(479) The four types of planetary civilizations, explained by Michio Kaku -
(479) The four types of planetary civilizations, explained by Michio Kaku - Humanity is a type 0 civilization. Here’s what types 1, 2, and 3 look like, according to physicist Michio Kaku.Subscribe to Big Think on YouTube ► https://ww...extraterrestrial lifeLINK