Monday, March 14, 2016

Listening for gravitational waves

On February 11, 2016 the National Science Foundation put out a press release titled Gravitational waves detected 100 years after Einstein’s prediction.

Allan Adams gave an eleven-minute TED talk on What the discovery of gravitational waves means. He began by stating that:

“1.3 billion years ago, in a distant, distant galaxy, two black holes locked into a spiral, falling inexorably towards each other and collided, converting three Suns' worth of stuff into pure energy in a tenth of a second. For that brief moment in time, the glow was brighter than all the stars in all the galaxies in all of the known Universe. It was a very big bang. 

But they didn't release their energy in light. I mean, you know, they're black holes. All that energy was pumped into the fabric of space and time itself, making the Universe explode in gravitational waves.” 

On February 26th at his Executive Speech Coach blog George Torok linked to that TED talk in a post titled Open your presentation with a startling fact. What Allan said really was even more startling. Physicists and astronomers are used to describing masses as multiples of the Sun’s mass. I’m not. How does that compare with the Earth’s mass?

One Sun mass = 332,946 Earth masses, so 3 Sun masses is almost exactly A MILLION earth masses, which is way more startling.

There is another three-minute YouTube video in which Brian Greene explains the discovery of gravitational waves.

The Advanced LIGO observatory wasn’t the first try at finding gravitational waves. At Wikipedia there is a web page on Gravitational Wave Observatory that discusses previous experiments.

On March 21, 2014 I blogged about a recent one in a post titled Microwave telescope down at the South Pole finds gravitational waves from the Big Bang. Unfortunately that experiment got questioned and discredited later in 2014. See a New York Times article on September 22, 2014 titled Criticism of Study Detecting Ripples from Big Bang Continues to Expand.

Back in the late 1960’s Joseph Weber also tried to detect the waves, as described in a December 22, 2005 article in Physical Review Focus titled A Fleeting Detection of Gravitational Waves. Physicists are very persistent though, and kept on listening.

The image of an Ear Trumpet was adapted from one found in Benjamin Bell’s 1791 book, A System of Surgery seen at the Images from the History of Medicine web site.

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