We’re back after our mid-summer hiatus with a bit of astrophysics. Everyone loves black holes, and in “Black Hole Flasher” we talk about one that has awakened from 26 years of dormancy to spew out a burst of X-rays that has astrophysicists sputtering with excitement. Meanwhile Tracy and Addie witnessed the unfortunate loss of a Space-X vehicle en route to the ISS, and Josh makes random attempts to sound like a valley girl. All that and more in the latest episode of Walkabout the Galaxy.