How Can Gravity Trap Light If Light Has No Mass?
Sleep On Physics
5,299 views
Light has zero mass. It travels at three hundred thousand kilometers per second and nothing can slow it down. So how does a black hole, which uses gravity, trap something that weighs absolutely nothing? The answer isn't what you think. It has nothing to do with force, nothing to do with weight, and nothing to do with light slowing down. The real answer changes how you understand gravity itself.
In this video, we start with the paradox that Newton's gravity cannot explain: why massless photons respond to gravitational fields at all. We trace the history from Newton's corpuscles through John Michell's dark stars to Einstein's radical insight that gravity is not a force, it is the curvature of spacetime. We explore how Einstein's equivalence principle demands that light must bend in a gravitational field without ever invoking mass. We then journey to the event horizon of a black hole, where spacetime curvature becomes so extreme that every possible direction a photon can travel curves inward. Light isn't pulled. Light isn't slowed. The exit is removed from the geometry of reality itself. Inside the horizon, space and time swap roles, and the singularity becomes not a place you fall toward but a moment in time you cannot avoid - like next Thursday.
Sources:
Misner, C.W., Thorne, K.S. & Wheeler, J.A. (1973). Gravitation. W.H. Freeman and Company.
Carroll, S.M. (2003). Spacetime and Geometry: An Introduction to General Relativity. Addison-Wesley.
Event Horizon Telescope Collaboration. (2019). "First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole." The Astrophysical Journal Letters, 875(1), L1. https://doi.org/10.3847/2041-8213/ab0ec7
Abbott, B.P. et al. (LIGO Scientific Collaboration and Virgo Collaboration). (2016). "Observation of Gravitational Waves from a Binary Black Hole Merger." Physical Review Letters, 116(6), 061102. https://doi.org/10.1103/PhysRevLett.1...
Thorne, K.S. (1994). Black Holes and Time Warps: Einstein's Outrageous Legacy. W.W. Norton and Company.
#BlackHoles #GeneralRelativity #Spacetime #EventHorizon #Einstein #PhysicsExplained #SpaceScience
10 Comments
But space has no mass either, same as a photon, so what is going on here ?
At the even horizon, time slows down so much that the speed of light cannot overcome the time dilation and comes to a standstill.
It just proves that the universal constant (C) isn't so universal in a high gravity environment.
Because in that area of space, 168,000 miles per second is meaningless if a second there is a million years to an observer on Earth.
Light will just never reach your telescope.
That is propaganda from the failed Einstein versions of light and gravity.
The galactic core is highly visible in far x-ray and gamma.
How Can Gravity Trap Light If Light Has No Mass?
Sleep On Physics
5,299 views
Light has zero mass. It travels at three hundred thousand kilometers per second and nothing can slow it down. So how does a black hole, which uses gravity, trap something that weighs absolutely nothing? The answer isn't what you think. It has nothing to do with force, nothing to do with weight, and nothing to do with light slowing down. The real answer changes how you understand gravity itself.
In this video, we start with the paradox that Newton's gravity cannot explain: why massless photons respond to gravitational fields at all. We trace the history from Newton's corpuscles through John Michell's dark stars to Einstein's radical insight that gravity is not a force, it is the curvature of spacetime. We explore how Einstein's equivalence principle demands that light must bend in a gravitational field without ever invoking mass. We then journey to the event horizon of a black hole, where spacetime curvature becomes so extreme that every possible direction a photon can travel curves inward. Light isn't pulled. Light isn't slowed. The exit is removed from the geometry of reality itself. Inside the horizon, space and time swap roles, and the singularity becomes not a place you fall toward but a moment in time you cannot avoid - like next Thursday.
Sources:
Misner, C.W., Thorne, K.S. & Wheeler, J.A. (1973). Gravitation. W.H. Freeman and Company.
Carroll, S.M. (2003). Spacetime and Geometry: An Introduction to General Relativity. Addison-Wesley.
Event Horizon Telescope Collaboration. (2019). "First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole." The Astrophysical Journal Letters, 875(1), L1. https://doi.org/10.3847/2041-8213/ab0ec7
Abbott, B.P. et al. (LIGO Scientific Collaboration and Virgo Collaboration). (2016). "Observation of Gravitational Waves from a Binary Black Hole Merger." Physical Review Letters, 116(6), 061102. https://doi.org/10.1103/PhysRevLett.1...
Thorne, K.S. (1994). Black Holes and Time Warps: Einstein's Outrageous Legacy. W.W. Norton and Company.
#BlackHoles #GeneralRelativity #Spacetime #EventHorizon #Einstein #PhysicsExplained #SpaceScience