3 ms·
I understand that, for a stationary black hole without spin (which does not exist), an object that falls into it will freeze, then the image will redshift until
by chasil 9d ago
I understand that, for a stationary black hole without spin (which does not exist), an object that falls into it will freeze, then the image will redshift until it disappears.
https://en.wikipedia.org/wiki/Event_horizon https://en.wikipedia.org/wiki/Event_horizon
I also understand that there is a cosmological (event) horizon, where galaxies freeze, then rapidly redshift in the same way. This happens because these distant objects are accelerated away from us faster than light.
It appears to me that we are seeing black hole event horizons from the outside, and the cosmological event horizon is seen from the inside.
The similarities do give one pause.
The mechanisms are different; one is gravity, and the other is dark energy.
https://en.wikipedia.org/wiki/Cosmological_horizon https://en.wikipedia.org/wiki/Cosmological_horizon
- pieter3d 9d agoMaybe dark energy is inside-out gravity
- nxpnsv 8d agoWhat does that mean?
- cobbzilla 8d agoNot OP, but it’s not incompatible that dark-energy expansion (and ultimate big rip event) in a child universe correlates to the same process as black hole evaporation (and final event) for the originating black hole, if the “black hole universe” theory holds and they remain geometrically connected.
- nxpnsv 8d agoI’ll have to take your word for it, my general relativity isn’t that up to date… thanks for giving me context though!
- Gagarin1917 9d agoI mean they’re similar because it’s the same thing happening… light not being able to reach us.
- shevy-java 8d agoA black hole stands still? Would that not defy gravity? I mean a black hole also loses energy, right? So I would not expect it to be completely still. After all if you lose energy, you may also lose mass and shape and size - E = mc².
- PowerElectronix 8d agoStill from a far away observer. As matter gets close to the event horizon, its local clock as viewed from far away slows down to the point of freezing completely when it reaches the horizon (this you won't see from outside). As this happens, what you see is a very hard dimming of the emited light and a very hard redshift because everything takes so long now (from the perspective of a far away observer) that the frequency of the light emitted and the luminous power emited basically go to zero (along with everything that has time in the denominator).
- chasil 7d agoThere are three parameters that define a black hole: mass, spin, and charge. There is nothing preventing spin from being zero, as far as I know.