How do we know that dark matter exists? Are you sure that scientists aren't just making things up because they're lazy? What makes it dark anyway? I discuss these questions and more in today's Ask a Spaceman!
Keep those questions about space, science, astronomy, astrophysics, and cosmology coming to #AskASpaceman, Twitter@PaulMattSutter, http://www.Facebook.com/PaulMattSutter, and http://www.askaspaceman.com for COMPLETE KNOWLEDGE OF TIME AND SPACE! Music by Jason Grady and Nick Bain.