Science Friday - Second Black Hole Image, Last Days Of The Dinosaurs, Rising COVID Cases. May 13, 2022, Part 1

Episode Date: May 13, 2022

As COVID Cases Rises, Effectiveness Of Vaccines Lessens In Kids As parts of the country continue to see waves of infection from the omicron variant of COVID-19, parents of children over age five have taken heart at the availability of vaccines—while parents of kids five and under have continued to wait for an approved dose. But even as the case numbers continue to climb, the vaccines are less effective against the more-virulent omicron variants—and, for some reason, dramatically less effective in kids. Koerth joins Ira to discuss the story, and why experts say it’s still worthwhile getting vaccinated even if the vaccines don’t have the dramatic performance seen at the beginning of the vaccination phase of the pandemic. They also talk about a bird flu outbreak troubling poultry farms around the world, the odd immune system of the sleepy lizard, and how scientists are trying to catch a whiff of the odors of ancient Egypt.   Meet The ‘Gentle Giant,’ Your Friendly Neighborhood Black Hole It wasn’t long ago that the idea of capturing an image of a black hole sounded like a joke, or an oxymoron. How do you take a picture of something so dense that it absorbs the very light around it? But three years ago, we got our first good look with help from the Event Horizon Telescope, which is actually multiple radio telescopes all linked together. That picture was a slightly blurry, red-and-orange doughnut—the best picture to date of the supermassive black hole at the center of a galaxy called Messier 87, which is called Messier 87* or M87*. (Black holes are given an asterisk after the name of their location). Today, it’s possible to buy jewelry and t-shirts with that picture, drink out of a M87*-adorned coffee cup, or just make it your phone background. Now that the first picture of a black hole is practically a pop culture meme, how do you one-up that? In the past weeks, the Event Horizon Telescope team alluded to a new ‘breakthrough’ hiding in the Milky Way. On Thursday, the team unveiled that breakthrough: the first image of our nearest black hole neighbor in the heart of our galaxy. Sagittarius A* is a “gentle giant,” says Feryal Ozel, a member of the global collaboration that created this image. It consumes far less of the gas swirling nearby than M87*, and is far fainter as a result. The Milky Way’s black hole also lacks the galaxy-spanning jets of M87* and, due to its smaller size, the gas around it moves so fast that it took years longer to capture a clear picture. Ira talks with Ozel about what it takes to obtain such a picture, and what it can tell us about the extreme, high-temperature physics of black holes throughout the universe.   What Was It Like To Witness The End Of The Dinosaurs? 66 million years ago, a massive asteroid hit what we know today as the Yucatán Peninsula of Mexico. Many people have a general idea of what happened next: The age of the dinosaurs was brought to a close, making room for mammals like us to thrive. But fewer people know what happened in the days, weeks, and years after impact. Increased research on fossils and geological remains from this time period have helped scientists paint a picture of this era. For large, non-avian dinosaurs like Triceratops and Tyrannosaurus rex, extinction was swift following the asteroid impact. But for creatures that were able to stay underwater and underground, their post-impact stories are more complicated. Joining Ira to discuss her book The Last Days of the Dinosaurs is Riley Black, science writer based in Salt Lake City, Utah.   Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flito. Later this hour, the first images of the black hole at the center of our Milky Way. But first, as parts of the country continue to see waves of infection from the Omicron variant of COVID-19, parents of children over the age of five have taken heart at the availability of vaccines, and parents of kids five and under have continued to wait for an approved dose. But even as the case numbers continue to climb in some areas, the vaccines seem to be less effective against the more virulent omercron variants and for some reason dramatically less effective in kids. Joining me now to talk about that and other stories from the week in science is Maggie Kerth, senior science writer at 538. Welcome back, Maggie.

Hi, thanks for having me. You're welcome. Now, I know that you have kids, so you're following this closely. Tell me more about the vaccine and kids. How ineffective is it? Well, so I was really excited about this like a lot of parents when it first came out because the original data was saying 90% efficacy against infection. So my kids have been vaccinated, but here is the thing. All of these vaccines have waned in efficacy over time for all of the age groups. But when you're talking about the Pfizer vaccine in kids 5 to 11, it has really gone down. In the last couple of months. There's been two different studies, one of them by the New York State Department of Health, and the other is by the CDC, and they found that the vaccine and little kids

fell to these extremely low efficacy rates against infection during the peak of the Omicron wave. So the CDC was finding 31% efficacy, and the New York study was just 12%. Wow. So how much of this is due to these new variants being more contagious? How much is due to something going on with kids immune systems? Well, it's most likely got something to do with the Omicron variant because we know that the efficacy against infection has fallen significantly for all age groups when it comes to the Omicron wave. But the experts I spoke with said that it's still worth getting little kids vaccinated, even if that efficacy against infection is really low. The short explanation for that is that there is evidence that suggests the vaccines are still effective against severe illness at rates

that are high enough to make it worth it, probably around 40 to 50 percent. It's hard to say exactly how effective because severe illness and kids is rare to begin with. But we do know from other research that the hospitalization rate for unvaccinated kids during the Omicron wave was twice that of vaccinated kids. Yeah. So that's that's the good news, though. The really cool thing, though, is that when I went to talk to researchers about this, I got a better understanding of what is sort of going on with waning efficacy, which I think is just absolutely fascinating. So scientists have known for a long time that viruses with longer incubation periods have more effective vaccines and vice versa. And that's likely because vaccines work in two different

ways. So first, they're producing these short-term antibodies. And then the second, they're helping your body produce memory cells that can create antibodies down the road the next time you run into the virus. And those short-term antibodies are what is fading quickly, right? Like, those don't last a real long time, and that's what we see as the waning efficacy after you get your first two shots, after you get your booster. But the memory cells are what is there for the long haul. The problem is that memory cells need time to work. So if a virus incubates in your body for a week or two before causing illness, that's long enough for those memory cells to produce antibodies and stop illness before it starts. So that's why you get close to 100%, 90% efficacy with things

like measles, mumps, rebella, because they have these long incubation periods. COVID is like a day or two incubation period, and it's not quite long enough for those memory cells to actually produce the antibodies to stop the infection. They still produce antibodies. They still produce antibodies. stop severe infection, but it's that incubation period that seems to be really making the difference. Wow, what a great lesson, Maggie. There won't be a test on this, but I learned something right there. Parents have younger kids under five.

Now, this is, I know they're concerned, and they're still waiting for any vaccine, right? Any word on when that might be. Right now, it sounds like June. Both Pfizer and Moderna expect to have their little, little kid, vaccines ready by then. Pfizer delayed theirs in February when they figured out that the two-dose regimen wasn't producing enough of an immune response. So they're planning to increase to three doses. And Moderna's trials have proven to not be very effective against infection, but again, it's probably more effective against severe illness. Yeah. Okay. Well, wait to see those come out. Let's move on to some other news.

I know there's a different epidemic going on, and this one is in birds. Tell us about that. We are in the midst of the worst bird flu outbreak in seven years. So this is just spreading everywhere. And it's infecting wild birds. It's infecting birds on farms. The virus has a near 100% mortality rate among infected birds. And it's just been spreading like crazy since the fall of 2021. And it's having an impact on agriculture. So already the U.S., more than 37 million chickens and turkeys, have been killed in an attempt to stop this thing from spreading on farms. Because these farmed birds, you know, they live in these giant barns with thousands of other animals. Once one of them gets sick, they're all going to get sick and die. And to keep it from spreading to other barns, they're killing them off and some kind of really horrific forms of mass chicken slaughter. You know, we're talking about suffocating foam in a whole barn or just shutting off the ventilation and letting all of the birds slowly overheat. Oh, my goodness.

But it's also, I know, it's kind of wild, but it's also meant that, you know, some of the birds that had better lifestyles that were free range have had to be moved indoors so that they can be kept away from wild birds and kept away from birds another part of the farm. So this is spreading so rapidly, the best way to keep it from killing these domestic birds or having to kill them yourself is to just not let them have any contact with other birds. So these chickens are basically going on lockdown. And in France, that became mandatory back in November. And the UK has even had to change its egg labels. So it doesn't say free range anymore. It says barn eggs. Oh, that's interesting.

So you can't market them as free range. Because people are looking for those kinds of birds, those kinds of eggs. Right. They can't really be free range right now. Well, you know, when you hear bird flu, one of the things that comes to mind is the possibility. It might jump to people with all those millions of birds. I mean, have we seen any sign of that yet? So there have been people who have caught this, but it's not been really severe illness.

It's only been in people who had lots of contact with the birds. So for instance, one of the people who caught it in the U.S. is an inmate at a prison who had been working as part of a work release program, culling some of these birds on chicken farms. Let's go on to something a little bit lighter. A story you point out about some cool rock formations on the seafloor. Yeah. Ocean rocks. They're awesome. So there is this remote conservation area in the northern Pacific where only 3% of the seafloor has been mapped. And scientists are working on this project using remotely operated submarines to explore down there. And they've been live streaming their discoveries on YouTube. And this last week, they stumbled across something really cool, which is these cracked rocks that end up looking like a paved brick road. Not yellow brick. No, not. I mean, kind of greenish gray brick from what I've seen in the video.

And definitely not the road to Atlantis. That was just a joke that one of the researchers made on the live stream. Oh, is that right? They were joking. Yeah. But this is rock that's called hyaloclastite. It's a glassy volcanic rock and it's produced when lava comes into contact with water or ice and just cools really rapidly. And this formation then has been fractured over the years as this other nearby volcanic activity heated it and cooled it over and over again.

So you get like all of these really interesting crack patterns going one way and the other. And that's what makes it end up looking like bricks. Really interesting. Speaking of interesting geology, there's word that scientists have been experimenting with samples of lunar regolith or what we might call lunar dust, soil. What's going on there? So NASA-funded scientists grew plants in lunar soil. And this plant in question is a relative of mustard and broccoli, and it's really, really teeny. So we're talking about something that is small enough that it could grow in only a gram of regolith per plant.

But these scientists grew these seeds. They put the seeds in there with water and nutrient solution. And they had these little teeny, tiny vials. and part of why it's so small, and why we had to do something so small is we just don't have that much regolith on Earth at present. The stuff these plants were growing in literally came from the Apollo 11, 12, and 17 missions.

Huh. You know, my definition of soil is it has to have organic matter in it, certainly lunar regalith doesn't. So were the plants stunted? I mean, they didn't grow as much as they would here on regular soil, would they? No, they did not. So they were compared to plants grown in some boring old Taron volcanic ash, and they did not do as well as the ash-grown plants. So they grew more slowly. They had less well-developed roots. Some of them even had these little funky, reddish, stunted leaves. So the good news here is that, yes, you can grow plants in moonsoil. And the bad news is that they are not going to be as good of plants as what you get on Earth. And we don't really know why yet. So this is just a first step to further

research and it's stuff that we need to figure out if we were really serious about building new and permanent moon bases. Speaking of moon bases and the astronauts that might go to them, if you, if you talk to astronauts, they'll tell you that things can get kind of stinky and their enclosed capsules after a while. But you point out... This is a great transition. I'm working hard at it, but you point out a story about researchers trying to recreate the smells of ancient Egypt. What's that about? Yeah. So I love this. Bruce Bauer at Science News has this story about a variety of different ways that scientists are trying to get a better understanding of the smells of the ancient world. And it's being done in several different ways by different teams. So some people are sampling molecules of organic material off of physical artifacts and analyzing the chemistry of that to kind of figure out what these molecules came from. And they're finding things like Frank. rinkinsence and myr left behind on incense burners. They're finding things like dried fish and barley flour in ancient jars at the molecular level. And so we can kind of know, like, these are smells

that existed thousands of years ago. Another team has even tried to recreate Cleopatra's perfume. Are we going to see that on the market by Christmas, do you think? I don't know. It's supposed to smell really nice, something kind of spicy, sweet, date oil, mer, cinnamon, and pine resin. let's end on that sweet-smelling note today. Thank you for taking time to be with us today. Absolutely. Thank you. Maggie Kerth, senior science writer at 538 based in Minneapolis. We're going to take a break, and when we come back, we're going to talk about taking a picture of the black hole at the center of our galaxy. What is it telling astronomers? Stay with us.

This is Science Friday. I am Ira Flato. It's been three years since the first ever picture of a black hole shook the science world, a giant found in a galaxy called M87 more than 8 billion times the mass of the sun. But hold on, because the world of astrophysics is again a buzz this week, with our first glimpse of the black hole at the center of our own galaxy, the Milky Way. Yes, this time, it's personal, with a stunning donut-shaped image of what is called Sagittarius A-star. If you look at the constellation Sagittarius, you won't exactly see. see it, but you'll know it's there. And here to share her excitement with us is Dr. Feriel Ozil,

Professor of Physics at the University of Arizona, and a member of the Event Horizon Telescope team. Hi, Ira. So nice to be here. Nice to have you. Now, tell us why you and your colleagues are so excited to get an image of the black hole at the center of our galaxy. I mean, last time we talked to you, what, it was about three years ago. It was about that first black hole picture of, M87. So why is this so different? It's true. We talked about M87 first, and that was a few years back, and obviously we've been hard at work at imaging Sagittarius A Star in the meantime. Well, there are two answers to this, really. One is the emotional one, which is it's our black hole. It's the one in the center of our galaxy, the Milky Way. So getting to meet it is,

super exciting. But the second reason why we're excited is that it is also a donut. And you might say, well, isn't that boring? But no, actually, the fact that two very different black holes, the one in M87 and the one in the Milky Way, different in mass, different in activity, different in many different ways, have the same features of the image when we get all the way, near the horizon of the black hole and capture that point of no return, the fact that they look similar is extremely exciting. And Fariel, I'm looking at this brand new image, and I'm seeing the same, as you say, bright donut we saw for the last black hole picture around a dark shadow in the middle,

the black part. But there are three kinds of extra bright blobs around the rings. Like if you think of a clock, it's like 1 o'clock, 5 o'clock, 9 o'clock. Does that sound right? And why are these bright areas there? When we look at environments of black holes and we write codes in order to model the physics around it on supercomputers, these types of features do appear in our simulations. They could be, for example, a magnetically enhanced region that looks brighter, or it could be some other thing in the turbulence that is made.

making a particular spot look brighter than another spot, just like how clouds form, for example, in the sky. Sometimes it's in one place, sometimes it's in the other. However, having said that, the particular features that we see in our image are probably artifacts of the missing information and how we fill them in. And in particular, these brighter spots in the image tend to line up with the directions of where we have. have the most telescopes. So even though it's natural to expect these from a theoretical point of view, we are not confident that that's what we are seeing in these pictures. Let's talk about what we are actually seeing. We see this bright image of this bright orangey donut, but we're not seeing visible light here, are we? That's not how the image was collected. It's not a light telescope that collected, but a whole network of radio telescopes. That's correct, Ira. The types of

of black holes that we're looking in the vicinity of the earth, our black hole, Sagittarius A-star, as well as the one in M-87, they emit most of their light in the radio wavelengths and also some light in the x-rays. They are actually pretty dim, even dimmer than in the radio in the optical wavelengths that our eyes are sensitive to. So for the event horizon telescope targets, we we observe at 230 gigahertz. That's still a radio frequency. It's higher than, for example, what we use for our cell phones, but it is a radio frequency,

and we collect it with radio telescopes that are sensitive to that frequency, and then we combine the information that we get from, in the case of Sagittarius A star today, eight telescopes around the world, looking at the source all at the same time in order to synthesize this image. Tell us why there is a black hole at the center of our galaxy, and is that probably the norm for a lot of galaxies?

That is a great question. That seems to be the norm for pretty much every galaxy that we look at, anything that is at least sizable, like the Milky Way, like M87. They seem to be a key feature of how early star formation and galaxy formation leads to the form. of these massive giants that then settle to the center of those galaxies and interact with it throughout its life. I mean, throughout cosmic history, pretty early on, Black Hole seeds seem to form. And then depending on how much gases available in their surroundings, either go through periods where they are growing fast and look like quasars, or go through periods where they're pretty quiescent, like eating very little like Sagittarius A-star is. So it seems to be this

dynamic give and take between the galaxy and its supermassive black hole in the center. That's a great way of describing it. And in terms of describing this black hole, does it confirm theories we have about black holes or does it upset our ideas about black holes? It does some of both. In terms of the gravity around black holes described by Einstein's theory of general relativity, which we keep on trying to crack, we think it can't be the complete theory, it needs to give in someplace, we're still finding that it fits, our predictions fit our observations perfectly, or vice versa, our observations confirm the predictions when it comes to the, gravitational effects. But black hole you might think of is being made up of two parts. It's gravity and then this plasma around it that is swirling around it. And that also has its own challenges and outstanding physics and astrophysical questions. And when it comes to those aspects of black hole environments, these extreme conditions, we found that our

Our theories do well in predicting some of the gross features, but they predict too much variability. If you think of ocean waves, for example, they have a frequency that's set by the gravity of the Earth, and then there's an amplitude. It can be one-foot waves or 30-foot waves. And our simulations in the environment of Sagittarius A-star were telling us that, that things should be moving fast and they should look more like 30-foot waves. And what we're finding is that the time scale is correct. They are moving fast. But it's more like two-foot waves. So we're probably missing that physics. Now when you look at this picture or now that we've got this

picture, does it tell us whether the black hole is spinning or not? That's a great question. We're getting the first hints that it might be. And we're getting that from a couple different things. One is when we perform this test of general relativity by comparing the mass and the predicted size of the horizon that we get from stars orbiting around our galactic center to the image that we get from the event horizon telescope. The only real uncertainty there is the spin of the black hole. It has a small effect on the size of the shadow. And what we're finding is that models where the black hole is spinning are in better agreement than the models where the black hole is not spinning in terms just of the shadow size. It is a very small effect.

So I would not claim any sort of confidence in this result. But it's just a hint that, you know, they're in better agreement when the black hole is spinning. Speaking of comparing black holes, I mean, one of the images we saw from the old M87 image was that it had a jet, right, tweaking out of it. But this one does not have a jet. It doesn't appear to have one, as they said in the news conference. Why would M87 have that? and this one not have that jet? That's a hard question.

Something about how magnetic fields organize in the flow around the black hole must be responsible for launching powerful jets in some cases, like M87. We have tried to get hints of whether there might be a jet, even a small one hiding somewhere, and we haven't detected one to date. So from that point of view, M87 and Sagittarius A-Star as, are as different as black holes get. We don't know exactly what launches these jets, but one of our excitement today in sharing the picture of Sajj Starr

was that the donut is there at the heart, even when on large scales, two black holes could behave very differently. The Event Horizon Telescope was gathering this data at the same time as it was looking at that first black hole, but why did it take then? three years longer to create this image? This took longer for a couple of reasons. One is COVID.

I mean, it just slowed things down a little bit. The second reason is that Sajai Star actually turned out to be a more challenging environment. We are looking through the disk of our galaxy, through the gas clouds in that disk, the arms of the galaxy towards our galactic center. And that scatters the light that we obtain in our telescopes. I mean, it scatters the light that the source emits on its way to our telescopes. So there are some corrections that we need there. And also because it's a smaller mass black hole, you're going to say,

how could a 4 million solar mass object be small? But M87 is 6 billion solar masses. So things happen more slowly around M87 compared to Sajjah Star. The material close to the horizon can go around it in a matter of minutes. So our techniques needed to be improved and we needed to understand the additional blurring that that motion causes and really perform extra tests, both because of the scattering in the galaxy and because of the motion of the motion of the gas around. around the black hole to make sure that there are robust features like that donut that we trust. This is Science Friday from WNYC Studios.

In case you're just joining us, we're talking to astrophysicist Ferial Ozil about the stunning new picture of our very own black hole at the center of our Milky Way. And there was a sonification turning the image the E.HT collected into sound. I want to play a selection of that and have you tell us what we're hearing. It almost sounds like waves. It does, doesn't it? Waves, whether they are sound waves or waves or waves of light that our telescopes are sensitive to have quite similar properties. So we are able to get some of this, the properties of the image, as we see.

it in waves changing over time and turn it into amplitude of sound waves. And hopefully in the future, when we observe in different frequencies, maybe we will even be able to combine different frequencies of sound to really get a fuller picture of what we hear in that environment if we could hear it. You know, this announcement makes me think of the LIGO discoveries of merging black holes and gravitational waves when we had that first announcement. It was much anticipated. Then we had a second one where we weren't sure what to expect, but it kind of helped verify the first. And now we get results fairly often, but we don't talk about them anymore. They're not unique. Do you think that's what, that's going to happen with the event horizon telescope?

We'll be just taking pictures of black holes left and right. And, you know, it'll be common occurrence. I hope so. I mean, the fact that LIGO releases its new data sets and, of course, scientists talk about it, but, you know, we don't talk about it as broadly as we're talking about their first two announcements or the Event Horizon Telescope announcements means that they've really transformed into an astrophysical observatory where we're, you know, we're doing our daily things. oh yes there is another source what is its mass what are its properties so one can only hope that with future observations and with all the algorithms we now have in the bank that we're going to be able to do these observations more frequently maybe maybe the first movie is going to be if we ever get that and the sources behave in the way that that we hope maybe that's going to to be big news, but other than that, we would love to just churn out results that people are like, okay, okay, thank you, another one. You know, you say you've been studying black holes for 20 years.

When you look up now at the Milky Way in a clear summer's night, now that you've seen our black hole at the center of the Milky Way, is it going to make you feel a little bit different? I think it will. You know, being part of that gallery, and being able to see it when the sky is clear is already a wonderful feeling. But now we're like, you know what? There is a black hole that is 26,000 light years away from us, and we took a picture of it, and I know where you are. I hope that our listeners too can feel that when they look up at the night sky. I hope they will too. And I want to thank you. And congratulations to you on the announcement, and to all of your colleagues and people who helped out, I know there were a lot of

them. Thank you. Indeed. I just want to emphasize again, I was blessed to be the person sharing it, but it is a large team, a huge effort over a long period of time, and we really value everybody's contributions. So thank you. Dr. Ferial-Ozell, Professor of Astronomy and Physics at the University of Arizona and member of the Event Horizon Telescope Science Council. And if you somehow haven't seen the picture of Sagittarius A-Star yet, you're in luck. Head to our website, ScienceFriday.com slash Milky Way to see the new picture and take a listen to the sound of two black holes colliding while you're there. That's sciencefriiday.com slash Milky Way.

We have to take a break. And when we come back, we'll go back in time to the last days of the dinosaurs and we'll learn how their loss was our game. Stay with us. This is Science Friday. I'm Ira Flito. For the rest of the hour, we're going back in time, way back, to explore what happened on Earth after that massive asteroid wiped out the dinosaurs. A new book traces what happened from the immediate aftermath to thousands of years later. The world changed literally overnight, if not faster. As for who human, says the author, We wouldn't exist without the obliterating smack of cosmic rock that plowed itself into the ancient Yucatan. Wouldn't you like to know more I would?

Joining me is Riley Black, author of The Last Days of the Dinosaur based in Salt Lake City, Utah. Welcome back to the show. Thank you so much for having me back on. You're quite welcome. You know, I know you have written several books, many about dinosaurs. Why did you want to focus on the last days of the dinosaur in this book? Yeah, I realized that I hadn't really done justice to the story to borrow that Seinfeld line. I kind of yada yada this extinction, right?

Because a big rock strikes the planet. We assume that it's going to cause a mass extinction somehow. But there have been other impacts at other times. I had nothing to do with any major extinction event. So this seemed different. And I realized I didn't know as much about it as I probably should. And the more that I started to research on this, and I mean, paleontologies might beat, I write stories about some of these new discoveries.

I realized that I had the story kind of not entirely wrong, but I didn't understand how much we had learned about it. Well, let's begin where you just left off there. You say in your book that there have been other impacts of similar or greater scale that did not trigger biological disasters. So what was it about this impact that did? Yeah, that's a really strange thing because it's not as if this asteroid or whatever this body of rock was.

We're pretty sure it was some kind of asteroid, a carbonaceous kind of. I think is the best working hypothesis right now. It wasn't just hanging out near Earth and decided to stop in. It had been traveling towards our planet for a very, very long time. And this was kind of like a galactic skill shot, in a sense. Like, you know, it could have just as easily missed or come closer, hit somewhere else on the planet. But the fact that it hit at an incredible amount of speed that was so very big,

and it hit all this limestone. So basically these ancient fossil deposits, the ancient remnants of reefs that had existed millions of years before the impact itself that contained all these chemical compounds that contributed to the impact winter. So when you put all these things together, the size and the speed, the angle at which it hit, the sheer force of it, all these things came together. And basically the worst case scenario that nothing quite like this has ever happened before in Earth's history and certainly not at such sort of a vulnerable moment for life on Earth. And all these things came together, not just in the first 24 hours, we had this incredible heat pulse and all this

debris, but in the years following. So it really was every single way that this could have gone wrong for life on Earth, just about that's how this played out. It's really spectacular, how quick and violent this was. Yeah. So it was the perfect asteroid storm, you're saying, is what it is. Oh, absolutely. Yeah. Let's talk about the sequence of events, and that's what you do in the book. You go through the first days, months, years, eons, thousands, million years. Let's look at the timeline on this. You're right that this calamity was as immediate and horrific as a bullet wound. Explain that.

Yeah, so when we think about this mass extinction, or at least a lot of the visuals that I get or got growing up about this mass extinction, you'd see these emaciated dinosaurs wandering through this like nuclear winter kind of scenario that they made it through the first day, but it was really the debris clouds and the cessation of photosynthesis and all these big environmental changes. but we now know that they probably didn't even make it that far, that basically all our favorite non-avian dinosaurs, T-Rex and Triceratops and Demosaurus and all those, were probably gone within about the first 24 hours

because what happened in the minutes to hours following this impact, you had all this pulverized rock, so millions of cubic miles of rock that's been thrown up into the atmosphere, that start to spread, basically that start to spread all over the planet. And as they're coming down, each one, each little piece, is creating a significant amount of friction by itself. Any one of those isn't very much, but you do enough of that. It's just so much debris and so much basically damage created by this impact that all that friction creates an infrared pulse.

It raises the air temperature all around the planet to about 500 degrees Fahrenheit. So if you ever broiled a chicken, that's about what you broil a chicken at. And T-Rex was more or less a broiled chicken within about 24 hours of this impact, that it, If you couldn't get underground, if you couldn't get underwater in somewhere, had some other way to block yourself from this pulse. Wow. You're basically out in the open. It was so hot that some forests were spontaneously catching fire based upon some of these models

that geologists and paleontologists put together. So it really was incredibly extreme. And then we had a cold period. That's right. About three years of impact winter. So you had this terrible heat pulse that did most of the major initial damage. But in the years that followed, you not only had the sun. from forest fires all of the planet.

You not only had all the dust and debris thrown up by the impact itself, but all these sulfur-based compounds that we know from observations during our own history are really good at reflecting back sunlight. So it's estimated that the sunlight reaching the earth was reduced by at least about 20%.

And that was enough to curtail, if not stop photosynthesis, over much of the planet. And if you take out plants, it's the basis of our ecosystem, is the basis of our oceans, it's the basis of how we got our oxygen, it's something over those three years that not only temperatures dropped, but ecosystems almost entirely

collapsed, and those survivors during those three years had to get by on scraps. There was one factor that made this extinction not as bad as it could be, you write, and that's a very unlikely source. I'm talking about volcanoes. Can you explain this? Yeah, so in the past, we've had at least five mass extinctions so far. We may be entering a six, but most of those. or at least a significant number of them prior to this asteroid impact at the end of the Cretaceous were caused by volcanic activity.

And in particular, prior to the asteroid impact and after the asteroid impact 66 million years ago, it had incredible outpourings in what's called the Deccan traps in what's now India, just thousands of miles just covered by molten rock and all the greenhouse gases that are being spewed into the atmosphere as part of it. And those greenhouse gases, in fact, counteracted. the effects of impact winter. This is not what we think of when we think of volcanic eruptions like this. We often think about them in terms of causing extinctions, but in this case, it kept the impact winter for being as bad as it otherwise could have been at raised temperatures, just

enough to allow some forms of life to be able to survive when otherwise they would have gone extinct in the chill of that impact winter. So even though those volcanic eruptions were previously considered to be a contender for this extinction, it turns out that they kind of mitigated the effects of the asteroid impact and kind of came to the rescue for at least some forms of life. Yeah, that is really something new that we haven't heard before because we've heard of research that says the dinosaurs were already weakened by natural forces and possibly volcanoes. They were on their way out. And the asteroid just provided that final push.

But are you saying that's not true? That's right. It seems to be the opposite case, that volcanic eruptions actually assisted some of these surviving animals. Most of the non-avian dinosaurs, if not all of them, were already gone by time, you know, this counteracting force would have come into play. But that's the other part of this, is that so much of what we understand about this extinction comes from Western North America. It comes from the Hell Creek Formation, the overlying rock layers in Montana and the Dakotas. There's so much that we don't know.

So the decline that paleontologists previously thought they saw is because there are fewer rocks from the relevant time period. So just as an absolute level, we have less dinosaur diversity because there aren't as many rocks. rocks from the very end of the Cotaceous that actually preserved them as compared to 10 million years before. So we're really learning in a sense how much we didn't previously know about this mass extinction and how it played out. And how long did it take for plant life to come back? Yeah, there's a seed bank or there was a seed bank in the soil. So a lot of plants, you know, they spread their seeds. They spread nuts. They spread their fruits as far as they possibly can. And some of those already existed in the soil and would have been shielded by some of the heat effects.

it really only takes about a couple of inches of soil to really shield what's in the soil from the effects of things like forest fires. We know from modern-day forest fires that get about as hot as that infrared pulse. It doesn't take all that much. So that sea layer was there. It actually allowed beaked birds to survive. That's why we have dinosaurs around us now is because beaked birds are able to subsist on the seeds and nuts that still existed.

But it took at least about 100,000 years before. before you started to see vegetation make a real recovery. You have what's called us a fern spike where we see fossil ferns in their spores everywhere in the fossil record around this time. And that's because ferns are what we call disaster taxa. They're really good at coming into spaces that have been disturbed, that have been disrupted. And they're kind of the first initial signs that life is beginning to recover. And then by about a million years after impact, that's when you start to have these thick, dense forests starting to grow up, that you have the rise of flower plants and angiosperms rather than conifers. So it took about a million years before anything

recognizable as a forest started to reestablish itself. Very interesting. And one of the interesting topics you talk about in the book is the evolution of the bird life following the impact. In fact, I found it fascinating to learn that it was the evolution of a beak and not the teeth of the dinosaur birds. That's right. That allowed these birds to survive. What What's there about a beak that nature likes? Yeah, we've had beaks of all multiple times, you know, over and over again. And the case of dinosaurs, why beaked birds were able to survive, if you think about what birds and bird-like dinosaurs were doing prior to the impact, you had basically

things like Velociraptor covered in feathers, you know, very sharp teeth. We had toothed birds that were able to eat insects and the lizards and things like that. And then you had beaked birds that primarily ate seeds, nuts. plant material, they're already adapted to this kind of diet. They probably already had things like a gizzard or ways to grind up that plant food. So they, in a sense, were pre-adapted to life after impact, whereas all those carnivorous species, there's nothing for them to eat because there are no more plants, therefore no more insects. There are very few small little critters for them to eat. So basically, if you were a carnivore trying to survive through this impact

winter is much, much more difficult, whereas beaked birds, they were already adapted to eating things that had survived, and that's why they're able to hang on. Interesting. So what else was different about plant than animal life post-impact? You see forests grow a lot denser. If you think about forests and habitats in the age of the dinosaurs, basically in those and Cretaceous heyday, it would have looked somewhat similar to areas in like Eastern Africa today, so more conifers, than flowering plants, there's certainly no grasses, but that kind of open, habitat, and open woodland, because many dinosaurs were big. Where they walked, where they pushed over trees, where they fed, this all influenced the ecosystem,

it shaped it around them. So you're going to have dinosaur-sized holes, basically through any ecology that you're looking at. But once they were gone, once you don't have things like Triceratops mowing down vegetation or pushing over trees anymore, forests could grow a lot denser. They could grow a lot closer together, and they could grow tall. And that provided a multi-tiered ecosystem for their survivors, whether you were a bird or a mammal or an insect. Life could be different at the canopy than on the trunk of the tree than at the surface of the soil or down below that soil. So it had all these different new opportunities for evolution and pioneering new niches open up.

Right. This is Science Friday from WNYC Studios. Talking to Riley Black, author of The Last Days of the Dinosaurs. Really interesting. As I said in the opening, I read a portion of your book where you said, we, meaning humans, we wouldn't exist without the obliterating smack of cosmic rock. Why is that? There's no reason to think that the age of dinosaurs would have stopped without this.

I mean, in a sense, we still are because we're still here, but the kind of dinosaurs that we think about and see in the movies all the time. They would still be here. If you think about 66 million years, there's a very long time. But if you were to start from the day before impact, so, you know, T-Rex and Tricerotops are still doing fine, project that backwards, 66 million years further into the Cretaceous. Dinosaurs are still around. They're doing fine.

Like, basically, there are more time, there's more time between Stegosaurus and T-Rex than there's been since T-Rex went extinct. So dinosaurs were the dominant vertebrates on land. They're the most prominent vertebrates on land for so very long. And they'd survive so many different changes between the continents moving around, volcanic eruptions, climate changes, sea level changes, they would have made it through. It took something really unexpected and unprecedented to really change up life and what it was. And our ancestors could have very well gone extinct in this very same extinction. It's one of the things that blows my mind, honestly, is that there were primates around during the last day of the Cretaceous.

This little animal called Purgatorius is the earliest known primate. And it was able to survive where the big and terrible dinosaurs weren't. So it's not just that we evolved as a result of this extinction, but our ancestors, our primate ancestors, actually eat right through it. That is cool. Are there other things we can see now that are direct remains of this extinction? You can look almost anywhere, basically, whether it's seeing all the flowering plants and they're pollinators. That that's something that those interactions and those kinds of plants were around before impact, but they're much more prominent now. Or things like beans. I loved a good taco.

I like to put refried beans on it sometimes. Beans only came about because legumes evolved about a million years after impact that plant life got this reinvigorated kind of evolutionary pulse after the impact. And basically plants like legumes that are rich in protein are part of that as well. So whether it's just our own existence or what we eat or the sort of vegetation we see around us, there are so many little hallmarks that we can draw back. to this mass extinction. Who knew how important beings were? As you say, rarely, you've written a lot about dinosaurs

and written many books. What surprised you the most about writing this book in your research? I felt like so much of it was a surprise because I had so many assumptions going into it. I think what really struck me was how the way the world recovered after impact, how relatively quick that was.

I mean, a million years has a long time, but to think that prior to the mass extinction, the largest mammals that we know about were about the size of a house cat. And then a million years later, the largest mammals that we know about were about the size of a German shepherd, and that's quite a bit bigger.

And we're starting to understand so much of how and why they evolved. In the pattern of their evolution, there was a paper that just came out. I wish I could have included it in the book, but it's still fascinating to me about how mammals were getting big so quickly that their brains pretty much remained

at the same size as they had been post-impact, so that you have much bigger-bodied mammals, but their brains are about the same size. And it wasn't until about another 10 million years or so after that, after impact, that you start to see a lot more sort of changes to the prefrontal cortex and changes in behaviors and interactions and things like that. So that life really raced to fill in the voids that were left by this mass extinction in such a way that it was a really formative and interesting time for evolution in general. Like it wasn't a sense of progress or mammals picking up the torch where dinosaurs had left it.

But something entirely new happening and seeing and understanding some of these interactions that we never got to view before. So much of this research has come out in the past five or ten years. You know, even the last year we've made a lot of new discoveries. So this is rapidly changing and giving us this view, this timeline that we never really had before. Time for a new book, Riley. We'll have you back on that next one. Thank you for taking time to be with us today. Oh, it's always a pleasure. Thank you so much.

Riley Black author of The Last Days of the Dinosaurs. And coincidentally, this month, the SciFri Book Club is reading the Last Days of the Dinosaurs. You can find out how you can become a member and read along with us at ScienceFriiday.com slash book club. That's ScienceFriiday.com slash book club. Here's Shoshana Bucksbaum with some of the folks who helped make this show possible. Thanks, Ira. Kyle Marion Viterbo is our engagement producer. Danielle Dana is our executive director, and I'm Shoshana Buxbaum, radio producer.

Thank you, Shoshana. BJ Leidman composed our theme music. Have a great weekend. I'm Ira Flato.