Asteroid impact and hydrothermal systems

This BBC podcast is supported by ads outside the UK Summer smells like citrus in the sun. Turn your home into a daily getaway with Pura's new summer collection. Find your flow and fragrance and explore the scents at pura. com Close your eyes. Summer smells like sunshine, fresh citrus and salty air. What if your living room could feel just like that? With Pura's new summer collllection, it can restestore your sense of wellbe with fragrances designed to move with your day. Fr bright energizing mornings to soft, relaxing evenings, makeake the invisible unforgettable this season Visit pure. com to find your new favorite summer scent Hello, I'm Tom Whipple and welcome to Inside Science from the BBC World Service. It turns out there is an invisible network of life right below our feet And it's so important it has its own society to protect it. Roland Pes will tell us about these fun guys Later Well I look instead at what's going on above our heads. If you're a structal engineer and your client is God How do you build an impossible tower And is it ever right to deliberately make One of God's creatures extinct that and incredibly we will also find time to squeeze in journalism god Caroline Steele, who has been scouring the scientific literature for the best new studies out this week. Caroline tee us up. Well it's been a really interesting week. I've been through everything from new research into endometriosis to the origin of stonehenge' stones, but coming out on top It Is news about the asteroid that wiped out dinosaurs. Excellent. We are for nothing if not making you listeners worried. But let's make you elevated first of all Well over a century ago, a young and unknown architect called Antony Gauddi was given a commission build a new church for Barcelona. The Sagrada familiar. It spires, gnarled and noobbled like the trees of an ancient forest. would be taller than any other Its style at a time on the cusp of modernism, would go its own way Construction continued through World War and Civil War Galdi was happy to take his time to get it right His client, he always said G God was not in a hurry But some of the details he had to leave to God. and future architects including the most important detail of all The technology did not exist build all of those towers. Now though, the tallest tower is finally finished. But how was it built Over a decade ago, Tristram Carfrey, structural engineer and designer at Ap receive the sort of commission that structural engineers at AP don't expect to receive He was asked to help complete Guddi's vision to solve the problem of one particular unbuildable tower. Anntony Gaddi was not actually the first architect for Sagrada famamiliar. There was a man by the name of Villar, who was first appointed, who designed a relatively modest classically gotothic church church was under construction when Villar resigned from the project. and they appointed Antony Guddy instead, who designed a much, much bigger church on the same footprint. But one of the big towers, the Mary Tower, sits vertically above the crypt that was built for Villars's Church, which didn't have foundations sufficient to support this massive tower So they thought the resolution, the solution would be to build a steel frame and then clad it with something that would look like stone. quite sure what that would be So that was their main problem. and they came to us saying, canan we design a lightweight towel So basically Gudi had designed this amazing but using the technology he had at the time, it wasn't achievable. It wasn't achievable in the conventional sense, yes. OkayK, so you came along and you'd got this problem and you'd got what they thought was a solution. What happened next? Well, we sat down together and brainstormed it and eventually came up with this idea that actually if we used stressed stone panels that would pre fabricated off site, then we could get down to the weight limit without using a steel frame. We could make a structure that was inherently strong enough and robust enough to take the wind loads and the earthquake loads. of stone itself. Okay, so before we explain what the pre stressed panels mean, talk us through the stress that happens to these towers. In a normal cathedral of this size, you would have buttresses, you'd of all sorts going on, but Gaudi didn't want that. Gaudy, and I think he did this himself. I'm not aware of an external engineer helping Gaudy at the time, but he came up with this idea that masonry, conventional masonry all works by forces holding the masonry shut. so the joints on masonry can open and close the mortar joints. And the way they work is that the weight of the masonry above each joint it shut, if you like. And that's what stops you it falling over sideways. So what Gidy did is he worked out in his head that if you wanted this thing pushing downwards in masonry, if you started instead by a steel chain hanging the other way up, like a washing line with all the weights of the stone hanging off it, you've got the right shape that when you turned it upside down, it worked theemasonry. And he did this in three dimensions and it's an amazing technique The idea of a hanging chain existed, but the idea of doing it in three dimensions with little bags of lead shots and your but all different points represent the weight of the materry at that point is uniquely gauddy So he sort of created a mechanical computer to perform his structural calculations for him, but upside down Absolutely correct. And then he took photographs in fact or he put a mirror underneath it and looked looked at it downwards in it and it turns itself the right way up. It was amazing. and they also used There's a thing called graphic statics, which is a way of calculating thrust lines using drawings basically in two dimensions. He also used that technique as well And so you came up with this idea at A of pre stressed stone. What is that and how does it work So the idea is you take pieces of stone accurately, which you now can using computer control cutting equipment and you put them together maybe twenty pieces of stone And then you put steel rods through holes in the stone. and then jacket with hydraulic jacks that clamp the stone joints together And then you can make big panels up to twenty tons in weight, bring them on trucks to the site and then assemble them literally like giant Lego blocks to make the towers itself. It's not only efficient in stone consumption It is a faster method of construction And their third issue is they wanted to reduce the amount of site usage for construction So why does squeezing it and stressing it make it better? Well' the rods, the elastic bands, whatever you want to think of them as, pamp the joints in the way that the weight of the masonry did traditionally. So instead of having to have all that ninety eight percent of extra stone, which is only there for its weight, you replace that with a thin steel rod clamp it together with. And you use this for the Merary Ter. Is it being used elsewhere as well Yes, well they enjoyed the process so much on the Mary Tower that even though the other five main towers, the four evvangelists and the Jesus Tower, had foundations that were big enough, they thought, how, this is a nice way of doing things. for the other five towers as well. So now we did all six. Thanks to Tristram Carfrey from Caroline have you ever been to Gread familiar? No, I haven't. Now I really, really want to go. haveave you? I went there last year when they were just completing this. It is absolutely extraordinary. My favourite anecdote from all of this to show Guddi's attention to detail and maybe sort of divinely inspired madness. He wanted to get everything right and on the Nativity Freeze, which was the first external piece of decloration that he built, He wanted to show the donkey Jesus's donkey or or Joseph's donkey, Jesus wasn't around yet. So he went around Barcelona to find the most emaciated donkey he could. and this donkey was already presumably having a bad day He then chlorophformed the donkey And he raised it on a crane. So you could take a plaster cast of it. in situ and produce this sort of most realistic donkey. and you can look at this poor donkey. The donkey survived. say, didid this poor donkey live to tell the tale? He did along with some of his friends. Some of his friends were sort of the Roman guards. I don't think he chloropformed his friends. I think he just got them to stand still. It's quite something and it definitely changes how you look at it, but it's an amazing building. I think it's also worth saying that this build is far from over, right? There's a lot of work ahead. The church's main front, the glory facade is still to be finished. And the engineering challenge isn't over as well. So the building is going to need serious maintenance and monitoring over time because wind and changes in temperatures can lead to cracks So up until recently Climbers have been surveying the building constantly basically, it takes them two years to complete a survey. Whereas now I was quite sad to hear that they've basically been replaced by drones and AI that do it much faster. G, I said I'd elevate people. We've just depressed them further. Depressed all the climates, at least. I don't know if the next section is depressing or not. Depends on your view on screwwormms Is there any creature? is so awful So unpleasant, so without redemption that we should not merely control it, but make it extinct It's a question for science, it's a question for philosophy. it's a question for ethics. It is also a question that two years ago Dr. Gregory Kabnick. Co editor of the Hastings Center Report, which is an academic journal on bioethics Cvened a meeting to consider This week, a flesh eating parasite called the screwworm has returned to the U.S. It was originally kicked out in this epic of veterinary public health where starting in the sixties it was pushed back due to a mass release of sterile worms that were used to eliminate it. It pushed it down to the daring gap in Panama But now it's back. And it returns at a time when genetic technology suggests that something more effective control it instead? and it leads to the question do we ever have the right to eliminate a species? And if so, can we Greg explained to us why of all the animals in the world, a zena we might consider worthy of extinction, it's the screwworm The candidate is something called New World sccrewworm, which is a very unusual fly because it feasts when in its larval form, on liivving flesh And then the eggs hatch, the larvae burrow in, they have a sort of they have little ridges that give them the appearance of a screw. So they're sometimes described as screwing in, but they burrow in with their mouths on the inside eating away And and then that attracts more flies the wound enlarges, they keep eating. it becomes a great festering thing eventually it's infected bacterially infected and Most of the time, withithout treatment the host will die, typically of sepsis. And it affects mostly it affects all warm blooded animals. There are some ghastly stories about it can infect people, hence the Latin name you my Carmen ofvorax, the last part meaning manator. The reason why you were able to consider the prospect of making this extinct is because of a new sort of technology. Talk to us about this theory. Yeah. Well, so I mean, the thing that really got us going is the possibility of using Je drive The Ge dririve is a strategy for making changes not to a single individual, but to a population and in principle maybe a whole species. So normally I have a fifty percent chance of passing my genes onto my offspring A gene drive, that's something where you genetically modify an organism so it's almost one hundred percent guaranteed to pass the genes of whatever trait I want on. That's exactly right, essentially through an entire population, maybe through the whole species. And presumably with screworm, you're not thinking of sending something nice through the whole population. No, in this case, what it would be it's not something that causes agony to the screwworm, but it does prevent the female larvae from developing unless they are exposed to an antibiotic you might be able in principle to release a relatively few individuals and cause a massive crash in the population. You talk about concern of gene modification. Is there some way in which a Ge drive could escape. you could horizontal transfer to other flies or something like that. That is something Yes. Yes. That is something that needs to be thought about. in each case in which a gene drive might be contemplated for release into the wild, you gota look at that kind of thing. And so okay, No, we come to your meeting where you're discussing what this means. Who did you invite and what were the agendas We had sort of deliberately skewed it skewed the membership of the group in favor of people who would be pretty skeptical like myself, even though I may sound I actually I find myself feeling that there's species have an intrinsic value and we really ought to be finding generally ways of keeping them with us keeping them in the wild U, we have this technology that in principle be used destructively, and we wanted to consider whether there would be any cases in which maybe you know, that kind of argument could be made. So with then we talked through some of these cases, New World screw arm among them and had a conversation. So with the scroom, let's leave aside that I guess there's a fundamental philosophical argument, which is simply that a species has innate value and for that reason alone you should leave it be. But leaving that aside, other other ical arguments that you considered Well, the other real worry about eliminating a species is that you'd be causing some sort of environmental somewhere down the line you don't know fully for sure what it's doing in the wild and you might end up making some kind of mistake. It'd be some sort of unintended consequences. But is there anything that Eats it? is there anything that it eats that you disturb the balance by getting rid of it Yeah it's probably Eaten sometimes the adult The form of the screwworm is just a fly. It looks like a sort of a largish red eyed house fly. It's probably eaten by birds and frogs and what have you I But there are many, many, many, many, many flies, many, many other things for the birds and the frogs to eat. Proably not important ecologically to keep it in the mix. The things that it's preying on in South America are already under pressure from various other things. The populations are already somewhat suppressed from habitat change and human hunning in what have you. So Alleviating the pressure just a little bit by taking this predator out of the mix is probably a good thing for those populations, those other wildowns. You're not presenting to me terribly many counterarguments. What did you conclude Um, we so at the end of the meeting Somewhat to my surprise, I realized that we had possibly the seeds of consensus and thing that was really persuasive to us in this case is the animal suffering It's really ghastly And these are animals that are The livestock are animals that are under our care and we probably we owe some special duty to take care of them to ensure that they are Okay, while they're while they're alive Last question, do you think this is something you'll see? doneone There's no movement that I've seen right now to do anything more than try to reestablish fence at the Daren Gap. So I haven't yet seen that there's been a great movement to take up our recommendation to think about full eradication of it But I think it's I think one of the lessons of this fresh outbreak is that sterile insect technique is probably not really an effective permanent solution. It's also a super expensive thing And I think it's conceivable that somewhere along the way, the more research will be done and we'll end up trying this. But there's so much concern about gen modification And we have to do a little bit of thinking before we get there. and I'm fine with that. That's all that we're calling for really is more thinking That was Dr. Gregory Kabnk You're listening to inside science from the BBC World Service. Tell us what science you think we should be investigating Our email address is inside science at bbc. co. uk When it comes to looking your best, Beachbum tanning does it better. 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And once I switched, the difference was obvious Bet digestion, better skin, more energy, dogs who actually feel good instead of just surviving dinner Here's the thing, you care about quality, you make an intentional choice to be healthy. So why are you gambling with your dog's health? So let's think about our furry babies. Go to just foodfdogs dot com right now and get fifty percent off your first box. No code, just try it Because once you see the difference, you're not going back Now over to Roland Peees, who, as promised, has been finding out about these hidden networks of life beneath our feet. Over to you, Roland talk about the invisible networks of thread like hphi of fungi that make up a vital living part of soil worldwide. Ecologists regard the fungus so important that there's a society for the prrotection of underground networks We coordinated a global survey to quantify their reach. Co founder Toby Kears told me why they care about these small things These hyphi are smaller than the hairs on our head. So they're about five microns across And they're open tubes and that's what's really interesting is that in the lab we can actually see the nutrients flowing through them. Now this is a partnership with plants. and so plants are photosynthesizing They're taking CO two out of the atmosphere and they're feeding carbon into these arbuscular micorhizal networks. But they're not doing it for free. In return, the fungi are out foraging for phosphorus and nitrogen and water that they return to the plant root. The point is that these high feed networks, they penetrate deep into the soil and they're sort of gathering stuff from all over the place. Exactly. They're the connection between plant roots and the deep soil And that the weird thing that you've done in this study is you've worked out if you sort of were to put a ruler along every little bit of high feet in the soil, how long that ought to be across the whole planet Exactly, we were mapping this circulatory system, this underground circulatory system. And so if you were to stretch these arbuscular microhizo hyphe, end to end, it would reach about one hundred ten quadrillion kilometers And that's just in the top fifteen centimeters of Earth soils. I mean, that's enormous. So it's two hundred or something kilometers to the sun. Exactly. So this distance is about one billion times the distance from the Earth to the sun. I mean, so you does this really underline the importance or the significance of hidden sort of life support system. Yeah, exactly. like just as these circulatory systems in our own bodies move around resources These microscopic fungal pipes, they're the ones connecting plants to soil and really forming this living infrastructure of terrestrial life. How much does it weigh if you add it all It weighs about three hundred megatons of carbon. So to give you a sense, that's between four and six times the total biomass of all humans alive on Earth So it's a lot more than humans, but It's sort of quite small, I suspect compared to I don't know, I think plant life is the major biomass on the planet. Exactly. So it's small but important It's light but important. And I think here really what we're trying to explain to people is just the extent and the density of this network across the Eth. So again, you have to remember, it's a microbe. It's very small. It's invisible to the naked eye But what it does is it's moving down carbon into the soil. So these mycrohizal networks, just this one type of our bususcular mycrohizal networks, moves about four billion tons of CO two into soils each year. So that's equivalent to roughly eleven percent of all human related carbon dioxide emissions That's incredible. so it's a sump That as you say, it's being fed by the plants then. So the plants are sort of pumping sugars down into these funky which is part of the sort of the trade that they're doing. and then the fungi sort of just store it in the soil Yeah, so the plants are pumping down this carbon and the fungi use that carbon to build their bodies and go and collect phosphorus and nitrogen and even water and transport that in the opposite direction up these open pipe tubes to the root system of seventy percent of all plant species on Earth How does this vary across know different ecosystems. We found that these networks were densest across grasslands And that actually the Earth's grasslands hold about forty percent of this arbuscular myicorhizal biomass. But what really surprised us is the density of these networks also in desert and dryand ecosystems We've been working in the Gobi desert in Mongolia for a few years now and collecting very what we call endemic species of these micrhizo fungi that are found nowhere else on Earth. So basically these are fungi that have evolved very special capabilities to move water in really dry systems What about agriculture? whereere we're plying up the fields? Our vuscular micrhizal fungi are very important in agriculture because many of our crop plants depend on these fungal associations However, we found that these hyphold densities were on average, about fifty percent lower in crop lands. So yes, these agriculture was associated with a decreased density of these networks, but our paper wasn't able to tell us specifically what farming practices led to that decrease. And so more work really needs to go to understand what it is about agricultural practices that decreases the density. We have some ideas from past literature. For example, we know that fungicide is very dangerous to fungi by design. And so fungicide, having really high chemical inputs like high fertilizers, phosphorus and nitrogen. If you add a lot of chemical fertilizers, then plants stop feeding carbon to their myicroizal partners and they start to disappear A tillage can also be quite hard on them. But in other cases, agriculture can be quite good for these fungi. so it really depends on the specific farming practices. I mean, it's trying to say it, but it feels to me like These are like so many uncharismatic species that things are just so It almost that we don't appreciate how wonderful they actually are. It's so funny to hear you say that. I think they're the most charismatic species on Earth. When you see them in the lab, they're absolutely beautiful. Again, they're these open pipes of nutrients flowing through them. And we've developed ways with scientists at physics inststitutes at the Eoff Biophysics Institute that allows us to tag the carbon inside these networks so it fluoreses in bright colors and we can watch it flowing through the network. It's some of the most beautiful science I've ever seen. Toby Kiers of the Amsterdam Institute for Life and Environment, who won the Tyler Prize equivalent to an environmental Nobel This year Thanks, Roland. Now Caroline, as mentioned the beginning, you've been looking through the week's other science news. What have you found? News about the asteroid that wiped out dinosaurs. So pretty monumental event, right? sixty six million years ago, an asteroid collided with Earth, wiped out three quarters of species. What I think is less well known is it also deformed the rock underneath this impact up to thirty five kilometers down. so rock melted It combined with seawater from the Gulf of Mexico, and it basically created this kind of porous material with pockets of hot water. So an incredibly important hydrothermal system