Holograms are mostly used as novelty tech with a futuristic twist, but the science behind them may help us finally solve a major problem when it comes to black holes. Black holes are cosmic objects from which nothing, not even light, can escape.
The cardinal theories of physics, relativity, and quantum mechanics don’t play along well when it comes to black holes. For quantum mechanics, black holes need to hold the information of everything they have interacted with and are the sum of everything they have absorbed. For relativity, they are instead simple, smooth, and everything about them can be derived from a handful of parameters such as mass and area.
Holograms come into the fold in an attempt to reconcile these two views. Similar to how holograms are two-dimensional but appear 3D, the holographic principle is the idea that a lot more information is encoded in a state with one less dimension than we are considering, for example in 2D rather than 3D.