Way Speed of Light - Einstein-Ring-Like Setup Solves It?

Can we use curved spacetime to measure the one-way speed of light?


Physics models using (non-lorentzian) Indefinite metrics


Something special about energy eigenstates when it comes to time evolution?


Is mathematical physics theoretical physics?

Difference between theoretical physics and mathematical physics?


Why do I see a saddle in this picture of a computer screen?


Why do we use Root Mean Square (RMS) values when talking about AC voltage


Is there any mathematical meaning to words like: Event or Cause or Effect etc

Is there a notion of causality in physical laws?


A Light is shone out the side window of a spaceship ( moving close to light speed ), what speed will the light travel in it's own forward trajectory?

A Light is shone out the side window of a spaceship ( moving close to light speed ), will the light still travel at the speed of light in the B axis?


What is spin as it relates to subatomic particles?


What does the star mean in $\rightarrow ZZ^{(∗)}$?

What does particles with asterisk superscript * mean, such as $Z^*$ or $W^*$, in decay production?


How can I calculate the minimum and maximum frequency in a medium?


Why can't particle nature of light shows Young double slit experiment?

Double Slit experiment with just one photon or electron


Poincaré maps and how they are used in dynamic systems


Finding symmetry from conserved quantity (reversed Noether's theorem)

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


How much does light curve due to gravity compared to what Newtonian mechanics predicts


What is meaning of the phrase "The laws of physics are the same in all inertial frames of reference."?

What does the statement "the laws of physics are invariant" mean?


Why does it seem like there is always a Lagrangian?

How general is the Lagrangian quantization approach to field theory?


Why does voltage not increase when batteries are connected in paralell?

Why is voltage added when batteries are connected in series but not in parallel?


Does the atom get the impulse from a photon?

How does one account for the momentum of an absorbed photon?


Why does the irradiance of two intersecting waves not contradict the conservation of evergy?


Suggested textbooks for statistical physics

Recommendations for statistical mechanics book


Good alternatives to Georgi's Lie Algebras in Particle Physics?

Comprehensive book on group theory for physicists?


Proper (restricted) Lorentz group has the property of groups

How to prove that orthochronous Lorentz transformations $O^+(1,3)$ form a group?


What is an example of Gibbs free energy?


How does increasing the binding energy per nucleon release energy


Clarification on electric quadrupole moment definition

Traceless multipole moments vs non-traceless moments


How is the action for a point particle defined in general relativity?

Action of a massive free point-particle in relativistic mechanics


How to express the elementary work definition as an explicit functional expression

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


Estimate error of the steepest descent method

Why does the classical path give the dominant contribution in the path integral?


If the Landé $g$-factor of an electron is its magnetic moment due to its inherent quantum spin, and its spin is its magnetic moment, why isn't it 1?


Two formulations of Lagrangian for Maxwell's equations in the vacuum (revised question)

Expanding electromagnetic field Lagrangian in terms of gauge field


How to decompose tensor products of $SU(3)$ representations?

$SU(3)$ irreducible representations with tensor method


Does the age of the universe depend upon a specific choice of referential?


Why are the laws of thermodynamics "supreme among the laws of Nature"?


Kinetic energy of spacecraft appears to violate conservation of energy

How do chemical propulsion systems not break the law of conservation of energy?


Testing space-time warp on a smaller scale, "Breaking the Warp Barrier: Hyper-Fast Solitons in Einstein-Maxwell-Plasma Theory"


Physics history -- the Ultraviolet Catastrophe

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


Why are there only four fundamental interactions of nature?


Does entanglement mean that information travels faster than light?

Quantum entanglement faster than speed of light?


Non-locality of pre-Klein-Gordon equation

What's wrong with the square root version of the Klein-Gordon equation?


Is $E=h\upsilon$ applicable to an electron

Why can we apply the $E=hf$ equation for electrons?


How should get the expectation value of $1/r$ in the hydrogen atom?

Expectation value for $\frac{1}{r}$ in the $|nlm\rangle$ state of hydrogen


What is the theoretical upper limit, if any, to the quantity of information bits that can be encoded within a given volume of space?


What is the next step in solving the time derivative of expectation value of the momentum of a particle

Am I doing this right? Finding the time derivative of expectation value of momentum


Calculating charges from electric field diagram

Angle of electric field lines leaving a postive charge and entering a negative charge in dipole


Why don't electrons and protons collide inside Atom?


Has the gravitational interaction of antimatter ever been examined experimentally?


What could the new physics be if the experimental value of the muon's $g-2$ factor turns out to be truly different from the theoretical value?

Muon $g-2$ experiment: is there any theory to explain the results?


What happened in the recent Muon $g-2$ experiment, and what do the new results indicate that deviate from the existing theory?

Resolving Conflicting Reports on Fermilab $g-2$ Results


Apparent violation of the law of conservation of angular momentum in the torques experienced by two interacting electric dipoles


What is the benefit of studying atomic and molecular physics in such a detailed manner, if it is proved wrong, why don't we focus on quantum model?

Why do we study Atomic and molecular physics as a separate part in physics and that also in a very very detailed manner ,when we have proved it wrong


Do we have to use a magnet in the compass?

Would a compass with unmagnetized needle work?


How does voltage behave in a parallel circuit?

Why does the voltage drop at each resistor remain the same in a parallel circuit?


Rigorous textbook about special relativity

Textbook on the Geometry of Special Relativity


Does Einstein's Equivalence Principle ignore time dilation?

Time dilation in a gravitational field and the equivalence principle


Can a camera affect the Quantum Entanglement?

What is an observer in quantum mechanics?


How can astronauts rotate their body in empty space ? How do they undergo "angular displacement" without any external torque?

Is there a way for an astronaut to rotate?


What are the applications of WKB approximation?


What is the meaning of the equation of the change in entropy?

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


Does $E=mc^²$ mean there is a maximum attainable temperature?

Why is there no absolute maximum temperature?


Is spacetime an actual tangible "fabric of the universe", or a mathematical construct?


Is it possible to prove or disprove the Einstein Synchronization Convention with astronomy?


In the theory of special relativity speed is relative so who decides which observer’s time moves slower?


Could there exist a situation where a system of electrons is well-described by a classical Dirac field?

Classical field limit of the electron quantum field


Moment Of Inertia and Stability of Rotation

Why certain rotations are unstable? (Euler Equations)


Can singularities be ever formed from an outsiders perspective?

Can black holes form in a finite amount of time?


Can we exit the event horizon of merging black holes?


Why isn't the product rule used in the definition of mechanical work?


Does $E=mc^2$ have a constant? If not why?

Why isn't it $E \approx 27.642 \times mc^2$?


Potential drop across a wire with zero resistance

Why is the voltage drop across an ideal wire zero?


Books about alternative interpretations of quantum mechanics


Why should the energy (of an eigenstate) be greater than the lowest point of the potential?

Lower bound on energy is potential minimum


Why don't we prove that functions used in physics are continuous and differentiable?


What exactly happens during the reflection of light at the atomic level?


Where must one use $x=A \cos \omega t$ and $x=A \sin \omega t$?


Quadratic Divergences in Dimension Regularisation

Dimensional regularization: removing more than just logarithmic divergencies?


Transmon: why do we need unharmonic hamiltonian to isolate energy levels?

Procedure to cut an Harmonic oscillator to two first level to obtain a qubit


Random question about magnetic fields and relative movement

How do moving charges produce magnetic fields?


Solve the hanging rope shape using the variational principle?

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


Static solution to the Friedmann equation


Is the wave-particle duality a real duality?


Finding the time required for an object to move from point A to B when the Force exerted is a function of distance? (Proportional to the inverse sqr)

The Time That 2 Masses Will Collide Due To Newtonian Gravity


Mathematically rigorous books on special and general relativity

Mathematically-oriented Treatment of General Relativity


Interval preserving transformations are linear in special relativity


In what sense is a scalar field observable in QFT?


Defining the exterior derivative with torsion

Different definitions of exterior derivative


Is an obstacle obscuring the EHT's view of Sagittarius A- star?

Why was M87 targeted for the Event Horizon Telescope instead of Sagittarius A*?


Is an obtical obscuring the EHTs view of Sagittarius A-star


Hooke's law and elastic potential energy

Elastic potential energy and equilibrium position when mass changes in vertical mass-spring system


Mathematically rigorous books on newtonian mechanics

Classical mechanics without coordinates book


Supersymmetry with two independent supercharges, $\mathcal N=4$, or $\mathcal N=(2,2)$, and physical significance?

What do the supercharges in extended supersymmetry do?


March 2021 CERN discovery? What would be the properties of the new particle/force from decaying bottom (beauty) quarks?

Breakthrough at the Large Hadron Collider -Leptoquarks skepticism?


Why rubber part of Shuttle Cock always ends up in badminton racquet not the feather part?

Why do archery arrows tilt downwards in their descent?


How can black holes emit detectable magnetic fields and gravity if nothing can escape the event horizon?


Is it in general? $[\Lambda,\Omega]=i\hbar\{\lambda,\omega\}_{x,p}$

What is the connection between Poisson brackets and commutators?


How can black holes have charge when the Standard Model requires forces to exchange carrier particles?

What happens when an electric charge crosses the event horizon?


How does the scale factor depend on temperature?

Why is scale factor inversely proprotional to temperature?


Why matter is transparent to gravitational waves?

How much energy does the Earth absorb when a gravitational wave passes through it?


Is the Sun losing mass and pushing the Earth further away?

Is the distance between the Sun and the Earth increasing?


Why can't anything return after crossing the event horizon?


Force of gravity at a level of fixed escape velocity

What is the weight equation through general relativity?


Symmetry condition for continuous coordinate transformations


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


SQL server language media doesn't support the language of the OS

SQL Server setup media does not support the language


Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


What is stopping my Visual JVM remote connection?

How do I fix a 'Failed to retrieve RMIServer stub' JMX error?


Non interactive git clone (ssh fingerprint prompt)

Can I automatically add a new host to known_hosts?


Make mod_wsgi use python2.7.2 instead of python2.6?


Is it safe to install windows updates on Server 2008 without restarting it?

Is delayed restarting a security issue after updating a Windows Production Webserver?


MySQL 5.5.16 allows anonymous connections


How to have PRTG Server running beside Apache?


finding files that match a precise size: a multiple of 4096 bytes


How can I implement an ip whitelist to protect my server?


Server monitoring for medium scale UNIX network

What tool do you use to monitor your servers?


How do I tell apt to never upgrade a particular package?


How to send emails and avoid them being classified as spam?


Why are my mails sent from Postfix recognized as Spam?


What do these email newsletter services do to prevent their emails from going to SPAM folders?


issue when promoting a second server as domain on r2 2008

Issue when promoting a second server as domain on R2 2008


How can i resolve all external addresses to internal address?

Using dnsmasq to resolve all hosts to the same address


DKIM, spam probability, signing with key at mail server vs sender domain?

Fighting Spam - What can I do as an: Email Administrator, Domain Owner, or User?


What does * * * * * (five asterisks) in a cron file mean?

Why is my crontab not working, and how can I troubleshoot it?


Redirect an url to another url with apache


How can I determine the method of this DDoS attack?


How to set the Internet Explorer Home Page via GPO?


Installing mysql from source or using apt-get?

Install software from packages, or build it from source?


How can I do daily backups for my VisualSVN Repos?

What ways there are to backup repositories for Windows VisualSVN?


Emails going to Junk for Hotmail recipients

How to send emails and avoid them being classified as spam?


Sending SPAM free mail through my website


Indepedent pairs of RAID 1 is superior to RAID 10

What are the different widely used RAID levels and when should I consider them?


Need Server requirement estimates for my application

Can you help me with my capacity planning?


Why is Linux reporting "free" memory strangely?


Disabling RAID feature on HP Smart Array P400


Globally recording Bash history: Dealing with long-running commands


How to use DNS/Hostnames or Other ways to resolve to a specific IP:Port


Someone is abusing my server but how do I stop the abuse?

How do I deal with a compromised server?


Why is my crontab not working, and how can I troubleshoot it?


Meta alerts in Nagios ? Alert if two other checks are failing

Nagios check whether at least one out of two services is OK


Free alternatives to M/Monit interface for the Monit systems management system

What tool do you use to monitor your servers?


What's a good way to run a point-to-point network speed test over a WAN?

How to test real network throughput between two points?


Completely delete confidential files and folders

Deep Format of a Harddrive on a Linux System


Why does operating system need to know subnet mask?


retrieve software RAID information using WMI

How do you monitor the health of a mirrored disk in Windows?


A ghost process started automatically and drains CPU


Benchmarking hosting providers IO with Bonnie


"POSSIBLE BREAK-IN ATTEMPT!" in /var/log/secure — what does this mean?


Can I downgrade SQL Server 2008 R2 Standard To Web Edition?


How to remove old kernels on CentOS 6 (to free up boot partition)?

How to free up space on RHEL6 /boot safely?


Is it wise to install WAMP on Windows VPS in order to make use of already written PHP application?


How to find out all installed software in our RedHat Enterprise 5 server?


difference between /bin/false and /sbin/nologin

What is the difference between /sbin/nologin and /bin/false?


making a software router for my private network

want to Make software router having two nic cards using centos 6.4


Can I assign a virtual interface (VPN) to a 'real' interface / NIC of my choice?


MySQL: "UPDATE command denied to user ''@'localhost'"

How to reset or recover admin account password for MySQL?


NAT mode virtual machines shows same IP address

Cannot communicate between two VM on the same physical machine using NAT IP Addressing


I really want a wildcard NS record in BIND. Is there a workaround?

Overriding some DNS entries in BIND for internal networks


Assistance on why email is being marked as spam

How to send emails and avoid them being classified as spam?


Hotmail and Live.com rejecting all emails


What is the network address (x.x.x.0) used for?


google search engine architecture- how do so many concurrent users do a search on it

Where to go to learn about web architecture? Youtube example?


Can't start my Windows XP Virtual Machine: Insufficient Disk Space

VMWare ESXi 3.5 "Could not power on VM: No space left on device"


How to delete cached temporarily credentials for a network share on a Windows machine without rebooting or logging off

How do I remove login credentials for a network location in Win7?


htaccess rewriterules for multiple pages with parameters

Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


Can i remove the virus from website scripts from unix shell

How do I deal with a compromised server?


How can I use etckeeper via sudo with different users and have the correct user in the commit message?

Correct user names when tracking /etc/ in git repository and committing as root


Disk full, du tells different. How to further investigate?


Is there a difference between RAID 10 (1+0) and RAID 01 (0+1)?

What are the different widely used RAID levels and when should I consider them?


How much ram do I need to use a 4gig MySql Database?

Can you help me with my capacity planning?


Ubuntu 9.10 server requires frequent reboots to free up memory

Why is Linux reporting "free" memory strangely?


Why is my crontab not working, and how can I troubleshoot it?


Apache/Windows is very slow on only local network


Working with different PHP version at the same time, php_value extension_dir not working?


Alias for Drupal "Sites" folder with Apache on Windows Server 2008


WordPress 404 errors on all pages except home


Blocking directory listing on a wamp server


in Ubuntu, what is the difference between en_US:utf8 and en_US: when setting LANGUAGE

For setting locale in Ubuntu, what does the LANGUAGE environment variable mean?


Rewrite recipient mail queued in postfix


Using Varnish (only) for DDoS mitigation


Ubuntu Server: Attack on blocked ports leads to Ping timeout


Ubuntu 12.04 Server - MySQL keeps crashing - Possible InnoDB problems


Why can't a CNAME record be used at the apex (aka root) of a domain?


How are my DNS entries safe in a shared hosting environment?

Can someone using the same DNS server as me hijack my domains?


is there anyway to know if your supposedly fully dedicated server is really a virtually resource-shared machine?

VMware Linux Server -- how can you tell if you are a vm or real hardware?


stop apache from asking for SSL password each restart


Using a single-level domain for Active Directory

Windows Active Directory naming best practices?


What is the difference between SAN, NAS and DAS?


Software that distributes the performance load over multiple computers?

Multiple servers acting like a single one with all the hardware?


What are the cheapest licenses for Windows Server (current) which I can legally run

Can you help me with my software licensing issue?


How do I deal with a compromised server?


Server was hacked. Now login wont accept 'root' as username comes up invalid


How to secure Cpanel/WHM from malacious uploads


Planning trunk capacity for multiple GbE switches

Can you help me with my capacity planning?


Why is my crontab not working, and how can I troubleshoot it?


Use cron to run a bash script that runs a bunch of sub-commands


Server currently under DDOS, not sure what to do


In Linux, does using route to blackhole an IP result in better performance than dropping in iptables?


Backup Subversion Repositories with rsync


How can I redirect a subdomain to a different URL via Windows DNS?

How to use DNS/Hostnames or Other ways to resolve to a specific IP:Port


exchange address book include all AD users


Monitoring virtual host on ESX5 with Nagios


log bash command centralized server or any auditd saas

How to log every linux command to a logserver


Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


vmware-fusion: How Clones affects Windows Licenses

Can you help me with my software licensing issue?


Windows Server 2012 & Exchange Server 2013 CAL's


/usr/bin/host being used in HTTP DDoS on Debian?

How do I deal with a compromised server?


login page permission has changed suspiciously


Logs show lots of user attempts from unknown IP

Is it normal to get hundreds of break-in attempts per day?


Cisco ASA/PIX Can't Access Internal Resources Behind NAT

How do I reach my internal server on the external IP?


Unable to set proper permission in my centOs6

What permissions should my website files/folders have on a Linux webserver?


Recommended Nginx Configuration for High Traffic Website on Wordpress

Can you help me with my capacity planning?


a client is requesting what are the bandwith requirements for remote desktop


How much free memory should I have on my webserver?


How to evaluate if my Apache needs another server and/or load balancer?


How do I add a broadcast IP to the loopback interface under os/x using ifconfig when my machine has no network?

How to add a broadcast address to loopback with ifconfig on a OS/X?


What is the equivalent of 127.255.255.255 for OS/X machines so I can test broadcast udp packets without a network?


du, df and ls report wrong free / used space

No space left on device -- but there is space


List remote desktop administrative sessions in Windows Server 2012

How do I access the list of currently logged on users through Terminal Services Manager in Windows Server 2012?


Mixed IP and Name based vHosts with SSL issue

Two domains (when SSL) on same directory


Hyper-V File Server Clustering - at my wit’s end

Just a few questions about Hyper-V virtual machines and clustering


centos rely access denied postfix send mail

554 5.7.1 <mail_addr>: Relay access denied centos postfix


Different name servers for different countries. Speed up DNS lookup time

DNS, multiple nameservers and geolocation?


PHP-FPM/nginx-SELinux: No input file specified

Nginx static file configuration for CenotOS 7 Minimal Installation


Looking for script to pull server stats and display on a web page I host

What tool do you use to monitor your servers?


Spam sending on my machine with not write on log of exim and ASSP

How do I deal with a compromised server?


I have multiple instances of nginx, but not sure which one is "correct"


Why is Linux reporting "free" memory strangely?


ipa-server failed to make a configuration?

FreeIPA : Installer not resolving domain name from hosts file


Custom domain private email server goes directly to spam?


OpenVPN connection fails from RHEL 7.3 client on EC2

Why can't I reach my Amazon EC2 instance via its Elastic IP address?


How to maintain PCI compliance on a LAMP server when repositories don't keep up with versions


Cronjob unable to restart apache in CentOS 6

Why is my crontab not working, and how can I troubleshoot it?


How to import pop3/imap mails to new server (backup and restore IMAP/POP3 account)?

Migrating from any IMAP/POP3 server to Dovecot


Are SSL certificates for constant.*.example.com allowed?


Why isn't my scheduled task triggered reliably?

Windows Server 2016 scheduled task schedule must be in future


AWS route53 second level SSL cert wildcard

Wildcard SSL certificate for second-level subdomain


Does disabling root login enhance security?


A previous IT worker probably left some backdoors. How can I eliminate them?

How do you search for backdoors from the previous IT person?


Prevent SSH from advertising its version number


How do I deal with a compromised server?


Running Oracle DB Server on RHEL with less memory

Can you help me with my capacity planning?


Having trouble setting up a nginx web server on Amazon EC2


How to fix Padding Oracle vulnerability on CentOS 7

How to maintain PCI compliance on a LAMP server when repositories don't keep up with versions


tcpdump shows traffic until I use a filter


Why do some commands require su instead of just sudo to do?

`sudo echo "bla" >> /etc/sysctl.conf` permission denied


Better to deduplicate inside VHDX on client or outside VHDX on host?

Server 2012 deduplication: run on Hyper-V host or guest VM?


Return A records but not AAAA records on specific domain in bind9


Azure RM NSG Port Forwarding Not Working


mimic kernel's response to a program that network is not connected?

How to prevent process from knowing Network is up?


OOM killer invoked despite tons of memory available?

Linux process killed even though enough memory available


How to solve the spam outgoing emails from a VPS?

How to send emails and avoid them being classified as spam?


Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


Learning Curve and time needed to install/manage Centos Server

What a beginner should know/learn for sysadmin job?


Looking for script to pull server stats and display on a web page I host


how to find if a host is a physical server or a virtual server

VMware Linux Server -- how can you tell if you are a vm or real hardware?


How can I join a Lubuntu machine to a Windows 2008 domain?

How can I have a Linux machine join a Windows Domain?


How to programmatically determine dynamic IP from behind a subnet

Finding the Public IP address in a shell script


"Masquerade" mail sender on a multi-domain shared hosting


Does having too many files on a filesystem significantly impact io performance?

Maximum number of files in one ext3 directory while still getting acceptable performance?


Any way to find what is filling up my disk?


how do I give the client access to remoteapp but prevent ts login?

Allow only RemoteApp, not Remote Desktop


VCenter 5.0 Server shows error on Hardware Status for hosts (port 8443)

VCenter Server shows error on Hardware Status for hosts


Trouble configuring sendmail to relay mail

SMTP 25 closed even though I allow everything in firewall (Debian server running sendmail)


RewriteRule preserving path across environments

Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


Rewrite a directory to another directory without a redirect


http:// to https:// Redirection with page reload in Apache 2 (HD Web Hosting)


Redirection of subdomain working, but server not found error : Linode


Individual licenses needed for guests on 2012 datacenter?

Can you help me with my software licensing issue?


Microsoft licensing in a virtualized environment questions


What are the IPv6 Public and Private and Reserved ranges

What is the IPv6 equivalent to IPv4 RFC1918 addresses?


How to detect malicious script in my CentOS server?

How do I deal with a compromised server?


My URL has been identified as a phishing site


Hacked website, code is encrypted in hex, unable to identify


Determine from where is "sh" being run under apache www-data user using using PF or NETSTAT


Redirect apache configuration not working


redirect rule for http://www.example.com/http://www.example.com


Getting windows 8.1 installer to recognize the OEM key in Bios


Install guest CentOS 7 on KVM also on CentOS7 without GUI

KVM Guest installed from console. But how to get to the guest's console?


debian testing / stretch resetting /etc/resolf.conf

Find out which process is changing a file


Understanding Linux Permissions - Apache with user "apache"

What permissions should my website files/folders have on a Linux webserver?


Would an extra gigabit ethernet card improve server performance

Can you help me with my capacity planning?


Large Application - should I be concerned about running on VM Ware?


Ejabberd server on AWS t2.micro instance?


only www.*.domain.com certificate for wildcard domain

Can a DNS wildcard only be the leftmost part of a record?


Use of unused pairs in cat5 ethernet cables?


Why is my crontab not working, and how can I troubleshoot it?


Why multiple PTR records in DNS is not recommended?


How to make Samba4 Internal DNS resolve names without domain

Computer can't resolve other computer names


Prioritizing Security Updates Across Web Server

Which Red Hat / CentOS updates should be applied and on what schedule?


How do I create a SSL certificate with LetsEncrypt with CertBot? "Could not install OS dependencies. Aborting bootstrap!"


Unable to make incoming connections when VPN is connected

Allowing SSH on a server with an active OpenVPN client


$server_name not matching domain when multiple subdomains listed in nginx

What is the difference between Nginx variables $host, $http_host, and $server_name?


Host name "DNS" at registrar versus AWS Route 53

Why is geo-redundant DNS necessary for small sites?


SSH Connection refused after running pkill

What causes the 'Connection Refused' message?


Cannot login via ssh into CentOs machine after setting ulimit for open files to unlimited

SSH closes connection after login Exit status 254


Using Centos Firewall how to assign multiple IPs to a Port?

FirewallD : Allow connections only from certain IP addresses


Block user from connecting MiFi units to computers

How to detect whether a user is using USB tethering?


Trouble creating PID file in systemd service script

Systemd drop-in fails to create PID file


sftp permissions limited to primary group after update?

Centos 7 - sshd sftp group permissions messed up after update


How can I block a malicious port scanner currently running on my server?

How do I deal with a compromised server?


Almost all of our websites within our server is redirecting to a porno scammy sites


How can I find out the very first time linux machine start up?

How to determine the "age" of a linux system since installation?


Is there a term for Second Level Domain and Top Level Domain

What is the canonical name for domain names with extra parts?


ifdown interface not configured (Debian 6)

getting error "SIOCADDRT: File exists" when trying to restart network on ubuntu


403 Forbidden on files with different names but identical content and permissions

Apache serves some files, others get 403


NS records chicken and egg: NS in the domain it's serving


How to find which file is under heavy use/IO


How is the parity calculation in a RAID 6?

What are the different widely used RAID levels and when should I consider them?


Which is the RAID level meeting the following criteria?


Hardware RAID0: what happens when a drive fails?


How do you do load testing and capacity planning for web sites?


How to interpret output from Linux 'top' command?


Can you help me with my capacity planning?


Hosting Requirement for an Online Journal and Advice


Resource requirements for cloud OpenVPN server


What is Active Directory Domain Services and how does it work?


One bigger Virtual Machine distributed across many OpenStack nodes

Can a virtualized machine have the CPU and RAM resources of multiple underlying physical machines?


Difference between DL380 rails for different generations?


Why is RAM usage so high on an idle server?

Why is Linux reporting "free" memory strangely?


Why is my crontab not working, and how can I troubleshoot it?


Yum install php-pecl-memcached - No package found (Have epel-release-6-8.noarch.rpm)


How do high traffic sites service more than 65535 TCP connections?


Authenticate Radius user using pam and ssh


"Recursive" Wildcard DNS for Amazon Route 53


Is there a way to dump MySQL table rows live? (similar to 'tail -f')

tail -f equivalent for MySQL logging database


apache2 mod_rewrite redirect without http body

NGINX 301 and 302 serving small nginx document body. Any way to remove this behaviour?


Finding the first and the last address for a given IP address


Use Different port for Different IP bind


How do I deal with a compromised server?


Can my pi server handle 1000 mysql queries per second?

How do you do load testing and capacity planning for databases?


RHEL 7.5 Cannot Yum install from text file


High performance, high availability backend configuration

Can you help me with my capacity planning?


What is the best-practices' reasons for having several partitions for servers?

How bad is it really to install Linux on one big partition?


Enable Nginx authentication for a specific URL


DEBEZIUM -- Mongodb primary node not Resolved in Debezium Kafka Connect -- Docker Compose

Mongodb primary node not Resolved in Debezium Kafka Connect — Docker Compose


Why shouldn't root be allowed to login via ssh?


Apache rewrite rule not working for blocking spamdexing referrer http://site.ru

Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


What is the best way of testing million concurrent requests?

How do you do load testing and capacity planning for web sites?


SSH login are disabled after chmod 444 -R myfolder /


How to include multiple domains in an spf TXT Record ~all and ?all

What are SPF records, and how do I configure them?


How to plan for buying drive capacity for a NAS?


How To Ristrict SSL for one domain in VHOST Apache2

Stop default SSL response on Shared IP using SNI


Using UFW to completely block internet provider


How does a load balancer get around the 64k port limit?

How do high traffic sites service more than 65535 TCP connections?


Why do I receive [Errno 14] PYCURL ERROR 7 - "couldn't connect to host" when running yum commands in Red Hat Enterprise Linux and CentOS?

Do I need a RHEL subscription to install packages?


Supervisord - Supervisor exit status 255 not expected on A

Supervisor process exits with 'exit status 1; not expected'


403 error after changing `DocumentRoot` to `/home/` subdirectory


Exim sending email (-53) retry time not reached for any host

How to get rid of "defer (-52): Retry time not yet reached" exim4 logs?


Whats is the best user to manage webserver?

What's the best way of handling permissions for Apache 2's user www-data in /var/www?


502 Bad Gateway/ failed (111: Connection refused) while connecting to upstream

docker-compose for nginx and nodejs server


What tool do you use to monitor your servers?


How do I diff two text files in Windows Powershell?


Preventing domain controller from adding A/AAAA for domain root

Active Directory: Is it required that the "A" record for a domain point to a Domain Controller?


Nginx force port 8080 to use SSL and rewrite or redirect http to https

Handling http and https requests using a single port with nginx


How to send emails and avoid them being classified as spam?


How to set DNS to my IP and port - Atlantic.Net

How to use DNS/Hostnames or Other ways to resolve to a specific IP:Port


Is it OK to use local. in an active directory domain name

Windows Active Directory naming best practices?


Failed to open /etc/webmin/apache/site for writing : No space left on device

Linux - Help, I'm running out of inodes!


Someone is trying to brute force SSH access to my server

Securing SSH server against bruteforcing


PuTTY slow connecting to Linux SSH server


htaccess redirection on specific domain to specific path

Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


htaccess RewriteRule for multiple files or path


Apache Rewrite URL while acting as reverse proxy


Mod_rewrite rule to redirect from a specific path to another is completely ignored


htaccess rewrite rule, root url to index.php fake directory to different .php file


Can I use any install media for Windows 2012 r2 Standard for licensed VMs?

Can you help me with my software licensing issue?


Spam from unexisting address of my own domain with Postfix

How do I deal with a compromised server?


LAMP/ webdav: my apache error.logs show "su: must be run from a terminal" - but that wasnt me


Is it worth it to install VMWare Tools on a non-graphical Linux guest (Red Hat 7 hosting an Oracle server)

Should VMware Tools always be installed in headless Linux guests?


How to configure an email server so that outgoing emails are not classified as spam


New Linux CentOS setup using sendmail - misconfiguration causes spam issue


AB benchmark: why is my app 10 times faster increasing concurrency 10 times?


infected this directory public_html/.well-known/acme-challenge/index.php


vsftpd single user with multiple directries


How can I mnually code a 301 redirection via nginx by adding HTTP fields without return and rewrite?

NGINX 301 and 302 serving small nginx document body. Any way to remove this behaviour?


Can I clean these two hacked servers withour reinstalling?


local RAID vs server RAID with a 10GbE connection

Can you help me with my capacity planning?


Redirecting an entire domain to another in one CNAME record


How to clear cache in centos remote server?

how to drop_caches in OpenVZ centos6 container


Should I completely rebuild my server due to Heartbleed?

Heartbleed: What is it and what are options to mitigate it?


Trying to install php-devel on AWS EC2 server to compile a PHP extension, but getting errors "httpd24 conflicts with httpd-2.2.27-1.3.amzn1.x86_64"


iptables: REJECT not working, but DROP does


Ubuntu 12.04 LTS: Changing Mysql root Password

How to reset or recover admin account password for MySQL?


How can I selectively override some A records on a Bind DNS Server?

Overriding some DNS entries in BIND for internal networks


How to send emails and avoid them being classified as spam?


Are DNS server responses categorized as "ESTABLISHED" by iptables? If so, why?


Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


Redirect entire site to URL with 302 - All URLs to 1 URL


Zend Server 5.6 Community Edition has Expired in 2014. Can it still be renewed?

Can you help me with my software licensing issue?


Can I salvage a project from a compromised server?

How do I deal with a compromised server?


Process "redis-server" runs fine. After ~6 hours, another process named "redis2" starts and hogs up entire server CPU


what to do in case of command substitution on a linux server?


Is an HP Proliant 350e Gen8 server appropriate for Primevera and Sage applications?

Can you help me with my capacity planning?


Where to put frontend in load balancing configuration


starting nginx on mac fails with 48: address already in use

Debian - Port 80 is blocked, but I don't know by what


Apache serving modified static assets incorrectly: serves obsolete file with sizes adjusted to match that of the new file

Apache on CentOS 5.9 VM serves modified files incorrectly


Linux containers (LXC) on Red Hat/CentOS EL6 - lxc-create versus libvirt?


Why is my email being marked SPAM by gmail?

How to send emails and avoid them being classified as spam?


Apache Rewrite redirect all pages except for specific

Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


Can you help me with my software licensing issue?


What MS licences would allow us to host client systems?


Windows Server 180 days evaluation period for individuals


Licensing: Windows Server 2016 with Remote using


One of My domain is not working on "Google-Chrome"

How do I deal with a compromised server?


How to migrate the sonatype-nexus repository from one instance to another?

Migrate Sonatype Nexus repo from one machine to another


appending to a filename w/ a date from within a cron job

escaping double quotes and percent signs (%) in cron


What happens if you have NS domains be resolved by their own NS servers?


setup apache www directory for multiple users over sftp

What permissions should my website files/folders have on a Linux webserver?


What are SPF records, and how do I configure them?


Need help to choose a desktop or server for the 50 clients in a local network?

Can you help me with my capacity planning?


Bandwidth: How many nodes can a 15Mbps connection serve?


Is it bad practice to run a web application server directly on port 80/443


Redirecting hotspot's traffic through the TOR

How can I block all traffic *except* Tor?


running scripts that have sudo in it as sudo at startup?


What happens if I overload a load balancer? Can I have two load balancers, and how would I set this up?

Is it possible to balance load between multiple Nginx load balancers without using a hardware load balancer?


Normal Shutdown, Thank you for playing in SSH logs

What does "Normal Shutdown, Thank you for playing [preauth]" In SSH logs mean?


DNS registration, basedomain and CNAME records not wanting MX records broken

Why can't a CNAME record be used at the apex (aka root) of a domain?


SELinux preventing Apache from writing to a file


Difference between www.sub.example.com and sub.example.com

Why does my wildcard SSL certificate cause a domain mismatch error on a second level subdomain?


traffic to openvpn server not using tunnel

OpenVPN not default gateway for all traffic


Is it necessary for the production server(CentOS 7) to start the tuned service?


'502 bad gateway nginx error' and 'connect() failed (111: Connection refused) while connecting to upstream' in logs

What causes the 'Connection Refused' message?


-bash: cannot create temp file for here-document: No space left on device


Exim: send select outgoing mails through different server

How to choose a smarthost based on From: address in exim4 on Debian


TeamViewer installed but not running on CentOS


Retrieve malicious IP addresses from Apache logs and block them with iptables


Cassandra native port 9042 slow on ec2 while 9160 is fine


Any drawbacks for using same time zone configuration in Data Centers across time zones?

Local timezones on servers considered harmful?


Understanding Auth Logs on Ubuntu Server


How to add debian "testing" repository to apt-get

How can I run Debian stable but install some packages from testing?


How to send emails and avoid them being classified as spam?


Can message go to spam because of X-AUTH and X-SID fail on hotmail


QQ.com does not accept email from our domain


How could Load average numbers from 'htop' exceed 100% CPU utlization?


Redirect non-local connections to HTTPS in nginx

In Nginx, how can I rewrite all http requests to https while maintaining sub-domain?


Can DNS redirect all HTTPS traffic to a specific IIS application

How to use DNS/Hostnames or Other ways to resolve to a specific IP:Port


Windows Active Directory naming best practices?


Domain.com vs domain.local issue in Windows server 2008r2


How to kick somebody from an RDP session


How can I restrict a group to reading only two particular folders with Windows Server?


Are SMTP headers retained when an email is forwarded or replied to?

When an email is forwarded, does it lose its original headers?


CentOS 6.4 : Cannot login as root ssh anymore


How to setup phpmyadmin without prompts in one line?

Disable prompts while installing a Debian package


apache force if url has specific pattern redirect to https

Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


Apache webserver: How to redirect all requests to domain.com to www.domain.com


How to set up htaccess to transfer from http to https?


Can I double my throughput when I double my cores?

Can you help me with my capacity planning?


Stop default SSL response on Shared IP using SNI


SMTP mail error 452 4.3.1 Insufficient system storage


How do I deal with a compromised server?


Gmail marks all my emails sent by exim4 as spam


When should I consider a 2 socket motherboard for Server?


Challenges of dealing with large disks/partitions


nginx suspicious symbols warning in my nginx config file


Improve RSYNC scan speed / Alternate approach?


How to delete all files and subfolders older than 5 days by cmd call

Expire Files In A Folder: Delete Files After x Days


For an intranet server would you buy a ssl cert or use a self signed cert?


Bind: Overwrite one host of foreign domain

Overriding some DNS entries in BIND for internal networks


How can I route SSH traffic based on a subdomain?

Is there a name based virtual host SSH reverse proxy?


PTR Record setup with separate incoming and outgoing servers

How to send emails and avoid them being classified as spam?


Are two IPs with different subnet masks but same netword IDs on the same network?


Public DNS conflicts with Networks internal DNS

Windows Active Directory naming best practices?


redirect link with question mark in htaccess

Redirect, Change URLs or Redirect HTTP to HTTPS in Apache - Everything You Ever Wanted to Know About mod_rewrite Rules but Were Afraid to Ask


Using windows server 2016 essentials without licence

Can you help me with my software licensing issue?


High load average but low CPU usage and disk I/O


Create logical volume again on Ubuntu after deleating it

Recovering Accidentally Destroyed LVM2 Information


Best way to recover mysql from a "chmod -R 777 /" with databases intact


AWS S3 + Route53: Always redirect to www prefixed domain

Redirect non-www requests to www on Amazon Route 53


Why can't a CNAME record be used at the apex (aka root) of a domain?