The evolutionary price we pay for longer lives; the asteroid coming VERY close to Earth; how dinosaurs shaped the ecosystem

0:27This episode is brought to you by Google Chrome. The evolutionary price we pay for long life is an immune system that protects us most of the time, but then comes back with a vengeance. Heart disease, type 2 diabetes, kidney disease, but also mental health and ageing. Inflammaging, as it's known. Inflammaging. Inflammaging. An asteroid is going to pass by Earth very close, so close it will be visible to the naked eye. One of the astronomers said three times in a row, this will not hit Earth, this will not hit Earth, this will not hit Earth. dinosaurs were big and so they had a big physical impact on the earth.

1:00So when they disappeared there were quite dramatic and wide-ranging changes to the landscapes. This is the world, the universe and us. Welcome to the show. I'm Dr Penny Sarche. And I'm Dr Rowan Hooper. We live much longer than other primates. Why is that? And do we pay a price for it? Yeah, so this story is about inflammation and the ageing it causes and the idea that this is an unavoidable side effect of the longer lives that we get to live. We live into middle age and beyond. Okay, so let's just wind back about inflammation because that's when the immune system mistakenly attacks healthy tissue in our body, right?

1:37That's right. So there's inflammation happens if I've got a cold and my body has to fight off the cold. But what, you know, if I cut my finger and the body, you see a bit of red sore around the cart. Is that inflammation? Yeah, that's inflammation too. So inflammation is brilliant. It allows us to survive infection. So often if you've got a cold, many of the symptoms you experience aren't actually from the virus itself. You're actually experiencing your inflammatory symptoms. And that's what's killing off the virus. Likewise, like you say, if you get red and puffy somewhere because it's healing, that's inflammation.

2:09It's really good. What's not good is when it keeps going when we don't actually need it. And it just ticks along on this low alert level. And so it's not necessarily attacking your body in the way that autoimmune disorders are, but instead you've just got your whole immune system and body on this kind of slightly higher alert level than it needs to be. OK, so acute inflammation is when you've got this cut or something like that and it's fighting off a disease. But you're talking about chronic inflammation and that is something that we're hearing more and more about. And that is bad for all kinds of things.

2:41Yes. So chronic inflammation has been described as the scourge of the modern world or modern lifestyles. And like we say, it's when the body's defences against infection remain constantly activated at a low level. So you have things like cytokines, which are inflammatory proteins persisting in the body way longer than we actually need them. And that leads to this low-grade, constant chronic inflammation that's bad for us in all kinds of ways. OK. And so we know that this low-grade inflammation, that contributes to a whole range of things like heart disease, type 2 diabetes, kidney disease, but also mental health and ageing.

3:15Yes. We're uncovering increasingly strong links with all kinds of things, but chronic inflammation does really affect the brain. Things like Alzheimer's and schizophrenia, depression, anxiety, there are links there. And aging is the big one. And inflammation, as it's known. Inflammaging. Inflammaging. Very clever. Who coined that? I can't tell you. Okay. So we're going to get into that. But I want to ask you first, what are the reasons for this chronic inflammation? Is it, you know, modern life is rubbish? Is it the modern environment that's contributing to it? There's a lot of thought there. Yeah, potentially it's what we eat.

3:47It's our sedentary lifestyles. It's being overweight. All of these factors probably seem to be key. But the new study that we're talking about this week also looks at are there inherent properties within our immune system that also sort of set us up for chronic inflammation the older that we get? All right. So inflammation, this is the process where you get this chronic inflammation and it steadily starts sort of contributing to the deterioration of the body as we get older. That's a very downside of it. But the exciting side that we're turning to is that if we know that, then we can try to reduce inflammation.

4:22And that has the potential to make us age in a more graceful, healthful year. Yeah, extend our lifespans and also make us healthier as we're older. So that's really exciting. And there is also this question of why. Why is it that our immune defences, which are vital for survival, inevitably also contribute to our decline and deaths? And that's where this new finding comes in. OK, so what is the new finding? So this new research has revealed the role of a key kind of protein that primes our immune cells to destroy invading pathogens. But this kind of clever trick also keeps our immune cells on a hair trigger.

4:55And that places them at risk of needlessly destroying themselves and triggering unnecessary inflammation. And it all centres on these extremely metal sounding proteins that have been called death fold domains. When you said metal, I thought there'd be a metal in the protein. Not a quaternary structure. Yeah, yeah, yeah. That's the metal I mean. Death metal. What is going on with death metal, with a death fold domain? The death fold domain. Yeah, there we go. What is it? So when an immune cell, like a macrophage or a neutrophil, these are these cells that sort of gobble up bits of invading pathogens or even an entire virus.

5:31When they do that, death fold domains rapidly crystallize, so they come into this special kind of structure. And that causes the immune cell to then kill itself and release inflammatory proteins that then prime the wider immune system to fight this particular thing off. Randall Hoffman at the University of Kansas Cancer Center told our reporter Carissa Wong that these immune cells have only a tiny bit of information, so a molecule of viral DNA. Just a few minutes to decide what to do about it once they've detected it. And the decision that they make because of these proteins is often to kill themselves, destroy their own cell in a sort of altruistic suicide, as you put it, that then amplifies inflammatory signals and helps protect the body.

6:14Wow. So it is important, though, this way that cells can commit altruistic suicide, isn't it? But how does it go wrong? What is this amplified inflammation? So that amplified inflammation helps kind of pass on the message that something's invading. This is what it looks like. We need to crack down on it. But what Hoffman and his colleagues found when they study these proteins in the lab is that having a lot of these proteins in an immune cell, it primes them to make these rapid, important sort of decisions, as it were, about should they shut themselves down or not. But it also leaves them vulnerable to spontaneously do this, kill their own cells, even if no specific danger has happened, that these proteins can just suddenly crystallise of their own accord.

6:55Yeah, so that's not a good thing, a domino effect. And then you get this amplification of the inflammatory signals. And so that spirals out of control and you get this chronic inflammation. That's the thinking. It could be contributing to that. So in essence, we have this immune system that prevents us from dying many times over from all kinds of infections that would otherwise get us throughout the course of our lives. But ultimately, it could also be contributing to the diseases of ageing by misfiring. And potentially that might happen more as we get older. So this is the Darwinian bargain side of things.

7:27Yeah. It reminds me of a story I edited nearly a decade ago that found that people with higher levels of self-reactive antibodies, so that's kind of immune molecules that are supposed to detect invading pathogens, but instead are detecting bits of your own body. People who have more of those are less likely to die prematurely. but they're also more likely to suffer some really nasty autoimmune conditions. So again, you have this trade-off and this evolutionary link between having an immune system that's really effective at defending you, but also it does tend to put your body at risk of other things too.

8:01How, if at all, does senescent cells fit into this? Because we hear a lot about that. Yeah. And, you know, that's another link between ageing and inflammation, isn't it? And, you know, why don't these senescent cells just top themselves? Yeah. So senescent cells can be any kind of cell, not just immune cells. And what happens is with time and age, some cells get so much damage that they can no longer repair themselves and potentially not even program their own demise and enter into a zombie-like state instead. And what they do is they start emitting lots of inflammatory molecules. And the sort of purpose, as it were, of those is to sort of flag down immune cells to come and gobble them up and clear them out and take them away.

8:42But the problem is, is as we get older, our immune systems generally just get less good, less effective. So these cells aren't getting cleared out by the immune system and instead just keep releasing these bad inflammatory molecules, again, contributing to this chronic inflammation as we get older. And how can we stop it? Are there drugs that we've got that will dampen down this inflammation? Yeah, so there's loads of exciting angles here. Like, can we have senolytic drugs to destroy those senescent cells? Can we block immune cells from accidentally hitting the self-destruct button, as it were?

9:15But Andy Clark at the University of Birmingham, he pointed out to our reporter Carissa that developing drugs that stop cells from dying like this could also make people more susceptible to infections. And that trade-off might not be worth having. and also I think it's worth saying that anything that kind of dampens the immune response might also have the risk that your immune system becomes less good at recognising cells that have really gone awry like cancer and we don't want that either. Yes so double-edged swords. All right so there's a lot to figure out. In the meantime we do have some tips.

9:45This week actually New Scientist has a special issue how to live to 100. It's online now it's in the shops and I thought we'd ask Alison George and she edited that special feature on the main takeaways and how we can live longer. Ali, hello. Did you learn anything about all this and about things we can do to reduce this inflammation? Yes. And it's to do with our microbiome. Yay. Yay. We love the microbiome. So as we age, so does our gut microbiome. And what I mean by that is its composition changes. There tend to be fewer good bacteria, ones that are healthy for your body, and more bad ones that induce inflammation.

10:28This imbalance between the good and the bad is thought to be a key driver of inflammation. So one way to dial down inflammation and inflammation is to nurture your gut microbes. This is actually, I mean, shifting a whole ecosystem in your gut is not easy, but you can do this by eating a long-term high-fibre diet, eating lots of plants, eating the Mediterranean diet, There's some evidence that taking a prebiotic supplement, which is filled with loads of different plant materials, can help. And surprisingly, if you mix with younger people, you might pick up some of their youthful microbes, because we pick up a lot of our microbiome from the environment around us, which includes other people.

11:13And pets as well, isn't it? Oh, yes, yes. But I don't find that very good to think about too much. And there are some really more radical ideas, too, like faecal microbial transplants. our old favourite. But, you know, if you don't want to have to put someone else's faeces up your bum, what ways are there? What other ways are there that we can do this? Living to 100. Well, a lot of living to 100 is luck, having good genes and not having accidents. But lifestyle habits really do make a huge difference. They can literally add decades to your life and healthy decades. Exercise is one of the most important ones.

11:52So just by following the recommended weekly amounts of physical activity, which I think is something like 150 minutes of moderate intensity activity. This can reduce your risk of dying over the age of 40. The risk halves compared to someone who's very sedentary. But to really ace older age, you need to be going beyond that. And you need to focus on specific things like strength training, balance training, and flexibility training. and this will i mean this is just good for you in general but it also it will dampen inflammation as well cool i don't know if that's so surprising that exercise helps you live longer but one of the really surprising things to me was the impact of psychological factors on healthy aging one of them is a sense of purpose and that's something that gives your life direction or makes it feel meaningful and um this doesn't sound very scientific does it but a number of really good studies show that a strong sense of purpose really does keep you alive for longer don't really know why this might be but one explanation is that people who have more purpose just behave in healthier ways they're more active they sleep better and having good social connections makes a big difference to longevity too um have you read um man's search for meaning anyone victor Frankl oh my so about purpose he wrote it in Auschwitz I think he survived it and it's it's about how he got through it and it's about purpose it's the most incredible piece of writing yeah Viktor Frankl so I just thinking about it as you were talking about how a sense of purpose is so important and that and this book really crystallizes it time for a short break to talk about New Scientists Live Penny yes that's coming up in October it's the world's greatest festival of science here in london it's on october 18th the 20th at the excel center and it's streaming online um what are you looking forward to benny very much the live recording of this podcast of us yeah yeah looking forward to us of course doing our thing i'm looking forward to that i'm also i'm chatting with chris packham live on stage uh what a legend i'm really looking forward to that we're hearing about his favorite animals lots of cool stuff um i'm also looking forward to hearing from gut health expert megan rossi talking about prebiotics and all that kind of thing there's loads of other fascinating talks as well.

14:10Search New Scientist Live and get your tickets now. Penny, I've got a date for your diary. April 13th, 2029. I'm probably busy, I'm afraid, right? That's the day an asteroid is going to pass by Earth very close, just 31 ,600 kilometres above us. That does sound very close. It does sound close. And well, for the Moon, it's 384 ,000 kilometres above us. So this is really, really close. So close it would be visible to the naked eye. That is really close. How worried do we need to be? Is this the same asteroid that is coming in 2032? No, it's not that one. That's coming later. But that's not going to hit us.

14:50It might hit the moon. Is this new one going to hit us? This is another one. It's not going to hit us. But we might need to worry a little bit about it. Alex Wilkins is here to tell us about it. What I forgot to say was it's big as well. So if you put it next to the Eiffel Tower, it towers above that. And it's an even bit bigger than the Empire State Building. 450 metres long. So it's big. It's coming close. Alex, how worried should I be? I'm here to reassure you. Great. We don't need to worry. I've just been at a gathering of thousands of astronomers at the Europanet Science Congress in Helsinki.

15:24And the message there when they were talking about this asteroid is, we don't need to worry. This will not hit Earth. one of the astronomers said three times in a row, this will not hit Earth, this will not hit Earth, this will not hit Earth. Okay, sounds like wishful thinking. Okay, that's good to know. Although they have named it instead of like a number, this one's called Apophis, which is the Greek name of Apep, who in ancient Egypt was the uncreator, an evil serpent that tried to swallow the god of the sun. Not scary at all. Slightly, slightly scary. Yeah, and Apophis might not get us, but there are many other asteroids that might.

15:59The real trick with asteroid detecting and making sure they don't hit Earth is finding out exactly where to nudge it off course safely so that it won't impact us in future. Or blow it up and then all the pieces rain down and zoom in on all major cities in the US with camera crews ready. Yeah, that is one very bad outcome. We don't want that to happen. What you need to do, and we now have a new system for, is finding the perfect spot to basically crash on a spacecraft into it and send it off target oh yeah and so this is we we did this a while ago didn't we not we in this podcast but nasa did it did that thing where they they hit a deliberately went to hit an asteroid yeah so in 2023 nasa's double asteroid redirection test or dart for short showed for the first time that we can divert an asteroid by smashing a small probe into it and they did this on the two asteroid system dimorphos and didymos it posed no threat to earth but it was a really good test case and they showed that we could change the orbit of the smaller satellite by about 30 minutes as you say a maneuver like that isn't without risk we didn't know how that asteroid was going to react when we smashed into it it could have as you said shattered into pieces or gone really AWOL and shifting asteroid into new orbits does pose a lot of risks and there's something called a gravitational keyhole which are these tiny spots in space that if an asteroid passes through orbital mechanics and kind of gravity of large planets can almost boomerang the asteroid back after it's passed through this to then crash into a planet at a later date.

17:27That sounds really bad. Yeah it's not ideal at all and there was actually at one point a gravitational keyhole for Apophis back when it was detected in 2004. It had a kind of low percentage chance of going through and even if it missed us the first time maybe kind of boomerang back again. We now know that that gravitational keyhole won't be passed through but it could exist for other asteroids so rahil mccadia at the university of illinois um he was one of the presenters at the conference and him and his team have come up with this new method for basically finding the best spot to collide a satellite into an asteroid to really minimize the risk first of all you need lots and lots of data about the asteroid size its shape all sorts of things about its surface and its composition the more detailed the better really and sometimes you have to go and visit the asteroid for that sometimes you can get a kind of idea from earth and then you can make this probability map of an asteroid surface you can find all these points where some will be much more dangerous than others and once you do that you can then pick the lowest probability uh impact site while you were talking i was just thinking that christopher nolan is in the frame for the new bond film i probably won't do it but if he did the bond villain could be someone who hits this gravitational keyhole and knocks an asteroid into some, well, it'd be self-defeating because it would come to hit us.

18:46But that's a good Bond villain thing. What's to stop someone doing that? I mean, if you were a billionaire with lots of resources and you had a good understanding of orbital mechanics and you, I want to say, run a space company. And you wanted to destroy the world. And you wanted to destroy the world. I mean, this is sounding like a Bond villain. Or a Marvel villain. Then there's nothing really stopping you for doing that. Okay. But it raises a good point. Access to space is pretty much unregulated. And in fact, after the Apophis talk, a researcher or someone who worked for a space mining startup he stood up in the audience and he said we've worked out that we could have a chance to potentially go to Apophis before any of the major space agencies and kind of conduct a scouting mission and he asked one of the researchers do you think this would be a bad idea and the researcher was predictably a little bit horrified because this is a really good natural science experiment and we'll never really get a chance like this as long as we're alive probably for thousands of years and so this is a real kind of real problem was it from luxembourg the startup do you know it may have been yeah it's a real like hotbed of of space mining yeah yeah going on there is there a chance they could do that in time get up there so they said according to their calculations they might be able to intercept it before any major space company could wow what was the mood in the room when they said kind of shock And I heard astronomers afterwards in small groups kind of saying, can you believe that guy stood up?

20:08Yeah, can you believe it started? Yeah, exactly. Wow. What about the gravitational keyhole plan? Have they tested that at all? So they've tested it in theory for the asteroid Bennu, which we know quite well. We visited it and they identified more than 2000 possible keyholes. And they produced this map of locations where they could safely hit a spacecraft with it. But gathering the specific information for an asteroid, you really need detailed data. data you need to send a probe there you can do it with ground-based telescopes you can get an idea but it might not always be feasible especially if the asteroid was discovered close to a potential earth impact so there's like quite a lot of peril here because there's good keyholes where it's good to nudge it and then there's bad keyholes where it's like disastrous to nudge it and how do we learn more without testing it and do we really want to test it on something like Apophis, which might be a really good example for us to have a go, but equally it could turn what is a safe asteroid into a dangerous one.

21:04Yeah, well, I was also worried about that. We had a press conference in Helsinki and I asked that specific question and they said, we don't have to worry about that. It won't be going through any keyholes, any potential keyholes, and we're not planning to kind of crash a really large spacecraft into it. So we'll be okay in terms of Apophis. But because it's passing so close to Earth, and this is a kind of one in 7 ,000 year event we are scrambling space missions to go and visit it because it's a really rare opportunity to sample an asteroid like that up close do we know what kind it is because some are quite loose congregations of rubble aren't they which which could knock apart and some are more solid and we don't know that do we know anything about this asteroid i don't know specifically i mean i know with asteroids you really have to go and visit it and until you test it or even land something on the surface we can't know for sure exactly what the composition will be but if they accidentally crash a probe into it it could could deflect it into earth i also asked that question and they said that the mass would be too small and and yeah that there aren't there aren't any potential chances that they kind of said if there was any chance at all we wouldn't be going anywhere close to it so how are they planning to get close to it and find out more about it so there are two big missions planned um one is from nasa the osiris rex spacecraft which has already visited the asteroid benu um it's now been redirected to apophis and and the mission's been renamed to osiris apex from osiris rex um and also the european space agency have a mission called ramses um which will hopefully be able to view it as well that's also repurposed from from egypt aren't they these names yeah apparently um asteroids are named either after egyptian gods or greek gods depending on what classification of what orbit they're in uh and apophis is actually the greek name of the egyptian name for the god right and the reason it has kind of two names like this is because after it passes by Earth, it will turn into a different kind of orbit.

22:57So it would be named a Greek god, but because it's kind of in this different orbit as it comes up, it's got two different names. You need quite an in-depth knowledge of Greek and Egyptian to be an astronomer, it seems. So those missions then, OSIRIS and Ramses, do they have payloads on them already, little mini spacecraft that they could hopefully land on the asteroid? Yeah, they hope so. So the Ramsey's researchers hope to put these little CubeSats, these kind of kilo-sized satellites, and send them down. And they'll be able to get all of this key information like we were talking about before.

23:28So composition and shape. They'll also be able to measure things like seismic vibrations. There's been predictions that when asteroids pass really close to planets, that they'll kind of vibrate from the gravity of the planet. And Apophis is moving so close that they think there'll be these kind of minor asteroid quakes that they'll be able to measure on the surface. I can't wait for an asteroid viewing party when it comes close. You can see it closer than the moon. There will be billions of people watching it in 2029. Amazing. And I spoke to a astronaut Richard Binzel, who has been monitoring asteroids, researching asteroids for 50 years.

24:01And he was comparing Apophis to the Apollo missions in terms of space awareness, because so many people will be able to see this in the sky, talk about it, kind of look up and think what's out there. He also devised the Near Earth Object Hazard Index, which is this 1 to 10 scale. It's now called the Torino scale, which basically helps us categorise how much we should worry about an asteroid that's coming near Earth. And here he is on that. When you discover an asteroid that has a non-zero impact probability, however small, just be a little patient and we'll get enough data to make it go away. So in other words, if we discover an object like that, we don't want to keep it secret.

24:36That's the worst thing we could do, because then no one ever trusts you because they never know what you're not telling them. so we collectively decided that we needed to tell people what we know as soon as we can when we know it and then later when it goes away it's not that anyone made a mistake or made an error it's just that we now have better information to know it goes away and so that was the genesis of what was first called an earth object hazard index there happened to be a united nations conference on near-Earth asteroids and that's where it first presented the idea. And so you say he so it was this other index and then he he proposed they called it the Torino scale that got approved by NASA and this Torino scale gives us a way to assess the threat so you've got like what is it one is an asteroid that's got no chance of coming and 10 is it's gonna hit us and we're in deep trouble.

25:31Yeah exactly and we've never got above four on the scale so Apophis briefly was four back in 2004 when we first spotted it quickly went down to zero this asteroid 2024 yr4 which got everyone very scared at the beginning of this year i think that briefly went up to three maybe it pipped up to four but again it's gone back down to one or maybe zero so yeah it's very rare that something gets high up on this scale but in the future we are going to see many many many more asteroids compared to the ones we know about now we have the vira rubin telescope which is this enormous telescope, the largest camera ever put into a telescope, and it'll be scanning the night sky every day for years, kind of gathering all this data, and it will be discovering orders of magnitudes more asteroids.

26:14So there will be a lot more asteroids to categorise in future. But they won't necessarily be high up the Torino scale, we hope. We hope. I do not expect in my lifetime, or even our grandchildren's, or great-grandchildren's lifetime that we'll ever see an object reach the highest levels on the Torino scale, 8, 9, or 10, which is the levels for a certain impact. We may see things that, say, a few objects that get numbers like 4 or maybe 5 on the Torino scale, but never in the red zone. I don't expect we'll ever see that in anyone's current lifetime or even in our great grandchildren. It's just incredibly, incredibly rare.

26:57But if we do, we have a method for people to immediately know, should I pay attention or should I not? Okay, let's talk about the extinction of the dinosaurs. It's pretty familiar now, right? We've got the Chukchulub asteroid, the Yucatan Peninsula, potentially the Deccan traps. We've got the extinction event 66 million years ago. We lost all of the non-avian dinosaurs. We saw the beginning of the age of the mammals. But although that might seem very familiar to a lot of people now, there's a new angle on it this week. We love new angles. And Sam Wong is here to tell us about it. Sam, what did I miss there?

27:35Yeah, so the new thing that we haven't really thought much about before is something that it might seem kind of obvious in retrospect. Dinosaurs were big. And so they had a big physical impact on the Earth and the environment where they lived. So when they disappeared, there were quite dramatic and wide-ranging changes to the landscapes, like shifting rivers. I mean, let's give the paleontologists a pass on this because, well, they didn't die like a flick of a switch. It was a long, you know, hundreds of thousands of years this extinction took place, wasn't it? And of course, the Earth was massively disrupted at this time anyway, so it's quite hard to pick up.

28:09Yeah, and you're normally looking at fossils, you're looking in those age of rocks for the change in fossils rather than the change in the geology, perhaps. Yeah, so geologists have noticed some changes in rock formations before and after the dinosaurs died out. So in North America, you have the Hell Creek Formation, which stretches across Montana and the Dakotas from before the dinosaurs. Deathfold domain. Hell Creek Formation versus Deathfold domain. So there you've got this grey-green mudstone from the time of the dinosaurs. But in nearby parts of the US, you have the Fort Union formation from the Paleogene after the extinction.

28:49And that's got these colourful striped layers that contain a lot of lignite, which is a low-grade form of coal formed from plant matter. So these changes have been noticed before, and people have generally thought that they were due to the direct effect of the asteroid strike, so increased precipitation particularly. But Luke Weaver and his colleagues at the University of Michigan have looked at this again, and they're suggesting a different cause. They examined sites in the western US, like river floodplains, that display these sudden geological changes around the boundary of the extinction event.

29:24So these colourful layers, after the dinosaurs were extinct, they were thought to be deposit formed as water levels increased and created ponds. But this study found there was no evidence of a change in water levels at this time. Weaver and his colleagues think that actually some of the key sandstone layers after the extinction event are deposits from the inside of a big meander in a river. They're called point bar deposits rather than being pond deposits. And they're really thick because the rivers weren't transient. They'd become stable. Right. So what is that telling us about how things change sort of after we lost the dinosaurs?

30:01What's that got to do with the meander? Yeah, so they think this is down to the dinosaurs disappearing because when dinosaurs were around, they were knocking over vegetation and trampling things. They grazed on saplings. They prevented plants from establishing themselves. And that meant that rivers flooded regularly. They didn't meander around forests. And this created huge expanses of boggy land that turned into mudstone. But once the dinosaurs were gone, forests became more established. The roots of trees trapped and stabilised the sediment. So the rivers were corralled into these big meanders and that creates these point bar deposits that you see today.