Quantum Simulations of the Origins of Life: Life-Giving Molecules From Planetary Impacts--Dr. Nir Goldman, Lawrence Livermore Laboratory

Before there was life on Earth, there was something called "the period of maximum bombardment" when comets, meteors and other space objects crashed into the planet.  Some of those carried materials necessary for life to emerge.  Dr. Nir Goldman of Lawrence Livermore has been using computer simulations to investigate the hypothesis that some of these collisions synthesized the building blocks of life. He spoke at a "town talk" sponsored by Telluride Science.  Moderators: award-winning broadcast journalists Judy Muller and George Lewis. 

Transcript

Science Straight Up, Season 5, Episode 4 script

“Simulations of the Origin of Life: Life-Giving Molecules from Planetary Impacts”

Dr. Nir Goldman—Lawrence Livermore National Laboratory.

(THEME MUSIC)

(JUDY) From Telluride Science…this is “Science Straight Up.”

(GEORGE) And on this episode…

(NIR) (16:10) So it's it's life building, we formed something life building from this mix right here, that was really exciting.

(GEORGE) I’m George Lewis.

(JUDY) And I’m Judy Muller. So, here’s the hypothesis: In the beginning, billions of years ago, Earth was this lifeless rock with no trace of any organic material. And then suddenly, Comets, meteorites and other space objects begin raining down on Earth during something called the period of maximum impact.  And those objects carried the first building blocks of life.  Dr. Nir Goldman, a chemist from the Lawrence Livermore National Laboratory set out to prove that hypothesis.

(NIR) And so it turns out that during this period, a lot of organic matter was delivered to Earth. And some estimates are as high as 10 to the 13 kilograms per year. So you can sort of say roughly, you know, 10 to the 13 tons per year of new organic, Extra Terrestrial organic materials delivered to Earth.  

  (GEORGE) Dr. Goldman spoke at one of the “Town Talks” sponsored by Telluride science.  Each summer up to 14-hundred scientists gather in Telluride for a series of workshops, seminars and brainstorming sessions, and once a week, they share their cutting-edge ideas with the community.  His talk was recorded before a live audience at the Telluride Conference Center in Mountain Village, Colorado, with thanks to our sponsors, the Alpine Bank and the Telluride Mountain Village Homeowners Association.

(NIR) So we're not talking about a comet impacting a planet and like, Yay, there's a pony, you know, nothing silly like that. It's much more like, you know, the comet impacts the planet and the simple molecules clumped together in a way that is then biologically processable, let's say, you know, something akin to a protein.

(JUDY) There is a problem with this:  A direct hit by a comet on the surface of Earth produces a lot of heat and pressure, something not very friendly to life.

(NIR)  So that would be on the order of, you know, temperatures up to around 5000 Kelvin. So let's say 4700 Celsius or 8500 degrees Fahrenheit, so very hot and really Fantastic pressures. So pressure is on the order of 1 million times Earth's atmosphere is up to that, you know, those sound crazy.

(GEORGE) Yeah..all your building blocks of life sizzled and crushed beyond recognition.  But Dr. Goldman and his colleagues had a different idea…that not all the impacts on Earth were head-on, that there were also glancing blows that wouldn’t have destroyed all the organic material carried by the comets.

(NIR) (06:44) We wanted to see, could we make some kind of computational prediction about what would happen on what would have happened on early Earth when a comet came flying down and hit at some specific angle that hopefully generated just the right set of pressures and temperatures.

(JUDY) Dr. Goldman and his colleagues are lucky.  They have access to Lawrence-Livermore’s supercomputers, able to do the complicated calculations that would simulate comets hitting earth. It would take a lot of programing and an intimate knowledge of quantum mechanics to create the simulations, a process he calls “whack it and watch it.”

(NIR) I have my quantum mechanical code or model, and I can then basically do whack it and watch it experiments. You can take the material with certain set of conditions give it a good whack, which corresponds to the shock compression, we're not really whacking. Of course, you never kind of squishing things computationally. We did a bunch of whack it and watch it numerical experiments on this icy mixture. And we saw glycine. So what's glycine? Well, glycine is the simplest protein forming amino acid. So it's it's life building, we formed something life building from this mix right here, that was really exciting. It didn't mean it was real, right, because we saw it on a computer. But it was still very exciting, because we could tell someone who's doing difficult experiments, what to do, we could say, if you make this mixture, and you whack things, in your experimental way, up to these pressures and temperatures, you you're likely to see something prebiotic happen.

(GEORGE) And experimenters came along.  Some of them creating a sort-of giant BB gun, smashing steel balls into ice blocks.

(NIR) You  take a block of ice, and you put in this, this giant stainless steel ball bearing or something similar, and there's an explosive charge behind it, and you detonate the explosive, and this ball just goes launching, flying into, into this ice block that you've made. And then afterwards, experimentalist, see some goo and they scrape it out and analyze it. And they they saw a lot that was really exciting. 

(JUDY) And he says there’s a lot more work to be done as science learns more and more about the origins of life on Earth and how the shock of comets colliding with the planet may have started the whole thing.

(NIR) I'd say there's sort of two take home points about shock synthesis. So one is that the shot the comment has raw materials and then you have an impact, and you get the shock synthesis and the impact gives an abundance of energy and then you get small but important life building molecules like amino acids and other things, where maybe there's some complexity already in that astrophysical icy material, not just amino acids, but other large molecules. And then when they smash into a planetary surface, they clump together in interesting and important ways. And that's where things stand for now. And thank you for your time

(APPLAUSE)

(GEORGE FROM LIVE TALK) Whack it, whack it and watch it. So you guys ask questions first, then shoot later on. And then ask some more questions. Right? 

(NIR) Yeah, that's exactly right. Yeah, this was very hypothesis driven. You know, we it's not out of the dark. Like we had some notion that this was a good hypothesis, but it was definitely hypothesis.

(GEORGE) What do you say to the guys with the other hypothesis is that we didn't need comets to form the building blocks of life on Earth. 

(NIR) I can only speak to this as a chemist, which is I can say comets impacting early Earth definitely produce things that are conducive to the origins of life, whether it was the most important or the relative importance. I just can't really comment on. But I would argue most likely it was important enough because of the period of late heavy bombardment, because of the reasonable probability of of comets impacting the planetary surface at specific angles that yield these conditions, and, and so forth. I mean, there, I think the real answer here is that there just lots of avenues and pathways for things to happen. And this was a was one that was possibly significant.

(GEORGE) But, you think that that the heat and the kinetic energy from those impacts were necessary for forming these these compounds that lead to the building blocks of life?

(NIR) I think I'd phrase it a little differently, which is, it was a good way to form them. But there are definitely other ways. A good one is you can form interesting prebiotic material in the ocean, there are these things called hydrothermal vents. 

(JUDY) I was gonna ask you about that…

(NIR) Yeah, so it's actually it turns out something we've studied to a smaller degree, honestly, but the idea is, what if simple molecule like glycine, this, you know, great protein forming amino acid was in early Earth, and it kind of, you know, cycled through that hydrothermal vent. So it gets its editor a little bit of pressure, but under pretty high temperatures, like, you know, 2000 Fahrenheit, let's say it's this the steam jets that happen. I think that's too high, let's say 1000, something like that. They're very hot. And it causes the glycine molecules to clump together and form small molecules and whatnot.

(JUDY) I had read a challenge to your theory, saying that the likelihood of life or the precursors of life traveling across vast distances of space, and then seeding life on Earth. That likelihood is extremely low. And that conditions on early Earth, such as the hydrothermal vents, as you mentioned, would be more likely. Is it hard to convince people who are skeptical?

(NIR) I don't think so I think the evidence for shock compression is really solid. It's hard to make relative comparisons, at least for me. So, I think it's, it's fair to say that, you know, just not just with our work, but actually, at this point, a lot of work that there's this, the shock synthesis produces reasonable amounts of prebiotic materials. And again, it's just one element of the picture. There's a lot of dots to connect between producing an interesting amino acid and an impact and actually getting life and there's a lot of things that can happen there. Like you could imagine a comet producing amino acids, and then some other cataclysmic thing happens, and it wipes out a lot of the organic material on Earth. I don't know. But I don't think it can be discounted at all. I don't think anything can be discounted at this point.

(JUDY) Oh, okay. So, but you also mentioned that the angle of the hit yes, is important. It was like all meteors coming down. During the I love this. Yeah, the late heavy bombardment.

(NIR) In fact, rate to you can estimate the probability of a comment coming down at the right angle through me, it's an estimate, but 24%. That's what I estimated a while back. And I would say it's a reasonable way to think of things. So of all the comets raining down on Earth, probably about a quarter we're doing what we're interested in. 

(JUDY)Why is the angle important? 

(NIR) That's a great question. Because direct impact just yields very high pressures and temperatures. Whereas if the angle, the comet, kind of comes in at a smaller angle, the resulting pressure wave from the impact is slower. And then as a result, the pressure..peak pressures and temperatures are lower. They're still very, it's still ridiculous, but it's lower. And so that's why it matters. Whereas if you have a direct impact, the pressure, the pressure wave is so fast. The pressures and temperatures are so high, it probably obliterates everything.

(JUDY) Wow!

(GEORGE) Yeah, you would think that everything would be cremated in this process, even even in a glancing blow. But you'd say 25% of the time, it might yield something.

(NIR) Yeah, I would say conditions similar to what I show, will it not just in comet- like materials, but in an organic mixtures will always yield more complexity rather than obliterating everything.

(GEORGE) You have invited experimentalists to follow up on your work, to what degree is that happening? How many people are involved? How many different experiments? 

(NIR) Oh, there's a lot of talk in general about these things, because it's exciting, but the funding is tough. So the work I showed there is previously is relatively old that that was done by a small group of three or four people. There are reliable, you know, really wonderful scientists that I work with at Lawrence Livermore Lab that do high pressure, high temperature experiments. The funding is a bit of an issue here. So that's probably what slows things down more than anything.

(JUDY) Why?  Are they not as interested in how life began on Earth? It’s a big question.

(NIR) Oh, so the funding issue Well, honestly, they're is really one funding agency here, which is the NASA exobiology program. And the funding is competitive and the amounts aren't so large. And, you know, if I, if I'm lucky enough to get funding, I, you know, I'm likely to mostly fund computational tasks that I can actually be in charge of…

(JUDY) The New Yorker magazine had a great article about about this, and you are quoted liberally that 10 years ago, I think it was okay, at least. And it quotes you is saying, we've put the ideas out there, the hard part is doing the experiments to test those ideas. They're difficult to set up, and it's hard to isolate the chemical products that result from the impacts. Is it getting any easier? 

(NIR) I mean, that's a great question. 

(JUDY) Are your theories gaining wider acceptance?

(NIR) I would say these computational predictions are gaining, they have acceptance, that's less, you know, partially due to this collaboration that I showed the result for. And then others who have several groups in Japan, for example, who would have done shock synthesis experiments and seen similar things or more complicated things.

(JUDY) If life on earth did come for meteors hitting us from space, you're, you're gonna hate this question. What might that suggest about the possibility of life and other planets? You know, I've heard of this term directed panspermia. Great. And that's the intentional spreading of life by an advanced civilization. Oh, you're gonna hate this? Oh, no, I hadn't thought about that, or is that just to speak?

(NIR) Well, a good element of that? Yes. Which is, I would say that this kind of research is agnostic to where the comments landing. And you know, that's in a large part, because I'm a chemist, and again, I like I'm hopeful to find simple rules for things not not very specific rules. And there are icy moons of Saturn, for example, that contain organics and a lot of water ice. And they're not so cold that Titan and Enceladus are the two that are usually mentioned. And this kind of research applies to that too, which is suppose some kind of astrophysical icy material bombarded a Titan or Enceladus? I could say with confidence that prebiotic material will be synthesized by that what happens after that? I can't say I haven't. I don't know how to think about exactly, but…

(JUDY) Maybe they're having a talk just like this. 

(NIR) Yeah. All the way outside Saturn in their space heating suits. 

(GEORGE) Shall we go to questions from the audience?

(JUDY) Yeah..

(GEORGE) Judy, while we’re waiting, I have a question for you.

(JUDY) Noooo!

(GEORGE) Why does a shooting star taste better than a comet?

(JUDY) This is going to be a bad pun.  I’m just learning.  Why?

(GEORGE) Because it’s meatier (meteor) 

(laughter and groans)

(NIR) That was a good one. I liked it.

(GEORGE) And…without further ado…

(JUDY) Yes, sir.

(QUESTION FROM AUDIENCE) I'm curious to know, what are some of the leading theories about how this I call it a soup of organic molecules and proteins are

might become self-replicating?

(NIR)  This molecule glycine, this amino acid can actually form helical structures that resemble DNA. It's called like poly glycine, nucleic acid, for example. So how, you know, I think there are simple things like that that can happen that can create a potentially replicating structure. But beyond that, I don't think I really know. I think that's a great question.

(JUDY) 36:37 We got one here… Yes, sir.

(QUESTION FROM AUDIENCE) So I want to go back to the heavy bombardment period, which is fascinating to me. But it begs the question, if asteroids and comets are bouncing all over the place, where did they come from? 

(NIR) Oh, that's a great question. I think I can only again, I can only kind of answer it. But you know, comets originated, like in the Oort cloud, and the process by which that material kind of condenses? I don't know that I really know, to be honest. But I think, you know, there's a process meaning you get, there's a lot of dust grains out there. And then at some point, those collide, and then they coalesce and so forth, is gravitational poles, but I don't really know that I know the answer to that. 

(QUESTION FROM AUDIENCE) Okay, I guess we just pass the mic here. This is totally fascinating. I'd always heard of the silver vents, the lightning as places for energy to come from? Are you doing any research into other sources of energy besides the compression?

NIR: Yes. We've looked at sort of seismic events. So that's shearing. And that actually causes these, if you look at solutions of amino acids, and you share them, this relates back to your question, the amino acids start forming these chains and clusters and whatnot. We also at once upon a time we're looking at, we're curious about hydrothermal vents. And so we were trying to calculate how difficult it would be for two glycine molecules to condense if they were being cycled through hot and cold temperatures.

(QUESTION FROM AUDIENCE) Can we do? And can you do a high enough energy impact here on the planet without killing a bunch of people to really test this? Or do we really need to do this? (laughter)

(NIR) Or? You absolutely can? Yeah, because you do it on a small scale, and no one gets hurt, hopefully?

(GEORGE) I'm sorry, sir. Did you see the movie don't look up? (laughter)

(JUDY) Another question from the audience came from Mark Kozak, the executive director of Telluride Science.

(MARK) How important is the heat versus the pressure? Or is it both? I mean, can you get any of this occurring with one or the other doesn't have to be both?

(NIR) I think it's it works fastest If it's both. That's an excellent question. So you can activate chemistry through temperature, you can also activate it through pressure, because things are just getting close, and bonds loosen up and things like that. I think we see interesting things because it's the simultaneous pressurization and heating, and we see this very rapid chemistry.

(JUDY) I have one and this is kind of philosophical question. But why do you think we are so fascinated with what Earth was like before with us with our large egos showed up? I mean, you know, it's such an amazing question to think about Earth before any kind of protein. I mean, you know, anything, but rock. Right. So, what do you think when you talk to people? Why is there an such an interest in this?

(NIR) I think it’s a great question. I think it's, it's fun. It's not, you know, honestly, at least for me, it's it's not anti religious or religious. It's just saying, given the rules Was that we know what could have happened. It's not saying why or, or anything. It's just saying how given these rules, not why do we have these rules? Why do we have comets? Why did they accumulated? Why did they impact? And so it, it just kind of, it can be an easy thing to discuss in that sense.

(JUDY) Whether it's coming from a religious point of view or chemical point of view, the question always remains, yeah, but before that, what, right, you know, so it's always there.

(NIR) And it's tantalizing. You know, we don't really know, but, but it's just like, you know, it's like, the, you know, origins of life is like this, you know, it's a pot that's been shattered and the shards are scattered. And so, you know, we picked up a shard here, and that's really all it is. But that's exciting, because it gives us some clue about something, you know, whether the pot’s big or small, whether it's actually an elephant, I don't know.

(GEORGE) Are you like the seven blind men surveying the elephant? 

(NIR) Yeah, that's right. Maybe it's the trunk? Maybe it's the tail. That's exactly what I was thinking.

(QUESTION FROM AUDIENCE) It’s an unclear question.. (laughter)  Would your theory though, suggest that we should look at planets out there where we know there was heavy bombardment, as well. And maybe every every planet in the universe, every body is the subject of this, but could we use your theory to maybe identify places where we want to watch?

(NIR) Yeah. So I think evidence of bombardment and, and evidence of water and organic material. That's that's a simple chemical, kind of way of thinking about things. So yeah, I would say those would be things to identify.

(

(GEORGE) But bombardment probably wiped out the dinosaurs and gave rise to the mammals here. Right. So yeah, so it probably might have been a factor in our evolution. over the intervening period, right?

(NIR) That's absolutely right. Yeah. So it's, yeah, I it really big hit is low probability, but not impossible. And then that would change everything, right? So we have this amazing mechanism for producing amino acids. But then all sudden, there's a direct hit, and that just obliterates everything. That's true.

(JUDY) Aaah…Ya win some….

(LAUGHTER)

(JUDY) OK…

(GEORGE) I think that's about all the time we have. We want to thank our sponsors, Telluride Mountain village Homeowners Association, and the Alpine bank and let's give a big hand to Dr. Nir Goldman. 

(NIR) Thank you everybody…(APPLAUSE)

(THEME MUSIC)

(GEORGE) And thanks, of course, to Telluride Science.  Our audio engineer for this Town Talk was Dean Rolley.  Mark Kozak is Executive Director of Telluride Science and Cindy Fusting is Managing Director.

(JUDY) Annie Carlson runs donor relations and Sara Friedberg is lodging and operations manager. For more information, to hear all our podcasts, and if you want to donate to the cause, go to telluride science-dot-o.r.g.  I’m Judy Muller.

GEORGE:  And I’m George Lewis, inviting you to join us next time on Science Straight Up. (THEME MUSIC UP AND THEN FADE OUT)