It may feel like something from Star Trek, but a fourth state of matter exists and it has been created by two independent groups of scientists in their laboratories.
They are called time crystals and are a phase (like solid, liquid or gas) where the atoms repeat through time instead of space.
The concept was first speculated in 2012 by MIT physicist and Nobel laureate Frank Wilczek but many physicists were sceptical because it defied the laws of physics.
As the atoms in the time crystals loop forever, with no need for extra energy, the hope is that they could one day be used to develop quantum computers.
