Could advanced civilizations be using a network of black holes for interstellar travel? In our last video, the "halo drive" was discussed covering the basic physics of how this new system could potentially enable interstellar flight. Here, we go much deeper on the halo drive concept, answering many of the questions which have been raised, and going further by considering the possibilities of a galactic wide network of such systems. This video is based on research conducted at the Cool Worlds Lab at Columbia University. You can now support our research program directly here: https://www.coolworldslab.com/support Chapters: 0:08 Introduction 4:39 The Halo Drive 7:14 Non-Binary Halo Drive 13:41 Leaving the Black Hole 18:40 Deceleration 21:15 A Halo Network 26:29 Civilizations around Black Holes Academic articles used: ► Kipping, David (2018), "The Halo Drive: Fuel Free Relativistic Propulsion of Large Mases via Recycled Boomerang Photons", JBIS, In Press: https://arxiv.org/abs/1903.03423 ► Kipping, David (2017), "Relativistic Light Sails", AJ, 153, 277: https://arxiv.org/abs/1704.04310 ► Dyson, Freeman (1963), "Gravitational Machines", in A.G.W. Cameron, ed., Interstellar Communication, New York Benjamin Press: https://www.ifa.hawaii.edu/~barnes/ast242_s14/Dyson_Machines.pdf ► Breakthrough Starshot homepage: https://breakthroughinitiatives.org/initiative/3 ► Cool Worlds video giving some background on Breakthrough Starshot: https://youtu.be/Ksb6Vh0BT ► Cool Worlds video on relativistic moving mirrors: https://youtu.be/msK9d9k6K0E ► Cool Worlds video on mirror distortion effects: https://youtu.be/1iNA-GTocI0 ► Semyonov, Oleg (2006), "Radiation Hazard of Relativistic Interstellar Flight": https://arxiv.org/abs/physics/0610030 ► Hoang et al. (2017), "The interaction of relativistic spacecrafts with the interstellar medium", ApJ, 837, 16: https://arxiv.org/abs/1608.05284 ► Heger, et al. (2003), "How massive single stars end their life", ApJ, 591,