## Does a black hole suck things in faster the closer it gets to the center?

Question

Or is the speed things are sucked in a constant speed no matter what point you’re at in the hole (top vs singularity?) thank you in advance!

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General Physics
4 years
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## Answer ( 1 )

A metaphor supported by the mathematics of general relativity is the so-called waterfall model. Under the influence of gravity, a geodesic ‘ball’ of space will contract over time. This is difficult to understand mathematically, but easy to understand if you think of gravity as space flowing toward the source of gravity, carrying free fall objects with it (which feel no local acceleration). Space within the event horizon is actually contracting faster than light with respect to the space outside a black hole. The speed of space contracting, and the the speed of the objects carried with it, will continue to increase as the singularity is approached.

It can be difficult to describe speed with this model. Relative to what? Outside the black hole? The local space-time flowing into the black hole?Additionally, since we also get a exchange of space and time within the event horizon, the idea of a speed is hard to Relate to anything meaningful.

A more meaningful way of looking at it is the proper time it takes an object to free fall through the event horizon to the singularity. The proper time is the wristwatch time of an observer falling through the event horizon. For small black holes (e.g. solar size), an observer falling through the event horizon will record only milliseconds of time to get to the singularity. For super massive black holes, it may take hours or even days to cross the event horizon to the singularity. It is really better to think of how long for the observer, rather than how fast.