Huge eruption on a distant star confirmed at last

0:23Welcome back to the Nature Podcast. This week, an explosive emission of plasma from a distant star and the genetics of ADHD. I'm Nick Petra-Ciao and I'm Benjamin Thompson.

0:45Back in 1859, the sun got a bit overexcited, firing an explosive and enormous burst of plasma from its corona out into space. Down here on Earth, that plasma had quite the impact, causing a huge geomagnetic storm. Intensely vivid auroras were seen all around the world, and surges of electricity led to telegraph operators reporting being shocked by their machines, and some were still able to send messages, despite these telegraph machines not being plugged in. This event, known as the Carrington event, was a powerful example of a coronal mass ejection, or a CME. Less intense CMEs are actually pretty common, and the result of these ejections can sometimes be seen in the night sky as beautiful auroras.

1:40But astronomers don't have to rely on their eyes. they can also detect them thanks to the distinct bursts of radio waves that these events produce. These intense bursts are described as being bright compared to the background, and researchers have used them to glean a lot of information about the make-up of CMEs. And one of these distinct bursts appears to have been identified somewhere else, specifically a star some 130 light-years away from Earth. And this is unusual because, despite there being a huge number of stars in our galaxy, and despite researchers looking for a long time, so far the only definitive evidence of a coronal mass ejection happening has been from our Sun.

2:28This week in Nature, a team report details of what they say is the strongest evidence yet of a distant CME. They hope that their finding will help figure out the impact that these events might have on planets outside our solar system, helping to constrain the number of these exoplanets that might harbour life. To find out more about this work, I spoke to one of the team, David Conine, from Astron, the Netherlands Institute for Radio Astronomy. I asked him to explain a bit more about the characteristic radio signal of a CME. Once such a burst erupts from the star and it moves away from the star into the interplanetary medium, it can create a radio emission which is directly linked to the density of that region.

3:16So as the burst moves away from the star, it moves into less dense and less dense regions. So the frequency at which this radio emission is emitted drops down as the burst moves away. So you have this very distinct decrease in frequency over time as you see the burst in your radio data. And we see this tons of times on the sun, beautiful drifting bursts from higher frequency to lower frequency as it moves away from the star. So we try to look for that drifting signature on other stars. And this hasn't been seen before, because I imagine this is looking for a needle in a haystack. There are countless stars in our Milky Way, right?

3:53Yep, there are indeed countless stars in our Milky Way. And we try to look at the stars in the radio to see, hey, do we see such bursts? and especially with the now older telescopes, we could not really see any of these specific bursts. So people thought, well, maybe it's a sensitivity thing. Maybe we need just bigger telescopes or more observation time. Or maybe these bursts scale with magnetic field. Maybe if the magnetic field of a star is larger, if it's more active, maybe throws out these particles more often. So let's just target a nearby star for over 50 hours and see if we can find these bursts.

4:28And they could not. So they really thought, well, why can't we find this from the nearby stars, which is super active, which should show it more often than the sun does? Well, maybe these particles can't leave the star because the magnetic field is too strong. Well, it could be a very valid theory explaining why we don't see them in the radio. And then we just said, you know what? Let's just look at so many stars. That's such a huge amount of data. At some point, then we might find a real drifting burst, which could then be a CME. And you used a very special telescope to do this then. Tell me about the setup you used.

5:02It was the LOFAR telescope. Exactly. It's the low frequency array. We can say it is one of the largest telescopes in the world at lower frequencies, which has over 100 ,000 little poles of antennas across Europe. And we tried to, with this array, combine the stellar information in such a way with a very smart mathematical trick to act like we have a telescope with a dish that is the size of Europe. So we tried to find, we assume, very faint bursts from these stars very far away. And how long did your experiment run for then? How long were you looking at the sky? So with our work, we used the LOVAR 2 meter sky survey, which is a survey that tries to survey the entire northern sky.

5:45And each of these pointings has approximately 100 stars in them. And together with our French colleagues, we looked at each of those stars, which is around 100 ,000 individual stars for eight hours at a time, leading to a total of 100 years of stellar data, which we searched through to find this singular event. Let's talk about it then. So you did find an event that had this characteristic radio signal analogous to what's seen from a mass ejection from the sun. Tell me about it. Yes, exactly. We looked through our data and immediately by eye it was very clear that we found a sort of bursts from a star.

6:22So we have our eight hours of observation and we found a burst approximately a minute long which looked at least 20 to 30 times brighter than the background noise if nothing was there. As intensity, as energetic, it was a very vivid source. So we confirmed, well, does it actually come from a star? Is it not a satellite passing over? Yes, we confirmed it was actually from the star. And then we dove into the burst and we saw that it has this very characteristic drift, which we expect from the solar data, a perfect sweep from high frequencies to low frequencies. So it was very easily to spot. And so what do you know about this star?

6:58This star is a M dwarf, so it's a younger type star with lower temperature compared to the sun. It's a small one, it has around half the mass, half the radius of the sun, and its name is STKM1-1262. So it's really like a full phone number, and it points to the specific star which was found in which catalogue back in the day. You found evidence that there is a coronal mass ejection coming from this star. Of course, you've said there that this is a very different star to our sun. Could it be then that actually this isn't analogous, that this is something new, something different? It's not a mass ejection?

7:36That is, of course, always something that can happen. We can't go there and check. We have to deal with the information which we found, and we have to compare it with what we know. And we really know the sun very well. And really, on many different aspects, it really agrees with what we see on the sun. and therefore we really think it is a tracer of a coronal mass ejection. In any case, it will be a tracer of some mass moving away from the star. Let's say then that it is a coronal mass ejection. As you say, your evidence suggests that it is. People have been looking for these for a very, very long time and now maybe n equals 2 now, I suppose, in terms of stars that have these coronal mass ejections.

8:12Is this an interesting thing that we didn't know exists but now it does or is this of actual use in terms of what we know about how the galaxy and the universe works? It is definitely of use, like you said, and is now two. But more interestingly, for a lot of things, like what's the impact of stars on exoplanets, we always scale from the sun because we know the sun the best. We just say, well, if this star would be acting like the sun does, then it would reach this energy or it would influence the planet in such and such way. and now we actually have this stellar data point. So we now not only can extrapolate from the sun, we can actually use the data that we actually found from a star to make more robust estimations.

8:55You mentioned exoplanets there. Obviously, they're something of great interest to everyone, really. How might these coronal mass ejections affect exoplanets? And of course, the big question that everyone always has is, is there the potential for life somewhere outside of the solar system? Yeah, so this research definitely has to do with that as well, because the Kerington event for the Earth, it already influenced the magnetosphere of the Earth as it produced these beautiful, vivid aurorae. But if the Kerington event was brighter, two times as bright, you can actually partly ionize the atmosphere or start stripping away this atmosphere.

9:28So especially for the stars at which these coronal mass connections happen, for the exoplanets that are nearby, it's of quite high importance how this star behaves. Because of course we know it is very interesting to see how close this planet is to the star. Can there be liquid water? Or as we expect, life needs liquid water. It needs to be not too far, not too close by. It needs to be in a perfect zone, the habitable zone. But also now, does the star produce so many particles, it just strips away the atmosphere entirely? We assume that without an atmosphere, you cannot have life on an exoplanet.

10:04And so does this throw in another factor then, in terms of narrowing down the range of planets that may be able to support life, for example. Exactly. We can cross out a couple more if the star's activity would be too large. And your paper's out now. What does this work not do, do you think? What questions does it leave to be answered? And what do other folk looking at it who have been searching for these things for a long time, what do you think they'll make of it? For one, there's another way that radio emission can occur, produced by the electron cyclotron maser instability. And we tried our harness to really see, can this produce our burst as well?

10:42And it has difficulty doing so. So we're leading towards our more coronal mass ejection produced mechanism, but we can't really confirm that a hundred percent. And a way to do that would be by having simultaneous observations with optical telescopes and with radio telescopes, because you can see in the optical telescope, well, actually the star gets brighter as this explosion happens. And then in the radio telescope, you can see your drift. But it's super difficult to get these telescopes to observe a star at the same time, because the rates are so very sparse, with only one in 100 years of data.

11:17You can't just spend 100 years of pure optical telescopes looking at a potential star. So where does this work go now, then, do you think? What's the plan to make n equals three or four or five and so on? Yes, this burst was extremely bright in the data. So we expect maybe there are other dimmer bursts. So we're going to search through this entire data set very deliberately, very carefully to maybe find some more dimmer bursts. And if we do, or we're very happy, if we don't, that puts an extra additional factor on the rate of these bursts on other stars. And then we then can maybe opt to go to telescopes at lower frequencies.

11:55So maybe more bursts occur at these lower frequencies. or we can use a telescope which has even more time on sky to try to get this haystack even bigger and bigger to find our little needles. That was David Canine from Astron, the Netherlands Institute for Radio Astronomy. To read his paper, head over to the show notes for a link. Coming up, how understanding rare genetic changes could help unpick the mechanisms of ADHD. Right now though, it's the Research Highlight with Dan Fox.

12:30Video footage of a devastating earthquake in Myanmar has provided a first-of-its-kind glimpse of a dramatic rupture. The magnitude 7.7 quake hit near Mandalay in March and killed at least 3 ,800 people. Seismometers and other instruments measured the rupture tearing through the ground at high speeds, but researchers were also able to analyse CCTV footage from a camera that happened to capture the quake just metres from where the fault broke. This camera recorded pillars, fence posts and other structures heaving past one another as the ground shifted. The video revealed that the two sides of the fault slipped three metres past each other in just 1.4 seconds.

13:14The researchers suggest that setting up video cameras next to large geological faults could provide an innovative way to study earthquakes as they happen. Read that research in full in Science.

13:30Astronomers have observed a flock of comets outside of our solar system. Researchers observing the star RZ Piscium noticed a peculiar periodic dimming. Typically, such a dimming suggests that an object is passing in front of the star, causing it to appear fainter by blocking a small patch of light. After analysing the star's light, the team decided that the culprit wasn't one object, but 24, a group of comets, each between 1 and 7 kilometers in diameter, that passed in front of the star about once every two days. Because these objects are so rare, many questions remain. Most importantly, what are they made of?

14:10The team hopes that observations by a potential NASA mission called EVE might provide some answers. You can find that paper in the Astrophysical Journal Letters.

14:27Next up, a new study is unpicking the genetics of ADHD by looking at rare variants of genes. Attention Deficit Hyperactivity Disorder, ADHD, is a condition that affects around 1 in 20 young people. As the name suggests, it's characterised by prolonged inattention and hyperactivity that are severe enough to affect people's daily lives. For instance, without intervention, some may struggle to perform well in school or at work. Currently, the causes of ADHD aren't fully understood. Although environmental factors are believed to be important, researchers think genetics plays the biggest role. Getting an insight into the complex interplay between genes may help researchers understand exactly what biological mechanisms are involved that could increase the risk of someone developing ADHD.

15:20For example, while it's known that the brains of people with ADHD are less sensitive to the neurotransmitter dopamine, what happens at the genetic level could help unpick what proteins and cellular mechanisms are involved. That's where a new study in nature may help. The researchers behind it have been looking for gene variants associated with ADHD. Gene variants are differences in DNA between individuals and in some cases they can lead to different or non-functional proteins being produced. In this work, the team have found particular rare variants of genes that appear to play a role in the cells that produce dopamine, amongst other things.

16:01To find out more, I spoke to Didi De Montes, one of the authors of the new study. She laid out for me how they went about looking for these rare variants. So what we did was we used a subsample of a Danish cohort that is called iSYC where we generated exome sequencing data for a lot of individuals with ADHD, so almost 9 ,000 individuals with ADHD. And when I say exome sequencing data, I mean that it is sequencing data for the coding regions of the genome. And then we also have some control individuals, also from eyesight, around 9 ,000 individuals. And actually, we also combined the control individuals with individuals from the NOMAD database, which is also a huge database that has collected exome sequencing data from a lot of different studies.

16:52So in total, we had around 53 ,000 individuals in the control group. And then we had this exome sequencing data, and there we could identify genetic variants, and then we could annotate the variants with respect to their functional significance. So we identified variants that were nonsense variants. So they introduced premature stop codon to the gene. So they destroyed the function of the gene. And also mutations that could also potentially be deleterious and mutations with a high impact on, for instance, a protein folding. So again, the protein would not function well. And is it just a case of looking at the people without ADHD and looking at the people with ADHD and just seeing what the difference is?

17:37Or how exactly do you do it? Yes. So what we did when we identified these variants, then for each gene, we could summarize how many do we see of these deleterious rare variants in those with ADHD and how many do we see in the controls. And in that way, we could do a statistical test in order to identify genes that were significantly enriched in individuals with ADHD. And in that way, we were able to identify three genes, the first three rare variant risk genes for ADHD. So you found these three genes then that were enriched, they occurred more often in people with ADHD than in people without. What were these three genes and do we know much about them?

18:17Can you tell me what it is that they do? Yeah, so the three genes are MAC1A, NO8 and ANC2. And we know from different other data sources that all of them are expressed in the brain and in particular neurons. So that makes very good sense with respect to the phenotype of ADHD. And we also know, for instance, ANC2 has also been identified as a rare variants risk gene for autism. And so what are you able to understand by finding these three variants? What are you able to, I guess, tell us about ADHD by finding these three? So what we did after we identified these three genes, we then asked the question, could these genes potentially be involved in protein networks that tells us something more about ADHD?

19:09So we took these three genes and then we looked in different neuronal cell lines and then we pulled down the protein encoded by these three genes in excitatory neurons. And we also got a range of other proteins that directly interact with these three proteins in order to generate protein-protein interaction networks with these three genes. So this was done in cells derived from neurotypic individuals, so not individuals with ADHD. So we identified these three protein-protein interaction networks. And then we asked the question, okay, these networks, are they enriched in rare variant risk genes that have been identified also in autism and neurodevelopmental disorders?

19:58And we found that they were. So that again tells us something about that these three genes and also the interacting partners potentially could be involved in general mechanisms related to development of the nervous system and the brain. So you looked at these three rare variants then, and you also then found the interactions that they have with different proteins. And you found some things like, you know, their involvement in development and their involvement with neurons. and you also then looked more broadly at the top 100 genes that you'd identified. What did you find with these? So for that we used single cell sequencing data from midbrain neuronal cell types and there we found that these 100 genes had a significant increased expression in dopaminergic neurons and this result is actually also of particular interest with respect to ADHD because dopamine is playing an important role in ADHD.

20:58And we actually know that because stimulant medication medicine that is used to treat ADHD symptoms actually treats the symptoms by going in and increasing the concentration of dopamine in certain regions of the brain. So do you think there's a pretty good likelihood that these top 100 risk factor genes that you've identified are doing something mechanistically. Yeah, that potentially could be, yes. And so because of that, do you think there are potential ways that this work could help people with ADHD? Yeah, so I think this can really help us to pinpoint, again, the specific genes and we get closer to the biological mechanisms that are involved.

21:45But I want to add two things. First of all, we have identified these three genes, but there are certainly more rare variant genes that needs to be identified. That's one thing. And another thing is also that I would like to mention that when we looked broader at these deleterious variants in individuals with ADHD, we found that it's actually only one in five individuals with ADHD that has such a rare deleterious variant that increases the probability of getting ADHD. So in other words, it's not everybody with ADHD that has such a rare variant that contributes to the probability. And so what do you think all of this means?

22:29Like, what would you like people to take away from this study? I think what our study is really contributing to the knowledge about the complexity of ADHD. What we are now picking up with respect to genes that are involved in ADHD is most likely also genes that are involved in other neurodevelopmental disorders like, for instance, autism. It's genes that have most likely a very fundamental impact on the development of the nervous system. That is why some of these genes are really shared across conditions. That was Diti DeMantis from Aarhus University in Denmark. For more on that story, check out the show notes for some links.

23:12Finally on the show, it's time for the briefing chat, where we discuss a couple of articles from the Nature Briefing, which is of course Nature's daily email roundup of science news. Nick, why don't you go first this week? What have you been reading? So I've been reading in Nature about a kind of Google map, but not a sort of map that you may be familiar with. This one could tell you, for example, the way to Iboricum, or to Singidungum, or even to Rome. This is a map that researchers have built that shows the extent of Roman roads, and it's basically the most in-depth one of these yet. Oh, fantastic.

23:51Well, I grew up in a town that was once the Roman capital of Britain, and that is Colchester. So I'm a big fan of Roman roads. We had loads of them. The longest one was just called Straight Road because it was a very long, very straight road. But I'm guessing that these roads crisscross much of Europe and beyond. What was and what wasn't known about them? Well, there's a lot that isn't known about them, actually. So in this analysis, they've compiled together and created a map of 300 ,000 kilometres worth of these Roman roads. So as you say, it is very much crisscrossing all of Europe. But what they did find as well is that despite being able to map out 300 ,000 kilometres, they could only say that around 3 % of them are in the right place with surety.

24:38Another 7 % they've got some evidence for and most of the roads, almost 90%, are basically, they've got an idea that they should be there but there's no good evidence for it. And one of the lead authors of the study said that this was a huge and sobering realisation that 3 % certainty figure isn't a failure. It's a call to action that gives us a precise confidence map of what we don't know and where to look next. So this is a really in-depth analysis that is showing us exactly where all these roads we think are, but it also shows us how much we don't know about these roads as well. Right, because a long time's passed since things like Straight Road were put down.

25:17But while they exist and exist contemporaneously, you're right, I'm sure a lot of stuff was buried under years, decades, centuries of what came later. So what information were they using then to say there was probably a road somewhere around here? As much information as they could get, basically, they have compiled a lot of different things. So they've got atlases, surveys, historical sources, archaeological sources, milestones, so like literal existent milestones that you can see out in the world today, like Straight Road probably has. And they've combined this with satellite data and aerial photographs from now and in the past as well to come up with this essential, like I say, almost Google Maps for Roman roads.

26:00It's called Itina E, like Itina, which is Latin for road and E as in, you know, electronic like email or something like that. And obviously itinerary. They're having a bit of fun with the name. And so the map, for example, could tell you the way from Colchester to Londinium, which is the Roman name for London, amongst other places. Anywhere you want to go in the entire Roman Empire at its greatest extent in 150 AD, this map could show you how to get there. and you could see how long it would take you to go by walking, or if you wanted to go with a pack animal, or if you wanted to go by cart. They've plotted all this out for you, so you can have a go and see.

26:39I mean, it seems like a lot of fun being able to plot how long it would take me to get to York using a chariot. But other than it being a lot of fun, is it helping archaeologists and folk studying the Roman Empire learn more about what was going on? Yeah, as I say, it shows us what we don't know, which is very useful for archaeologists and historians to try and figure out like you know where do we need to do the next bit of archaeology what do we need to do to understand these roads better and also by having this network of roads it could help us understand how things spread around the roman empire and that's not just disease that could also be people that could be ideas anything that spreads if you look at epidemiology they tend to spread along the places where people move.

27:24So that could help researchers understand that and what role things like pandemics had on the Roman Empire. I must confess I'm slightly surprised Nick that this hasn't been attempted before because of course a lot of that data is out there and the Roman Empire is incredibly well studied. So why has it taken until now to really give this a go? Well it's not actually the first time that it's been done. There have been other attempts to do this so for example there is something called the Barrington Atlas of the Greek and Roman world which is basically an atlas as its name describes of this and there's also a digital atlas of Roman and medieval civilizations that has also done this sort of work and digitized what we know about the roads to try and understand it but the difference between what they have done and what this has done is they've not drawn as many sources of data as this and when it comes to mapping where certain roads went they've just sort of gone from one place to another which doesn't necessarily represent what may have happened because for example if there's a mountain or something in the way it's unlikely the Romans just cut straight through it so this new map actually makes more winding roads where they're necessary to go through things like mountains and so part of the way that they've been able to describe a lot more roads it's actually doubled what's been done previously is because of this they've sort of been going around the sort of geography and everything and as I say combining this with satellite data and just all these different sources that allow them to get this really like as I say almost like google maps for the roman world I shall certainly be going to have a play with that one later on but before then let's move on to our second story this week and this is a story that I've been reading about in nature and it's based on a recent Nature Aging paper that came out this week, and it's about how speaking multiple languages could slow down brain aging and help prevent cognitive decline.

29:23I'm sorry to hear it because I speak English and Subskans. Absolutely right. This is the point where you say, yes, you do speak more than one language. Now, what I'll say is, previous research has suggested that speaking multiple languages as you do could improve cognitive functions such as things like memory and attention which boosts brain health as we get older but these previous experiments were kind of small samples perhaps they used methods that were considered unreliable for measuring aging so the results were somewhat inconsistent but now as i say this new experiment has come along and so what did they do in this new experiment then to try and i guess avoid some of this uncertainty that's come before well one thing they did was they included a lot of people.

30:11So it's a big study. It uses a computational approach to explore whether there is this link between speaking more than one language and slowing down brain aging or preventing cognitive decline. And it includes 86 ,000 participants aged 51 to 90, and they came from 27 European countries. And in this work, they determined the bio-behavioral age gap of these people. Now, let me explain what that means. This is the difference between someone's chronological age, literally how long someone has been alive, and their predicted age, which considers physiological, lifestyle, and socioeconomic factors, things from cardiovascular health through to education levels.

30:54And a high bio-behavioral gap, so a big gap between these two figures could indicate that someone was aging more quickly. And the main part of this research is that the researchers compared the number of languages someone spoke with their biological age gap. So literally then speaking one, two, three languages, you can see a correlation between that and this expected age that people should be. Right. But it has to be said, this component of how many languages someone spoke was self-reported, right? So it didn't take into account levels of proficiency. But folk who spoke only one language were twice as likely to have a high bio-behavioral age gap than those who spoke two or more languages.

31:38And the effect increased with the number of languages spoken. So as you say, the more people could throw in there, the smaller that gap would be. And one of the folk quoted in this article says that this really large study, quote, really strengthens the interpretation that multilinguism rather than other factors protects us during ageing, end quote. And do they have any idea of what the mechanism of this might be? I've never read before that maybe it's something to do with, you know, the difficulty of trying to learn another language. And I can certainly attest it is difficult. Is it something like that, that's sort of like keeping the brain going?

32:14Yeah, this is a great question. And I think it's one that's unanswered currently. So what is it about being multilingual? Is it, as you say, the act of learning a language. Now, I wouldn't describe myself in any way as a multilinguist, but the Brazilian Portuguese lessons that I took for several years a decade ago, is that enough? Or is it the act of using them day to day, which, of course, are very different experiences? Now, this is something that needs to be unpicked. But the researchers do hope that their findings will influence policymakers to encourage language learning in education. Because, of course learning a language offers many many benefits certainly cultural benefits right it expands one's horizon but it seems like maybe this is some evidence that it could help lead to healthier aging too well i will be looking forward to the next 50 years then as i age more healthily or at least i hope so but that's really interesting ben thanks for telling me about that and listeners that's it for this week for the briefing chat if you are interested in those stories and you want to read more or you want a link of where you can sign up to the nature briefing to get more like them straight to your inbox, check out our show notes for some links.

33:21And that's all for this time. If you'd like to stay in touch with us, you can reach out to us on X or Blue Sky. We're at Nature Podcast. Or send an email to podcast at nature.com. Benjamin Thompson. Aya sam, Ník Petru, cao. Avala vam na pažni.

33:48you