This is what lightning on Mars sounds like

0:23Welcome back to the Nature Podcast. This time, micro-lightning heard on Mars. And what was agreed at the COP30 climate conference. I'm Benjamin Thompson. And I'm Nick Pertrichow.

0:48Lightning. This dramatic phenomenon continues to pose problems to researchers. We don't know much about how it starts and propagates, for example. And that's just here on Earth. On other planets, even less is known. We've seen evidence of lightning on Jupiter, for example, but closer to Earth, on Mars, there's never been compelling evidence. Well, perhaps until now. So, low in frequency, you hear the rumble of the wind. And then in the middle of the recording, you hear a loud noise. You know, as if you unplugged the jack cable of your speaker, you know? This sound is basically the sound of the discharge.

1:32This is Baptiste Schid, a planetary acoustician describing the sounds of mini lightning recorded by a microphone on the Perseverance rover on the surface of Mars. Now, as you may be able to hear, this is quite unlike the sound of lightning we're familiar with on Earth. and that's for good reason. It is quite different to earth lightning. Baptiste calls it micro scale lightning as these discharges are only millimetres to centimetres in length and they have much less energy. A nice analogy would be you know during winter if you touch your car door sometimes you have an electrical discharge between your car and your hand you can feel it.

2:15It's like really small in energy still you can feel it but it's really small in energy and it would be about the order of magnitude of the energy that is released on the discharge on Mars. Any kind of lightning on Mars would be like this due to the thinner atmosphere. Certain gases in the atmosphere can act as insulators, meaning that charges need to reach higher levels to overcome this. Thinner atmospheres, like Mars' have lower resistance and so would allow more frequent smaller discharges. Now researchers have figured for a long time that Mars should have electrical discharges like this. Experiments on Earth and models of Mars have suggested that dust particles there should produce electrical fields.

2:59Now exactly how lightning on Earth or on Mars forms is a little bit debated, but in general it's thought that it starts when particles collide with one another. In the turbulent environment of a storm cloud, particles of water and ice can hit one another and transfer electrons, creating a charge difference. Eventually, the charge difference can become big enough to ionise the atmosphere, and then...

3:29So on Mars, we basically have the same phenomena, which is called tribo-electrification, but the particles at stake are the dust particles. Dust is certainly something that Mars has a lot of. At times, the entire planet can be covered in dust storms. As these particles rub together, it's been thought that electrical discharges, this tribo-electrification, should occur. Actually documenting that, though, has proven challenging, as it's pretty tricky to get the right equipment to Mars. There was an instrument, part of the ExoMars Caparelli lander, that was supposed to land on Mars in 2016. Unfortunately, it landed on Mars, but at a speed that it crashed on Mars, basically.

4:16So there was an instrument part of this mission that was supposed to measure electric field. But because of the crash and the failure of this mission, it was still unknown. Fortunately, Baptiste was struck by a brainwave while listening to a talk at a conference about how electrical activity propagates on Earth. And then I thought, wow, but that could happen on Mars. And if it happens on Mars, we should be able to hear it with the microphone. The Perseverance rover happened to be equipped with a microphone, and thunder is basically a shockwave, something that should be quite noticeable if captured on the microphone.

4:52The only wrinkle is that sound propagates quite differently in the thin Martian atmosphere than it does here on Earth. But that's when another stroke of luck hit. the rover had been capturing the sounds of shock waves for quite some time part of the perseverance rover we have this laser instrument which is called superchem it's a geology chemistry instrument it basically ablates some fraction of the rock with a laser this laser is so powerful that it vaporizes a small fraction micrometer micrograms of the rock at the surface it creates a plasma and this plasma creates a shockwave so we listen to this shockwave every time with the microphone so we knew really well how a shockwave would sound on us and indeed scanning through the recordings they found this this was another stroke of luck as the microphone was only turned on for three minutes every two days it happened to be turned on just as a dust devil a whirlwind of dust passed by the rover.

5:57Some more data diving and they found 55 such distinctive bursts, and seven of these coincided with another clue that this may be extraterrestrial micro lightning. The microphone, like a lot of electrical equipment, was sensitive to electrostatic interference. The team were able to pick this up just before the sound of the micro lightning. Baptiste and his colleagues think that this is compelling evidence of microlightning on Mars. Dan Mitchard, a lightning expert and news and views author for this new study, agrees that it's likely these signals are evidence of such electrical discharges on Mars.

6:38I think they have a very convincing case in their paper that this is coming from outside the rover, some centimetres away. It is correlated to dust storms, which is what we'd expect. So yeah, I think it's a very convincing case that there is lightning as we would expect there. Such signals have been sought for a long time though, so the question remains, will everyone be convinced? Seeing is believing after all. I think as humans we tend to like pictures and I'm sure it will inspire some new cameras or some new technology to go there to try and image this. I think it's a very good step forwards.

7:16But there has been a debate for many, many years. And I'm sure there are people out there who will not be fully convinced that this isn't something from the rover itself and is something in the atmosphere. But the authors of the paper have given a very convincing overview and very good in-depth discussion and some good analysis as to why these discharges were to hear as kind of little energetic bursts, which are accompanied by some electrical interference, why these exist in the atmosphere outside of the rover and why they're not coming from the rover themselves. To unequivocally confirm it, future missions will need to send equipment specifically designed to capture data about this micro-lightning, possibly including cameras.

7:59Although getting this micro-lightning on videotape may be tricky as it happens within dust storms and is probably a lot dimmer than the lightning we're used to on Earth. Finding such data may be particularly important, though, if we ever plan to go to Mars, as dust storms are a regular occurrence there, so these discharges will probably be pretty common. And lightning, even at the microscale, can cause all sorts of problems. If we think about future astronauts at the surface of Mars, we need to design some spacesuits for these astronauts exploring at the surface of Mars. And these spacesuits will have to be designed with the knowledge of these discharges and make sure that there cannot be a hazard for astronaut spacesuits.

8:45In the more immediate term, this finding may help researchers understand the atmosphere and chemistry of Mars. Here's Dan again. On Earth, lightning has a huge input into atmospheric chemistry. It has the energy to break apart molecules. And those sparks that we see will have enough energy, or at least we think they have enough energy to break apart some of that chemistry within the atmosphere so breaking apart the carbon and the oxygen and the nitrogen molecules so it's very important for understanding atmospheric processes on Mars but also it may create organic molecules it may also degrade organic molecules so it kind of links back into looking for evidence of life or organics on Mars as well, whether lightning may have played a role in creating or destroying some of that evidence.

9:38So yeah, it's a very important find. These discharges could also explain the mystery of methane on Mars. The gas has been shown to rapidly appear and disappear, and while there have been a range of explanations suggested, nothing is entirely clear yet. But micro lightning could be a piece of that puzzle, as these energetic bursts could increase the rate of destruction of methane in the atmosphere. This will all need more research to figure out. For now, Baptiste is happy that he's found something else that will help researchers understand our mysterious red neighbour. Such a small phenomena might have very important consequences on atmospheric chemistry, surface chemistry and even an impact on the climate of Mars because it influences the transport of this particle.

10:29So I guess we've just discovered one of the missing parts to understand the Mars atmosphere in general. That was Baptiste Scheid from the University of Toulouse in France. You also heard from Dan Mitchard from the Lightning Laboratory at the University of Cardiff here in the UK. For more on that shocking discovery, check out the show notes for some links. Coming up, the UN's climate conference, COP30, has come to a close in Brazil. We'll take a look at the key outcomes. Right now, though, it's time for the research highlights with Dan Fox.

11:07Seahorses, pipefish and sea dragons share a unique trait. The males give birth to live young. Now, new research suggests that the molecular and cellular development leading up to this point is remarkably similar to that involved in mammalian pregnancy. Males of species like the lined seahorse have evolved specialised pouches to carry and birth their young. To get a better sense of how these pouches develop, a team examined the cellular, DNA and RNA profiles of pouch cells. As with the mammalian uterus and placenta, seahorse pouches form from a combination of stem cells, epithelial cells and connective tissue.

11:51What's more, the RNA profiles of pouch cells are similar to those of uterus and placental cells in mice and humans. Pouch development is driven by the hormone androgen rather than a female hormone. but the authors say the similarities suggest universal challenges that had to be overcome as live birthing evolved. Read that research in Nature, Ecology and Evolution.

12:19Researchers have identified subtle genetic differences that might have contributed to Neanderthals' beefy jaws and gained an insight into how the human face developed. Neanderthals tended to have bigger noses, a more pronounced brow line, and larger lower jaws than modern humans do. To investigate why, researchers examined a stretch of DNA that causes the underdevelopment of the lower jaw if it is deleted or rearranged in humans. This sequence controls the activity of a nearby gene, called SOX9, and differs by three DNA residues between humans and Neanderthals. Introducing the Andephal variants into zebrafish embryos resulted in higher regulatory activity in embryonic cells involved in forming the lower jaw, compared with when they introduced the Homo sapiens version.

13:11Meanwhile, cranking up expression of human SOX9 protein in zebrafish embryos also resulted in a larger volume of jaw-forming cells. The authors say these results might help researchers to understand how subtle genetic changes have led to the diversity in human faces. Keep your chin up and find that research in development.

13:36This weekend saw the conclusion of the UN's COP Climate Conference, this year held in Brazil. Joining me to unpick what was decided at the event is Jeff Tollefson, senior US correspondent here at Nature. Jeff, how you doing? I'm good, Ben. Thank you. Well, COP is over then, and I don't think it's an exaggeration to say that it was very much a bumpy ride at the end there, but an agreement has been reached between the participating nations after a marathon negotiating session. Yeah, that's right. It wasn't easy. There were some threats that maybe no agreement is better than a bad agreement. But countries came through.

14:16They settled on a series of agreements that are all part of a package outcome that nobody is satisfied with, but that keeps the process alive. So I think that's the good news. Let's start breaking those down. But first, then, what's the take home of what has been agreed then? Well, it's kind of hard to say. If you look at the big issues, like how do we stop greenhouse gas emissions and halt climate change? Not a lot, actually. There are some processes in place to try and speed things up, but the negotiators were unable to come to an agreement on creating a viable roadmap for phasing out fossil fuels.

14:50That was one of the controversies at the very end. The negotiators did come up with an agreement to triple finance for adaptation, which is basically money from wealthy countries that can be used by their poorer counterparts to help prepare for inevitable impacts of global warming. And then there was another portion that some of the researchers we spoke to were very happy with, which was about creating a mechanism that would enable a just transition. So this is basically the idea that you don't want to cause more problems as you're transitioning to a green economy for people who are vulnerable.

15:26This could be workers, it could be vulnerable communities that are dependent on fossil fuels. There are all sorts of situations. And this new mechanism is basically a way for maybe countries to align their policies and make sure that their development is equitable going forward. So there are small hits here and there. But overall, there's not a lot that you can point to that says this was a massive achievement. And interesting, because we are now what, 10 years after the Paris agreements. And this COP in Brazil, COP30, was dubbed the implementation COP, right, getting things done. And it seems like a mixed bag, to say the least, that in.

16:04That's right. Ten years. And if you think about it, what the Paris Agreement was designed to do was create kind of a five-year stepwise process that would allow, enable, and encourage countries to, over time, increase their ambition to do more, to reduce emissions faster, to tackle climate change, and to do what needed to be done. Because everybody recognized in 2015, when the Paris agreement was signed, that the commitments were woefully inadequate. But the hope was that over time, countries would build trust as they learned to do what needed to be done to reduce emissions. And as you built trust, then maybe countries would increase their efforts and slowly you would reach the kind of ambition levels that would achieve the agreement.

16:52And what we saw here was, you know, kind of exactly the opposite. Something like 40 % of the countries didn't even bother to submit new pledges for 2035. The rest, those who did, submitted commitments that won't really change things very much. So the world is still looking at nearly three degrees, maybe 2.6 degrees, according to some projections of warming this century. And Jeff, you're someone who's covered many COPs and been to several of them too, it has to be said. It did feel from the outside that this one was particularly fractious in terms of the negotiation. And it seems that, as you say, a lot of people were very unhappy with what was agreed upon.

17:31Do you think that's the case? Oh, I think that's definitely the case. The science is clear. We know what needs to be done. Scientists have told policymakers what they need to know, what they need to do. And really, it's about implementing policies that will speed up the transition from dirty fuels to clean fuels. So to some extent, we know how to do this. And that's the frustrating thing, I think, for a lot of people who go to these COPs is, you know, why are we still arguing about details rather than trying to actually get the work done? So yes, this was supposed to be the implementation COP, and we don't see a lot of implementation coming out of it.

18:11Presumably, there'll be some nations, though, that aren't too sad about that, though. Well, that's right. I mean, if you look at the disagreement over the language to create a roadmap to phase out fossil fuels, and then you look at who opposed that, not surprisingly, these are petrostates and others. But yes, there is a large set of vested interests among countries and communities that are still benefiting economically from fossil fuels. And this is one of the discussions that's being had coming out of this COP is how do you overcome those political obstacles and economic and social obstacles.

18:47And so this overarching roadmap then of phasing out fossil fuel use didn't come to pass in the final COP text then. But Brazil, as hosts, did commit to outside of COP developing two other roadmaps, one to transition away from fossil fuel use and the other one about ending deforestation. What's the word on these? Will they be binding in any way? Will they have any teeth? I don't think we know. So Brazil pushed hard for some of these ideas. I think the Brazilian leaders were as disappointed as many others that they weren't able to get commitments to develop these roadmaps in place. So they're saying they're going to carry this process forward to develop these ideas further outside the COP.

19:29I don't think we know exactly what that means, but perhaps we will learn more in April of next year when Colombia and the Netherlands host this conference to discuss a just transition away from fossil fuels. So there is kind of movement to say, OK, well, if we can't do it here at the COP, maybe we can do it outside the COP. The question will ultimately be, how do you then bring it back to the COP? And does it have more teeth or fewer teeth? We don't have the answer to that question. And of course, one thing that we do need to discuss is the elephant in the room, perhaps the lack of elephant in the room, I suppose, with the US not sending a delegation.

20:08How might that have affected how things panned out? The folks that I've spoken to say that, you know, if you're going to have an intransigent giant sitting at a table throwing rocks in the spokes, that is perhaps more disruptive than having an intransigent giant not at the table throwing rocks in the spokes. I think some parties were certainly relieved that they didn't have to deal with an American administration, which is opposed to kind of action on any of these fronts and which declares global warming to be basically a hoax. The larger question is whether other countries are kind of hiding behind the US and doing less because they know that the world's largest economy is not taking global warming seriously, at least at the federal level.

20:57I don't know if we know those answers yet. It's certainly a danger. One story that you'll hear from people in the US and outside the US is that even though the Trump administration is not taking these issues seriously and is actively working against the climate agenda. There are plenty of states and communities and American businesses that are still taking it very seriously. And what of researchers then, Jeff, what does the document say about climate science and how have they taken what has been agreed? Well, the scientists I've spoken to, I mean, again, in many ways, and this is a good thing, this process was not about the science in that nobody was debating whether global warming is real and whether we need to take this seriously.

21:41So, you know, this is the good news. The science is and was, in many senses, kind of taken for granted. The real question is, you know, what you do about that. So, you know, again, the scientists I've spoken to are relieved that the process is continuing to move forward, but disappointed that governments still do not seem to be taking their commitments to reduce global warming this century seriously. And again, those commitments are already enshrined in the Paris agreement. Governments have already said that they intend to do this. They just do not seem to be ready to put forward policies that would actually accomplish those goals.

22:18Well, Jeff, thank you as always for joining me to lay out what's happened at this year's COP. Jeff Tollison, thanks for being here. Thank you, Ben. To read Jeff's coverage of COP30, look out for links in the show notes. Finally on the show, an analysis has shown that women seem to retract fewer medical research papers than men. To dive into the details of this and discuss why this might be, I'm joined by Jenna Ahart, a reporter here at Nature. Jenna, hi, how's it going? Hi, I'm good, Nick. To start off with, can you give me a bit more details about this analysis and what they found? Yeah, sure.

22:51So, this is a paper that came out in PLOS One about a week ago. They looked at 900 different retracted medical journal papers published between 2008 and 2017 and just using an AI tool inferred the gender of the different authors on all the different papers and found that only about 23 % of them were female authors. You know that sort of clearly jumps out as women being underrepresented in these retracted papers but what I think makes this study a little bit more unique is that they also looked at the non-retracted work as well. So looking at the first authors and last authors they found that 16 % and 12 % respectively were women in their retracted papers.

23:30And then looking at the same journals over the same time period for all papers, not just retracted ones, they found that that number is 30 % and 40%. So it sort of shows that not just that women are underrepresented in retracted papers, but they're even more underrepresented than in non-retracted papers. Right. So when women are on papers that are retracted, it's almost a 20 % difference compared to just all other papers. Yeah, yeah. And I should note that that 30 % and 40 % are pretty rough numbers. But yeah, it is a pretty stark contrast, which I mean, I didn't expect when I was reading it. You mentioned that they used an AI tool to go about this as well to infer the gender of the authors.

24:08So was this just scraping all the data about these papers and the authors on them and then assigning male or female like that based on the name? From my understanding, that's how it worked. And there are definitely caveats to that. For instance, it doesn't recognise non-binary identities. And I think it doesn't work as well for non-Western names as for Western ones. But the authors did check a lot of the names and there weren't any mismatches. So it seemed to be working well. And then I guess the big question is why this might be the case. And you talked to a lot of different people to try and understand what might be going on here.

24:44What were their thoughts? Yeah, so right now, it's hard to say for sure, because the authors are very careful in this study to clarify that they aren't investigating causality, and this is really just about the numbers for now. But the authors did tell me that they think it could be that women still aren't in these senior positions or leading projects as often, which could lead to fewer retractions. And then I spoke to, I think, three different outside commenters who were involved with the study just to get their take on this. They mentioned how it could be that, you know, similarly that because men might have more visible careers in science, they're subject to more scrutiny, which could lead to more retractions.

25:23And then others thought it might be more of a matter of how women are socialized versus men. So it could be that women are trained to be more detail-oriented while men are trained to be risk-takers, which could lead men to make more retractions. And then one of my sources pointed to a really interesting study that showed that women tend to work in more tight-knit research groups and work with the same collaborators for longer periods of time. So when you're building that level of trust, you know your collaborators work better and you can trust them to do it well and ethically. So that could also lead to fewer retractions.

25:53So yeah, lots of different possible explanations. I think all in all, the different sources I spoke to agreed that these results were really interesting and novel, but they weren't terribly surprising because this is a phenomenon that we already see a lot in scientific research. So do they mean that this is more evocative of a broader trend in science? It seems to show this larger gender imbalance in the sciences. It seems to exaggerate this issue in their attractions. So maybe their attractions themselves seem new and are a little bit surprising, but I think it sort of underscores this underlying issue.

26:27And obviously, there's a lot of different ideas that have been presented as to why this might be happening. Did anyone offer any ideas for research in the future that could help unpick exactly what's going on here? Yeah, I spoke about this with the authors a little bit. And they said that one option and one they're interested in after the study would be to conduct some interviews with the authors involved in these retractions, just to better understand, you know, how personally their gender experience or their socialization and upbringing may have shaped how they approach their research or something like that.

26:59And one of the other sources I spoke to said that it might be a good idea to look more in depth at the teens involved in these studies. So like I was saying, how it could be a matter of how tight knit and how long these teams have been working together as well. And so what do you think the implications of this study are? What could it mean for our understanding of gender imbalances in science? Yeah, I think right now there's no easy answer because it seems that these different factors are very intertwined and there's so many possible explanations for why this could be occurring. And also the authors are still sort of figuring that out themselves what the big takeaway is here.

27:36But just from my conversations with different sources, it seems that this more just demonstrates how retraction statistics seem to further exaggerate the imbalances that we already know are there in science. And so that could be something to keep in mind when talking about publishing literacy and ethics and how to navigate retractions. Jenna, thanks so much for joining me. Thank you, Nick. That was Nature's Jenna Ahart. For more on that story, check out the show notes for a link to genus news story and that's all for this week as always you can keep in touch with us on x or blue sky we're at nature podcast or you can send an email to podcast at nature.com i'm benjamin thompson and i'm nick petra ciao thanks for listening