Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: annie123 on 15/04/2019 23:24:44

Title: where does light/matter go when absorbed into black hole?
Post by: annie123 on 15/04/2019 23:24:44
Tried to make sense of importance of photo of 'black hole' but explanation I read talks about matter and light going into the hole - this seems still metaphorical - gives an inaccurate account really since it isn't a 'hole ' as we would know one, so what is it?  And what about 'worm holes '- another metaphor but how can it be explained in terms of going 'into' another universe
Title: Re: where does light/matter go when absorbed into black hole?
Post by: Kryptid on 15/04/2019 23:48:28
You're right in saying that it isn't a hole in space: black holes are three-dimensional objects like a sphere (or at least the event horizon is). When it is said that matter falls into a black hole, it means that matter crosses the event horizon (the radius around a black hole where the escape velocity equals that of light). The event horizon isn't made of matter, it is just a location. Once inside of this critical radius, no light emitted by the matter can get out of the event horizon. This is why the hole itself is black.

Wormholes are closer to being "actual" holes, although they are not two dimensional holes either. They represent areas of highly curved space where the way that space itself is connected to other regions of space is altered. It's somewhat like comparing a balloon to a doughnut. Normal space without a wormhole is represented by the balloon. If you want to walk to the other side of the balloon, you have to take a path around its surface. The doughnut represents space with a wormhole in it. You can choose to get to the other side of the doughnut by walking around its outer edge, or you could go through the hole in the middle instead. Of course, these are only lower-dimensional analogies and the actual way that space is structured in a wormhole is not something that the human mind can visualize.

Title: Re: where does light/matter go when absorbed into black hole?
Post by: chris on 16/04/2019 00:44:43
Presumably the light adds to the momentum of the black hole?
Title: Re: where does light/matter go when absorbed into black hole?
Post by: pensador on 16/04/2019 12:34:52
Presumably the light adds to the momentum of the black hole?

The photons INERTIA increases the MASS ? of the blackhole, If the photon can not exceed c inside the black hole, can it increase its momentum/inertia by blue shifting.

The matter that enters, a BH has inertia the momentum increases as it is accelerated towards the singularity increasing the black holes MASS. The momentum increases as the matter approaches c. Does the inertia stay the same as matter approaches c or does this increase also.

It is the black holes inertia that is increased via photons and other matter falling into BH, which might increrase its angular momentum.
 
How do we define mass in a black hole, is it rest mass inertial mass or what, which definition of mass is used.

Edit if things are torn apart inside the BH, converting them to quantum foam, is the quantum foam also part of the mass of the BH or is it like virtual particles having inertia and no mass. I'm flummoxing myself again:(
Title: Re: where does light/matter go when absorbed into black hole?
Post by: Kryptid on 16/04/2019 14:31:12
How do we define mass in a black hole, is it rest mass inertial mass or what, which definition of mass is used.

To the best of experimental measurements, all forms of mass are equivalent.
Title: Re: where does light/matter go when absorbed into black hole?
Post by: yor_on on 16/04/2019 21:50:41
Maybe it's just energy? You have two kinds of energy, mass energy and kinetic energy. The kinetic is due to relative motion and accelerations, the mass energy is a equivalence to the energy a mass represent when not in motion. If you think of it there is no way, I know of at least, proving uniform motion to be moving in any local sense. No way to measure it locally, no matter what 'speed' you might want to define to Earth, the solar system or galaxy, as you look out at the universe. So kinetic energy looked at locally measured is slightly weird, even though existing. The mass energy though is easier to understand.

And the way it seems to me anything passing a event horizon should close in to 'c' doing so, as defined from a far away observer.
=

Hmm, the last part is not correct if we take in the time dilation which to the far away observer will make the process slow down to a stand still. But in essence I still think it has to be 'c' locally defined even though any observer inside that in falling object still would be weight less, ignoring tidal forces etc. It's most definitely weird ;)