**Sioux Falls Scientists endorse ***Understanding Gravity *for a good

explanation of how gravity works, but no good explanation of why

gravity cannot be unified with the other fundamental forces.

**Understanding Gravity**

Black Holes, Tides, and Curved Spacetime

Lectures by Professor Benjamin Schumacher

Understanding Gravity (2013) - 24 lectures, 12 hours

Understanding Gravity at TheGreatCourses.com

The force of gravity rules the universe. It governs our everyday lives on Earth and it controls the motions of the heavens above. Yet it is one of the least understood of all the forces of nature. To endeavor to understand this fundamental force is to experience anew something as simple as getting out of bed, throwing a ball, or diving into a pool; and it gives deep insight into the central organizing principle of the cosmos.

**Consider these crucial aspects of gravity:**

**Gravity governs the rising and falling of tides - not only tides in the ocean, but tides in the solid rock of Earth itself.**
**Gravity molds the sun and planets into spheres, and it holds celestial objects in their orbits.**
**Gravity ignites the nuclear fires inside each star, then fights a billion-year battle to determine its fate.**
**Gravity collects stars into galaxies and causes galaxies to collide in intricate mergers that we can model with supercomputers.**

Without gravity, everything would dissolve into a gas of randomly interacting atoms. It is the only truly universal force, affecting not just matter but also light, time, and, at a basic level, all information. The study of gravity helped spark the Scientific Revolution in the 17th century, and it continues to be at the forefront of physics today, as scientists rely on gravity to investigate otherwise inaccessible phenomena such as dark matter and dark energy. An understanding of gravity - what it is, how it works, and why it is the most dominant and puzzling force in the universe - is both endlessly fascinating and accessible to any curious person, regardless of his or her science education.

**Black Holes, Tides, and Curved Spacetime: Understanding Gravity **plunges you into this compelling subject in 24 intensively illustrated half-hour lectures, presented by Professor Benjamin Schumacher of Kenyon College. Professor Schumacher is an award-winning teacher, a prominent theoretical physicist, and a protégé of John Archibald Wheeler, the distinguished gravity theorist who first coined the term "black hole."

No book or other comparable product exists that presents gravity in such comprehensible detail as this course, which covers the key ideas in gravity research over the past 400 years and gives you the background to understand today's path-breaking theories in physics. Professor Schumacher even walks you through some of the fundamental equations in the field, such as Isaac Newton's law of universal gravitation and Albert Einstein's equation governing the curvature of spacetime by matter, giving you a firsthand look at the power of these mathematical expressions to explain reality - plus further opportunities to explore them with the course guidebook.

**Professor Benjamin Schumacher **is Professor of Physics at Kenyon College, where he has taught for 25 years. He received his Ph.D in Theoretical Physics from The University of Texas at Austin. Professor Schumacher is the author of *Physics in Spacetime: An Introduction to Special Relativity*. For his contributions to quantum information theory, he won the 2002 International Quantum Communication Award and was named a Fellow of the American Physical Society. Professor Schumacher has spent sabbaticals working at Los Alamos National Laboratory and the Institute for Quantum Information at the California Institute of Technology.

**24 Lectures - 30 minutes each**

1: The Strangest Force |
13: From Forces to Fields |

2: Free Fall and Inertia |
14: The Falling Laboratory |

3: Revolution in the Heavens |
15: Spacetime in Zero Gravity |

4: Universal Gravitation |
16: Spacetime Tells Matter How to Move |

5: The Art of Experiment |
17: Matter Tells Spacetime How to Curve |

6: Escape Velocity, Energy, and Rotation |
18: Light in Curved Spacetime |

7: Stars in Their Courses - Orbital Mechanics |
19: Gravitomagnetism and Gravitational Waves |

8: What Are Tides? Earth and Beyond |
20: Gravity's Horizon - Anatomy of a Black Hole |

9: Nudge - Perturbations of Orbits |
21: Which Universe Is Ours? |

10: Resonance - Surprises in the Intricate Dance |
22: Cosmic Antigravity - Inflation and Dark Energy |

11: The Million-Body Problem |
23: The Force of Creation |

12: The Billion-Year Battle |
24: The Next Revolution |

4-11-18 Why we will never unite gravity and quantum forces

**Generations of physicists have tried and failed to marry all nature’s forces. Now their sights are set on a lesser goal: the theory of not-quite-everything.** GRAVITY just doesn’t play ball. It is the odd one out, the square peg in the round hole. It is a party pooper, a stick-in-the-mud, an old fuddy-duddy: unreformed and, seemingly, unreformable. Its crime, in the eyes of many fundamental physicists, is that it refuses to kowtow to quantum theory’s claim to be the one true theory. Our understanding of every other phenomenon under the sun – and indeed the burning of the sun itself – is underwritten by models with quantum particles at their heart. Gravity is the eternal refusenik. Our current picture of gravity is painted by Einstein’s general theory of relativity. Einstein is one of many who have attempted, forlornly, to broker an understanding between the two theories. But gravity has resisted any attempt to force it into a quantum straitjacket. Now a bunch of physicists are advocating a gentler approach: let gravity be gravity, and look instead at how quantum theory might change its ways to accommodate it. Their thinking is that perhaps then quantum theory and gravity might join, if not in perfect union, then at least in amicable cohabitation. With a first few theoretical successes already ticked off, now it is time to put the idea to the test. The cosmologist John Wheeler came up with probably the best way of visualising how general relativity works: “space-time tells matter how to move; matter tells space-time how to curve”, he wrote. A large agglomeration of matter (Earth, say) curves space-time around it. Other matter (a falling apple, for example) moves along those curves and so feels gravity.

**Understanding Gravity**

Black Holes, Tides, and Curved Spacetime

Lectures by Professor Benjamin Schumacher

**Sioux Falls Scientists endorse ***Understanding Gravity *for a good

explanation of how gravity works, but no good explanation of why

gravity cannot be unified with the other fundamental forces.