Gravitational waves arrive on Earth
The first ever detected gravitational wave signal traveled for over a billion years from a distant corner of the universe. It hit Earth on September 14th, 2015, and was detected by LIGO Livingston, LA, and LIGO Hanford, WA. .
The First Gravitational Wave!For the first time, scientists have observed ripples in the fabric of spacetime called gravitational waves, arriving at the earth from a cataclysmic event in the distant universe. This confirms a major prediction of Albert Einstein’s 1915 general theory of relativity and opens an unprecedented new window onto the cosmos.
Binary Black Hole Merger
The two black holes had masses 36 times and 29 times the mass of the sun. The final black hole is 62 times the mass of the sun and if you do the math, you will realize that 3 times the mass of the sun is missing. Remember E=mc²? This mass has been radiated away in the form of gravitational waves.
The Source: Binary Black Hole
Inspiral, merger, ringdown
The gravitational wave signal is a signal we call a chirp. The signal became detectable when it reached 35Hz, less than a second before the final merger. The frequency and amplitude then increased to 150Hz followed by a wobbling of the final black hole with a frequency of around 250Hz.
About 1.3 billion years ago
The event happened somewhere between 0.8 and 1.9 billion light years in an unidentified galaxy somewhere in the southern hemisphere.