Artwork conceptualising the idea of quantum foam - a description of subatomic spacetime turbulence at distances on the order of the Planck length On these scales, the Heisenberg Uncertainty Principle dictates that particles and antiparticles can come into existence, exist for a brief instant, and then annihilate before the Universe 'knows' about the creation of these so-called 'virtual particles' - thus avoiding a violation of the conservation of energy Einstein found that energy and mass can curve space So on small enough scales, the energy fluctuations that give rise to virtual particles can cause significant departures from the 'smooth' spacetime that we see on large scales - causing spacetime to have a foamy appearance that has been describe as quantum foam