Video Transcript

>> ANNOUNCER: Please welcome Physics Professor, University of Toronto, NASA Sonification Specialist, Matt Russo.

(Applause)

>> MATT RUSSO: There's geometry in the humming of strings. But is there music in the spacing of the spheres? Do planets orbit according to a musical harmony? We now know the answer to this ancient question, and it's a resounding sometimes. I'm going to show you what I mean.

In February of 2017, astronomers announced the discovery of the Trappist-1 system, this is seven earth sized planets orbiting a nearby red dwarf star, Trappist-1. This is now the most well studied solar system other than our own and it's a prime candidate in our search for life in the universe. It's also the most musical solar system ever found. And here's why, Trappist-1 is a resonant chain. For every two orbits of the outer most planet, the next one in orbits three times. And then four, six, nine, fifteen, and twenty-four. So, this solar system is playing a fixed repeating rhythm. And if we imagine speeding up this motion even more, until the frequency of each planet can be associated with an audible musical pitch. Then we get a consonant and intriguing harmony and that's because of the simple ratios between their orbits.

So, instead of talking about it, let's hear it. I'm going to play a note for every orbit of each planet. And the pitch of the note I play is determined by the actual orbital frequency of that planet. Once all the planets have entered, you are going to start hearing drums. And those happen every time a planet passes its neighbor. That's when they give each on a little gravitational tug to keep themselves locked in this fixed repeating pattern.

(MUSIC)

(Applause)

>> MATT RUSSO: Thank you. So that's Trappist-1. But you may be wondering now, what about our solar system, what does that sound like? And I really hate to be the one to show you this, but it's not going to be pretty. So for one thing, there's a much bigger difference the orbits of the outer most planet and the inner most planet in our system. So, if we set Neptune to be the lowest note we can hear, Mercury is pretty much the highest note we can hear which is not going to be pleasant. But also our solar system is not in resonance. So the planets are more like eight musicians playing in different rooms, different tempos and different keys. So it's quite an experience. Let’s hear it, and once again I’m sorry. That's Neptune, Uranus, Saturn, Juniper, Mars, Earth, Venus, and there's Mercury.

Okay. Sorry. So, our solar system is not as harmonious as Trappist-1 but Trappist-1 is not alone. Since its discovery we have now found a handful of other musical solar systems, each playing their own song. And we expect to find tens of thousands of new planets in the coming few years, so that will certainly include many more musical planetary systems, I wonder what they sound like. Now you may find this interesting but there's a actually greater purpose here. You see, astronomy is a very visual field which poses a barrier for people who are blind or visually impaired. So by finding ways to listen to the cosmos, we can make astronomy not only more engaging and emotional, but also more accessible. So, sometimes there really is a rhythm and a harmony in the spacing of the spheres and we can use it to connect to each other and to our wonderful and musical universe. Thank you very much.