Eistein, a hundred years ago gave a recepie for a predection of how you might be able to detect the kind of gravity that he described in his famous 1916 paper
to him, gravity was not a force of attraction between objects as newton would have you think of it
Einstein,said that gravity is the distortion in the fabric of space and time
imagine that space is a giant sheet of rubber and this that have mass causse that rubber sheet to bend
like a bowling ball on trampoline
if i have a masssive object i'm distorting it deeply , it kinda falls into the distortion
so you're really just staying with the flaw
just like the earth goes around the sun
because the sun is very masive causing a big distortion in the fabric of space and time
so now if you have a disturbance
in this fabric of space and time
it will emenate forth as ripples moving at the speed of light
travelling across the universe stretching and squeezing space and time
as we can see in this exp ,it's exagerated a bit just to show you how it works
and these are what we call gravitational waves
if me and my friend started to dance around each other , would we also cause ripples?
YES, but that would be extremly small pratically undetectable
so you need something really really massive moving very fast to cause that ripple that can be detected
AND THIS IS WHERE THE LIGO EXPERIMENT COMES IN : it works by spliting a laser beam and sending it in two directions
the beam has to travel precisely the same distance
and they're reflected of mirrors and then they come back
so they counsel each other out and nothing will reach the light detecter
but when a gravitaional wave passes through
it kind of change the distance every beam has to travel so they won't counsel each other out
and the signal will be detected
an so black hole! bad ass black holes coalescing  is what did it
and in fact in the last instant before these black holes coalesce ,it is radiating som much energy
more than all the stars of the universe
but only did it for a quick fraction of a second
but enough to travel 1.3 billion years!
came across the detectors changing the length between the mirrors by stretching and squeeing
can you imagine this!?
and by the way how much the length changed as the ripple went across
a fraction  the diamter of an atomic nuclues
the effect of a gravitational wave is so miniscule and easily confused with random noise
the needed a smart data analysis technique
to identify it by comparing the wiggles they measured before to the ones they expected from a gravitational wave
it's like being able to identify a song being hummed at a very noisy party
“Matter tells Spacetime how to curve, and Spacetime tells matter how to move.”
THANK YOU FOR WATCHING
