AaS! 128: Why Are We Missing All the Baryons?

What is the "missing baryon problem"? How do we know how many baryons there ought to be? What does the cosmic web have to do with it? What the heck is a baryon, anyway? 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 Watch on YouTube: http://www.youtube.com/PaulMSutter Read a book: https://www.pmsutter.com/books  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: Matthew K, Justin Z, Justin G, Kevin O, Duncan M, Corey D, Barbara K, Neuterdude, Chris C, Robert M, Nate H, Andrew F, Chris L, Jon, Cameron L, Nalia, Aaron S, Kirk T, Tim R, Joe R, Neil P, Bryan D, Irene P, 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, Steven L, Ulfert B, Dave L, Stace J, S Stark, Richard K, Carol S, Stephen M, Grace M, Jeremy K, Russell W, David B, Tamara F, Robert B, Fr Bruce W, Catherine R, Nicolai B, Sean M, Nate H, Edward K, Ped, Chuck C, Jose Pablo V, Stephen S, Elizabeth W, Eric F, Tracy F, Callan R, Nils M, George, Tom G, Monika, Michael H, Tom, Sarah K, Robert S, Gerald, Jens O, Ella F, and Sarah K! Music by Jason Grady and Nick Bain. Thanks to Cathy Rinella for editing. Hosted by Paul M. Sutter, astrophysicist and the one and only Agent to the Stars (http://www.pmsutter.com).