What do physicists mean when they say we may be living in a holographic universe?

Question

Can someone explain the holographic universe theory to me in the dumbest way possible? My mind can’t grasp what it means.

In: Planetary Science

Answer 1

The layman way I understand this is that all the information necessary to describe any given place & objects in reality can be stored in a 2 dimensional ‘flat’ object. The size of the 2D slice needed is directly proportional to the size of the 3D area covered, and in principle our full 3D world could be represented as information held on a 2D plane.

Just because it could, doesn’t mean it is – it’s an interesting mathematical quirk that could be a hint at something more fundamental

I am no doubt way off and missing a ton of nuance, but this is ELI5 anyway