Is confirmation of alien life closer than we think?

0:03Hi, I'm Julie Banks and welcome back to The Standard Podcast. If you're new here, hit follow and give us a rating. Coming up, the Easter bank holiday weekend is almost here and The Standard's food and drink writer, Josh Barry, is on hand with ideas of what to do and where to go in the capital to keep the family entertained. Brixton Village has got an Easter egg hunt going on and there's so many great restaurants and bars and so on in Brixton Village for kids or adults or both.

0:39But first, astronomers believe they have discovered the strongest evidence yet that life may exist on a planet outside our solar system. A group of scientists, led by the University of Cambridge, have published the results of their study in the Astrophysical Journal Letters. Dr Subhijit Sarkar is a lecturer and astrophysicist at Cardiff University and is one of the co-authors of the paper. Subhi, this sounds like a very exciting discovery. Can you tell us a bit more about this particular planet, where it is and how it compares to Earth in terms of its size? The planet is called K218b. It's what we call a sub-Neptune exoplanet.

1:20So it's a planet somewhat intermediate in size between the Earth and Neptune. It's actually about 2.6 times the size of the Earth. And it's about 124 light-years away and it orbits a red dwarf star. So it's quite far away. It's a very different type of planet to the Earth. But actually, the type of planet that K218b is, the sudden-etering planets, are interestingly the most common type of planet that we know of. And also, we just don't have this kind of planet in our own solar system. And so what are the signs that you've discovered there? Tell us about that. Yeah, so we did an observation using the James Webb Space Telescope to obtain what we call the transmission spectrum of the planets.

1:57This gives us the spectrum of the atmosphere. We are able to work out the composition of the atmosphere. So the molecules we found are DMS and DMDS, which are dimethyl sulfide and dimethyl disulfide. On the Earth, these molecules are very, very specific biosignature molecules. That means they are produced only by life. And in fact, they're produced mostly by life from the sea, marine life. And so obviously, it's very exciting to have detected these molecules in the atmosphere of an alien planet. But obviously, we have to be very cautious here. doesn't necessarily mean that the molecules on K2A18b are coming from a living process.

2:37In the words of Carl Sagan, claims require extraordinary evidence. And so we have evidence at this point, but we need to go back and do more observations and verify the results, get stronger detection of significances. And also, we need to make sure that we can't explain the molecules with non-biological processes as well. So there is some work to do before we can be really, really sure that this is coming a living process on the butt. Everyone sort of jumps the idea of sort of alien life, intelligent or otherwise. But what do you think the possibility is that eventually scientists will find evidence of alien life?

3:14I think it's very, very high. If you think of just the statistical argument for alien life, it is very strong. We know that there are billions of galaxies like our own. And in each of those galaxies, there are billions and billions of stars. and in the exoplanet era we know that every planetary systems are very common around stars and so we even know in fact the fraction of stars that have planets in their harvestable zones and roughly between 20-30 percent something like that that doesn't mean that all those planets are inhabited or that they have life but it shows that there's the potential for life there and so I think even if a very very small percent of those planets gave rise to life it would still be a universe teeming with life just on the numbers alone.

4:00So I think that there's a very high statistical probability that one day we will find life somewhere. How did you go about determining the chemical composition of a planet that's so far away? Yes, so we obtained the spectrum using James Webb, which was the most powerful telescope we have. It's in outer space, about a million miles away. And we point telescope at the star of K2 18, the red dwarf star that K2 18b actually orbits, the planet orbits the star. And we wait until the planet actually crosses in front of the star. That's called a transit. And when the planet crosses in front of the star, we can detect the dip in starlight.

4:35And we basically measure that dip at different wavelengths of light. And when we have atmospheric molecules, what we can find is that variation in the transit depth, that traces out the molecular absorption features. And we're able to produce this thing called the transmission spectrum, which basically shows the fingerprints, if you like, of the molecules that are in the atmosphere. And then we have to go about a process of working out what those molecules are. And the most common way of doing that is to apply an atmospheric model, which has those molecules in it, and we try and match it to a best fit atmospheric model.

5:10And we can then infer from the best fitting model what the molecules in the atmosphere are likely to be. So in the case of this particular study, we found that there was a very good match to these two molecules, VMS and DMDS, and in fact, no other molecules. So it was a very clear match to these two molecules. And it could be one molecule, or it could be both, or it could be either. We're not able to distinguish between them at this time. But that's the basic process. What made you aware of this planet in the first place? How did you know to look for it? Oh, that's a very good question. So K218b itself was discovered relatively recently, only a few years ago.

5:50And sometimes we find planets that just appear to be good targets for what we call follow-up spectroscopy. So once we find a really good planet, let's say a planet that is quite close by and it's going to be thick, going to give us good singleton noise, that's often a very good argument to then point a big telescope like James Webb at it and try and get the spectrum. So I think originally K218b was observed because it was a sub-Neptrine planet. We know very little about the sub-Neptrine planets. And so it is a very interesting planet to observe for that reason. It was originally observed actually by the Hubble Space Telescope a few years ago, but the wavelength range that Hubble covers is very, very narrow.

6:27And when James Webb finally came up, we pointed that our telescope had James Webb at that planet again to get a spectrum which was of much greater wavelength coverage. And that first spectrum our team actually obtained in 2023, that spectrum itself was very interesting because it was consistent with the idea of a thing called a high-sean world. High-sean world is a possible model of sub-Neptunes where they are able to sustain a liquid water ocean. And that liquid water ocean obviously makes them candidates for possible habitability. And so our first spectrum two years ago had some evidence for the liquid alteration was consistent with it having that.

7:06And so basically, it was an interesting kind of to start with, and it's become more and more interesting as we continue to study it. Yeah, absolutely. Can you tell us a little bit more about the James Webb Space Telescope and the collaboration of scientists that have been involved in this research? So the James Webb Space Telescope is a massive space telescope. It has what we call a large primary mirror, which means that the collecting area has diameter of 6.5 meters. It's the largest space telescope in history. And it's actually located about a million miles away in space. And the collaboration of scientists who've been involved with the K2-18b observation is led in Cambridge by a person who met a student.

7:44But it also involves the institutions, people at Cardiff, like myself, Birmingham and other institutions. So it's an international collaboration. And we were very lucky to be awarded observing time to actually look at K2-18b, which we used to obtain the spectra that we're talking about today, but also a previous spectrum that we obtained two years ago, which itself was very interesting. What will be the next steps for your research? So I think in terms of K218b, it's really important that we, or someone, if it's not us, but exoplanet scientists, we go back and we look at it again with the James-Otto Space Telescope.

8:18So we need more observing time just to really verify our results and shore up that signal to noise so we get higher detection significance. So that needs to be done. We also need to look at possible non-biological causes for these molecules, DMS and DMDS, and make sure that we've excluded other causes for the molecules. I think in general, the field of exoplanets and sub-Neptunes, there's plenty of other sub-Neptunes out there. And it's similar to K218b that we can observe. And indeed, we are starting to observe. So it'll be interesting to see how other planets in the same category also compare with K218b.

8:58And finally, Subi, how excited are you personally about this latest discovery? Well, personally, I mean, it's absolutely thrilling to be involved with a study like this. because in exoplanet science, I mean, the Holy Grail really is the search for life and finding life. Although we're very careful to say we were not saying we found life. I mean, it's a giant leap in that direction. And it's the strongest hints up to this point of possibility of a planet having life. And so it's just wonderful to be involved with that study.

9:30Let's go to a break. Coming up in part two, ideas of what's on in London over the Easter weekend, including places to hunt for Easter eggs or to enjoy a musical tradition dating back to 1876. We'll see you back here in just a moment.

9:50Welcome back. So the long Easter weekend is almost upon us and if you're looking for something to do over the next few days then luckily the standards food and drink writer Josh Barry is here with some ideas of what's on and where to go. So Josh, a pretty busy weekend across town, no doubt. What are some of your top picks for how to keep the kids entertained this weekend? Yeah, absolutely. Lots going on. Obviously, a lot of Easter egg hunts for kids and so on. A good thing to do would be to go out to one of the palaces, perhaps, or one of the parks. Hampton Court Palace is a good place to go. There's an Easter egg hunt this year with gold bunnies figurines not chocolate hidden all around the grounds and obviously they'll be rewarded at the end with a prize a little bit closer to town Brixton Village has got an Easter egg hunt going on and there's so many great restaurants and bars and so on in Brixton Village for kids or adults or both really lovely way to spend a weekend in Brixton Village lots to see and do or out west there's Chelsea Physic Garden which is hosting its own art trail so So a little bit more of an emphasis on crafts and art and so on, rather than chocolate and eating.

11:05But obviously there's still a tree for kids at the end after they finish the journey, which takes on learning about the flora and fauna that's there. Now, sadly, the weather forecast is looking a bit mixed for the weekend, and there is a fair chance of some rain coming in. What are your suggestions of things to do if people need to dodge the showers? I mean, a couple of options. I mean, you can always get your umbrella out, but my choice would probably be the Horniman Museum's Fate, which has got kind of food and drink, circus acts, games, seed planting and stuff. And a lot of that is tented. Or another top pick for me, I would say, would be London Zoo.

11:47A lot of that's inside. That would be a grand day out as well, but obviously a little bit more expensive than some of the other activities. There are also some musical events taking place. Which of those have you chosen to highlight? There's Royal Albert Hall, which is hosting its annual Easter concert. Likewise, Symphonia Smith Square Hall, that's hosting a musical Easter festival all throughout the week. There's also some musical stuff going on, which, you know, I think kids would be very welcome to go to or something for the adults to do in the evening, especially the Royal Albert Hall thing, actually.

12:18that's been going since 1876. So the Royal Choral Society will be performing a rendition of Handel's Messiah and there with the Royal Philharmonic Orchestra. Tickets for that are £32 which is pretty reasonable really for something that's been going for 149 years. Wow that sounds amazing. And Josh as food and drink writer for The Standard what would be your advice for anyone who's looking to head out for something to eat over the weekend? if people don't want to cook i'd book a roast dinner probably for the sunday or the monday even i'll probably be roasting is still going bleeding into monday which is a bank holiday isn't it so that's always a good thing to do all you have to do is go into google and search best roast dinners in london standard and we've got a great list with loads of inspiration or you know book a restaurant or go to the west end you know for a matinee performance i think that would be a good way to spend um the bank holiday weekend great stuff and all the events that we've talked about are of course available on the standard website yeah everything is is on there all you have to do is google and we've got guides to best roast dinners we've got guides to best bars best pubs our mega list of 50 best pubs in london in jores um and it's always updated as well online as well as being imprint so there's always plenty to see and do and links to tickets and the websites and addresses to each place is always on there.

13:46And that's The Standard. For all the latest news, head to standard.co.uk and please do drop us a line at podcasts at standard.co.uk. This podcast will be back tomorrow at 4pm. We'll see you then.