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The first 100 people to click our description link will get a one-week free trial. [♪ INTRO]. Something that might come as a surprise with Saturn is that it is...fluffy.

Or rather, its average density is lower than water, suggesting that it could float in a bathtub… if a bathtub could get very big. Well, it turns out that Saturn may not just be fluffy. This week in the journal Nature Astronomy, scientists found that Saturn’s core may also be kind of fuzzy.

And they learned that by studying Saturn’s rings. Here at home, we’ve learned what Earth’s interior is made of by studying how earthquake waves move through the planet’s layers. Then, once we started putting probes on places like the Moon and Mars, quakes there could give us hints about the insides of those worlds, too.

But gas giants unfortunately don’t have surfaces to put probes on. And even if they happen to have a solid core, the pressures and temperature that far inside a planet’s atmosphere could destroy a probe before it got anywhere close. So instead, scientists can use orbiting satellites to learn about the interior of places like Saturn.

See, different compounds, of course, have different masses, and the more mass you have packed into an area, the stronger the gravitational pull is there. So, scientists can actually watch a satellite and see if it experiences any small changes in gravity as it moves over different spots on a planet. If it does, that can clue in researchers to what kinds of compounds are inside that world, and where they’re found.

But while those data are helpful, they can't tell us everything, like if a planet's insides are liquid or solid. Also, on Saturn in particular, winds deep inside the planet muddy the data. Thankfully, Saturn has rings.

In previous research, scientists found that the tiny particles inside Saturn's rings are really sensitive to changes in gravity. So, they can be affected by things like passing rocks or moons, but also by changes in Saturn's gravitational field. In fact, previous data collected by the Cassini probe had revealed spiral patterns in Saturn’s C ring.

And those patterns hinted at gravity pulsations inside the planet. In other words, that there was regular, ongoing seismic activity. But it wasn't exactly clear what was going on down there.

So, in this new paper, a team ran models to see what scenario could have produced those data. And they found that the best match was a situation that runs counter to the standard perception of Saturn’s insides. The standard idea is that Saturn has a solid boundary between its core and its other layers.

But these models found that the most likely scenario is that there is a huge transition zone, stretching the whole core up to 60% of Saturn’s entire width. You could line up five Earths in that space with room to spare! Also, that core may be sloshing around, kind of like it's playing in a giant space bathtub.

That kind of seismic activity would create denser waves of material moving around inside the planet. And that would create those spiral patterns way up in the rings. Now, the caveat is, the models don’t perfectly predict everything the scientists saw in Saturn’s ring.

So, there’s still some work to be done. But clues like this one will help us pin down exactly how Saturn formed billions of years ago, and why it looks the way it does today. Meanwhile, a long time ago, in several galaxies far, far away, some supermassive black holes were having a snack.

Matter was falling into them, and along the way, this process released so much light that the black holes outshone all the stars in their galaxies. It’s taken millions of years for this light to reach us here on Earth. But now that it has, astronomers have learned something about it:.

The flickers in this light can tell us how massive these black holes actually are. And they published their results last week in the journal Science. Astronomers have a specific name for a supermassive black hole at the heart of a galaxy that’s actively consuming nearby matter.

It’s called an active galactic nucleus, or AGN. The matter it feeds on comes from a thin disk called an accretion disk. And as matter spirals closer to the black hole, it heats up and starts to glow.

But that glow isn’t constant: There are random moments when that signal surges. Scientists don’t know why yet, but previous research suggested that the time between these flickers could be connected to a black hole’s mass. Except, those research results were inconclusive.

So in this new study, another team tried to learn more. They studied the visible light coming from 67 AGNs that researchers had already estimated the masses of. Then, they measured the time it took for the flickering effect to weaken.

In the end, they found that these times consistently correlated with the black hole’s mass. The more massive the black hole, the longer the flickering from its accretion disk lasted. Also, this is the same relationship astronomers have seen in the accretion disks around another type of object: white dwarfs, which are the dead cores of stars like our Sun.

So, even though scientists don’t know why the flickering happens, this suggests that there may be a universal relationship here, that flickering is related to mass no matter what kind of object is munching on an accretion disk. This means that, even while scientists try to pin down those physics, they have a new way to measure the masses of some of the heaviest objects in space. If there’s a theme with both studies this week, it’s that scientists have taken one step forward in understanding the universe… and have run into plenty more questions on the way.

But hey: That’s research. This episode of SciShow Space was brought to you by Endel, an app that creates personalized soundscapes by combining sound and technology. They use your real-time location, weather, and heart rate to create soundscapes that help you focus, relax and sleep.

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