Gravitational Waves Detected
An exciting announcement last week marked another milestone in our understanding of the universe. Almost 100 years ago Albert Einstein predicted the existence of gravitational waves, or ripples in the fabric of space-time.
The existence of gravitational waves had been confirmed for the first time in the late 1970s, but they were not able to detect them and prove their existence here on Earth.
Not until last week: scientists were finally able to directly observe ripples of gravitational waves. They also decoded the signal and determined its source. The wave was created by a collision of two massive black holes 1.3 billion light years away.
This was done at LIGO (Laser Interferometer Gravitational-wave Observatory). LIGO watches for a minuscule stretching of space with laser light sent through an L-shaped contraption that stretches 4 kilometers in two directions. LIGO is so precise, they were able to compare lengths to within 1⁄10000 the width of a proton.
The radius of a proton is about 0.84–0.87 fm. 1 femtometer is a millionth of a nanometer. And 1 nanometer is a billionth of a meter. 1 femtometer is 1 x 10-15 meters. This number already is mind-boggling. I can’t even begin to imagine a device that can measure with a precision of 1⁄10000 of a femtometer. What an amazing achievement.
- Gravitational waves, Einstein’s ripples in spacetime, spotted for first time by Adrian Cho, Science, published 2/11/2016
- Scientists make first direct detection of gravitational waves by Jennifer Chu, MIT News Office, published 2/11/2016
- New insights emerge from LIGO’s gravitational-wave data by Tushna Commissariat, Physics World, published 2/15/2016
- Gravitational wave Wikipedia