What if the entire universe as we know it - with its galaxies, stars, planets and all that lives on them - was nothing more than a projection? An intriguing question, perhaps reminiscent of science fiction, but this concept is actually based on a profound physical theory: the holographic theory of the universe. The basic idea of this theory can be summarized as follows: Everything we perceive in three-dimensional space could in reality be just a two-dimensional projection, similar to a hologram. This means that all information about the universe, about all objects and events, is stored on a flat surface that is outside of what we experience as "space". This surface encodes reality, just as a hologram on a two-dimensional plate can contain the three-dimensional image of an object.