The Reach of a Giant | A Black Hole Story

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Language: en

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Picture


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a [music] black hole 2 and a half


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billion times the mass of our sun. Now


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stop [music] picturing it as a drain


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because the one we're opening with today


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isn't just swallowing. It's blowing.


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[music] And the blast it drives reaches


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across 300,000


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lightyear stirring [music] an entire


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cluster of galaxies. 300,000 lightyear.


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[music] That's roughly three times the


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width of the Milky Way. the reach of a


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single black hole.


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>> That's our lead. Then dead stars that


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hide their meals, a metal world mission


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using Mars as a rehearsal studio, and


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the growing problem of traffic on the


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road to the moon.


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>> And because it's the 30th, there are two


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meteor showers peeking over your head


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tonight. We'll tell you exactly where to


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look north and south.


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>> It's Thursday, the 30th of July, 2026.


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I'm Anna.


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>> And I'm Avery. This is Astronomy Daily.


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>> So, let's start with a question that


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sounds simple and isn't. What does a


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black hole actually do to the space


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around it?


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>> The cartoon answer is it eats. Anything


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that gets too close falls in and never


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comes back,


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>> right? And that part's true, but it's


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only half the story. When a super


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massive black hole is feeding hard, it


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doesn't swallow everything cleanly. It's


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a messy eater. Enormous amounts of


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energy pour out of the region around it.


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Radiation and powerful outflowing winds


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of gas. And astronomers have a name for


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the way those winds push back on the


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wider universe. They call it feedback.


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>> Feedback as in the black hole feeds and


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the galaxy gets a response.


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>> Exactly. And it matters enormously


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because feedback is one of the ways


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galaxies keep themselves in check.


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Here's the puzzle it solves. At the


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center of a big galaxy cluster, there's


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a huge reservoir of hot gas, millions of


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degrees, glowing in X-rays. By all


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rights, that gas should be cooling,


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sinking to the center and collapsing


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into vast numbers of new stars.


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>> And it doesn't.


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>> And it doesn't. These cluster cores are


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far quieter than the simple physics


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predicts. Something is reheating that


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gas, keeping it stirred up, stopping the


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runaway cooling. For years, the leading


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suspect has been the central black hole.


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That its outbursts dump energy back into


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the gas and hold the whole system in


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balance. But there's been a stubborn gap


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in the evidence,


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>> which is


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>> we could see black holes driving winds


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on the scale of their own galaxy. What


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we couldn't show was those winds


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reaching much beyond the galaxy out into


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the space between galaxies on the scale


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of the whole cluster. That's the part


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that stayed theoretical until this


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study.


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>> So, who did it and how?


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>> A team led by Satoshi Yamada at


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To<unk>hoku University in Japan with


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colleagues from Kanazawa, Tokyo


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Metropolitan, and Kyoto Universities.


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It's published in Nature Astronomy this


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week on the 28th. And their target is a


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genuinely special object, a quazar


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called H1821


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+ 643. Quazar meaning a black hole


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that's feeding so ferociously it


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outshines its entire galaxy.


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>> That's it. Some of the most luminous


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single objects in the universe. This one


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sits in the constellation Draco about


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3.4 billion lightyear away. And its


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black hole weighs in around 2.6 billion


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solar masses. But here's what makes it


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the perfect laboratory. It's the nearest


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quazar that lives right at the heart of


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a galaxy cluster. So, you've got a


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raging black hole and a giant reservoir


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of hot cluster gas in the same place


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close enough to study in detail. That


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almost never happens.


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>> And to study it, they used XRISM, which


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longtime listeners will remember.


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>> We've talked about it before. Yes.


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XRISM, the X-ray imaging and


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spectroscopy mission, is the


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Japanese-led X-ray observatory with NASA


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and the European Space Agency aboard.


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And its superpower is a kind of


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spectroscopy so precise it can read the


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motion of hot gas from the light it


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gives off.


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>> Explain how that works because this is


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the clever bit.


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>> It is the hot gas in a cluster contains


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iron atoms and those iron atoms emit


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X-rays at very specific sharp energies


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like a particular note. Now, if that gas


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is turnurning and swirling, some of it


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moves towards us and some away. And just


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like a siren changes pitch as it passes


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you, the motion smears that sharp X-ray


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note out. It broadens the line. Measure


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how broad the line is, and you've


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measured how violently the gas is


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moving.


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>> So, the iron lines become a speedometer


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for gas you can't otherwise see.


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>> A speedometer for turbulence. And when


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they pointed XRISM at H1821


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+ 643 and read those lines, the gas was


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far more turbulent than anyone expected.


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Compared with a calm, well-behaved


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cluster like Perseus, the motion here is


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dramatically more violent. And it's


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violent across a huge span of space.


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>> How huge.


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>> The disturbance reaches out to something


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like 300,000 lightyear from the black


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hole. well beyond the host galaxy out


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into the cluster itself. And the energy


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tied up in that turbulence is on the


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order of a hundred times greater than


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earlier estimates.


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>> 100 times. So this isn't a tweak to the


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model. It's a different order of


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magnitude.


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>> It really is. What they've shown is that


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this black hole is pumping something


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like a few to 10% of its radiative


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energy straight into the surrounding


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cluster gas on scales of tens to 100


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kiloparex. That's the missing link.


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That's direct evidence of a black hole


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heating and stirring its cluster from


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the inside. Exactly the process


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theorists needed to explain why all that


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gas isn't collapsing into stars. Yamada


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had a nice way of putting it, didn't he?


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>> He did. He said, "Black holes are famous


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for sucking matter in, but they also


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eject gas in powerful winds." And this


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study says those winds are immensely


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stronger than we understood. For the


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first time, he says, we've shown a black


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hole influencing the broader cosmos


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through a shock wave of astonishing


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power. And the reason to care beyond wow


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big number is that this is really a


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story about how galaxies grow up.


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>> That's the heart of it. Black holes and


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their galaxies grow together and


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feedback is the thermostat. Too little


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and the gas cools and the galaxy makes


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far too many stars. Too much and it


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blows the fuel away and star formation


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shuts down. Get it right and you build


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the galaxies we actually see. What


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Yumatada's team has done is catch that


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thermostat in the act, working on a


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scale we could only assume before,


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moving energy and eventually the


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chemical elements forged in stars out


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across the cluster.


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>> A black hole redecorating a whole


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neighborhood it never touches directly.


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>> More than three times the width of the


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Milky Way from a single point at the


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center. And this is really just the


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opening chapter. XRISM is still young


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and objects like H1821


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+ 643 are rare and precious. Expect more


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of these hot cluster cores to get the


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same treatment. And expect our picture


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of how black holes shape the universe to


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keep getting bigger, which is a lovely


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irony, isn't it? The more we look at the


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objects famous for pulling everything


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in, the more we find them reaching out.


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>> Reaching out. Good place to leave the


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giant. Let's bring it right down to a


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single dead star and a mystery about


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what it's been eating. So, story two, a


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white dwarf is what our sun will become


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billions of years from now. The burnt


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out Earth-sized core left behind when a


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star like ours runs out of fuel. And for


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a long time, we've known these dead


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stars are a bit macob. They're


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surrounded by the shredded remains of


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their old planetary systems. Asteroids


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and even planets torn apart and pulled


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in. The star literally raining its old


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planets down onto itself.


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>> Beautifully grim. Yes, we can tell


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because we see the metals from that


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debris polluting the stars atmosphere.


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But new research says we've been


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underounting the meal that white dwarfs


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are eating far more planetary material


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than we thought. And the reason we


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missed it is magnetism.


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>> Magnetic fields hiding the evidence.


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>> Exactly. Some white dwarfs are strongly


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magnetic. And when debris falls in,


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those magnetic field lines funnel the


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infalling material down to the stars


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magnetic poles, concentrating it into


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small patches instead of spreading it


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evenly. And patches at the poles are


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much easier to miss.


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>> And here's the part I love. The


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researchers point out it's essentially


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the same physics as an aurora.


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>> It is. Think about how our own auroras


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work. The sun throws charged particles


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at Earth. They follow our magnetic field


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lines down to the poles and they light


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up a glowing patch in the atmosphere. On


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a magnetic white dwarf, swap the solar


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particles for the debris of a dead


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planetary system and you get the same


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choreography. Material guided along


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field lines to a bright spot at the


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pole.


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>> An aurora made of ground up planets


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>> on the corpse of a star. And the


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practical upshot's real. If this


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magnetic funneling is common, then a lot


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of white dwarfs we've written down as


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clean may actually be feeding just


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quietly in a way our surveys don't


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catch, which changes how we estimate


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what these old planetary systems were


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made of.


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>> A window into the guts of dead solar


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systems, including one day our own.


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Speaking of dress rehearsals for the


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future, let's go to Mars. Story three.


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NASA's Psyche spacecraft is on its way


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to one of the strangest targets in the


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solar system, the asteroid 16 Psyche, a


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world that may be the exposed metal core


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of a shattered baby planet. Mostly


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metal, not rock or ice. We've never


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visited anything like it.


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>> And it doesn't get there until 2029.


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>> Not until 2029. That's right. But on the


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way back in May, it swung past Mars for


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a gravity assist, using the planet's


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pole to bend its path and pick up speed


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for free. And NASA's just shared what


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the team did with that flyby, which is


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the fun part. They treated Mars as a


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rehearsal studio.


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>> A chance to switch everything on and


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check it works far from home.


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>> Exactly. They put the cameras, the


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magnetometer, and the particle


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instruments through their paces against


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a real world instead of empty space.


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They captured a striking time lapse of


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Mars sliding by. They even picked up


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neutrons coming off the planet. But the


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detail that jumped out at me, the imager


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managed to pick out Foss and Damos, the


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two tiny moons of Mars from a great


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distance.


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>> The little Martian moons. And that


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wasn't just for a nice photo.


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>> No, that was the whole point. Spotting


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two small faint moons against the glare


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is exactly the kind of needle in a


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haystack test they'll need when they


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arrive at asteroid psyche and go looking


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for any little moonletits orbiting it.


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So Mars became a practice run for a


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search they'll do for real in a few


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years time.


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>> Rehearsing the hard shot on a target you


00:11:51.360 --> 00:11:53.430
already know so you're ready for the one


00:11:53.440 --> 00:11:54.389
you don't.


00:11:54.399 --> 00:11:56.790
>> Precisely. Every instrument checked,


00:11:56.800 --> 00:11:59.350
calibrated, and confident 3 years before


00:11:59.360 --> 00:12:01.990
it matters. From one careful mission to


00:12:02.000 --> 00:12:04.389
a much messier problem closer to home,


00:12:04.399 --> 00:12:06.710
Avery, the traffic on the road to the


00:12:06.720 --> 00:12:07.590
moon.


00:12:07.600 --> 00:12:09.990
>> Story four. We spend a lot of time on


00:12:10.000 --> 00:12:11.750
this show talking about who's going to


00:12:11.760 --> 00:12:14.629
the moon. NASA's Aremis program, China


00:12:14.639 --> 00:12:16.949
and Russia's planned research station,


00:12:16.959 --> 00:12:19.430
Europe's Argonaut landers, and a growing


00:12:19.440 --> 00:12:21.750
crowd of commercial missions. The next


00:12:21.760 --> 00:12:23.910
decade could see dozens of flights into


00:12:23.920 --> 00:12:26.310
what's called CIS lunar space, the whole


00:12:26.320 --> 00:12:28.949
region between Earth and the moon. And


00:12:28.959 --> 00:12:31.030
everywhere we've ever gone in space,


00:12:31.040 --> 00:12:32.949
we've left junk behind.


00:12:32.959 --> 00:12:35.509
>> That's the worry. We've made low Earth


00:12:35.519 --> 00:12:38.069
orbit crowded and cluttered. The


00:12:38.079 --> 00:12:40.710
question this new study asks is, are we


00:12:40.720 --> 00:12:42.389
about to do the same thing to the road


00:12:42.399 --> 00:12:44.710
to the moon before we've even properly


00:12:44.720 --> 00:12:46.870
moved in? It's from a team at the


00:12:46.880 --> 00:12:49.110
Chinese Academy of Sciences. And they've


00:12:49.120 --> 00:12:51.350
looked at a specific clever kind of


00:12:51.360 --> 00:12:54.150
orbit out there, a distant retrograde


00:12:54.160 --> 00:12:55.269
orbit,


00:12:55.279 --> 00:12:57.269
>> which is one of those very stable


00:12:57.279 --> 00:12:59.750
parking spots in the Earth Moon system,


00:12:59.760 --> 00:13:02.230
>> right? A wide stable loop that's


00:13:02.240 --> 00:13:04.629
attractive precisely because spacecraft


00:13:04.639 --> 00:13:07.110
can sit in it for a long time without


00:13:07.120 --> 00:13:10.150
much fuel. The catch is if a spacecraft


00:13:10.160 --> 00:13:12.389
in one of those orbits breaks up, an


00:13:12.399 --> 00:13:14.790
explosion, a collision, the debris


00:13:14.800 --> 00:13:16.949
doesn't just fall away and disappear the


00:13:16.959 --> 00:13:19.030
way it might near Earth. The team


00:13:19.040 --> 00:13:21.430
modeled how those debris clouds spread.


00:13:21.440 --> 00:13:23.590
And out there, the fragments can linger


00:13:23.600 --> 00:13:25.750
and drift in ways that are genuinely


00:13:25.760 --> 00:13:27.269
hard to predict.


00:13:27.279 --> 00:13:29.910
>> And unlike low Earth orbit, there's no


00:13:29.920 --> 00:13:31.670
friendly atmosphere out there to


00:13:31.680 --> 00:13:33.670
eventually drag the rubbish down and


00:13:33.680 --> 00:13:34.870
burn it up.


00:13:34.880 --> 00:13:37.350
>> That's the crux of it. Near Earth, the


00:13:37.360 --> 00:13:40.150
atmosphere slowly cleans up after us. In


00:13:40.160 --> 00:13:42.629
deep cis lunar space, there's no such


00:13:42.639 --> 00:13:45.430
janitor. Debris can stay a hazard far


00:13:45.440 --> 00:13:47.829
longer. So, the value of work like this


00:13:47.839 --> 00:13:50.150
is that it's preventative. If we can map


00:13:50.160 --> 00:13:52.069
where the risky orbits and the lingering


00:13:52.079 --> 00:13:54.150
debris clouds are before the traffic


00:13:54.160 --> 00:13:56.550
arrives, we can design missions to steer


00:13:56.560 --> 00:13:58.550
clear and maybe keep the highway to the


00:13:58.560 --> 00:14:00.550
moon open for everyone who wants to use


00:14:00.560 --> 00:14:01.269
it.


00:14:01.279 --> 00:14:03.350
>> Cleaning up before we make the mess for


00:14:03.360 --> 00:14:06.150
once. Now, let's get you outside because


00:14:06.160 --> 00:14:08.710
tonight the sky is putting on a show and


00:14:08.720 --> 00:14:10.790
this one is genuinely for tonight


00:14:10.800 --> 00:14:13.030
wherever you're listening. Two meteor


00:14:13.040 --> 00:14:15.189
showers are peaking at the same time,


00:14:15.199 --> 00:14:16.949
the night of the 30th into the early


00:14:16.959 --> 00:14:19.509
hours of the 31st. The Southern Delta


00:14:19.519 --> 00:14:22.310
Aquariads and the Alpha Capricorns.


00:14:22.320 --> 00:14:24.790
>> Two at once. Tell us the difference


00:14:24.800 --> 00:14:25.910
between them.


00:14:25.920 --> 00:14:27.189
>> They've got very different


00:14:27.199 --> 00:14:29.030
personalities. The Southern Delta


00:14:29.040 --> 00:14:31.430
Aquares are the steady workh horses.


00:14:31.440 --> 00:14:33.910
more meteors, a bit fainter, radiating


00:14:33.920 --> 00:14:36.150
from the constellation Aquarius. Their


00:14:36.160 --> 00:14:37.990
parent is thought to be a comet called


00:14:38.000 --> 00:14:41.110
96P Mac Holtz. The Alpha Capricornids


00:14:41.120 --> 00:14:43.430
are the opposite. Not many, but the ones


00:14:43.440 --> 00:14:46.470
you get are slow, bright fireballs, real


00:14:46.480 --> 00:14:48.310
showstoppers coming from the direction


00:14:48.320 --> 00:14:51.590
of Capricornis from a comet called 169P


00:14:51.600 --> 00:14:52.470
meet.


00:14:52.480 --> 00:14:55.430
>> So, quality versus quantity sharing the


00:14:55.440 --> 00:14:56.629
same night.


00:14:56.639 --> 00:14:59.110
>> Exactly. Now, the honest catch this


00:14:59.120 --> 00:15:01.269
year, the moon. We had the full buck


00:15:01.279 --> 00:15:03.509
moon just last night. So tonight it's


00:15:03.519 --> 00:15:06.550
still around 98% lit. And that glare


00:15:06.560 --> 00:15:09.189
will wash out the fainter meteors. But


00:15:09.199 --> 00:15:11.269
and this is the saving grace. Those


00:15:11.279 --> 00:15:13.430
bright Capricorned fireballs can punch


00:15:13.440 --> 00:15:15.189
right through moonlight. As one


00:15:15.199 --> 00:15:17.350
astronomer put it, one bright one is


00:15:17.360 --> 00:15:19.269
worth 20 faint ones.


00:15:19.279 --> 00:15:21.670
>> So how do people actually watch? And


00:15:21.680 --> 00:15:23.590
this is where north and south really


00:15:23.600 --> 00:15:24.470
differ.


00:15:24.480 --> 00:15:26.949
>> It does. So let's do both properly.


00:15:26.959 --> 00:15:28.790
First, the good news for us here in the


00:15:28.800 --> 00:15:31.350
southern hemisphere. This is our show.


00:15:31.360 --> 00:15:33.670
Both radiants ride high overhead from


00:15:33.680 --> 00:15:35.750
southern latitudes, so we get the best


00:15:35.760 --> 00:15:38.150
seats. The Southern Delta Aquares can


00:15:38.160 --> 00:15:40.389
deliver something like 10 to 20 an hour


00:15:40.399 --> 00:15:42.949
from a dark sight under a better moon.


00:15:42.959 --> 00:15:44.949
And even tonight, with the moon bright,


00:15:44.959 --> 00:15:47.110
the south still comes out ahead.


00:15:47.120 --> 00:15:49.350
>> Dignity and the east coast, when and


00:15:49.360 --> 00:15:51.990
where? Head out after the moon and sky


00:15:52.000 --> 00:15:54.470
settle late evening onward, but the best


00:15:54.480 --> 00:15:57.030
window is the small hours local time,


00:15:57.040 --> 00:15:59.670
roughly 1 to 4:00 a.m. when the radiance


00:15:59.680 --> 00:16:01.749
are highest. Look towards the north and


00:16:01.759 --> 00:16:03.990
east. Get as far from city lights as you


00:16:04.000 --> 00:16:06.790
can and give your eyes a solid 20 to 30


00:16:06.800 --> 00:16:09.509
minutes to adapt. Lie back and take in a


00:16:09.519 --> 00:16:11.990
wide patch of sky rather than staring at


00:16:12.000 --> 00:16:14.550
one spot. And for our North American


00:16:14.560 --> 00:16:16.389
listeners, our biggest audience who


00:16:16.399 --> 00:16:18.389
don't get the radiant as high,


00:16:18.399 --> 00:16:21.110
>> you can still absolutely catch this. You


00:16:21.120 --> 00:16:23.269
just work with lower numbers and lean on


00:16:23.279 --> 00:16:26.150
the fireballs. Your best time is also


00:16:26.160 --> 00:16:29.749
the pre-dawn hours. Think 2 to 4:00 a.m.


00:16:29.759 --> 00:16:32.470
local, whether that's Eastern, Central,


00:16:32.480 --> 00:16:34.790
Mountain, or Pacific time once the


00:16:34.800 --> 00:16:37.030
radiance have climbed as high as they'll


00:16:37.040 --> 00:16:39.749
get. The pro tip for the moonlight,


00:16:39.759 --> 00:16:42.310
position yourself facing away from the


00:16:42.320 --> 00:16:44.949
moon with it at your back or blocked


00:16:44.959 --> 00:16:47.670
behind a building or a hill so its glare


00:16:47.680 --> 00:16:50.870
isn't in your eyes. Then watch a broad


00:16:50.880 --> 00:16:53.509
stretch of sky and wait for those slow


00:16:53.519 --> 00:16:55.430
Capricorned fireballs.


00:16:55.440 --> 00:16:57.829
>> No telescope, no binoculars.


00:16:57.839 --> 00:17:00.710
>> Done at all. Meteors are a naked eye


00:17:00.720 --> 00:17:03.829
whole sky event. Just you, a reclining


00:17:03.839 --> 00:17:06.710
chair, something warm and patience. And


00:17:06.720 --> 00:17:09.029
if tonight clouds you out, both showers


00:17:09.039 --> 00:17:11.350
stayed active for another week or two.


00:17:11.360 --> 00:17:13.270
So you'll get more chances as the moon


00:17:13.280 --> 00:17:15.829
thins out and conditions improve.


00:17:15.839 --> 00:17:18.470
>> Two comets worth of dust burning up over


00:17:18.480 --> 00:17:21.270
your head. Not a bad way to end the day.


00:17:21.280 --> 00:17:24.309
>> Not bad at all. Look up if you can.


00:17:24.319 --> 00:17:26.470
>> That's the lot for today. Every story


00:17:26.480 --> 00:17:28.630
with links and sources is over at


00:17:28.640 --> 00:17:30.710
astronomyaily.io.


00:17:30.720 --> 00:17:33.110
The news site has the full back catalog,


00:17:33.120 --> 00:17:35.029
a rolling news feed, and you can sign up


00:17:35.039 --> 00:17:37.029
for the newsletter, or drop us a line


00:17:37.039 --> 00:17:37.990
right there.


00:17:38.000 --> 00:17:40.549
>> We love hearing from you. Tell us if you


00:17:40.559 --> 00:17:42.870
catch a Capricorned fireball tonight.


00:17:42.880 --> 00:17:45.590
Find us at astroaily pod and on the


00:17:45.600 --> 00:17:47.909
bites.com podcast network.


00:17:47.919 --> 00:17:49.990
>> For Anna and for me, thanks for


00:17:50.000 --> 00:17:50.630
listening.


00:17:50.640 --> 00:17:53.547
>> Until tomorrow, clear skies. [music]


00:17:53.557 --> 00:17:56.789
[singing]


00:17:56.799 --> 00:18:03.990
told


00:18:04.000 --> 00:18:06.712
stories. [music]