The universe is growing all the time… clusters of galaxies exist with vast space in between them. What floats around in the huge expanse between galaxies? And what actually defines a cluster? Find out more about the universe and what it will become over time on this week’s SkyTalk. Also… Derrick Pitt’s tells you what to look for in the night sky.
Credit: NASA, ESA, S. Beckwith, and The Hubble Heritage Team