A fast radio burst leaves a distant galaxy, travelling to Earth over billions of years and occasionally passing through clouds of gas in its path. Each time a cloud of gas is encountered, the different wavelengths that make up a burst are slowed by different amounts. Timing the arrival of the different wavelengths at a radio telescope tells us how much material the burst has travelled through on its way to Earth and allows astronomers to detect "missing" matter located in the space between galaxies. Using CSIRO's Australia Square Kilometre Array Pathfinder (ASKAP), astronomers have proved that fast radio bursts are coming from the other side of the Universe rather than from our own galactic neighbourhood.
Credit: CSIRO/ICRAR/OzGrav/Swinburne University of Technology