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James Green: Could The Building Blocks Of Life Exist Elsewhere In Our Solar System?

Dec 21, 2018

Part 1 of the TED Radio Hour episode The Next Frontier.

About James Green's TED Talk

Earth may not be the only place in our solar system with life, says James Green. New data shows life might have existed on Mars, and could exist now. But what does that mean for us on Earth?

About James Green

James Green is a space physicist who has spent his career at NASA. In 2018, Green was named NASA Chief Scientist.

Previously, Green managed the Space Physics Analysis Network, and was the head of the National Space Science Data Center and Chief of the Space Science Data Operations Office.

From 2006 until his appointment as NASA Chief Scientist, Green served as the Director of the Planetary Science Division at NASA Headquarters, where he oversaw several successful missions.

Green has written over 100 scientific journal articles, and he is the recipient of the Arthur S. Flemming Award and Japan's Kotani prize.

Copyright 2018 NPR. To see more, visit https://www.npr.org.

GUY RAZ, HOST:

It's the TED Radio Hour from NPR. I'm Guy Raz. So what do we know about life out there beyond our planet?

(SOUNDBITE OF TV SHOW, "STAR TREK")

UNIDENTIFIED PERSON: (As character) Space - a final frontier.

RAZ: Does it even exist? And if it does, how close are we to finding it?

(SOUNDBITE OF TV SHOW, "STAR TREK")

UNIDENTIFIED PERSON: (As character) To seek out new life and new civilizations, to boldly go where no man has gone before.

JIM GREEN: So from a - the science perspective, the probability, I think, for life, even complex life, is getting better.

RAZ: This is Jim Green. He's chief scientist at NASA.

GREEN: And it's based on scientific knowledge of finding locations like exoplanets, like we now know in our own solar system - places where even the giant planets with tidal forces sitting out in the outer edges of those solar systems could indeed produce environments where there's a significant amount of water. And if you have the right organic materials and enough time, that perhaps life evolved in that - in those particular areas.

So I think we all are going to say, we haven't found it yet. We haven't found it in the solar system. But I think the probability is getting better. You know, I think we have the abilities and the technologies. It's a matter of will.

(SOUNDBITE OF MUSIC)

RAZ: Here's more from Jim Green on the TED stage.

(SOUNDBITE OF TED TALK)

GREEN: So how do we make this journey? What we decided to do is first look for those ingredients for life. The ingredients of life are liquid water. We have to have a solvent. We also have to have energy. We also have to have organic material, things that make us up but also things that we need to consume. So we have to have these elements in environments for long periods of time for us to be able to be confident that life can spark and then grow and evolve.

Well, I have to tell you that early in my career when we looked at those three elements, I didn't believe that they were beyond Earth in any length of time and for any real quantity. Why? We look at the inner planets. Venus is way too hot. It's got no water. Mars - dry and arid. It's got no water. And beyond Mars, the water in the solar system is all frozen. But recent observations have changed all that. It's now turning our attention to the right places for us to take a deeper look and really start to answer our life question.

RAZ: So what would it take for us to find or even sustain life outside of our own planet? Could we discover another place to call home? - another Earth? Well, today on the show, we're going to explore The Next Frontier - ideas about living beyond our own planet. Will we actually colonize Mars or another planet? Can humans become a spacefaring species? - and should we? Or does the real challenge of our lifetime actually start a bit closer to home? Well, for Jim Green, the possibility of life elsewhere is very real, especially when it comes to life in one of its simplest and smallest forms - as microorganisms. And they could exist in our very own solar system.

I have to assume that this is a question. Is there life beyond our Earth? I have to assume this is a question that is taken very seriously by scientists.

GREEN: Yeah. You have to take a broader view, too - I do, anyway - of the solar system. And that is when we look for life beyond Earth in the solar system, when we have a good idea as to what these planets look like and what their characteristics are today, they haven't always been like that.

RAZ: Right.

GREEN: We now know, you know, that our climate has done nothing but change. It's going to continue to change. That's true on our other two major terrestrial planets - Venus and Mars. In fact, we have great indications that both Venus and Mars were much more Earthlike early on in their life with a significant amount of water. You know, Venus had a significant ocean and maybe for a significant period of time before it went through a runaway greenhouse effect. And of course, what happens is you break the normal water cycle, and you start losing water. And water is also a great greenhouse gas.

And then you have Mars, which we also have great indication that it has a significant amount of water. And I mean, that's physical because we're sitting there right now making those kind of measurements with our rovers. In fact, two-thirds of the Northern Hemisphere, probably, was water, even up to about a mile deep. So those are wonderful environments, so they could have harbored life in their past.

(SOUNDBITE OF TED TALK)

GREEN: So what about Mars? Let's go through the evidence. Well, Mars we thought was initially moonlike - full of craters and a dead world. And so about 15 years ago, we started a series of missions to go to Mars and see if water existed on Mars in its past that changed its geology. We ought to be able to notice that. And indeed, we started to be surprised right away. Our higher-resolution images showed deltas and river valleys and gullies that were there in the past.

And in fact, Curiosity, which has been roving on the surface now for about three years, has really shown us that it's sitting in an ancient riverbed where water flowed rapidly. And not for a little while, perhaps hundreds of millions of years. And if everything was there, including organics, perhaps life had started.

Curiosity has also drilled in that red soil and brought up other material. And we were really excited when we saw that because it wasn't red Mars. It was gray material. It was gray Mars. We brought it into the rover. We tasted it.

And guess what? We tasted organics - carbon, hydrogen, oxygen, nitrogen, phosphorus, sulphur. They were all there. So Mars, in its past, with a lot of water, perhaps plenty of time, could have had life, could have had that spark, could have grown. And is that life still there? Well, it tells us that Mars has all the ingredients necessary for life. It has all the right conditions.

(SOUNDBITE OF MUSIC)

RAZ: I mean, if you know, as you say, we tasted organics on Mars - right? - carbon, hydrogen, oxygen, nitrogen, et cetera, I mean, would that be enough to allow humans to live there?

GREEN: Absolutely. And the more we know about Mars, the more feasible it's becoming. For instance, Mars doesn't have a moon like we do, and so its axis has really swung around significantly. We have found, buried, the ancient pole of Mars. And in some cases, it's 700 meters or more of ice. This would probably be pure water. The place is large. It's bigger than the state of Maryland.

RAZ: This is - you're talking about this frozen lake?

GREEN: No, it's a frozen polar cap. It's the ancient polar cap.

RAZ: Size of Maryland. OK. That's a lot of water.

GREEN: Yeah. Yeah. And it's mid-latitudes right now. So the ability to be able to have a base of operation where you can leverage and use that resource is completely viable. In fact, a Japanese research group at University of Kyoto is looking at how to grow poplars, OK? Trees...

RAZ: The trees. Yeah, sure.

GREEN: ...In Mars soil. They have a simulant, in addition to the carbon dioxide pressure and temperature of Mars. And you know, we'll check in with them in another year and see what happens. So conceptually, a lot of research can be move - move in the right direction that will really be quite exciting.

RAZ: I know that we humans, like, we are a self-absorbed species, right? That we think of ourselves at the center of everything. But if we do discover some kind of life on Mars, or even beyond, you know, like, single-celled organisms, or whatever it might be, and that of course will be super exciting, but just out of curiosity, like, what does that do for us? Like, how does it - does it actually make a difference for humans?

GREEN: Well, sure, it does. Oh, absolutely. So let's take a couple examples. All right. Once you find life, let's say single-celled organisms on Mars, a whole new series of questions come about, OK? Those questions are - how are we related to it? Is it DNA-based? Is it a concept of panspermia, the idea of impacts carrying life away from a planet until it falls on another planet and then seeding that planet and starting life again, is that the right relationship? Or is it really a second genesis? So now, if we jumped to a place like Europa...

RAZ: And Europa's one of Jupiter's moons.

GREEN: Correct. Europa has got this magnificent ocean with what we believe are hydrothermal vents. It's an active geological body where ice tectonics are going on, where one plate is slipping under others. As cracks are forming, water is circulating to the surface. There's an entire circulation of material in the ocean. The radiation environment that it sends seems to indicate that, as the high-energy particles hit the surface, that the oxygenation occurs in the ocean and has a fabulous environment. And it's been like that for 4 1/2 billion years.

RAZ: Wow.

GREEN: OK. And so that would definitely be a second genesis. We couldn't get rocks from Mars and Earth from impacts with life on them all the way up that far into the solar system to be able to pelt Europa so much that it could start life. So we would want to probe that.

But the bottom line is, we might have now answered the question, yes, life is elsewhere in the solar system - maybe related to us, verifying panspermia, maybe not. But we have opportunities, clearly, to potentially find life that's a second genesis.

(SOUNDBITE OF MUSIC)

GREEN: I wouldn't discount the outer part of the solar system, particularly once Mars is firmly in human grasp, and we're able to explore it freely and really understand it. Then there is the possibility of launching from Mars on outward. So that would be entertained in the very distant future.

(SOUNDBITE OF TED TALK)

GREEN: Well, is there life beyond Earth in the solar system? We don't know yet, but we're hot on the pursuit. The data that we're receiving is really exciting and telling us, forcing us, to think about this in new and exciting ways. I believe we're on the right track, that in the next 10 years, we will answer that question. And if we answer it, and it's positive, then life is everywhere in the solar system. Just think about that. We may not be alone. Thank you.

(APPLAUSE)

RAZ: Jim Green. He's chief scientist at NASA. You can see his full talk at ted.com. On the show today, exploring The Next Frontier. I'm Guy Raz, and you're listening to the TED Radio Hour from NPR.

(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.