Null. Nil. Zip. Nada. Zero. Call it what you like, it’s still nothing. But what is nothing? And is “zero” just a theoretical concept, or can it really be considered a number? At times, philosophy and mathematics meet in the middle to give us truly weird thought experiments. So, grab your graph paper, calculator and tweed coat, because we’re going to go on a journey down the number line to find out what “zero” really means. Evrim Yazgin is a Cosmos journalist with a Masters in Physics from the University of Melbourne. His love of science fiction has spurred an interest in all things flux capacitor to quantum-time-antimatter-inverters. See omnystudio.com/listener for privacy information.