1.3 billion years ago two massive, whirling black holes collided, sending a gravitational
ripple through the spacetime fabric of the Universe.
Like a tsunami moving through the ocean, that wave passed through space until it washed
past Earth last September.
100 years ago, Albert Einstein predicted exactly this type of event--that massive objects moving
in certain ways will cause spacetime ripples, or gravitational waves.
But the technology did not exist back then to try and catch one of those waves and after
a few years even Einstein himself began questioning the theory.
It must have been incredibly bewildering and frustrating to theorize on such a grand scale,
but constantly run into the limitations of man’s ability to verify the interstellar
events that your core scientific ideas are based on.
Time passed.
And in 1979, after a series of advances in gravitational astrophysics, the National Science
Foundation greenlit Caltech (the California Institute of Technology) and MIT (the Massachusetts
Institute of Technology) to develop a design for a gigantic instrument capable of detecting
Einstein’s gravitational waves.
Fifteen years later, in 1994, construction began on the $250 million Laser Interferometer
Gravitational-wave Observatory, or LIGO, which is a pair of L-shaped devices with arms 4
kilometers long--one in Washington state and the other in Louisiana.
They are essentially laser rulers, so precise they can detect differences as small as 1/1,000
of a proton’s width.
Theoretically, that sensitivity allows them to see a gravitational wave as it moves by
and stretches the arms just enough to cause the laser light to warble.
But for the first eight years LIGO gathered data it did not detect any waves, so an additional
$205 million was spent upgrading the system.
On the morning of September 14, 2015, when the advanced LIGO had just come back online
after 5 years of refurbishments, lo and behold, it caught a wave!
Both LIGO detection locations recorded the same exact changes in frequency.
“I knew that there was something going on because I subscribe to the logs.
This particular log pointed to something that looked like it might actually be a gravitational
wave.
What I saw is what called a time frequency plot called a chirp and it was strong, it
was unbelievably stronger than anything I expected to be a first detection.
It was so strong you could see it by eye and here is the chirp at Hanford, WA and there
was the chirp at Livingston, LA, and I though ‘my God, this looks like it’s it.’
It was just perfect.
In fact it was almost too good to be true.
When I looked at it I said, ‘somebody must have done something wrong and injected a signal.’
Nobody right away believed it.
Everybody thought it was a fluke—it was too good.
And it took us a while to get to the point where all of us believe it.
It’s monumental.
It’s like Galileo using the telescope for the first time.
They’re moving at the velocity of light.
Damn near that velocity.
Thirty solar masses moving that fast, I mean they’re putting out incredible amounts of
energy.
And when they collide with one another they produce a bigger black hole, but they also
produce gravitational waves.
And in that process about three solar masses just disappears and goes into gravitational
waves.
Oh its going to be amazing.
We have always said that this is going to be a field called Gravitational Wave Astronomy.
Gravitational waves carry information that you can’t get from any other way.
A supernova, two neutron stars colliding, even the Big Bang itself - the beginning of
the Universe - all produce gravitational waves.
This first detection by LIGO is the very first step.
It’s just the start of the story nature is about to tell us.
I would love to see Einstein’s face.
I mean he would have been as dumbfounded as we are because it’s a wonderful proof that
all of this incredible stuff of strong-field gravity is in his equations.
Just imagine that!
To me that’s a miracle!”
With the new and improved LIGO detectors online and gathering data, other detections will
likely now come quickly too, especially with other interferometers coming online around
the world, like Italy’s rebuilt VIRGO, which could begin taking data later this year.
For the latest mind blowing scientific discoveries, subscribe to TDC and to help more people discover
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Until next time, I’m Bryce Plank, thanks for watching.