Asteroid 2024 YR4 crisis averted?

Summary

Science In Action – "Asteroid 2024 YR4 Crisis Averted?"

BBC World Service | Host: Roland Pease | Date: February 27, 2025

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Overview

This episode of Science in Action dives into some of the week’s most compelling science news stories, with a timely focus on the near-Earth asteroid 2024 YR4 and how scientists verified that it’s no longer a threat to our planet. The episode also delves into looming threats to the dark skies above one of the world’s premier observatories in Chile, cutting-edge climate science on Atlantic currents, and a remarkable breakthrough in wearable computing.

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Main Segments & Key Insights

1. Asteroid 2024 YR4: How a Crisis Was Averted

[02:44–09:23]

Key Points:

• Just weeks ago, asteroid 2024 YR4 appeared to have a 1 in 50 chance of striking Earth in 2032.
• Continued high-precision observations, especially from Chile’s Very Large Telescope (VLT), refined the asteroid’s projected orbit, effectively ruling out the possibility of impact.
• Roland Pease interviews Olivier Heino of the European Southern Observatory (ESO) for a first-hand account of how astronomers track such threats.

Memorable Quotes:

• “Now the chance is essentially 0.001% is the number they're quoting.” – Roland Pease [02:44]
• “When you discover this kind of object, you know the orbit over one day, two days...the uncertainty is really large, like a huge beam covering a part of the sky. And the Earth happens to be in that beam.” – Olivier Heino [03:46]
• “Right now, we know the orbit well enough to know that we'll not be in trouble in 2032.” – Olivier Heino [07:42]

Interesting Moment:

• As more data rolled in and the uncertainty in YR4’s orbit shrank, the “beam” of possible Earth-crossing trajectories moved away from our planet, allaying fears of a future impact.
• The asteroid is now more likely to pass near the Moon, with Heino remarking: “The probability of impact for the Moon is getting higher and higher. But that's okay. It would be, would be entertaining.” [08:12]

Technical Insight:

• The challenge astronomers face as asteroids get fainter and tracking requires “stacking” dozens of images, similar to how sports photographers pan to keep a moving subject in focus. [05:53]

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2. Threats to Chile’s Pristine Dark Skies

[09:24–21:43]

Key Points:

• Plans for a large green hydrogen factory near the VLT could threaten one of Earth’s last untouched dark-sky sites due to increased light pollution.
• Astronomers, including exoplanet hunter Julius Seidel, warn that even a modest increase in local brightness could cripple advanced observations and planetary defense efforts.

Memorable Quotes:

• “All of this will basically make observing in many many instances completely pointless.” – Julius Seidel [02:12, 15:35]
• “There's no such thing as a little bit of light pollution for astronomy from a facility this big, this close, or friendly light pollution from your neighbors.” – Julius Seidel [18:49]
• “For a cutting edge telescope, the impact is very significant. And it will basically destroy one of the last true dark sky sights in the world.” – Julius Seidel [15:52]

Notable Moment:

• Seidel describes the beauty and sensitivity of the Atacama as an astronomical site: “When you're in the Atacama, if you give your eyes the necessary 10 minutes to adjust...you can actually walk around and see trees and see buildings just by starlight.” [12:14]
• He cautions: even distant city lights over 100 km away cause a visible glow, so a nearby factory only 11 km away could devastate observations. [15:52]

Heritage Angle:

• Seidel emphasizes the universal, ancient human experience of looking at dark skies—now endangered: “It's really part of the human heritage that we are robbing us and future generations of, which is very sad.” [13:42]

Scientific Impact:

• Light pollution would hamper not just exoplanet studies but also meteor observations vital for planetary defense: “For example, planetary defense will be heavily impacted by this project. It's quite dangerous actually.” [17:04]

Activism:

• Thousands, including former observatory directors, have petitioned for the hydrogen factory to be relocated to preserve astronomical research capabilities. [11:40]

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3. The Atlantic Meridional Overturning Circulation (AMOC): A Climate Safeguard?

[23:49–30:26]

Key Points:

• The AMOC, a colossal “conveyor belt” of ocean currents, is vital for Europe’s mild climate by transporting heat northward.
• There is concern it could collapse due to climate change, with catastrophic effects.
• Jonathan Baker and Met Office colleagues’ new modeling shows that powerful winds in the Southern Ocean act as a “pump,” stabilizing the system even as it weakens, making a total collapse this century unlikely.

Memorable Quotes:

• “The AMOC is a critical component of the ocean climate system...enough heat every five days to power the world for a year.” – Jonathan Baker [24:43]
• “In none of the models does the AMOC completely collapse. And so this gives us confidence that the AMOC is unlikely to collapse this century.” – Jonathan Baker [28:46]
• “But unlikely doesn't mean impossible. So we should be aware of these risks.” – Jonathan Baker [30:02]

Technical Details:

• Southern Ocean westerlies drive upwelling that sustains the AMOC, counterbalancing declines driven by Northern Atlantic changes.

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4. Computers Woven into Clothes: The “Thread Computer” Revolution

[30:47–40:10]

Key Points:

• MIT team led by Joel Fink unveils a breakthrough: a computer embedded inside a stretchable fiber, with processor, memory, battery, and sensors—all integrated into clothing.
• This innovation could transform wearable technology and healthcare, e.g., smart garments that monitor health metrics for soldiers or civilians in harsh environments.

Memorable Quotes:

• “It is a fiber that has a complete computer in it. It has a processor, it has memory, it has communication... it has a battery.” – Joel Fink [31:59]
• “Computers today are designed to get in your way...The big idea here is being able to incorporate computation into the things that we're wearing, which are called clothes.” – Joel Fink [32:26]
• “There isn't a single instance of a stretchable computer that we know about. These fibers actually do stretch.” – Joel Fink [34:09]

Real-World Testing:

• Royal Marines have worn these garments in Arctic conditions to test for cold injury and manage caloric intake.
• “These fabrics are helping protect them, alert them to frostbite, and to help manage their caloric intake...our view of the future is that fabric is going to be on us 24 7, and it's actually going to monitor our health.” – Joel Fink [39:20]

Contextual Reflection:

• Fink links this step to a “Moore’s Law for fibers”: “Fibers haven't changed. How do you get a Moore's Law for fibers? How do you rapidly advance what a fiber is and what a fiber can do?” [36:18]

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Notable Quotes & Timestamps

• “When you discover this kind of object...the Earth happens to be in that beam.” – Olivier Heino [03:46]
• “Now we know the orbit well enough to know that we'll not be in trouble in 2032.” – Olivier Heino [07:42]
• “All of this will basically make observing in many many instances completely pointless.” – Julius Seidel [02:12, 15:35]
• “For a cutting edge telescope, the impact is very significant. And it will basically destroy one of the last true dark sky sights in the world.” – Julius Seidel [15:52]
• “The AMOC is a critical component of the ocean climate system and it's a large system of ocean currents...enough heat every five days to power the world for a year.” – Jonathan Baker [24:43]
• “It is a fiber that has a complete computer in it. It has a processor, it has memory, it has communication, it has sensing in it, it has a battery.” – Joel Fink [31:59]
• “There isn't a single instance of a stretchable computer that we know about. These fibers actually do stretch.” – Joel Fink [34:09]

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Timestamps for Key Segments

• 02:44 – Asteroid 2024 YR4 no longer a risk to Earth; interview with Olivier Heino
• 09:24 – Threat to Chilean night skies from green hydrogen plant; Julius Seidel on astronomical heritage and risks
• 23:49 – Atlantic Meridional Overturning Circulation; Jonathan Baker explains new climate modelling results
• 30:47 – “Thread computer” breakthrough; Joel Fink on wearable computing technology

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Conclusion

This episode provides a multifaceted look at the frontiers of planetary defense, astronomy, climate science, and wearable technology. From the relief of averting a possible asteroid impact, to grassroots efforts to protect humanity’s last pristine night sky, to global ocean currents that stabilize our climate, and marvels of next-generation “smart” clothing—Science in Action delivers both scientific depth and the human stories behind the headlines.

Transcript

[Roland Pease]

This BBC podcast is supported by ads outside the uk.

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[Roland Pease]

Welcome to Science in Action from the BBC World Service with me Roland Pease. Later in the programme, the dark skies of one of the world's top telescopes under threat.

[Julius Seidel]

All of this will basically make observing in many many instances completely pointless.

[Roland Pease]

The weather shaping Atlantic Meridional overturning current new modelling about its future under global warming. And how about a computer in your underwear?

[Joel Fink]

And these fabrics are helping protect them, alert them to frostbite and to help manage their caloric intake and other things out in a very austere and harsh environment.

[Roland Pease]

Thread like computers. What and why? Coming up. We're safe in one respect for now. At least two weeks ago asteroid 2024 yr 4 had around a 1 in 50 chance of banging into Earth in 2032. Pretty low, but still high enough to make you think what if? Now the chance is essentially 0.001% is the number they're quoting. The expert we talked to back then told us further observations would allow them to refine their projections of why our force orbit over the next eight years and whether it would steer clear of our planet. The critical ones came from the astounding Very Large Telescope in Chile, taken as the receding asteroid faded into the black background. I thought it would be fun to get a glimpse of the life of an asteroid hunter and called the European Southern Observatory's Olivier Hayno about finding YR4's departing path.

[Olivier Heino]

When you discover this kind of object, you know the orbit over one day, two days, and then you extrapolate over four years. So that means that the uncertainty is really large, like a huge beam covering a part of the sky. And the Earth happens to be in that beam. So what we do is we keep observing the asteroid to observe it two days, three days, one week, two weeks, so that the extrapolation is getting much better. And so now we have almost two months. We know the orbit two months over the four years. And so that means that the beam is getting narrower and narrower and narrower. And what happens is that the beam is moving outside of the Earth or the Earth is moving outside of the beam. And so that's why originally the probability of impact was going higher, because the beam was becoming smaller. So if you want, the Earth was getting more and more illuminated by all these orbits. But now we keep refining it and the beam is moving outside. And so that means that now we are in the safe. And so the idea is really keep observing as long as you can. That's where I come in with the Very Large Telescope. As the name says, it's a pretty big telescope. It's 8 meters. And so that means that with that telescope in the desert, we can observe the asteroid much longer than most other telescopes.

[Roland Pease]

I sort of imagine that this is, you know, as you say, this is getting further and further away and it's getting fainter and fainter for you to see. You have an idea, I guess, with this big telescope, where to look. But do you, you know, when you turn the telescope to the right place, did you see it straight away or are you beginning to strain the optics? Are you having to look a little bit left and right and so on?

[Olivier Heino]

Okay. So the idea is that we point where we expect to find it, and the field of view of our camera is large enough that we are sure it's somewhere in the image. Okay? And in the case of YF4, the uncertainty was really small. It's like a Few pixels so we know exactly where to look. And last week it was still bright enough that we would see it after two or three images because you see that little dot moving in front of the stars. If we're going to observe it next week or so, and there it starts to be too faint to be visible in each image. So what we do is we take a sequence of 20, 30, 40, 60 images and we know exactly how the asteroid is moving, which means that we can shift the images, compensate for the motion. You know when you go, go to a race car and you see these fantastic photographers who follow the car with the tele lens to get the car sharp here while the background is trailed, we do exactly the same with our telescope. We know exactly the motion of the asteroid so we can stack the images to go super deep on the asteroid and all the stars will trail behind the asteroid.

[Roland Pease]

I mean the difference is with a Formula one race car, most of us really don't care who wins. But with this asteroid, a tiny difference in that orbit makes all the difference in 2032.

[Olivier Heino]

Yeah, yeah, yeah, yeah, yeah, exactly. And so that's why we try to follow it as long as possible. Now in the case of yr4, the problem is gone. Right now we know the orbit well enough to know that we'll not be in trouble in 2032.

[Roland Pease]

And that's because if you extrapolate forwards enough, it's going somewhere over our heads. Maybe somewhere between us and the Moon or something like that.

[Olivier Heino]

Yeah, the Moon. It's getting interesting for the moon. Actually the probability of impact for the Moon is getting higher and higher. But that's okay. It would be, would be entertaining.

[Roland Pease]

That would be interesting.

[Olivier Heino]

That would be super interesting, yes.

[Roland Pease]

I mean in a sense that would be a kind of planetary impact experiment, but one that's safe.

[Olivier Heino]

Yeah, it's super safe now.

[Joel Fink]

Okay.

[Olivier Heino]

The other thing is that yr4 is not dangerous anymore. But still we consider it as a very good exercise. And so we continue to refine the orbits, maybe not observe it as long as we could because the last observation are becoming more and more expensive. You know, right now it, the, the last one was half an hour. Next one would be two hours and then 10 hours, then three nights.

[Jonathan Baker]

That starts to be really expensive in.

[Olivier Heino]

Terms of telescope time. But we can still push it a.

[Roland Pease]

Little bit and then there's no chance of seeing it really until it comes close again in about three years time.

[Olivier Heino]

That's correct, yes.

[Roland Pease]

Now there's one other thing which was mentioned in your ESO blog. Which is that there are industrial developments planned for the coastal region of Chile that could make this a lot harder in the future. Just talk me through that.

[Olivier Heino]

Okay, so let's assume that the orbit would still be uncertain, that we need to observe that we need to observe as long as possible to refine the orbit and really know if it's going to impact and where or not. With the VLT in the desert, in perfect sky, perfect dark night and good conditions, I could observe that asteroid until May. If the sky is not perfect anymore because there is slight revolution, that means that I would have had to stop early April. This factory is going to produce green hydrogen using the solar energy. So it's, it's really fantastic. But it's a fairly big factory with quite many people and trucks, and there is going to be light, and that's normal. So that means that we would have a fairly big factory just a few kilometers from the observatory. And that means that no matter how careful they are, our sky is going to get brighter. Today, the sky at the observatory is really one of the best of the world. If you put a factory next to it, it's going to be just a good observatory, not one of the best anymore. And there are very few places that are so dark in the. On the planet, so it's really worth preserving it. So I really hope that somehow there can be an agreement to move that factory 50 kilometers north or 50 kilometers south. That would be sufficient.

[Roland Pease]

Olivier Heino of ESO, the European Southern Observatory. The risks to the VLT's dark skies and to Chile's leading place in astronomy has led to v vigorous campaigning by astronomers across the globe. A petition urging a more distant site for the hydrogen project has been signed by thousands of professionals and enthusiasts, current and retired directors of other observatories among them, one of the signatories is exoplanet hunter Yuli Zeidl, who has been an ESO fellow for four years. Very dependent on Paranel's dark, dark skies.

[Julius Seidel]

The fascination is that the skies aren't, aren't dark at all, because all of a sudden you can see all of the Milky Way and all of the different stars, and you can see the Magellanic Clouds like other galaxies in the Southern hemisphere, right? So all of a sudden, even on a completely moonless night, where in a city you'd be like, oh, there's no moon, it's really dark. You need all of the artificial light. But when you're in the Atacama, if you give your eyes the necessary 10 minutes to adjust to the low ambient light, you can actually walk around and see trees and see buildings just by starlight. And walking around by starlight gives everything a little bit of a different touch. It's actually quite fascinating. You can see the entire sky is lit up. There's very little darkness in that sense, actually. And it's fascinating to see these dark patches in the Milky Way and the different galaxies and you see meteors coming down and scatter into the different elements that they contain. So once I was driving the car down and a massive meteor shower happened at the time, and one came down and scattered into three green pieces that made giant streaks across the sky. It was really beautiful.

[Roland Pease]

I was with an astronomer down in Chile some years ago and he took me out and he said he always does this when observing because it connects the real world to what he was seeing through a telescope.

[Julius Seidel]

Exactly. And the other aspect is it's also kind of, I think, our heritage across the ages, because we might not have a lot in common with, you know, humans from 50 or 100,000 years ago, but we still have a very similar or the same sky, basically. And that's something that we've only very recently in human history lost because of artificial light sources. So it's really part of the human heritage that we are robbing us and future generations of, which is very sad.

[Roland Pease]

So the reason I wanted to talk to you is you're one of the many astronomers using this facility who are very worried about this development of a hydrogen plant in the area. Just tell me what you know about that.

[Julius Seidel]

Yeah, so this has been making waves very recently. So the company, which is a subsidiary of a US big energy company, they already have a rather small project quite close to Perna that was built I think in 2019. But as far as I know what the ESO spokesperson has said, they haven't really then consulted again with ESU and just because they came out to the public in Tal, which is the neighboring village, and we're kind of introducing a new megaproject. So they supposedly going to build a green hydrogen plant, which in itself is a very good thing, clean energy. But unfortunately the plans are to build this very close to Pernal and therefore also the building site of the elt, meaning that we'll have a construction site the size of a mid sized city that they're going to build in the middle of the desert. And that means, as you all know, construction sites in the big cities, they're very dusty, they're very loud, they use giant floodlights at night to Continue constructing. And all of this will basically make observing in many, many instances completely pointless.

[Roland Pease]

Pointless? I mean, it's. I suppose what I'm wondering is the, your telescopes are on the top of very tall mountains. You know, it seems even if the, there's something going on down below, the lights are down below as well. And you're looking up at the skies above.

[Julius Seidel]

Yeah, but so light also scatters, right? So it's not just you have to look at the light like a light tower to see it, but it kind of, kind of illuminates everything around it. And that also means the sky. So for example, when you stand on the mountain of Paranal, Antofagasta itself, the next biggest city is more than 100 km, more than 2 hours by bus away. But you can still see the faint orange glow in the sky of the city, which is the scattered light from the city itself. And if you now think of this, but only 11 kilometers away, then you change this pristine dark sky side to something that we would consider a rural sky. So what you would, you'd have in smaller cities or the countryside when you kind of move a little bit away from the city. For humans, there's a negligible difference. We will still see the sky, it will still be beautiful. But for a cutting edge telescope, the impact is very significant. And it will basically destroy one of the last true dark sky sights in the world.

[Roland Pease]

So even that faint glow reflecting off dust and stuff up in the atmosphere, cloud, you know, the thinnest of cloud veils that will become, basically it will overwhelm some of the objects that you look at.

[Julius Seidel]

It will overwhelm the observational capabilities. Most importantly, I think the capability of observing meteors because you do that at dusk and dawn most of the time. And that means that for example, planetary defense will be heavily impacted by this project. It's quite dangerous actually.

[Roland Pease]

I mean for your own work, you look at, I think it's exoplanets. So you're looking at planets orbiting other stars that would also be affected.

[Julius Seidel]

So for now, not because we are looking still at very bright targets. So we're looking at very bright stars because they're easier to observe and our field is still very young. But if we look into the future when we go towards the elt, so the Extremely Large Telescope which is built right next door, and this is a multi million dollar project that is currently being constructed with first light planned in the next few years. And once we use that, we're going to try and look for much fainter objects. Of course, because we have a much bigger telescope to look for fainter things and also smaller planets, Earth like planets in different configurations. And there this light pollution will also become quite an important factor.

[Roland Pease]

You know, I've been thinking about this and thinking about Galileo about 410 years or so ago when he got his crummy first telescope out and looked, looked up at Jupiter and saw things that had never been seen in the solar system before. And that in a, in a way that was the beginning of science. He would be fascinated by the work that you're doing, but at the same time other science progress threatens that work.

[Julius Seidel]

Yeah, exactly. And what I think is the saddest part about this, that first of all, it's a good project. It's supposed to provide clean energy. So it's a wonderful thing to do. And the Atacama Desert is very large. You literally just have to replace like de. Place it a little bit by 50 or 100 kilometers. So I understand that this is probably an infrastructure decision that there is, you know, that road access and so on. I'm not super aware of the details, but there is no such thing as a little bit of light pollution for astronomy from a facility this big, this close, or friendly light pollution from your neighbors. So the only thing to do really with this project is to move it very significantly away from the telescopes or to doom the Extremely Large Telescope telescope that we built that is the size of the Coliseum in Rome. And we doom it before we even started observing.

[Roland Pease]

Before we stop talking to you, you did just last week. I mean, this maybe illustrates the sensitivity of the kinds of measurements you're doing, but you just published some work on a Jupiter like planet orbiting another star and you were able to see by looking the filtered light the sort of the atmospheric circulation patterns.

[Julius Seidel]

Exactly. So what we do basically is that we observe planets while they provide something a little bit similar to a solar eclipse. So we wait for the planet to be in between us and the star. And while it is in between us, a tiny, tiny fraction of that stellar light actually goes through the atmosphere of that planet very, very far away before it comes to our telescope. But it's like a fraction of a fraction of a fraction of the total light that we get from the star. So we need very large and very sensitive telescopes with very little background stray light that comes from other sources because we only want the light that comes from the star and has interacted with this planetary atmosphere. So it's like a percentage of a percentage that we're looking for.

[Roland Pease]

It sounds Like a difference in the difference of that style.

[Julius Seidel]

Exactly, yeah. So if you don't want to read your tea leaves, if you want to be sure that this really comes from this 900 light years far away planet, then you need to be sure that there's no other pollution coming from other sources. And one of them is of course, emission and light from Earth itself and from the inhabitants of Earth. So this is why we would go to really remote places like mountains and islands and mountains in the driest desert in the world to mitigate all of these effects. And now we built the infrastructure there and everybody now follows us and we're like, no, please don't follow us. We want to be alone in the desert.

[Roland Pease]

Planetary weather guru Julius Seidel now at the observatory of Cote d'. Azur. Still to come, a computer woven into your clothes. Stay tuned here to science in action from the BBC World Service.

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[Joel Fink]

This is the story of the 1. As head of maintenance at a concert hall, he knows the show must always go on. That's why he works behind the scenes, ensuring every light is working, the H Vac is humming, and his facility shines with Grainger's supplies and solutions for every challenge he faces. Plus 24. 7 customer support. His venue never misses a beat. Call quickgranger.com or just stop by Grainger for the ones who get it done.

[Roland Pease]

Down here on Earth. The future of our weather under global warming has increasingly Directed attention to the Atlantic meridional overturning circulation. Amoc, a conveyor belt that carries vast volumes of water north through the Atlantic Oceans, past Europe, towards the Arctic at the surface, returning then at depth back to the Antarctic and then round all over again. It is slowing and there are well founded reasons to fear it might stop altogether if global warming continues. If it does, it won't Simply restart when CO2 levels return to pre industrial. The physics is complex and includes many factors. Jonathan Baker and colleagues at the UK Met Office say they found that one circulation in the Southern Ocean around Antarctica may prevent a complete stop. But first, why AMOC matters to climate.

[Jonathan Baker]

The AMOC is a critical component of the ocean climate system and it's a large system of ocean currents in the Atlantic Ocean that transports huge amounts of heat towards Europe, enough heat every five days to power the world for a year. So this is very important for keeping European climate mild.

[Roland Pease]

And as I understand it, is it such a complicated system. But the part that people tend to focus on, as I understand it, is that as this current heads north from, you know, near Florida and so on, it cools down and it evaporates and there's a kind of pull factor that the once it gets up to Norway or somewhere, it sinks because it's cold and salty and dense and that sort of then pulls the next lot of water up behind it.

[Jonathan Baker]

Yes, that's exactly it. So the waters become cooler and denser in the North Atlantic and there they can sink and form dense waters which flow southwards. We find that under extreme climate change scenarios, the AMOC upwells in the Southern Ocean driven by Southern Ocean winds. And these winds act like a powerful pump which keeps the AMOC running this century in these models.

[Roland Pease]

But when I hear concern that the AMOC may turn off, it's because if people are focusing on that saltiness and the coldness is it up at the north and that they think that if climate change weakens that, that's, that's the sort of the mechanism that people have been talking about very much for the past few years.

[Jonathan Baker]

Yes, exactly. The focus has been on the North Atlantic and we agree, we find that the AMOC is very likely to weaken due to global warming. And as you say, the focus has been on the North Atlantic rather than with those waters upwell in other parts of the ocean.

[Roland Pease]

So it's the other end of it. So this is the push factor, as it were, that you're talking about at the other end of this circulation pattern?

[Jonathan Baker]

Yes. So we as scientists refer to it as the pull factor, actually. And the push factor is in the North Atlantic. And so this pull factor continues as long as the Southern Ocean winds continue to blow.

[Roland Pease]

I mean, this is tens of thousands of kilometres away. What's going on there?

[Jonathan Baker]

AMOC is part of a global overturning system. And so the waters that sink in the North Atlantic up well in either the Southern Ocean or the Indo Pacific or in the Atlantic today.

[Roland Pease]

So they run north to south, back down to the southern end of the Atlantic and into the Southern Ocean.

[Jonathan Baker]

Yes, that's right. Most of the waters flow all the way down to the Southern Ocean before they come back up to the surface.

[Roland Pease]

And so what you're saying is that what happens around Antarctica can actually affect what happens to the North Atlantic surface currents.

[Jonathan Baker]

Exactly. So long as these Southern Ocean winds blow, they will continue to pull waters up to the surface. And that means you have to have sinking in either the Pacific or the Atlantic Oceans to balance that up. Well, in.

[Roland Pease]

My goodness. So it's a huge accounting exercise.

[Jonathan Baker]

Yes. I've never heard of it put that way, but yes, exactly. As long as the upwelling mechanisms continue in the Southern Ocean, there has to be sinking in one of the other ocean basins.

[Roland Pease]

So it's possible for the this sort of density driven circulation to weaken in the Northern Atlantic, you're saying. So it can slow down, but you'll still get this engine going on around Antarctica that could keep it going even if, as it were, in a lower gear.

[Jonathan Baker]

Precisely. So we look at climate models, so the latest CMIP6 models, and use extreme climate change scenarios. And even in these models, the AMOC weakens a lot and there's a wide range in the amount of weakening. But in none of the models does the AMOC completely collapse. And so this gives us confidence that the AMOC is unlikely to collapse this century because we find that these Southern Ocean winds sustain the AMOC in that weakened state.

[Roland Pease]

So these are very strong winds that are what they're circulating the South Pole effectively and that by driving waves and stuff on the surface, they can churn up the Southern Ocean enough to keep it going.

[Jonathan Baker]

Yes, these are very strong westerly winds over the Southern Ocean because there's no land masses in the way these zoom around the Antarctica and push waters northwards at the surface due to the rotation of Earth. And this means that waters have to come up from below and must be balanced somewhere to the north.

[Roland Pease]

I don't want to sound like a pessimist, but are you sure you've got this right?

[Jonathan Baker]

So we find that the AMOC is unlikely to collapse this century. But unlikely doesn't mean impossible. So we should be aware of these risks. But our study suggests that the AMOC is very likely to weaken. And so these are the risks that we should focus on, along with the wider impacts of climate change and increased temperatures globally.

[Roland Pease]

Jonathan Baker, whose study was published by Nature this week, but don't think it's over. There are fierce arguments already about the modelling and the meaning of the results were mere spectators in this massive and consequential argument among climate scientists. Lastly, it's 20 years or more since a nanotechnologist told me this.

[Joel Fink]

What we intend to do, and I'm taking you into our chemistry lab here, is make things at a molecular scale, literally with chemistry. So we're going to make things, and here you can see we're assembling things chemically. We're going to make very simple things and then use what we know from computer science and computer architecture, to electrically download a very complex pattern into the chip we built and make it as powerful as any one of today's computers. What this is going to mean, and I find it very exciting, is not just a computer in your watch, and not just a computer on the button of your watch shirt, but a full fledged computer that's small enough to fit well inside the fibers of your shirt.

[Roland Pease]

He was imagining molecular computers which we're still waiting for. Meanwhile, conventional electronics has shrunk so much, think Moore's Law, that there's a paper in Nature this week I simply couldn't let pass by. It proclaims the invention of a single fibre computer that can be sewn into clothing. Is that an exaggeration? I asked team leader material scientist Joel Fink.

[Joel Fink]

Not at all. It is a fiber that has a complete computer in it. It has a processor, it has memory, it has communication, it has sensing in it, it has a battery. So, yes, it is a complete computer in a fiber.

[Roland Pease]

And a fiber which is, what? Is it sort of the thickness of thread of wool or is it sort of more like, I don't know, fishing line or something?

[Joel Fink]

Yeah, I would say it's a. It's a bit thicker. It's somewhere between maybe a thick line and a very thin shoelace, if you will. One thing, you know, I wanted to mention right at the get go is, you know, this paper, this publication really lays out a blueprint for what we believe is the future of computing and how humans are going to interact with computers and how computers are going to show up in our Life in the years ahead. So that, I think, is really what makes this work really different. Computers today are designed to get in your way. They're in your face, they're on your glasses, they're on your wrist. The big idea here is being able to incorporate computation into the things that we're wearing, which are called clothes.

[Roland Pease]

I mean, so first I can tell the main computing parts of these are things you can buy off the shelf. So these are tiny little chips, a bit like the ones you can inject into a pet, as far as I can tell for chipping your pet, that sort of size. But then it's the way you've connected these things up, package them, that gets them squeezed into a thread.

[Joel Fink]

Yeah. And there's a very good reason why computers today are in boxes. And the reason is they really need to be protected from the environment. Environment is not just rain or the water in your washing machine or the sweat coming off your body. It also is the RF environment that we have in. Everywhere we are, all the radio noise.

[Roland Pease]

Yeah.

[Joel Fink]

The antennas that are broadcasting, the wires that are going through the walls that generate electromagnetic fields. So a lot of care, and probably even more important is that the distance between all the different parts of the computer has to be fixed. And so that forces people that build computers to put things in a very controlled and well defined environment. Now think about the shirt you're wearing. It is stretching. If it doesn't stretch, you're not going to wear it. It's going to limit your motion. It stretches, it folds, it bends, it goes into the wash, it walks around with you. And so how to get out of the box literally here is not just about arranging different chips in a slightly different way. It's a different approach to computation. And the reason you're phones are not elastic, I'm not talking about flexible. Flexible is different. Flexible means it can fold. Your clothes have to be elastic. They have to stretch. There isn't a single instance of a stretchable computer that we know about. These fibers actually do stretch. And you could, you know, in the paper we talk about up to 60% of stretch if they're designed to do so. So a lot of things had to happen here. Yes, it is true that we build and we use components that are available. Some of them are wires that we, you know, we don't, we don't manufacture new types of wires. But those wires have to be made elastic for them to work. The chips. Normally you would pack them into a box. Here we had to string them out onto a, you know, A very long fiber. How they communicate, how they, how we shield them from the outer environment. All of this had to be sort of reimagined.

[Roland Pease]

I mean, to me it's a, it's a, it's a, it's a real example of the power of Moore's law. Let's see, 60 years on since it was first.

[Julius Seidel]

Yeah, yeah, yeah, yeah.

[Roland Pease]

And the imagination that you can squeeze this stuff and you got this fantastic picture in the paper of a T shirt with basically a computer down each seam as far as I can.

[Joel Fink]

Yeah, yeah, yeah, yeah. And so, you know, I, I would say there are four big ideas that this paper introduces. You mentioned Moore's Law, and actually that is the first idea. What powered the evolution and the rapid advances in computation was the original Moore's Law. But if you think about fibers, fibers have remained pretty much constant in their properties for thousands of years. On occasion, we, you know, we discover a new material in a fiber like, you know, nylon, but it still is providing the same properties that wool or cotton or silk did. So fibers haven't changed. How do you get a Moore's Law for fibers? How do you rapidly advance what a fiber is and what a fiber can do? So that is the first, I would say, big idea that the paper introduces or really builds on prior research that my group and others have been doing. How do we embed advanced functions into fibers? And you know, a few years ago we published work on a fiber microphone. And that did not have chips in it. It actually had a continuous structure. So, but zoom out for a second. A Moore's Law for fibers. Fibers in the years ahead are going to become ever more capable. So that's, that's, that's sort of the first idea. And there's another three additional ones.

[Roland Pease]

We might not have time for them all, but, but in a sense, you know, so I'm massively impressed by the cleverness of it and the way it sort of combines completely unrelated technologies. But presumably someone wants to have a computer, let's say, in the seam of their clothes. And I'm not sure who that would be.

[Joel Fink]

Okay, so that, so I would say as we speak right now, there's a courageous group of servicemen. A few of them are actually from the Royal Marines who are in the Arctic region.

[Roland Pease]

Computers enclosed. Soldiers in the Arctic. Far fetched. I'm Sergeant Thomas Smith. And I'm Corporal Andy Berrigan. We're all Marine mountain leaders from srs. We're in the Arctic of Northern Canada conducting a long range reconnaissance patrol where.

[Joel Fink]

The temperature sits between minus 30 and.

[Roland Pease]

Minus 50 degrees Celsius. With the wind chill, frostbite and cold weather, injury is a real threat. Part of what we're doing is testing fabrics with computers built into them that help us understand how well our insulation is working, how many calories we are losing every day, and whether our extremities are at risk of frostbite. In the future, these base layer garments will be trained with AI to help us stay safe. This will allow us to work longer and harder in these harsh conditions. Okay, I'll go on.

[Joel Fink]

These are the Royal Marines. There's other people from Canada and the US and other countries. They're actually the first group on the planet that are wearing these fabrics. And these fabrics are helping protect them, alert them to frostbite, and to help manage their caloric intake and other things out in a very austere and harsh environment. So fabrics providing services and kind of our view of the future is that fabric is going to be on us 24 7, and it's actually going to monitor our health and alert us to changes in our, you know, in our health profile. And that is, in a way, going to be the future of healthcare. It's going to be delivered through fabrics.

[Roland Pease]

You'll think of MIT wrapping up this week's Science in Action with warm, smart underwear. I'm Rowan Peace. The producer is Alex Mansfield. And we won't rest here at the BBC till we can outsmart that. At the BBC we go further. So you see clearer. With a subscription to BBC.com, you get unlimited articles and videos, hundreds of ad free podcasts and the BBC News channel streaming live 24. 7 from less than a dollar a week for your first year. Read, watch and listen to trusted independent journalism and storytelling. It all starts with a subscription to BBC.com. find out [e-mail] unlimited.