2016-02-11. Gravitational waves, Einstein’s ripples in spacetime, spotted for first time.

posted Feb 13, 2016, 1:38 PM by Alan Gould   [ updated Feb 22, 2016, 10:03 AM ]
By Adrian Cho, Science. For GSS A Changing Cosmos chapter 6. Excerpt: ...two massive black holes—the ultrastrong gravitational fields left behind by gigantic stars that collapsed to infinitesimal points—slowly drew together... spiraled ever closer, until, about 1.3 billion years ago, they whirled about each other at half the speed of light and finally merged. The collision sent a shudder through the universe: ripples in the fabric of space and time called gravitational waves. Five months ago, they washed past Earth. And, for the first time, physicists detected the waves, fulfilling a 4-decade quest and opening new eyes on the heavens. The discovery marks a triumph for the 1000 physicists with the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of gigantic instruments in Hanford, Washington, and Livingston, Louisiana. ...Albert Einstein predicted the existence of gravitational waves 100 years ago, but directly detecting them required mind-boggling technological prowess ...[sensing] a wave that stretched space by one part in 1021, making the entire Earth expand and contract by 1/100,000 of a nanometer, about the width of an atomic nucleus.....  http://www.sciencemag.org/news/2016/02/gravitational-waves-einstein-s-ripples-spacetime-spotted-first-time -- see also New York Times video and article, MIT News story, and Remembering Joseph Weber, the controversial pioneer of gravitational waves. Watch a recorded seminar given by physicist Daniel Holz to a group at Lawrence Berkeley National Laboratory.