Black holes and higher dimensional universe

[pibb]

if black holes are 2 dimensional representations of our 3 dimensional universe, does that make our universe a 3 dimensional representation existing on the edge of (or entirely inside) a 4 dimensional universe? or to a 4th dimensional being would our 3 dimensional universe be considered a "black hole" since time will only flow in one direction after entering our universe?

 

[phinds]

if black holes are 2 dimensional representations of our 3 dimensional universe, does that make our universe a 3 dimensional representation existing on the edge of (or entirely inside) a 4 dimensional universe? or to a 4th dimensional being would our 3 dimensional universe be considered a "black hole" since time will only flow in one direction after entering our universe?

HUH ? Where did you hear that a black hole is a "2 dimensional representations of our 3 dimensional universe". Post reference please.

 

[pibb]

it was in string theory iirc.

 

[yenchin]

HUH ? Where did you hear that a black hole is a "2 dimensional representations of our 3 dimensional universe". Post reference please.

I think he meant the holographic principle...

To the OP:

But that is really not what it says! The holographic principle says that we can model physics of certain quantum field theory with has strong coupling (i.e. difficult to calculate and solve) with a black hole in a kind of space called anti-de Sitter space in a semi-classical regime (i.e. easy to calculate with). One then translate the result back into the language of the field theory.

Note that this can be treated as a mathematical tool in calculating - there is really no way to test whether such anti-de Sitter space "really exist". Even granting such possibility, the universe would then be the boundary of this anti-de Sitter space (which has 4 space dimension and 1 dimension). But I don't think we should take this too literally. I don't understand what it is meant by

"time will only flow in one direction after entering our universe?"

By the way a good popular science book about holographic principle is Susskind's "https://www.amazon.com/dp/0316016403/?tag=pfamazon01-20".

 

[pibb]

thanks for the reply. yeah i think it was leonard susskinds holographic principle that i must have not understood. thanks for the suggestion about the book also.