ultraviolet radiation as a trigger for generating and life dr ron john is a post doctoral fellow in the department of earth atmosphere in planetary sciences at mit his major interest is in how a life form elsewhere in the universe with special attention to read worf planets and the potential role of ultraviolet radiation now that hundreds of planets have been discovered there's a great hope that life will be discovered beyond earth however there are still many about how life even urges tonight dr ron john will explain the there's a great interest now in these exoplanets and we always hear about goldilocks region so not every planet is promising but could you tell us what that means sure so  idea of the goldilocks zone was started emerging in the seventy's and eighty's and the motivation for it was there big a big wasn't there murcia consensus from the biology side of things that life as we know it requires look at water and so folks started saying the obviously one place the one place in the solar system reno there's really a ton of liquid water running around in a ways that are accessible to biology is the earth so folks started asking ok what is a range of conditions that permit liquid water to exist on earth like planets and one of the main things they came up with was temperature if you get too hot the water is all going to boil off and you're going to end up like venus if you get too cold the water will all freeze and you end up like planets in the outer part of our solar system like europa and so the idea is that  planet there's going to be a range of distances from from it so star at which it will have the intermediate range of temperatures intermediate range of insulation that's required for clean and surface temperatures that are compatible with liquid water to exist now there's all sorts of ways you can you can come up with to get liquid water outside of this particular if you go farther out in the solar system if you have a very thick atmosphere or something like that there's all sorts of ways you can maintain climate surface conditions but if you just have a vanilla planet if you take the earth and move it around another star there's an intermediate range of distances around each star and that's the goldilocks ok so is that still valid you still think that way that zone that distance preferred distance while we're at it is there any question about water because that went on for years you had to have water you had to have water is that still valid i think people most people continue to focus on liquid water is a requirement because we have an however could you tell us about the chemistry of life a little bit i think that's not we'll know that life comes from nothing but i'm not sure if i describe it as coming so much from simpler components but yeah the idea the idea that people have is that life had to start from somewhere and it seems like the most plausible thing we can imagine is that for it to start from simple chemicals that are available and in planetary environments just from the planets formation history and so people try to figure out how do you go from these things that is that are being delivered from the plants from ation to things that can walk talk and chatter and more realistically how do you go to a chemical system that can replicate itself and preserve information so that's what people are people who are really trying to figure out a path to that ok and what have you got what do you have to have for ingredients you have ingredients and you have conditions to put together to get life to emerge so what would be the gradients that you think now are necessary well unfortunately we don't know yet because we don't have one of those complete paths that we have no one has gone and been able to demonstrate going from simple chemicals all the way to a living system yet so what we what we have are different avenues that people are working on different avenues  different groups and different collaboration's are trying to pursue and try to get from point a to point b one of the ideas it's very popular is the idea of what's called the r n a world arnesen information molecule similar to d n a it also includes genetic information and it's very ancient it seems to be the root of the tree of life and it's unique in that it can catalyze its own replication so it can bear information and reproduce itself so a lot of it's a very attractive idea that the first life might have been  been a lot of progress on the self replicating side but it's not entirely there it's not fully there yet there's a lot of progress on the on the plumber station side but mostly that requires you to be in a you know what dry environment the work that i did was focused on the supernovae and things like that like gold and so on so you're talking about things that are farther along not the most basic yakked so do you still have to have these most basic elements you need to have the elements there  those are synthesized in stellar events but on a planet you undergo a lot of secondary differentiation events and into the environment yes the reliance on copper is a weakness of this particular paradigm because copper is not as cop as we know that for example there's a lot of iron in earlier but ye them that it gets yes and reaches it doesn't necessarily have to happen you could have all these ingredients but they don't necessarily combine and then if you had all these ingredients on this happy planet then what conditions do you need in addition so presumably you need the u v is that a necessary condition that's known that's there are no necessary conditions that are known strongly because we don't have that complete that this u v is not getting darryl how would you account for that would you say well it started on the surface and then submerged is that the way you would see it in other words i mean what i'm saying is could you have life without that it's into a lot of folks think that you can ok the challenge is they have not yet done there is a number of challenge they have not yet been able to experimentally get as far as the groups that do depend and u v have ok and so i think we're definitely open minded to the possibility that you don't need you but we're waiting on the experiments there i think you raised another point i'm sorry i forgot what you were just that you could have life it seems as though personal so i in my opinion the broadly speaking i think that it's entirely possible that life for some parts of the elements or hard for life could have been formed at the surface and then it could have migrated down i particular liked that idea because we know that there is this thing called that i have in mind do thing and in your mind in your expertise would only life be the same or agents could you have different and what i mean is like just assume you have co evolution of say think that i think that depends on how easy it was to get it started in the first place if there was something that if it was some process that was very easy and it just happened that one happened without the competition and dominate all the rest then certainly you could have had multiple origin events or if it's something that happened it happens very very early in the first and probably not the case where unfortunately we're still not far enough along to figure that out ok i personally believe towards a relative a moderately easy origin of man from the evidence i've seen but i have no firm quantitative evidence for that so you think it's pretty easy for emerge given the conditions and the right conditions and yeah and the ingredients and these are abundant yeah and we're really just getting into this in the universe then you think that it should emerge it's a   my motivation was really just from the experiments we were we had grown my advisor and i had grown interested in this in this field and we saw that there had been there were a bunch of different ideas of wide variety but only one of them seemed to be really making a lot of progress and i was one that was using a lot of this u v stuff so that motivated our and that's what motivated our initial strong interest in this area and as and as we delved into it it seemed like this was more than a what one hit wonder that it wasn't it was more than just an artifact of time there were theoretical arguments  light can affect molecular states in some ways that other sources of energy like heat can't so there's a fundamental difference there on a theoretical level and also there is strong evidence that our own nuclear bases the molecules that are that  alter just a few bases so they for example recently they made they created or an organism that had two new letters in its genetic alphabet and it worked just fine so you might well ask why doesn't our life use that well it turns out that if you subjected issue of the red dwarfs then that is that sufficient that was another issue for you hello can you tell me were you do you know with whether it's sufficient or not yes that's a great question so just to go back to back it up a little bit so as you pointed out red dwarf stars are very different from some like stars and in particular they put out very little near u v light the kind of light that gets to the planet's surface ok so they have very little u v at the planet's surface and so this is not something that people had realized before because they put so much really hard to give the radiation that folks a lot of folks just kind of thought that will do must put up a lot of near u v but it turns out that they don't and so when we plug that into our models this is one of the things that we observed and what what this means is that it's not just a matter of waiting longer you might think well if you have less u v that's fine just give it more time and the reaction will still go forward that's not the case because in liquid water and at thermal temperatures there's always back reactions you need to have more than a certain threshold amount of your reaction rate in order for the reaction to proceed at all so we need to do experiments to figure out what that threshold is we have colleagues in at the university of cambridge in england who are working on that now so what they're doing is they're doing their experiments they're dialing then the u v and they're seeing at what point does this terminate excellent question and the answer is again we don't know we need to do the experiments and i think we're trying to get our colleagues to do those experiments as well yeah and if we could be super exciting because embers flare a lot so ok they put out a lot of u v so normally they didn't know with every few days oh yeah yeah ok so this is a big burst yes so flares are giant explosions on stars our sun has them all the time but they're relatively small on em graphs stared generally extremely large the entire prototypical very active star has very large has flares that do since you have to by a factor of one hundred two thousand once every ten days or so i had no idea it was that frequent now can i find out like ordinary star but a lot warmer a lot more u v evidently in the early days even that it was generating and presumably pretty steady no ozone layer to protect us or anything like that would that that level of u v would that be considered that's ok well the first thing is even in the early sun there were flares but they weren't as because there aren't any doors proportionally  see and it was still comparatively rare so that's one key difference ok the second thing i point out is up here on earth even on earlier it would be pretty well protected by our atmosphere it has a lot of c o two and water vapor and it has a magnetic field and those combine to ward off the worst effects of the flare i see very interesting so around the real stars regular ordinary stars average stars you might be generating pretty good conditions that that's that's great that's very interesting now hundreds of planets thousands maybe have now been discovered what ones do you think are the most promising that you've looked at i personally i'm most excited about i think all these objects are really interesting and i'm really i'm just hungry for any data we can get our hands on i think that there's a planet siri system that's been discovered called elitist eleven forty b that i'm really excited about because it orbits a nearby relatively bright emperor and as a result it's or it's as i should clarify it's a planet that we think is rocky and that's in the middle of that habitable zone that goldilocks zone so it's a great place to look for life and it's one of the only places where we can look for life because it's parent star a small enough it's one of the employers ok so it's a place where we can actually look so i'm really excited about someone going out and doing the looking ok what do you mean by looking at this point because you have a you have telescopes up there i guess you're waiting for the james  that adequate to give you enough information ok yes that's a really great point the telescopes that we have right now can tell us how big it is and how heavy it is but it can't tell us what's in the atmosphere can we tell you it's rocky yes it can  apparently life that you're looking for could there be other signatures that that is the other life types that are valid but they don't look they don't produce the signatures that light here does yeah and there's a lot of folks believe it your loved one my old one of the professors used to say you're allowed one degree of crazy not to be so it's your wonder if you want to give careers you can either be life different what we have no here or can be a remote section of life you it's tough to claim both yes i understand that i understand that it's well the whole field is really a big challenge very exciting though when you are looking you when you look into the deep past i just want to get that so that's that's ok that's not like billions of years yeah hester anything like that by the time that light gets to us you can still deal with that that yeah that's reasonable it's a like it's an eyeblink in geologic time if we don't have to worry that it's extinct by now it's probably going to die exactly that things if there's life there have change ok i would like to ask you about your how you got into this and so i'd like to tell the audience for one thing that you are  certainly so school sensor science collaboration on the origin of life so this philanthropic foundation the science foundation that gives money for research and different projects and they have different initiatives one of their initiatives that was started a few years ago is to try to figure out is to try to contribute to the search  into the search for understanding how life started and so they found a bunch of folks to work on that i wrote an application to join them and i was lucky enough to be accepted so there give me their funding me to work on the set of questions now as to how i got interested in that field overall  it's really just that there was a really interesting opportunity there there is a lot of there was kind of some low hanging fruit that wasn't being plucked you had a lot of progress on the chemistry side they were figuring out how to do a bunch of different things we didn't have a lot of people on the planetary science into that because do you have a very strong chemistry that mixed up on the or because it seems like the chemistry almost any geology you need a whole but yeah what do you need yeah so you're right in that it is a very interdisciplinary field interpretation is very interdisciplinary the way you do it is you acquire strong grounding in one field so my strong grounding is in physics planetary system astronomy and then you learn enough of the other field to talk to them and ask intelligent questions ok so that's what one of the things that we  in grad school yeah ok and then ultimately what would you like to do with this what would you like to discover life on another planet oh i look so what i would if i got all my druthers what i'd really like to do is understand the origin and distribution of life in the universe yes so that's the big that's the big picture airy fairy goal more specifically i would be unbelievably thrilled if at the end of my career we had a concrete path through which life could have emerged on earth in particular and that was prepared that was plausible that we knew it was high yield high throughput we felt certain about and i would feel even more thrilled if we could if we had detectors of life on a bunch of different planets around other stars and we can use them to test origin of life theories for example if my colleagues who do these experiments come up with the conclusion that u v dependent origin of life can't happen on planets or stars but you find life there anyway that tells you that there is enough life does not require u v or at least maybe there's a path that does u v but there must be paths that don't so there's an opportunity for an empirical test there which i think is very exciting and you can test it you will be able to test these things yeah it was the other you mentioned models and so yeah it sounds as though this is getting very very sophisticated now which is a bad thing do you think so i think so because ultimately the results that are most convincing are the ones that are very simple the ones that are like i have expedition i write prediction i we can hope to detect life on them understanding the distribution of life elsewhere in the universe will help us understand the origin of life here on earth because we can make testable predictions and then we can test them on these exoplanets yes we'll it's going to be very exciting and i'm sure i'm sure you're looking forward to seeing report periodic ledo they're working on this where they're working on this it's really an exciting thing i wish you the absolute best in your future in your career which i'm sure will be brilliant and i know we'll hear about you more down the line and i thank you very much for giving us all this wonderful information thank you very much thanks for the opportunity to be here