September 17, 2018
Shane Hanlon: Hi, Nanci.
Nanci Bompey: Hey, Shane.
Shane Hanlon: So, we’re back for a bonus clip, and it’s all about the Sun. And we obviously look at the Sun every day, or hopefully, if it’s not cloudy and gross. But I never really thought about does the Sun make a noise, does it sound like anything.
Nanci Bompey: Yeah, it actually does make a noise.
Shane Hanlon: Oh.
Nanci Bompey: Yeah.
Shane Hanlon: All right, so let’s hear about the sound the Sun makes.
Dan Seaton: The Sun itself actually makes noise. The Sun is noisy. At the surface of the Sun, it’s a fluid, and it’s basically boiling. It’s not boiling, but it’s undergoing the same process where the fluid is convected up to the surface, and it erupts and flows. And this is a very noisy process, just like a pot of boiling water makes a lot of noise, the Sun is making noise. And more than that, the Sun, it actually makes noise in coherent ways. So it actually rings like a bell, and there are frequencies you can measure if you study the Sun in just the right way.
And actually one of the cool things that people do is that those coherent ringing frequencies propagate back and forth inside the Sun. And as they do that, they change. And just like seismologists on Earth can characterize the inside of the Earth by watching how acoustic waves propagate out from earthquakes, you can do the same thing for the Sun.
So a lot of what we know about the interior of the Sun comes from actually looking at the Sun ringing. And they can even detect features on the side of the Sun that we can’t see, the backside of the Sun, by doing this. This is actually a technique that’s used in space weather forecasting. Sorry to always go back to space weather, but we don’t know what’s happening on the far side of the Sun, but we can get an idea by actually watching how the sound waves are propagating back and forth inside the Sun, and you saw there has to be something in the back side of the Sun, watch this thing. That’s one of the products they actually use to do the forecasting.
Shane Hanlon: That is really cool.
Nanci Bompey: So cool.
Shane Hanlon: Yeah.
Nanci Bompey: And those sounds from the Sun are from NASA, and Alexander Kosovichev.
Shane Hanlon: Great, so be sure to check out the full episode Inside the Boiling Center of The Solar System.