## Gravitational Waves

On September 14, 2015, the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) made the first direct measurement of a gravitational wave coming from deep space. That wave was generated by the collision of two black holes about 1.3 billion light-years from Earth. As the black holes violently merged, they released as much energy in a fraction of a second as our entire galaxy emits in 4,000 years. But by the time the resulting gravitational wave reached Earth it was tiny, stretching the 4-kilometer-long LIGO detectors by just a tiny fraction of the diameter of a proton. How can scientists be sure they have seen such a tiny effect? What can it tell us about one of the most violent events in the universe? Can we expect to see more gravitational waves, opening up a new type of astronomy? Dr. Brian Lantz discusses the implications of the gravity wave observation and the remarkable instruments that made it possible.

Gravitational Waves |

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The Hunt for Gravitational WavesIn March 2014, a team of astronomers stunned the scientific world when they announced that their BICEP2 telescope at the South Pole had possibly detected a signal of "gravitational waves" from the early universe. |

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Gravity and Me: The Force that Shapes Our LivesJim Al-Khalili tells the story of gravity, recreating Galileo's Leaning Tower of Pisa experiment, looking back at Newton's law of universal gravitation, and investigating Einstein's view of gravity as a geometric property of space and time. |

Einstein's General Relativity and GravitationThis course provides an introduction to Einstein's theory of gravitation, covering topics: a history of gravity, tensor analysis, Einstein's field equations, astronomical tests of Einstein's theory, and gravitational waves. |