Recently physicists have discovered a whole new form of matter, It is four dimensional matter called time crystal. Normal crystals, like diamonds, are an atomic lattice that repeats in space. That means, a three dimensional diamond crystal is a mass of repeated adhesion of similar carbon atoms. However, physicists recently suggested making materials that repeats in time. So, they have established that there is a group of particles which can move in a circle without radiating its rotational energy and keeps on returning to its original phase.
When Frank Wilczek first proposed the idea in 2012, it was heavily criticised by many renowned physicists and such matters were termed as theoretical structures. However, physicists have recently discovered the existence of such matters in crystal form. Last year, researchers established the phases surrounding a time crystal. They also figured out the method of measurement that would confirm that this new material is actually a stable phase of matter. This stimulated two teams to build a time crystal made of Ytterbium chain which is the first example non-equilibrium matter on earth.