Congress held its first public hearing on UFOs in over 50 years, signaling how lawmakers are pressuring military leaders to take the issue more seriously.
Astrophysicist Neil deGrasse Tyson joins MSNBC’s Ari Melber to discuss the hearing, the "multiverse" and black holes.
Tyson has previously joined Melber on The Beat to discuss anti-science and anti-climate change rhetoric on the Right.
