Quirks and Quarks - Sensing space junk, and other stellar stories

Episode Date: August 14, 2026

From filming a black hole to flaming hot water ice on Neptune, we revisit some of our favourite space-related stories from the past season.

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Hi, I'm Bob McDonald. Welcome to the best of Quarks and Quarks. Space must be my favorite topic. I grew up during the space race when we were first going to the moon, and now we're heading back there. We've had a spectacular year in space science with the success of the Artemis II mission that flew Canadian astronaut Jeremy Hanson and his fellow crewmates around the moon in April. So today's episode features some of our favorite space stories from the past season. like the smashing success of NASA's mission to deflect an asteroid, catching a black hole on video, IDing the cosmic collider that kicked up our moon, and discovering a new type of water that may be inside icy planets.

But first, how earthquake sensors could be used to track down incoming space junk. All this today on the best of quarks and quarks. Space is getting really crowded these days. We've got satellites, research payloads, and spent rockets floating around our planet. And as these things start breaking apart, they create even more of a mess in orbit. According to the European Space Agency, there are more than 1.2 million pieces of space junk over a centimeter in size orbiting our planet, though many are much larger than that. And more and more often, we're hearing of large chunks of this junk falling from space and hurtling towards our planet.

What the hell? At about 1.40 a.m. on Tuesday morning, Angelinos, who were out late partying, I guess, looked up in the sky and saw this trail of flaming debris. But it's often a huge challenge to figure out where this junk goes once it gets into our atmosphere. Yeah, a bit of sci-fi hitting home for a Michigan couple when a satellite crash landed in their backyard. As a farmer in rural Saskatchewan, Barry's... Zochuk is used to removing rocks and weeds from his fields, but he recently discovered this two-meter-wide, 40-kilogram heap of twisted, burnt metal. Whether it is his insulation, I have no idea.

Well, a team of researchers have come up with a way to keep tabs on this space junk after it re-enters using earthquake monitors to listen in on the sonic booms they produce. Dr. Benjamin Fernando is a planetary scientist and seismologist at Johns Hopkins University in Maryland. Hello and welcome to our program. Hi, Bob. Thanks for having me. So how often do we have space debris reentering our atmosphere? So we're now at a point where we often have multiple satellites per day reentering the atmosphere.

In the early part of last year, we had multiple Starlink satellites entering the atmosphere per day. And each of those poses some risk to life, both on the air if you're in a plane and on the ground. And they're beginning to change the composition of our atmosphere as well. Wow. Well, what kind of materials are these satellites made of that makes them so dangerous? That's a great question. And part of the problem is we don't know exactly what they're made of. There's no mandatory reporting in international standards for this. So the stuff that makes up battery packs, fuel tanks, solar panels, some of that stuff we think has a pretty substantial climate warming potential and also the potential to deplete the ozone layer. But the trouble is, without exact data, trying to understand. exactly what those impacts are is challenging.

Well, that's the upper atmosphere, but how much of that stuff actually reaches the ground? Again, we don't really know. Many of these companies say that their satellites demise entirely. That is, they burn up entirely within the atmosphere. Yet we've seen a few cases of pieces of space debris hitting the ground, and we don't always know where they've come from. Some of those fragments, they might be toxic, they might be flammable. There's even been a few instances of things that are radioactive being spread on the ground

from reentering space debris. Well, is there any current way to keep track of debris that's falling through our atmosphere? So people do this using radar, which is great, except that in many parts of the world, we don't have great radar coverage. And other nations keep their radar coverage classified, whether it's civilian or military. So very often, we don't have access to the sort of open source data that we'd like to track and characterize these re-entries as they're happening. Well, take me through your work.

How are you planning to track this? stuff more accurately. So what we've done is demonstrate that seismometers, that is, the sensors that are normally designed to record earthquakes, can also be used to track the sonic booms from reentering debris. So if you imagine debris comes into the atmosphere, it's going many, many time to speed of sound, it generates a sonic boom. And we showed that seismometers can record those sonic booms, and from that we can reconstruct things like the direction, the speed, the descent angle of the reentering debris, and also something about how it fragmented in the atmosphere. That's astounding, because we always think of seismometers as measuring the earth, what's going inside the earth.

I didn't realize they were so sensitive that they could detect vibrations in the air. Yeah, so what happens is those vibrations in the air actually shake the ground, and that's what we detect on our seismometers. These instruments are incredibly sensitive. In addition to detecting earthquakes, they often pick up things like ocean waves, things like vehicles, planes. occasionally they pick up whales as well. They really are incredible pieces of technology. So how much of a satellite's track can you follow using seismometers? How would it work? So in theory, we can follow the satellites track from the point where it starts producing a sonic boom,

which is somewhere around 100 kilometers in altitude, down to the point where it's going subsonic, so it slows to fasten the speed of sound or it hits the ground. And it can be a little more challenging than that, because often if these things are breaking up, the pieces that are left to hit the ground are quite small. They're quite quiet and difficult to detect. But what we're trying to do is characterize that sort of terminal phase of reentry, where all the stuff that's relevant to people on the ground is happening. So the breakup, the stuff separating, and then beginning to ablate that is burn up as it enters denser and denser portions of the atmosphere. Have you tested this? So we tested it on a case study from a piece of Chinese space junk.

called it Shenzu 15. Now Shenzu 15 was a particularly sort of risky target in some sense because it entered over metropolitan Los Angeles in April 24. But the good thing for us, at least, about this happening in Southern California, was that there were lots of seismometers that we had to test our theory on. And we were able to show that we could basically reconstruct the trajectory of that object using the seismic network in California. Oh, I see. You have a network. A bunch of seismometers on the ground, and each one of them tracked it as it passes overhead. Exactly. And so different ones on that network will see the sonic boom at slightly different times. And from putting all that information together, we can work out something about where the object was,

how fast it was going, and so on. How big was that object? So it started off in the atmosphere being a couple of meters across. By the time it crossed the coast of California, it looked like it had broken up into fragments that were more like a meter across, and then we see evidence of what we call sequential fragmentation, so that is, bits broke up, and then those bits broke up into smaller bits, and so on and so forth. So we kind of had this cascade of a big piece of space jump, breaking into many smaller pieces, which have the potential to fall over a much wider area. Boy. So can this method of using seismometers to track falling space debris be used anywhere on Earth? So California is a particularly good test location, because

it has a very dense network of seismometers. But we've also been able to make measurements like this in other locations where there are far sparser networks. For example, we've got some really interesting data from the Caribbean last year where we saw a series of SpaceX's starship rockets explode and rain down debris on beaches in the islands there. We've also been testing it by taking the data from California

and then imagining that we throw away or discard 50, 60% of the measurements we made to see how many stations we need in order to reconstruct that trajectory if we were working somewhere that has fewer seismometers on the network. So how few do you need to make an accurate track? There's some detections in the Caribbean where we have only one or two, and that still tells us something about the direction the object's traveling in. But the more sensors that we have, the more reliable the results become.

So how big or small are the items that you could see with this method? I'm thinking of the Starlink satellites where there's thousands of them, and SpaceX says, while they're small enough that they'll all burn up high in the atmosphere, you don't have to worry about them. So we've definitely seen some sonic booms from re-entering Starlink satellites. That is very clear. The question again is, of course, whether any of those fragments survive to reach the ground. But we've seen things down to around 50 centimeters or so in radius very clearly on our seismometers from dozens of kilometers away. So where do you see a system like this being used? Unfortunately, space debris is a global problem.

It doesn't particularly care what country you're in. It doesn't care whether your country or your company was the one who launched the satellite or not. And so what I'm hoping is that over time, we can develop this sort of network approach of seismic monitoring for space debris to try and understand and characterize re-entries wherever they occur on the planet in near real time. That is, as soon as we detect a series of sonic booms, we try to understand. Ryan put together a best fit trajectory for that object so that when it comes to trying to understand where it might have landed and what the environmental consequences both in the atmosphere and on the ground are of that re-entry, we're well placed to help locate it.

Dr. Fernando, thank you so much for your time. Thank you for having me. Dr. Benjamin Fernando is a planetary scientist and seismologist at Johns Hopkins University in Maryland. There's nothing quite like the site of the full moon hovering above the horizon. It's a site that's inspired poets and astronauts alike. But while we might take the moon for granted, it hasn't always been there. Billions of years ago, not long after the Earth itself formed, our planet was moonless.

And then scientists think that a planet-sized object smashed into the Earth, kicking up debris, that in time coalesced into our moon. This idea that the moon formed as a result of a cosmic collision, has been kicking around since the 1970s. Scientists have even named that body that crashed into our planet, Thaya, after the ancient Greek moon goddess. But it was never clear where Thea came from. But now, thanks to chemistry, we may finally have that answer.

Dr. Seth Jacobson is an assistant professor of planetary science at Michigan State University and was part of the team that did the research. Dr. Jacobson, welcome to Quarks and Quarks. Thank you for having me here. Now, before your latest study, how much did we know about Thea, the object that smashed into the Earth? Well, not very much. While we're confident that a giant impact is responsible for creating the circumplanetary disk around the Earth from which the moon accreted, we don't know much about the impactor itself, this object called Thea.

So how did chemistry help you figure out where it came from? So one of the ways that we have to constrain or learn about, is to compare the composition of the moon and the earth. And what we did is at the laboratory at the University of Chicago is Timohap and Nikdofa measured the iron isotopic composition of both lunar rocks and terrestrial rocks. And by comparing that composition, they determined that the moon and the earth were identical, nucleosynthetically, according to the isotopes of iron, which is really incredible because when we look across other bodies in the solar system, we see a great diversity in the composition, or rather the isotopic composition of iron. Wow. So the earth and

moon seem to be identical chemically, but what does that tell you about where Thea came from in relation to the early Earth? Yeah, so that's a great question. We can infer that information by comparing the Earth and the moon to all those other objects in the solar system for which we measured their iron isotopic compositions. And these include things like Mars, many meteorites from the asteroid belt, including objects that formed near the Earth or maybe even interior to Earth, and then also meteorites that we think formed exterior of Jupiter, the carbonaceous chondrites. So what happened when you compared all of those? Yeah. So what we found is that Earth and the Moon are much closer to the composition of these inner solar system meteorites and really far

away from the iron composition of these outer solar system meteorites, suggesting that the moon and the earth come from the inner solar system. So it was an inside job, after all. Yeah, that's correct. So Thaya is not some distant interloper sent in on a trajectory from the outer solar system. Instead, it's probably an object that was born right next to the proto-errori. Well, what do we know about how cosmically violent our solar system was back when Thaea's mashed into the proto-earth.

Oh, that's a great question. I would say that that is perhaps one of the most actively researched questions in planetary science, particularly in the field of plant formation today. Just how violent was the era of planet formation. How many giant impacts were there? Was the moon-forming impact a unique event or actually the last of a long series of events? And I think at the moment, I can't answer you. And no one could answer you with a lot of confidence.

But we do know that every object in the solar system has been hit. That's how planets are made, isn't it? It is by objects coming together and sticking and building up like you make a snowman by clumping more snow onto it? That's right. So we call that process accretion. And absolutely, plants grew via accretion. But did they grow through the gentle accretion of relatively small materials? Or did they grow through the much more violent accretion of similar-sized objects?

How big was Thaya back compared to the early Earth before the collision? Right now, there are proposals that Thayer could have been perhaps not much larger than the moon itself, all the way up to being almost the same size as the Proto Earth. Wow. So what would that have looked like? If you could go back in time and see it, take me through the sequence of events as if we were just watching it happen. Yeah, so Thaya, when Thaya collides with the Earth, it's going to produce a giant disruption of the Proto Earth. This is going to push a lot of material from both the impactor from Tha and the

Proto Earth into orbit. It's also going to deform the Earth itself. This is a very bad event if one were to be alive on the surface of the Earth. However, this will produce a very large circumplanetary disk, not so different from, say, the rings of Saturn, but a lot more massive relative to the planet and very high. temperature. Inside this disk, material will begin to cool, and in the outer parts of the disk, you'll form monotessimals, small objects, maybe a few tens of kilometers to a few hundred kilometers in size, that will start to accrete and grow by collisions with each other until you've

accreted something resembling our modern moon. Wow. How big a role has the presence of our moon played in the evolution of our own planet since that cosmic collision? That's a great question. and another topic of a lot of discussion among scientists. You know, one of the original proposals, in fact, I believe Charles Darwin's proposals for the origin of life suggested life began in tidal pools. So these are pools that are repeatedly filled and emptied by the ocean tides due to the moon. And so in this case, the moon would have been absolutely crucial for the origin of life. Now, it's not so clear that life actually originated that way, but the moon has been a constant

companion of the earth and these interactions between tides, drive motions in our ocean, and also have controlled the rotation of Earth over time. And finally, I guess without the moon, we wouldn't have all those great songs like, fly me to the moon, moon dance. I mean, the moon has had a huge impact on the development of humanity, having periods where the night is very dark and periods where the night is very light, probably controlled when groups went out to hunt and when groups stayed home and procreated. And this has had big impacts on how our bodies work and how we function. And that's a relationship we have with the moon.

Dr. Jacobson, thank you so much for your time. Thank you for having me. Dr. Seth Jacobson is an assistant professor of planetary science at Michigan State University in East Lansing. Let me see what spring is like on Jupiter in Mars. You might remember in grade school how you learned there are three forms of water, how frozen water becomes ice and heated water becomes a gas. Well, according to a new study, scientists now have evidence that there may be a fourth mind-boggling type of water in our solar system.

inside the ice giants, Uranus, and Neptune. And this may finally explain strange observations that the Voyager 2 spacecraft made when it swept by Uranus and then Neptune as it passed through the outer solar system back in the 1980s. Dr. Ariana Gleason and her team conducted an extraordinary experiment in an attempt to recreate the extreme conditions inside the ice giants

by combining pressures that are millions of times stronger than our Earth's atmosphere with temperatures hotter than lava. Their goal? To see if these conditions could give rise to this fourth type of bizarre water to figure out if it's behind the ice giant's unusual magnetic readings. Scientists call it superionic water, which is like ice, but it's unlike any ice we've ever seen before. Dr. Gleason is a senior staff scientist

and the deputy director for the High Energy Density Science Division at the Slack National Accelerator Laboratory in Menlo Park, California. Hello and welcome to our program. Thank you. Now, I have to admit that I was at the NASA, Uranus, and Neptune encounters when Voyager went by them in 1980s. And at the time, those were really bizarre planets. Everybody was scratching their heads because their magnetic fields were not lined up with

the planets north and south poles. They were off at weird angles and not even at the same. the center of the planet and everybody was going, wow, there must be something strange going on inside these planets. So how did you approach trying to figure out what was going on in there? Yes, such unusual magnetic fields often arise from an interesting and maybe complicated internal structure. We know from many different kinds of observations that these are really water-rich ice and gas giants. And we understand what the constituent components, basically the ingredients of the internal structure are likely to be. But we can't go excavate out

a piece of Neptune and bring it back to Earth to study. We have to simulate those conditions in our laboratory using unique tools. Now, you're calling this unusual water. super ionic. So just generally, what's it like? Yeah, great question. So it turns out that at these very high pressures, the oxygen atoms pack together in a way that sort of minimizes energy, meaning they pack together most efficiently. Think of sort of billiard balls or little spheres and you try to pack them as close as possible. And they end up stacking together in a way that forms what's called a cubic lattice. And so these different cubic stacking arrangements actually lead to differences in the properties of the ice. And the best part, the most interesting part, is that

this stacking arrangement enables the hydrogen atoms to flow freely, move around in a conductive fashion, and that leads to this novel property, superionic property of the ice. So it's a solid, but the hydrogens are zipping around. Okay, so you're saying it's a solid. It's under pressure. So is it hot ice? It is hot ice. That's exactly right. In fact, it's incredibly hotter than even the surface of our sun. It's pretty incredible. So how did you manage to create this superionic water in the laboratory? It's really exciting. I love my job. I get to use really big, lasers, and I basically blow stuff up. So what we do, there are many tools in the sort of condensed matter physics and mineral physics that we use to generate in the laboratory

extraordinary high pressures. And I do that by sending a powerful laser, think about as much energy as is in a bolt of lightning. That much energy we deposit on a sample and we generate a plasma just for a brief nanosecond or so, that plasma blows off and launches a shock wave in the opposite direction. The shock wave moves through the sample and momentarily generates the superionic state of water. And when we generated this high pressure state, actually, we saw new so-called peaks of diffraction show up in a few spots, and we were able to identify the structure. earth. So what does that tell you about what's going on inside the ice? Yeah, well, it tells us that it's a little bit more complicated than we first assumed. We found that there's a layering of different cubic structures,

and they're intimately integrated into one another, and this probably leads to a rich complexity in how the magnetic field then develops. You're saying these can be cubic? Exactly right. Yeah, think of a small cube, like another cubic material we're familiar with is maybe rock salt. And so think of, you know, very dense, hot, flaming hot ice in the shape of a cube, you know. Yeah. So how then does that explain the strange magnetic fields that we're seeing in the planets? Right. Well, it turns out when you have a conductive fluid, so like in our own planet, planet Earth. We've got a solid inner core and a liquid outer core, and that liquid outer core is actually convecting. So that molten iron is moving around, and that generates our geodynamo, our magnetic

field. But on Uranus and Neptune, because of the, we think, the complex layering of superionic ice, in the context of the other ionic liquid layers, right? There are briny, salty, water-rich regions that are also convecting. And the majority of the magnetic field is set up by this convecting, this moving ionic, salty liquid. But it's on sort of both boundaries, the top and the bottom, it's in contact with this very unusual form of ice, superionic ice, that has the increased conductivity due to those very highly mobilized hydrogens. And so what we think is going on is the multi-pole, right? This unusual magnetic field arises from the constant motion of both the ionic liquid

and the location of these different forms of very dense superionic ice. So it sounds like it's much more chaotic on these planets. Yes. We're stuff with swirling around. So you get a magnetic pole sticking out one place and then another one sticking out somewhere else. Exactly. And then it shifts around because of the interplay between these different layers. Exactly right.

Dr. Gleason, thank you so much for your time. Thank you very much. Wonderful to be here. I'm Bob McDonald, and you're listening to the best of Quarks and Quarks on CBC Radio One and streaming live on the CBC News app. Just go to the local tab and press play wherever you are. This is what summer basketball sounds like in Canada. The Canadian Elite Basketball League is back, bringing 10 teams, exceptional talent,

and non-stop energy all season long. And here's the best part. Every regular season game is live on CBC Gem with featured games. on CBC television, the future of the game is here. Don't miss the action. Watch the CBL all season on CBC and CBC Gem. We are delighted to be able to report to you today that we have seen what we thought was unseeable.

We have seen and taken a picture of a black hole. Here it is. Back in the spring of 2019, the world got to see the first image ever taken of a black hole. black hole. It looks like the eye of Sorin from the Lord of the Rings staring at you from the black depths of space, with a reddish-orange glow around a black shadow where gravity is so extreme no light can get out. It shows a supermassive black hole known as M87, sitting at the heart of the Messia 87 galaxy 55 million light years from Earth. The image was the first direct evidence

for the existence of black holes and represents one of the greatest achievements in modern astronomy. And as with all great discoveries, this is just the beginning. Well, now, here we are nearly seven years after that first image was released, and astronomers are back at it.

But this time, they're not going for a single image, but to record video footage of M87 in action. The project involving many radio telescopes and scientists around the world is now underway. Dr. Sarah Markov sits on the Science Board of the Event Horizon Telescope Global effort to capture the video likeness of M87. She's the new Plumian Professor of Astronomy at the University of Cambridge in the UK and a professor of theoretical astrophysics at the University of Amsterdam, where we caught up with her.

Dr. Markov, hello and welcome to Quirks and Quarks. Hi, Bob. Thanks for having me on. What kind of video are you anticipating you'll get from this new global effort to record a black hole in action? Well, it's kind of a slow video in the sense, you know, it's a, what we're trying to do is look at a black hole as it's changing in time. Actually, I should be really careful to say the black hole itself isn't really changing in human time scales. What is changing is its interaction with the stuff around it. It's sort of interaction with the environment. And so what we're trying to do is make a movie of these interactions. And for a black hole that's as humongous as M87, one of our primary

targets, it changes on time scales of a couple days to about a week. So in the past, what we've done is we've taken effectively one snapshot every year. And taking one frame of a movie every year is a little too slow, you know, even for us. But also it means that we're not actually stringing together the story. We're missing. We have big gaps. And so what we're going to be doing is, is looking every three to four days for about two months. Okay, so you're looking at the material that's circling the black hole that orange disc that we saw around it, the material that's whizzing around really, really fast and sometimes falling into it?

Yes, exactly. And sometimes not falling in, which is what's actually very exciting for us. Well, take me through that. What are you hoping to see? So, I mean, there's just an enormous amount of questions that we'd like to be able to answer about black holes in general. You can kind of think that they have a big magnetic storm or hurricane of super hot stuff, you know, as you say, whipping around them at nearly the speed of light. And so this is really matter at some of its most extremes that we're not going to be able to ever study in our laboratories on Earth.

And so we end up having a lot of competing theories about what's going on there. And so we're trying to settle various debates. We're trying to look at, for instance, things like, you know, what direction is the black hole spinning? how is it, you know, feeding off of its environment? And then how come some stuff does seem to fall in and grow the black hole? And how does the black hole somehow manage to launch, you know, these big fire hose-like jets of plasma out? And they don't do that all the time.

But M-87 is in the process of doing that. So we're trying to understand why it's doing that while other black holes like our other target, Sajah Star, are not. So tell me about M-87. What's it like? It's about the size of the solar system. It's one of the larger black holes that we know of. And how it got to be that size is a big mystery to us as well. But it's currently in what we call a kind of active phase,

which means that it is feeding off of its environment. And it's launching these really enormous jets of magnetized plasma. They actually are extending to be about the size, you know, say millions or billions of times bigger than the black hole itself. And to give you some example, I'd like to say this is as if you took your garden hose. turned it on, and then it ended up watering someone's lawn, you know, across the entire Earth. It's just a really big difference in scale. So we don't understand how this works.

That's unbelievable. A jet coming from a black hole that crosses the galaxy, that's like hundreds of thousands of light years in length. Yeah, exactly. They can basically be up to even a million light years across the biggest systems. So how does the black hole do that? We think of black holes as eating everything. falling into them, how do they launch stuff out such incredible distances? Yeah, that's a great question.

I mean, that's one of the primary questions that we're trying to understand using the Event Horizon Telescope, because all the power for this has to be coming sourced in some sense by the combination of the extremely deep potential well of the black hole. So it's basically the gravity of the black hole combined with the stuff that it's managing to eat from its environment. But, you know, other black holes are also in similar environments and they're not managing to, you know, spew out this kind of stuff. Some black holes give off winds instead of jets.

And some like our galactic center black hole, Sagittarius A Star, seem to be in a more dormant state. So we think that black holes go through active in dormant states. It probably has something to do with the buildup of extremely strong magnetic fields. And the magnetic fields can kind of act to hold. or kind of squeeze the material and guide it outwards, but exactly how it does it to that extreme power and then also keep it kind of going in the same direction in a very linear fashion, as you say,

like up to a million light years, is something that is very hard to understand. So we do a lot of work taking the data and making computer simulations to try to figure that out. What does the speed of the spin of the black hole tell you about it? So it gives you a little bit of a hint to the history of the black hole, you can kind of think of spin as a form of like a bank of

energy that the black hole is storing in some sense. And it tells you a bit about like what came onto the black hole because if the black hole was born with a particular spin, then if more material falls on it that's moving in the same direction, it can actually kind of spin up or wind up the black hole, make it spin faster. But if material falls on it in the opposite, direction, it can slow it down. Now, you mentioned that these huge jets that come out of the black hole can, you know, be bigger than the galaxy. How do they affect the galaxy that the black hole's in?

Very, very drastically, actually. One jet from one black hole like M-A-7 can go out into this and actually heat the gas, and heating gas means that it cannot cool, which means it cannot form stars. Because to form stars, gas has to cool so that it could. start to clump up into these little clouds that then collapse and form stars. So galaxies grow by star formation. And so we call this feedback because the black holes basically can stop its own feeding process. It can affect its galaxy, shrink the galaxy in some sense or stop the growth of it. Some people think that the black hole and its jets and the winds too might actually stimulate star formation.

So when we think about ourselves living, and you know, at this time and place in the universe, we're asking ourselves, too, you know, how do we get here? Why does the universe look the way it does? We know black holes play a big role, but also they play a big role in, you know, star formation. Maybe some of our environment was, you know, affected by prior black hole activity. So, yeah, what role do you think they played in galaxy formation in the early, early universe? For instance, they help, you know, they help basically like regularly. the growth of the galaxy. So what we see, when we study, by now we know of billions of galaxies,

but we can't measure the black holes that most of them harbor in their center very easily. So what we try to do is take a sort of census or population of all the black holes we know and look at their galaxies. And what we find is that there seems to be a kind of correlation between the black hole size or its mass and the size of the galaxy. And the black hole itself is tiny on the scale. of the galaxy, you know, our black hole in our galaxy, it seems kind of scary, but it's very far away from most of the galaxy, it's not really affecting it. So you have this question, how does the black hole talk to the outer galaxy and actually affect, you know, its evolution and its size? We think that it's via the action of these jets, that it's kind of regulating this over cosmic time. And the

spin of the black hole can also play, as I said, like a bit of a bank. And the jets can tap this energy and even bring more energy to the environment than what was being put in at the time. So it's a really interesting interaction. This is one of the more pressing problems in astrophysics at the moment. That's astounding. Black holes have a reputation of being the universal vacuum cleaners. You know, they're just going to suck up everything. But you're saying, no, they actually are recycling material in a way. Yeah, exactly. I actually joke. They're sort of like the big cosmic jacuzzis in some sense, but you can think of the universe as very dynamic. It has its own kind of almost like carbon cycles of recycling material. I would say they're very proactive players and really

part of this big ecosystem. And I think it's important for people to think about that. Instead of this, you know, the media always paints black holes as these sort of pits of despair and everything falls in. But they're much more fun than that. Well, your campaign has just started. So how long do we have? have to wait before we see this movie of the Jets coming out of a black hole. It takes quite a while to get all the data. We're talking, you know, petabytes of data have to be manually shipped to supercomputers and then be processed.

But it takes quite a long time to get to the point where we can analyze the data and start to construct, you know, these images that we're going for. We've gotten much faster and we have increasingly better techniques for doing this. So we're sort of hoping that we'll start to get a first glimpse. by the end of the year. But I mean, when it actually gets published is going to be a little bit of a different story. But we're hoping to do this much faster than the past. Dr. Markov, thank you so much for your time. Thank you for having me.

Dr. Sarah Markov is the Plumian Professor of Astronomy at the University of Cambridge in the UK and a professor of theoretical astrophysics at the University of Amsterdam. Well, now that the production of Black Hole the movie is underway, how exactly are they filming it? Here to explain this enormous technological feed is Dr. Vincent Fish. He sits on the Event Horizon Telescope Science Board and is the operations data manager for their 12 telescopes. Dr. Fish is also a research scientist at the Massachusetts Institute of Technology's Haystack Observatory. We caught up with him just before production got underway in California. Hello and welcome to Quarks and Quarks.

Hello, Bob. So first of all, set this up for us. What kind of telescopes are you using and where are they located? The Event Horizon Telescope is an array of millimeter wavelength telescopes. That's basically short radio waves. We have telescopes that are situated primarily on mountaintops because it's advantageous to get above as much of the atmosphere as possible. Those telescopes are spread all over the planet.

As far north as Greenland, we have telescopes in Europe and Hawaii and the southwestern U.S., Mexico, Chile, South Korea. We also have a telescope at the South Pole, which of course can't see M87. Well, I've been to one of the telescopes called Alma in Chile, and you're right, it's on a mountaintop. That one's at, what, 16,000 feet. I had to have oxygen going to go up there. And why do they have to be so high up? Well, the atmosphere does a couple of bad things to the signal. one is that it absorbs the signals that are coming from the object you're looking at in space, and then it adds noise to that. In addition, the atmosphere jumbles your signal.

If you look at the phase of the incoming radiation, it gets scrambled by going through the atmosphere. The largest component of the atmosphere that causes this to happen is the wet component, the water vapor in the atmosphere. So you really want to put your telescopes in the driest places on the planet. The Atacama Desert is one of the dryness. highest places on the earth. Well, how do you put the radio signal data together then from all these telescopes to get a video of the black hole in action?

As many of your listeners may know from optical astronomy, the larger telescope that you have, the sharper your image will be. And radio telescopes work in a similar way, radio interferometers, radio arrays work in a similar way, except it's not the size of an individual radio telescope that matters here, because we can't get nearly as sharp an image as you could with a single telescope in the optical. But we can combine signals from telescopes that are very far apart, and it's as though we had a telescope that was as big as the distance between them. So we need different distances between telescopes at different angles, you know, north, south, east, west, and so on. Part of what has made the

EHT much more capable over the years has been the addition of new telescopes to give us more of those pieces of information to be able to reconstruct an image. Radio signals are invisible to the eyes, so how does that become something we can see? We use false color images. So in other words, the color represents the intensity of the brightness that we see. And we traditionally have colored that orange because it stands out very well against a black background, but it's not actually a color image. So are we talking about a movie that runs for seconds or is there time for me to get out the popcorn? The movie will probably only run a few seconds. Of course, it depends at how quickly you play

the frames. But it will be a first. It will be the first time that we have many different epics that you can put together and you'll actually be able to see things move. Now, when you say epics, those are individual images? Yes. So a night of observations would be an epic for us. Ah, okay. So basically what you're going to end up with is a time-lapse movie. Yes, exactly. We have a time-lapse movie where we will be able to play two months' worth of movement around M-87 over the time scale of a few seconds. What makes M-87 Black Hole such a good candidate from your perspective to star in this movie? Well, there are two really prime candidates for the Eventhorizing Telescope. at least two. The largest black hole that you see on the sky in terms of the angular size

is one in the center of our galaxy called Sagittarius A-star. The problem with Sagittarius A-star is that it changes too quickly. It changes on the timescale of minutes. M-87, on the other hand, is much slower to vary. So we get the benefit of being able to combine all of our data in a night to make one image and then stitch those images together to make a movie. Oh, I see, because M87 moves so slowly, then you can capture more fluid action. Yes, exactly. So what do you think it's going to be like for you when you finally get to see these video fruits of your efforts? Well, it would be amazing.

We've wanted to do this for 10, 15, almost 20 years now. We thought that M87 would be the first source that would be relatively easy to image. I mean, this is still challenging to do observations with the event horizon telescope and make full use of the data. But we have a lot of experience doing this now, and it should be fairly straightforward to put this movie together. And that's not something we could have said a few years ago, where it was really a struggle to make the first images. But we've practiced a lot. We've refined our algorithms. And we have a lot of questions.

And I think it will be exciting. A lot of people tend to view space as being a very static place. And it's actually very dynamic. If you have an array that can resolve the movement of plasma around the black hole, you can see changes in days or even hours. Well, I can't wait to see the movie, and I'm really looking forward to the poster. Black Hole, the movie, coming soon to theaters near you. I want to see it, too.

That's why we're doing this. Dr. Fish, thank you so much for your time. Thanks a lot. Dr. Vincent Fish is the operations data manager. for the Event Horizon Telescope and a research scientist at the Massachusetts Institute of Technologies Haystack Observatory. Looks to me like we're headed straight in.

Just over three years ago, NASA deliberately crashed a spacecraft into an asteroid to see if they had the ability to change its course, all in the name of planetary defense. The double asteroid redirection test, or dart mission, as it was called, involved sending a spacecraft towards a binary asteroid system, where a small moon, named dimorphos, orbits around a larger asteroid called Didimos. The system was chosen not because it was a threat to hitting Earth, but because at 11 million kilometers away,

it was coming just close enough for us to be able to test whether or not this could work. We got some results early on that found that the impact altered the moon's orbit. but now new observations are showing that both of the rocky bodies have changed course, making this mission a smashing success. Dr. Rahil Makadilla is a planetary defense scientist who led this analysis for his PhD research at the University of Illinois at Urbana-Champaign. Hello and welcome to our program. Hi, Bob. Thanks for having me.

First of all, just recap for me what exactly happened with the DART mission. Like you mentioned, the DART mission was a test of what is called the kinetic impact method of deflecting asteroids away from the earth. And the target of this mission was this binary asteroid system called Didemos, where the secondary asteroid or little moonlit dimorphos orbits around Didemos. And before the DART impact, Dormorphos used to orbit every 12 hours around Didimos. And as a result of the DART impact in September of 2022, the Dormorphos now orbit. Dittimos every 11 and a half hours. So there was this 30-minute reduction in the time it takes Dormorphos to complete one orbit around Didimos. Well, tell me about these two asteroids, the asteroid and this moon.

What are they like? Dinnos and Dormos are what are called S-type asteroids. So they're rocky conglomerate asteroids. And Dormophos is around 160 meters in diameter, which is around the size of one and a half football fields. And Didimos is around 780 to 800 meters in diameter, so sort of the one and a half times the size of the CN towers. So, you know, there's this relative size difference between the two. And the reason why we targeted the secondary asteroid demorphose was this binary structure of the system as a whole. It was easier to hit the secondary and observe the changes in its orbit because it used to take only 12 hours.

So every day we would have two full orbits completed in the secondary asteroid, so more chances for us to observe what we did to it. Oh, I see. It's easier to see the orbit of the little one around the big one rather than the big one around, I guess, the sun. Exactly, yeah. So the big one, the whole system takes around 2.1 years to orbit once around the sun. So even to see one orbit would have taken us a couple of years instead of 12 hours.

Okay, so those are the early results that the, The orbit of the little moon was changed. Now, what were you looking for in your study? We were looking into what the entire system's orbit changes were around the sun. But like I mentioned before, since it took 2.1 years for the system to complete one orbit, it took us a couple of years after the impact to actually go ahead and observe what had happened. How did you study the orbit of the asteroid around the sun? Specifically, the two types of measurements we used were what are called radar range measurements,

and stellar occultation measurements. The radar range measurements specifically measure how far the asteroid is from the earth at any given moment when the observations happen. And those measurements are really powerful because even when the asteroid is millions of miles away, those measurements are able to pin down the position of the asteroid to around 10 to 15 meters. So that can help us figure out exactly how far it is. And the second type of measurement, the stellar occultation measurements, Those are measurements of the asteroid at the exact instant it's passing in front of a star. So from our point of view on the ground, when this happens, the amount of starlight we see dims temporarily because the asteroid is casting a shadow in front of it.

And in that exact moment, we know that the asteroid and the star have the same position. And because we can know the star's position is significantly better than asteroids because asteroids are moving in the sky, we can go ahead and assign the star's position to the asteroid and give us observations that are, you know, hundreds or thousands of times better than what we can usually get from the ground. So how did you do all of these stellar occultations where the asteroid passes in front of a star? I wasn't the one who personally went out and got these observations, but there was this massive collaboration to go ahead and notify observers in local areas where these occultations might be happening. So there were measurements from all over the world. I know there were occultations in Japan, in the States, in Australia. There's one occultation specifically, I think,

where someone drove two days each way into the Australian Outback just to get one of these measurements and send them to us. Wow. So when you put all this together, what did you find? What we were able to find is that the orbit of the entire system was slowed down by a tiny, tiny amount, just 11.7 microns per second. And like I said, it sounds extremely tiny, but the whole idea behind the kinetic impact is that you do a tiny shove early enough so that the shove has time to accumulate and change the orbits. Microns per second? A micron wants that a millionth of a meter? That's not much.

That's right, yeah, 12 of those microns per second. But what that accumulates to is around 360 meters every year. So then when we start doing the math by stacking time on that velocity change, that's when the real push. starts showing up. Okay. So how is it that the spacecraft hit the moon, but that changed the orbit of both bodies? Yeah. So as soon as the spacecraft impact happened, there was a bunch of material like rocks, pebbles, even boulders that were sitting happily on the surface of demorphos that were ejected

instantly as a result of this impact. And what happens when these kinetic impacts happen is this material that's ejected off of the target's asteroid surface acts as an additional jet plume. So as soon as the spacecraft comes in and hits the asteroid, we have an initial push from the spacecraft hitting the asteroid, and then

this material getting kicked off off the asteroid surface enhances the work done by the impactor. Ah, the stuff coming off acts like a rocket exhaust, action reaction. Exactly. Yeah, every action has to have a reaction, and that applies in space as well.

Wow. So the whole system lost mass and that caused that change of motion. Exactly. The whole system lost momentum and mass. So there was material that was ejected at a certain speed. And when that material escapes the system, that momentum has to be imparted back onto the system. So the sun's orbit used to take 2.1 years. Our measurements found that that time has now been reduced by a mere 150 milliseconds. But once again, like I said, these are tiny changes that have time to accumulate. Well, what does this mean, about the success of trying to deflect potential threats that are heading our way. Yeah, absolutely.

So the primary thing that it demonstrates and proves to us is that hitting the secondary asteroid in a sort of binary system is enough to effect change in the system's motion around the sun. And we have added to our capability of deflecting rocks away from the Earth, and we should be resting easier because we know how to push asteroids away from the sun and away from the Earth if we need to. and, you know, DART was, like you said, at the beginning, a smashing success. Now, what about the case if we have an asteroid coming towards us that does not have a moon going around it? Yeah, so the results from the DART impact that we found in our paper are directly translatable to individual asteroids as well.

We were able to measure something called the momentum enhancement parameter or the beta parameter. I won't go into too many technical details, but basically what this beta parameter does is characterize the total deflection on the asses. asteroid, you know, the initial spacecraft plus the rocket plume from the material that is ejected from it. And we were able to measure this beta parameter from DART, and that is directly usable for any sort of asteroid kinetic impact. Dr. Mukadilla, thank you so much for your time. Thanks for having me. Dr. Rahil Makadilla is a planetary defense scientist who conducted this research at the University

of Illinois Urbana-Champaign. And that's it for the best of quarks and quarks this. week? If you'd like to get in touch with us, our email is Quirx at cbc.ca.ca. Our web page is cbc.ca. slash Quarks, where you can check out our past episodes and find more information on the research we covered in the show. You can also follow our podcast, get us on SiriusXM, or download the CBC Listen app. It's free from the App Store or Google Play. Quarks and Quarks is produced by Rosie Fernandez, Amanda Bukowitz, and Scyxxx. Tonya Biting. Our senior producer is Hannah Hoag. I'm Bob McDonald. Thanks for listening.

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