Untitled episode

astronomers always discovering something new something unexpected I have every expectation that gravitational observatories will see something funny and that'll send fear is scurrying to explain [Music] and so if you've got one of these laser interferometers with the arms that are perpendicular and the wave comes through it's going to stretch one and shrink the other now this is where it gets really fascinating because we work out

the strength of a typical gravitational wave from an in spiral of two black holes in in a nearby Galaxy or something like that how much is that movement and the answer is it's equivalent to the width of a human hair in the distance to the nearest star I mean isn't that staggering so you've got this interferometer these things are kilometers in size and the light goes

back and forth so many times and they've got you know huge mirrors weighing more than a person and they can detect the motion of a mirror like that the the mirror itself moves less than the nucleus of an atom so that is really cutting edge technology I got interested in this stuff in the late 70s I wrote a book on it called the turtle gravity waves

back in 1980 and I never thought in my life I would see these things detected but in 2015 Bingo the first gravitational wave event was detected a pair of black holes in a galaxy I think 1300 light years away 36 roughly 30 something solar masses these black holes uh spiral together and collided and so this was uh you know Triumph of Technology but an incredible indication

because it was nearly 100 years after Einstein had predicted that there exists gravitational waves a hundred years a lot of people thought well are they really there but sure enough they are and uh there was a lot of fanfare but it wasn't very long before they saw another event and then another event another event so on and this is now uh established itself in the last

few years as a new branch of astronomy so having got these amazing instruments that can detect gravitational waves um what what are they good for well I've already mentioned the in spiral of black holes and neutron stars and there was one extraordinary event a few years ago where two neutron stars came together and collided and the gravitational bursts of waves from that was detected at the

same time as a satellite detected a flash of gamma rays and then there were there were Optical measurements as well and so it was uh clever people figured out that the coalescence of these two neutron stars which very violent event created uh a large number of elements particularly the element gold and so this called people's imagination more gold was made in that microsecond that those two

neutron stars um merged together and if the entire Earth was made of gold if more than an Earth's mass worth and so um that is part of the story of the origin of the elements in the universe and this can not only be studied just as that one burst but in Australia there's a proposal for a system called Nemo which if I remember stands for Neutron

extreme matter Observatory which would drill into the fine details of that because when those two neutron stars collide they recreate in a in a microcircuit the conditions that would have prevailed very early on in the Big Bang so you're sort of doing experiment not experimental but observational physics of one of the earliest epochs of the universe and you need the gravitational signature of that to be

uh primordial exposure and that Rumble the the gravitational waves have been stretched by the expansion of the universe so they're now sort of huge but there's a proposal uh to send an interferometer into space well constructed in space is called Lisa laser something or other and it will be mirrors which will be like millions of kilometers apart and it will be an interferometer in space so

we'll be able to detect uh gravitational waves of extremely long wavelengths like those coming from The Big Bang so that's the next step in this technology and the other just general points is that every time there's been an advance in astronomy with the instruments uh the first of all the optical telescope then the radio telescope and then all the other you know the satellites detect X-rays

and gamma rays and so on astronomers always discover something new something unexpected and so I have every expectation that gravitational observatories will will see something funny going on what's that you know that we never expected that this funny signature these waves with these peculiar properties um and that'll send theorists scurrying to explain that's a new type of object out there in space or a new type

of physical phenomenon there's one that some colleagues of mine get excited by you may have heard of string theory about uh super strings everything's made out of strings there are other types of strings not those strings cosmic strings these would be like threads that would have been produced just after the big bang they're like uh almost knots in the in the fields that permeate the Universe

um but one-dimensional and these would be long threads maybe forming Loops it's maybe stretching right across the universe and they they wriggle around like this prolific source of gravitational waves so if there are cosmic strings out there during their wriggle then that that will produce very distinctive types of gravitational waves and then there's one last thing I can't resist mentioning because um um a lot of

young people find all this stuff really exciting and an undergraduate she's just beginning so she'd be like 18. she uh emailed me to say I'm really excited by the work you're doing and can I do a project with you and so we sat down and I said well what are you interested in she said well gravitational waves and I'm also interested in wormholes well wormholes are

like black holes but different because in a black hole it's a one-way journey to know where you fall in and you don't come out again a wormhole has an exit as well as an entrance so it's sort of superficially it's a massive object and you fall in but you go through and you come out somewhere else and those of you old enough to remember the movie

contact will remember you know what a wormhole looks like as Jody Foster filmed through one and it's it's like going on the London Underground and you come out you come out somewhere else uh very hypothetical I happen to have just come from a conference in Rome with Roger Penrose who will be talking here tomorrow and that was all about wormholes and do they really exist and

could you turn them into time machines and so on and that's all very fascinating and highly speculative but but this uh this young lady uh is interested in what would be the gravitational wave signature from wormholes so basically a wormhole swallows a black hole it's a look it's in the throat of this thing and spits it out the other side or maybe two wormholes spiral together

hit each other you know what what would um what would that be like what type of gravitational wave signature so she asked me this I said well I haven't a clue um but it turns out that that also this Rome conference was Kip Thorne who just got the Nobel Prize uh I think last year for gravitational waves he was with the like the driving force behind

the laser gravitational wave into parameters but he was also the architect of this whole Wormhole Theory because he developed the theory of wormholes because Carl Sagan who who wrote a famous astronomer wrote the wrote the book contact on which the movie was based and anyone who likes science fiction will know how boring it is that it takes so long to get to another another star system

you know thousands of years at present rocket speed but even light would take me you know many many years to go between Star systems wouldn't it be handy if you had something like a Stargate or a shortcut that could get us from Earth to the other side of the Galaxy you know in a few minutes rather than having to wait take millions of years to fly

there so it was a science fiction idea but he asked kepthon at the California Institute of Technology to check it out so Kip and his students said well you know maybe if you did this did that you could actually make a wormhole and they soon realized if you could make the Wormhole could be turned into a time machine so I'm so very much off topic the

point being that this one man is the world expert at wormholes and the world expert on gravitational waves I said to him Kip my undergraduate student has asked me to ask you what would be the gravitational wave signature from a wormhole and he said I have the clue so that's that that's an open question um so we'll we'll see how how she gets on with her

project from our debates talks and interviews subscribe today to The Institute of Arts and ideas at IAI TV