God's Number: A Mini Documentary

Every Rubik's Cube scramble can be solved in under 20 moves... but *how do we know* ? How do we know that God's Number is *EXACTLY* 20? Today, I'm taking you on the 30-year-long journey that mathematicians all around the world took to pinpoint God's number. This is God's Number: A Mini Documentary. Download Cube Explorer by Herbert Kociemba: https://kociemba.org/download.htm Silviu Radu’s work: 28 Moves: http://forum.cubeman.org/?q=node/view/37 27 Moves: http://forum.cubeman.org/?q=node/view/53 Video Chapters: 00:00 Introduction 00:59 General Strategy 01:52 Finding a Lower Bound 04:46 Finding an Upper Bound 05:14 Morwen Thistlethwaite, 1981 08:40 Hans Kloosterman, 1990 09:44 Herbert Kociemba, 1992 10:55 Michael Reid, 1992 12:07 Dik Winter, 1992 12:30 Michael Reid, 1995 13:42 Michael Reid, 1995, New *Lower* Bound 14:27 Silviu Radu, 2005 15:07 Dan Kunkle, Gene Cooperman, 2007 15:20 Tomas Rokicki, 2008 15:29 Tomas Rokicki, John Welborn, 2008 15:34 Tomas Rokicki, John Welborn, 2008 (again!) 15:44 Tomas Rokicki, Herbert Kociemba, Morley Davidson, John Dethridge, 2010 17:13 Conclusion + Final Thoughts Music from #Uppbeat (free for Creators!): https://uppbeat.io/t/ak/time-flies License code: DVNXSCE7HF1F9FLH Stock videos from Pixabay: pixabay.com, by Sześcian, PIRO, William McDonald, DJStrawberry_4111, Coverr-Free-Footage, Joshua Malic, Tomislav Jakupec, u_rrc9sha8eq, Muhammad Rahad, and Sześcian. References (APA 7th): God’s Number and Rubik’s Cube - Numberphile. (2012). [YouTube Video]. In YouTube. https://www.youtube.com/watch?v=yF2J39Xny4Q The Search For God’s Number | Rubik’s Cube. (2023). [YouTube Video]. In YouTube. https://www.youtube.com/watch?v=YsWKrxAbopk ‌ Wikipedia Contributors. (September 14, 2023). Optimal solutions for the Rubik’s Cube. Wikipedia; Wikimedia Foundation. https://en.wikipedia.org/wiki/Optimal_solutions_for_the_Rubik%27s_Cube God’s Number is 20. (n.d.). Www.cube20.org. https://www.cube20.org/ Accessed August 1, 2024. Thistlethwaite’s 52-move algorithm. (n.d.). Www.jaapsch.net. Accessed August 1, 2024. https://www.jaapsch.net/puzzles/thistle.htm. Cube Lovers: an upper bound on god’s number. (n.d.). Rwth-Aachen.de. Accessed August 1, 2024. https://www.math.rwth-aachen.de/~Martin.Schoenert/Cube-Lovers/michael_reid__an_upper_bound_on_god%27s_number.html Cube Lovers: new upper bound. (n.d.). Rwth-Aachen.de. Accessed August 1, 2024. https://www.math.rwth-aachen.de/~Martin.Schoenert/Cube-Lovers/michael_reid__new_upper_bound.html Cube Lovers: new upper bounds. (n.d.). Rwth-Aachen.de. Accessed August 1, 2024. https://www.math.rwth-aachen.de/~Martin.Schoenert/Cube-Lovers/michael_reid__new_upper_bounds.html Cube Lovers: New upper bound on God’s algorithm for Rubik’s cube. (n.d.). Rwth-Aachen.de. Accessed August 1, 2024. https://www.math.rwth-aachen.de/~Martin.Schoenert/Cube-Lovers/Dik_T._Winter__New_upper_bound_on_God%27s_algorithm_for_Rubik%27s_cube.html ‌Computer Puzzling. (n.d.). Www.jaapsch.net. Accessed August 3, 2024. https://www.jaapsch.net/puzzles/compcube.htm#kocal Cube Lovers: superflip requires 20 face turns. (n.d.). Rwth-Aachen.de. Accessed August 3, 2024. https://www.math.rwth-aachen.de/~Martin.Schoenert/Cube-Lovers/michael_reid__superflip_requires_20_face_turns.html ‌Solving Rubik’s cube in 28 face turns | Domain of the Cube Forum. (n.d.). Forum.cubeman.org. Accessed August 3, 2024. http://forum.cubeman.org/?q=node/view/37 Rubik can be solved in 27f | Domain of the Cube Forum. (n.d.). Forum.cubeman.org. Accessed August 4, 2024. http://forum.cubeman.org/?q=node/view/53 Rokicki, T. (2008). Twenty-Five Moves Suffice for Rubik’s Cube. ArXiv:0803.3435 [Cs]. Accessed August 5, 2024. https://arxiv.org/abs/0803.3435 Twenty-Three Moves Suffice | Domain of the Cube Forum. (n.d.). Forum.cubeman.org. Accessed August 5, 2024. http://forum.cubeman.org/?q=node/view/117 ------ Remember to Subscribe if you enjoyed this video! http://bit.ly/subscribe-to-daniel-chen