Lost Space

[sethoflagos]

I've seen a number of references to space flowing across a black hole event horizon at the speed of light.

If space can be lost in this way, what happens to the vacuum energy associated with that space? i.e. Does it increase the mass of the black hole?  

[Markus Hanke]

4 hours ago, sethoflagos said:

I've seen a number of references to space flowing across a black hole event horizon at the speed of light.

It is important to remember that this is only an analogy - it’s a pedagogical device that can be useful to illustrate certain aspects of certain spacetime geometries (it’s called the “waterfall analogy”), but it isn’t to be taken literally. You will find this analogy often used for black holes that carry angular momentum and/or electric charge.
In actual fact though spacetime isn’t some kind of mechanical fluid, and it is not embedded into anything higher dimensional, so it doesn’t physically “flow” anywhere. The proper mathematical description of spacetime geometry doesn’t use such concepts. It’s just a visualisation aid.

 

[sethoflagos]

7 hours ago, Markus Hanke said:

It is important to remember that this is only an analogy - it’s a pedagogical device that can be useful to illustrate certain aspects of certain spacetime geometries (it’s called the “waterfall analogy”), but it isn’t to be taken literally.

All is clear. Many thanks, Markus.