[Music] scientists just invented an entirely new way of observing the universe and it's not with light because what we've detected is waves in actual space that is the stretching and compression of space itself in a ripple passing by us and as soon as we turned on the detector we saw the merge of two black holes scientists have been dreaming of this for a long time Einstein first proposed his theory of general relativity over a hundred years ago stating that gravity is really just the curvature of space and time or SpaceTime in other words a huge
mass like a star curves space and time like this ball placed on a sheet and if Mass could Bend space then accelerating or moving masses could send out ripples in the sheet and we call those gravitational waves Einstein came up with all the math to describe this over a 100 hundred years ago then nearly 75 years later in 1992 scientists founded ligo the laser interferometer gravitational wave Observatory to search for these waves but it wasn't until 2015 that gravitational waves were finally detected from the event where two black holes about 30 times the mass of
the Sun collided sending out shock waves that reached us 1.3 billion years later the technology had to come so far for this to be possible check it out in the Lago detector you've got two vacuum tunnel arms with lasers that go back and forth reflecting off of mirrors on the other end depending on the distance those laser beams travel after reflecting off the mirrors when they meet back up again you get interference like waves that interfere in water making patterns if space is stretched or squeezed in one of these directions by passing gravitational waves the
laser beams in that arm will travel for more or less time affecting how the two beams interfere when they meet back up and we can tell space has been stretched but this detector has to be so sensitive it's affected by quantum mechanical vibrations in the mirrors so sensitive it was picking up vibrations from trucks driving on roads nearby but scientists found ways to cut out that noise and in addition there are two Labs one in Louisiana and one in Washington making sure that the signal detected wasn't from something local that moment when those two detections
matched up perfectly was the Goosebumps moment when scientists realized we had heard a true signal scientists have been using the term herd which I think helps set the technology apart from anything we've ever done usually with light but the waves don't actually make a sound because sound doesn't travel through empty space but scientists did take the waveform and turn it into a sound wave form to make the chirp heard around the world but the way this chirp affects us is not immediately obvious to all I mean as little as you might follow biology or anthropology
it's easier to see the importance or excitement in finding the first homonid skeleton or finally sequencing the entire Human Genome because it opens doors the observation of gravitation waves in and of itself is exciting but these waves have hypothetically been passing through the universe since way before humans existed and we've never known for sure it's like being deaf your entire life and finally able to hear for the first time that's what we've done for Gravity that's what we've done for the field of astronomy and we can look out at the universe with an entirely new
metaphorical lens and at extreme violent events and at objects that we know very little about like black holes plus the technology is the most precise instrument ever developed it's improved cryogenics Optics and made contributions to a number of other fields and who can forget that though Einstein was ironically uninterested in the applications of his theory of relativity we rely very heavily on it for the multibillion doll industry surrounding GPS and lastly I'm going to venture so far as to say that we should care because it's relevant it's just cool if physics no longer had any
practical applications we'd probably still keep doing it because we are curious we want to know about our world this is how the universe works the same universe that works in such a way that it's possible for you and me to exist SpaceTime is the landscape in which we live and we've just created a new way to understand it thank you for watching this episode of physics girl and happy physics thing [Music]
