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From 'Short Wave': magnetosphere music, Jupiter's icy moons and a runaway black hole


Time now for some science news from our friends at NPR's science podcast, Short Wave. Emily Kwong and Regina Barber host the podcast, and they are here with us now. Hey to both of you.



CHANG: So I know that you two have been combing through the headlines, looking at the latest journals and social media, and both of you, I understand, have picked out three science stories for us to hear more about this week?

BARBER: Yeah, and it just so happens that this week, all three stories we wanted to bring to you take place in space.

CHANG: Woohoo.

KWONG: Yes - different realms of space at different distances from...


KWONG: ...Earth. The first is about what things sound like just beyond our atmosphere. Then we're going to venture a bit further to some distant moons.

BARBER: And finally we take a pit stop by something NASA has called an invisible monster on the loose, barreling through intergalactic space.

CHANG: Oh, my God, that sounds so ominous. I am ready for liftoff. Let's do this. Emily, what is first? Go.

KWONG: Ailsa, for our first story, we're blasting off from Earth in three, two, one - (imitating rocket lifting off)...

CHANG: (Laughter).

KWONG: ...To the invisible bubble that protects our planet - the magnetosphere...

CHANG: What?

KWONG: ...Which is just a magnetic field surrounding our earth and deflecting most of the charged particles from the sun away from our planet.

CHANG: OK, that sounds vital.

KWONG: Yes. Good summary. It's, like, crucial for life on Earth because, you know, that sun is a tempestuous star. It's constantly emitting this stream of particles known as solar wind, and sometimes the solar wind mixes with the gases in our upper atmosphere in a visible way - aka the aurora borealis.

CHANG: Oh, the northern lights - I still have never been able to see them in person.

BARBER: Me neither.

KWONG: I hope you do.

CHANG: Me too.

KWONG: You can get to witness their gassy little dance up there. But, you know, now that interaction, Ailsa, between Earth and the sun - it's not only visible, it's audible too. So back in 2007, NASA launched five satellites to study Earth's magnetic field, including solar wind striking Earth's magnetosphere, causing it to vibrate like the strings of a harp.


KWONG: And now a new NASA-funded community science project is turning that data into sound. Listen to this.


CHANG: That's really what it sounds like up there? That's amazing.

KWONG: OK. No, no, no, no, no. That's an important caveat. It doesn't sound like that up there.

CHANG: Tell me the caveats, come on.

KWONG: Sun-on-Earth vibrations - they're ultra-low frequency. They're way too low for human hearing, so the team behind this project, which is called HARP - stands for Heliophysics Audified: Resonances and Plasma - is speeding up those frequencies and converting them into sound waves, so all those wooshes and squiggles, the music of sun and Earth, can be heard by you and me and everyone.

CHANG: That is amazing. So you said that this is a community science project, what does that mean?

KWONG: Yeah, so this is, like, the coolest part to me. The HARP team has built an interactive tool for anyone around the world to listen to the waves, and it's not just for fun. The researchers, they say, like, we humans are sometimes better than machines at picking out unique sonic features in these recordings, and those patterns can help the scientists understand space weather, how the solar wind interacts with Earth's magnetic field - all kinds of things. So you can go help them. You can find these recordings at their website

CHANG: Sounds like a good date activity.

KWONG: That's something an audio person would say.


KWONG: But yes, Ailsa, completely. Like, it's one of the reasons I wanted to bring you this story. Science doesn't just happen in academia or in a laboratory. Sometimes it can happen on date night.

CHANG: Absolutely. OK, Gina - shortwave scientist in residence...


CHANG: ...For our second story, we are traveling, I understand, further into the solar system, all the way to Jupiter?

BARBER: Yep. One of my favorites.

CHANG: Me too 'cause of the big red spot.


CHANG: But why Jupiter in this case?

BARBER: So last week, the European Space Agency just launched a spacecraft called Juice, short for Jupiter Icy Moons Explorer.

CHANG: I love all the acronyms in this conversation - juicy.

BARBER: Astronomers love our acronyms. We try really hard, believe me.

CHANG: OK, so in this case, Jupiter Icy Moons Explorer, and I guess they were going for Juice because where there is ice, there is water, which could mean life, yeah?

BARBER: Well, yeah, yeah - that's the question, right? Like, because we know that three of the moons of Jupiter house water - Ganymede, Callisto, and my favorite moon, Europa - and if you have water and you have a heat source safe from the moon itself, in the case of these, like, large moons, then you almost have the ingredients for life.

CHANG: OK. But I am not the astrophysicist here, you are. So what I'm thinking - tell me if I'm wrong - is, don't you need, like, organic material like carbon or nitrogen for life to actually happen?

BARBER: Yeah, I mean, that is absolutely right, and this mission - that's one of the things that they're going to be looking for. Juice will be orbiting the moons, investigating how big these oceans are, what they're made out of, and imaging the surfaces of these moons, all in search for where there could be life.

CHANG: That's so exciting. So when is Juice going to get up there?

BARBER: Yeah, it's not going to get there until 2031.

CHANG: Oh (laughter).

BARBER: But this mission and another one from NASA called the Europa Clipper are basically my dreams come true. Like, they're both doing the same kind of science at the same time, seeing if these moons are habitable for life.

CHANG: OK, so we have visited the magnetosphere, a moon - what is our third and final stop on this whole space voyage?

KWONG: It is a runaway supermassive black hole.

CHANG: Oh, my God. That sounds metal.

KWONG: It is so metal. It's so metal.

CHANG: (Laughter).

BARBER: It is. It is.

KWONG: It was discovered also kind of by accident, by a team led by Yale University scientists who published their findings in the Astrophysical Journal Letters earlier this month. OK, Ailsa, this story is amazing. It first looked like a smudge in an image from the Hubble Space Telescope. They were like, what is that? But looking more closely, they realized the object in question was likely a supermassive black hole gone rogue.

CHANG: Whoa.

BARBER: Yeah. Listeners can't see me, but I'm just nodding my head. I'm so excited because - well, let's first - let's talk about a black hole. Basically, a black hole is just like a pothole in the 4D fabric of space-time, and there's a massive one at the center of our galaxy, actually. But what's weird about this one is it's sprinting through our universe all on its own, not really part of any galaxy, and it's possibly very, very big.

CHANG: Just how big?

BARBER: Yeah, roughly 20 million times more massive than our sun.

CHANG: Whoa.

BARBER: And it's leaving a trail of these newborn stars in its wake - a trail approximately 200,000 light-years long.

CHANG: And wait, Emily, you had said the word rogue. Like, what did you mean by that? Where did this maybe black hole even come from?

KWONG: OK, I'm going to let Gina explain this.

BARBER: Well, galaxies merge all the time. Our galaxy, the Milky Way, will actually merge with our neighbor galaxy, the Andromeda Galaxy, and that's going to happen in about 5 billion years. But remember, our galaxy has this supermassive black hole at its center, and so do many other galaxies. So researchers believe that this rogue black hole came from a merger of more than two galaxies. Maybe a third one came in, and that interaction shot out a central black hole of one of those galaxies.

CHANG: That is so cool. And did we know black holes even behave this way? Should we be concerned?

BARBER: No, we don't need to worry. First, this supermassive black hole that's, like, all by itself shooting around - it's billions of light-years away. And second, there isn't a candidate near us that would affect us like that. But as far as this behavior, we've seen stars form from mergers before, like galaxies merging into each other, but this is the first time we've seen a black hole create stars in its wake.

CHANG: Dang. That was Emily Kwong and Regina Barber, the two hosts of NPR's science podcast, Short Wave, where you can learn about new discoveries, everyday mysteries and the science behind the headlines. Emily and Regina, thank you so much and see you next time.

BARBER: Thank you. Bye.

KWONG: It was a pleasure. Thank you so much for having us.

(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.

Emily Kwong (she/her) is the reporter for NPR's daily science podcast, Short Wave. The podcast explores new discoveries, everyday mysteries and the science behind the headlines — all in about 10 minutes, Monday through Friday.
Regina G. Barber
Regina G. Barber is Short Wave's Scientist in Residence. She contributes original reporting on STEM and guest hosts the show.