What are galaxy clusters made of, besides galaxies? How can we use them to understand dark matter? And how can we make pretend ones on a computer? I discuss these questions and more in today’s Ask a Spaceman! Support the show: http://www.patreon.com/pmsutter All episodes: http://www.AskASpaceman.com Follow on Twitter: http://www.twitter.com/PaulMattSutter Like on Facebook: http://www.facebook.com/PaulMattSutter Watch on YouTube: http://www.youtube.com/PaulMSutter Read a book: http://www.pmsutter/book Go on an adventure: http://www.AstroTours.co Keep those questions about space, science, astronomy, astrophysics, physics, and cosmology coming to #AskASpaceman for COMPLETE KNOWLEDGE OF TIME AND SPACE! Big thanks to my top Patreon supporters this month: John, Matthew K, Helge B, Justin Z, Matt W, Justin G, Kevin O, Duncan M, Corey D, Kirk B, Barbara K, Neuterdude, Chris C, Erik M, Steve C, Digitalneo, Erik M, Tim R, Neil L, Gordon M, Joe R, Neil P, Gabriella G, Tom S, Bryan D, Irene P, Dustin R, Matt C, Iothian53, Steve P, Debra S, Ken L, Alberto M, Ron W, Chris L, Mark R, Alan B, Stephen J, David P, John F, Maureen R, Frank T, Craig B, Jesse A, Ron S, Steven L, Mark R, Ulfert B, Dave L, Stace J, S Stark, Richard K, Vladimir Z, Carol S, Stephen M, Grace M, Jeremy K, Russell W, Thomas S, David B, Tamara F, Robert B, Fr Bruce W, Catherine R, Nicolai B, Sean M, Nate H, and Edward K! Music by Jason Grady and Nick Bain. Thanks to Cathy Rinella for editing. Hosted by Paul M. Sutter, astrophysicist at The Ohio State University, and the one and only Agent to the Stars (http://www.pmsutter.com).