What is the Big Bang? | NASA Astrophysics FriendsofNASA.org: What is (or was) the Big Bang? Learn this and more with “Astro-Investigates,” the video series that explores and explains important astrophysics topics with the help of NASA scientists. In this episode, you will hear from: Dida Markovic - NASA JPL Astrophysicist Alina Kiessling - NASA JPL Astrophysicist Ami Choi - NASA Goddard Space Flight Center Astrophysicist Sangeeta Malhotra - NASA Goddard Space Flight Center Astrophysicist To lear