Stackexchange has been taken over by the wokesters (see the Twitter profile of one of the involved moderators, which is filled up with Farmville Screenshots and anti Trump propaganda). They already started to impose gender requirements on the users and even edited transinclusive pronouns into one of my postings (next thing they'll do is probably to edit Rainbow, Israel and Ukraine flags into your avatar and decide that the term black hole is racist). Therefore my postings that I made there have been archived here to save them from vandalism:
- Is there an event horizont if the mass is negative?
- Why are there so many objects perfectly orbiting each other?
- Time dilation and Doppler shift for different observers in Schwarzschild metric
- Sending photons in opposite directions in a closed universe
- Schwarzschild metric in cartesian {t,x,y,z} coordinates
- Gravitational acceleration of a spinning fan in a vacuum
- Lightcones in negative mass Schwarzschild spacetime
- Λ in the energy tensor
- Which photons will reach an object falling into a black hole?
- Can the universe contract in some areas while it expands in others?241-250
- Does rotation make black holes smaller?
- Energy gained by a black hole
- Effects on a stationary observer near a Kerr black hole
- Is the equivalence principle violated for photons in the field of an infinite massive plane?
- Is the mass of a black hole somewhere at all?
- Event horizon of black holes
- The physical meaning of the cross-term of Kerr metric
- The uniqueness of the Kerr-Schild form
- Density in the Oppenheimer-Snyder collapse
- Total precession of a gyroscope orbiting close to a black hole231-240
- Properties of Anti De Sitter space (AdS)
- How close does a charged particle have to be “attracted” to a charged black hole?
- Kerr Newman De Sitter metric in Eddington Finkelstein style Null Coordinates
- How to add gravitational and kinetic time dilation
- Is time dilation is due to acceleration in the twin's paradox?
- Where does the energy carried by gravitational waves come from?
- Orbital velocity formula in Schwarzschild metric
- Visualizing Kerr-Newman vector fields lines
- If light bends twice as much as Newton predicted, does it fall faster than other things?
- The slowing of expansion in the matter dominated era221-230
- The beginning of the Dark Energy era
- Photon sphere of a charged black hole
- The "speed of length contraction" in switching between inertial frames
- At what speed would a rocket below the photon sphere require the least thrust to remain at constant radius?
- Simultaneous events
- What would a standing wave of light look like?
- How to calculate the gravitational and kinetic time dilation between two planets
- Do the apparent Black Hole dimensions contract as the observer falls in?
- Static spacetimes and the cosmological constant
- Do vacuum particles move or rotate with spacetime?211-220
- Gabriel's horn and General Relativity
- Penrose diagram of hypothetical astrophysical white hole
- About the temporal coordinate in Eddinton-Finkelstein coordinates
- Would light emitted from a white hole be red-shifted or blue-shifted?
- Observed orbit of a planet around a black hole
- The twin paradox and general relativity
- Does the Hubble expansion cause apparent friction?
- Can I really see what is on the opposite side of a black hole?
- Where in the universe does time pass fastest relative to time on earth?
- Escaping close to the horizon of a black hole201-210
- Why is the FLWR metric dependent on the observer?
- Rotating space vs. inspiraling space
- Is frame dragging accelerating asteroids or comets?
- Rotation of astrophysical black holes
- Seeking a plot of the energy history of the Universe
- Why is climate change triggering faster rotation?
- Extracting energy from dark energy using springs
- What is the matter/energy flux on the cosmological horizons?
- Does the kinetic energy of fast-moving particles create attractive gravitational force?
- What is the greatest extent of the particle horizon?"191-200
- How does a charged particle respond to a charged black hole?
- The curvature of spacetime in the center of a Kerr black hole
- Frame dragging effect inside the event horizon
- Is there a maximum mass limit for black holes?
- Perceived shape of a black hole as it is approached at high velocities
- Confusion with Doppler Effect problem
- Conformal flatness FLRW
- What is the frequency of the light seen by an observer free-falling into a black hole?
- What should be the shape of spacetime to repel opposite masses from one another?
- Schwarzschild metric in terms of a free-falling observer's coordinates181-190
- Using time dilation to find an universal frame of reference
- The unit of the cosmological constant
- The scale factor of ΛCDM as a function of time
- The density parameter of ΛCDM as a function of time
- Orbital period and velocity around a Kerr black hole relative to fixed stars
- The strength of dark energy compared to the strength of the other forces
- Frequency of a reflection in a gravitationally accelerated mirror
- Reissner Nordström black hole and an accelerated observer
- The Landau-Lifschitz Pseudotensor for the Schwarzschild metric
- How to calculate the radius of curvature of a FLRW universe171-180
- Does the radio stop working when crossing the event horizon?
- Does light travel faster when it is in moving spacetime?
- Sound horizon in cosmology
- Interpretation of the horizon in de Sitter
- Could light travel around the closed FLRW universe precisely once?
- The energy difference between black hole and system has zero potential energy
- How does g-force relate to time dilation? (Interstellar)
- The view from inside a black hole looking towards the event horizon
- Gravitational Redshift in Kerr Spacetime
- Disintegrating as you enter a large black hole?161-170
- Can I get turned around backwards in time?
- Gravitational pull of a disc
- What does w=−1 mean for the equation of state of cosmology?
- Black hole cosmology vs. big bang cosmology
- Do gravitational waves cause time dilation or not?
- Black hole infinite distance finite time paradox
- Is the Schwarzschild horizon lightlike?
- Could a powerful gravitational wave tear apart an object?
- What is the effect of rotational frame dragging on an object?
- What is the sum of the angles of a triangle on Earth orbit?151-160
- How to calculate the radius of curvature in terms of energy density ρ?
- Newton's law of gravitation in de Sitter space
- Gravitational time dilation in weak field
- Is there a difference in energy walking with and against Earth's rotation?
- Age of Universe from Friedmann Equation - How to actually solve the integral?
- Horizons and other special surfaces on Kerr metric
- How exactly does spacetime change inside a black hole?
- Entering a black hole, does the incident angle matter at all?
- How does one approach negative curvature in the Einstein Field Equations?
- What is the distance from an object at which the gravitational force is exactly zero?141-150
- Does spacetime interval at event horizon become light-like for all trajectories?
- Are there GW spheres like photon spheres around a black hole?
- Effects of the cosmological expansion
- Deriving the 4-momentum of a free particle moving in curved spacetime
- Geodesic with decreasing value of time coordinate
- No apparent horizon in a Schwarzschild black hole?
- Solar frame dragging
- Distances in general relativity
- Does the no-hair theorem imply that dark matter cannot have any “charge”?
- What happens to a particle in the exact center of a Kerr black hole?131-140
- What wavelength was the CMB originally?
- Numerical Solutions for Equatorial Orbits in the Kerr Black Hole
- How much time has elapsed in a second inertial frame at a particular moment in the first inertial frame?
- How much in the past are we viewing the accretion disk of a black hole?
- Is the trajectory of an object falling toward a black hole always reversible?
- Black hole spins at X% of the speed of light, what does that mean?
- Event-Horizon Shape in a Binary System
- Relativistic Doppler Effect between rotating bodies
- Blinking flashlight infalling into the black hole, as frequency → ∞
- Increasing expansion rate and time dilation121-130
- Can a straight rod exist next to or inside a black hole?
- Geodesics in general relativity changing from timelike to spacelike?
- What is the probability of a photon being emitted by the sun actually being absorbed?
- At what cosmological redshift z, does the recession speed equal the speed of light?
- How much energy is radiated when matter falls into a black hole?
- For a given mass, how big can a Kerr black hole get?
- Bob sees Alice never reaching the event horizon. What does Alice see when looking at Bob?
- How far away must a galaxy be for its light never to reach us due to the expansion of the universe?
- What's the escape velocity of naked singularities?
- What's the meaning when Kerr-Newman metric's mass is zero?111-120
- Time dilatation of an observer falling towards a Kerr black hole
- Does it actually take infinite (observer) time for someone to fall into a black hole?
- Proper velocity vs relative velocity
- How can a refrigerator magnet be stronger than the Earth's magnetic field?
- Volume of hypothetical closed universe
- Does gravity sometimes get transmitted faster than the speed of light?
- Does Aμ transform with the coordinates, or as a vector in a tangent space?
- Escaping the Gravity well of the Moon
- Gravitation Acceleration in General of Kerr-Newman Black Hole
- Is a stable orbit possible inside the ergosphere of a Kerr (spinning) black hole?101-110
- Metric diameter of a ring singularity
- Gravitational wave equations
- Why arent black holes bright due to the bent light from nearby stars?
- How can matter falling into a black hole make it grow?
- Can you outrun a photon inside the event horizon of a black hole?
- The t-coordinate bounds inside a black hole
- Is there any moon without its planet?
- Gravitational time dilation and a race
- The experience of time while falling
- Alcubierre drive visibility091-100
- Does bending the direction of light generate space curvature?
- How to get rotation components in each axis?
- How can the red shift due to Hubble flow be consistent with the law of conservation of energy?
- Negative work done by dark energy
- If a satellite moves towards Earth, is negative work done against the force of gravity?
- Naked singularity: how would it behave?
- Why did the rapid inflationary expansion slow down?
- Negative mass in spacetime fabric
- A flyby of orbiting supermassive black holes
- Why is the photon-sphere around a Kerr Black Hole spherical and not ellipsoid?081-090
- Escape velocity from a rotating black hole
- What is the reference frame for the velocity of an object in the universe?
- Basics of a white hole
- Are electrons points or Kerr naked ring singularities?
- Explain Kerr-Newmann black hole spins in SI units
- What is the exact relation between the age of the universe and the cosmological constant?
- Preferred frame in closed universe
- Does Newtonian mechanics predict the bending of the course of light by objects with mass?
- Would neutron average life expectancy be shorten by gaining relativistic mass?
- Is the speed of light the escape velocity of the universe?071-080
- What caused the moon's initial inertia?
- Earth gravity vs Mars gravity
- Is there any limit for the size of the universe?
- Does an infinite universe imply infinite mass?
- Velocity of an object after leaving a ramp
- Can general relativity be translated to a language of Newtonian forces?
- Does the spot size of laser change as a function of power?
- Will a disco ball really end up inside a black hole?
- If the universe is very nearly flat how can space be curved?
- What is causality (travelling with v>c?)061-070
- Can superfluids communicate faster than light?
- Clarification of negative kinetic energy
- Is the potential energy of a black hole infinity?
- Does the center of a star age faster than its relativistic equatorial surface?
- What is the physical meaning of Schwarzschild coordinates?
- Gravity between two photons
- Relative velocity for a stationary observer
- Why is a spacetime with negative curvature assumed to have a hyperbolic, rather than spherical, geometry?
- Velocity vs time curve of negatively accelerating motor
- Can an electron stay still?051-060
- Relation between orbital velocity and escape velocity in strongly relativistic situations
- Does negative mass reverse the arrow of time?
- Escape velocity at an angle
- Can a photon have a wavelength less than the planck length?
- What is the physical meaning of the Schwarzschild radius for objects that aren't black holes?
- Cosmology parameters
- Can rails on the ground or blimps in the air be positioned to collect lightning?
- What is the most distant object light could reach?
- Is it contradictory to have a negative gravitational mass?
- Schwarzschild metric: acceleration of ball before it's dropped041-050
- Don't heavier objects actually fall faster because they exert their own gravity?
- How does the inclusion of vacuum energy modify Newtonian gravity equation of motion?
- In golf, what influences more on how far the ball travels?
- Two Robertson-Walker observers, at what time will a light signal be received?
- Is mass per surface area/gravity a constant?
- Calculating the velocity of an object far away
- Where does the energy of a photon trying to escape a black hole go?
- Angle of a pendulum as an explicit function of time
- How is this conflict about age of the universe resolved?
- What is the power given by centripetal force?031-040
- Is the cosmological horizon expanding faster than space itself?
- Projectiles ability to do work to a box when connected by string?
- Does the physical cross section of a projectile have an effect on the motion of a target?
- Can we detect gravitational waves generated from inside the event horizon of a black hole?
- Solving for r=0 in an inverse square law
- Planetary scale motor
- About the working of LIGO
- Is the universe bounded?
- Universe expansion and general relativity
- Does gravitational force attract bodies with mass or with energy?021-030
- Long and short barreled guns
- Twins paradox question
- Do photons have a maximum density per unit area?
- How confident are we that mass is not being lost in the universe?
- Length contraction alongside acceleration
- Distribution of dark matter in galactic halos
- Is the accelerated expansion of the universe consistent with conservation of energy?
- Do objects have energy because of their charge?
- Can a thrown egg chip or break a car windshield?
- Cosmic event horizon changes over time011-020
- How much dark matter is needed to gravitationally distort light?
- The ever increasing pull of a black hole
- If a theory gets two predictions right, how likely it is that the rest of it is true too?
- Does light have a gravitational pull?
- What lies at the very edge of the expanding universe?
- Who is moving and with who's relation?
- Would a black hole's rotational axis precess in orbit around the sun?
- How do photons mediate (or create) a force?
- Is it valid to apply Einstein's Relativity to scenarios involving expansion of space?
- Even the universe is infinite, it could keep expanding?001-010
- Two body problem with given start positions and velocities
- Kinetic energy and rest energy
- Cosmology: proper evolution of energy density ratios with time
- Could Dark Energy just be particles with negative mass?
- Height of a projectile with an angle
- Question about universe expansion
- How does light actually behave?
- Integrate the law of universal gravitation to get position
- What is the force required to move a raindrop?
- Will we ever be able to view the past?
251-260
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