Step outside the universe to kill time

摘要

Time really is an illusion - at least in a model universe made of two particles of light. The experiment could assist in uniting our two best theories for describing reality: quantum mechanics and general relativity. So far, attempts to combine the equations in these disparate theories have produced seemingly nonsensical answers. In the 1960s the Wheeler-DeWitt equation quantised general relativity -by leaving out time altogether, something that runs counter to our practical evidence.