8.6. NASA Institute for Universal Biology
Emergence of Life
일리노이대학교 어버너-섐페인캠퍼스
4.3(70개의 평가) | 9.9K명의 학생이 등록함
Week 8 - Astrobiology and the Search for Life in the Cosmos
No matter where you are or what you believe, sometime in your life you will look up into the sky and ask: What is out there? Where are we going? Is there life elsewhere in the universe? This course is dedicated to searching for answers to these questions. The fundamental concepts of life and habitable environments, established upon the modern synthesis of the Tree of Life, will direct us in recognizing biospheres that might be quite different from our own. In the last week of this course, we will look in detail at what the future has in store for space exploration and the search for life in the cosmos.
8.1. NASA Astrobiology: Roadmap to Life in the Universe11:44
8.2. NASA: A Platform for Inter-Disciplinary Science4:57
8.3. Mars Flybys and Orbiters: Getting the Picture8:37
8.4. Mars Rovers: Was the Red Planet Habitable?9:04
8.5. NASA Future Missions9:03
8.6. NASA Institute for Universal Biology8:59
8.7. Think and Wonder…Wonder and Think5:06
8.8. The Emergence of Life: Course Synthesis 6:33
Emergence of Life Outtakes3:58
[SOUND] [MUSIC] My name is Nigel Goldenfeld, and I'm a professor of physics at the University of Illinois at Urbana-Champaign. I direct the NASA funded Institute for Universal Biology in the NASA Astrobiology Institute. And I also work at the Institute for Genomic Biology at the University of Illinois. So, I'm going to talk about what is perhaps the most exciting, scientific question of all time, okay? Can you guess that that is going to be? Well, I'll tell you what it is. It's the question is there life on other planets. Now, you may say, well, that's an interesting question, and this is how we're going to answer it. We're going to build spaceships, or maybe we're going to build robots and put them in spaceships, and send them to other planets and eventually we'll detect life. Or maybe we'll detect life by radio waves or some other signature of life on another planet. But, actually, I don't think that's how we're going to do it at all. Because here's sort of a dirty little secret, if you like, about biology. And that is, while we know a lot about biology and about how the cells in your body work and, indeed, how your body functions, we don't actually know why the phenomenon of life actually occurs at all, okay? It's a very strange thing. Usually, when we try to understand something in science, we not only understand how it actually works, but we also understand why the phenomenon actually exists. But in the case of life, we don't have any sort of understanding of that. There's no understanding of science that says, yes, there should be things that live. There's certainly science that says there should be atoms and there should be molecules and there should be polymermolecules. And there should be rocks, and there should be minerals, and there should be waves, and oceans and so on. But why there should be the phenomenon of life, well, that's something that we don't understand. And so, I actually think that if we're going to understand whether life exists on other planets, we're going to have to understand why life exists on Earth in the first place. And I don't mean how did life start on Earth. I mean, understand why it exists. Why and not how. And that's a question of physics. In fact, it's a question which is very simply stated is life an inevitable outcome of the laws of physics or is it some kind of very complicated biochemical accident? That's actually my own personal research activity, something that I'm very interested in answering. Now, in order to answer such a question, we need to understand what we've come to call universal biology. And I want to tell you about what universal biology actually is. In one sense, it's universal, meaning in the sense of biology or life in the universe, and one sense in which it occurs. But there's another sense in which I mean the phrase universal biology. What I mean is, what aspects of biology can we understand without having to know all the details of the chemistry and the biochemistry and the molecules and the atoms that make up life? Can we understand living creatures without having to know everything? And, in fact, how much can we understand by knowing virtually nothing? Those are the questions that I want to understand. And that's, in a sense, universal biology. Now, we need to understand universal biology if we area going to understand the question about whether life exists on other planets. That question, one of the key questions, in the science known as astrobiology is something that we need to have a more general picture of life than what we have here on Earth. We can't assume that life on other planets is going to use the same chemistry and the same geochemistry, and so on, that life does on Earth. And so, we have to think about life in a very abstract way. And so, that's why my very abstruse theoretical physics perspective on what life is might be important in understanding astrobiology. So, first of all, let's ask the question if you want to understand universal biology, well, what do we mean by life in the first place? And my answer to that is very simple. The essence of life is not that it metabolizes, in other words, that it takes in food and then poops it out the other end. That's not what life is. What about replication? Is life machinery that replicates itself? Well, I would say, no, that's what life is either. I can program robots to build copies of themselves. That's not really life either. Life is the ability to evolve. Evolvability is the key feature of living systems. And so, that's the perspective I have. And so, I try to understand the universal properties of systems that are capable of evolving, and systems that are capable of evolving from essentially nothing and then start the bootstrap process of evolving their complexity. Now, that is, currently still, an open question. But it's one that's a subject of research. Now, if you're going to try to ask the question is there a science of universal biology, you probably want to have a model for how that kind of thing could be understood. So, I'm going to give you one so you can think about this in concrete terms. So, think about computers. So, what is a computer? Well, behind me you can see a picture of a computer. It's a sort of shiny plastic object made out of silicon and plastic and liquid crystals and glass and so on and so forth. That's a computer, right? Well, no, not necessarily. Here's another computer. This is a picture of a machine built out of springs and cogwheels and levers, built by Charles Babbage in the 1800s. And if you want to see this working, you can either go to the science museum in London or the Museum of Computation in Mountain View, California. And this is a machine that is also a computer. So, a computer is both something built out of silicon chips and plastic and so on, or something built out of cog wheels and springs. How can it be both? Well, a computer is neither one nor the other. A computer is the abstraction. It, in fact, is what we call a universal Turing machine with a Von Neumann architecture. That's the mathematical concept, the mathematical abstraction, that these machines, the ones built out of silicon, the ones built out of cogwheels and springs, that's a mathematical abstraction that those things instantiate. So, there's something that can happen, something that has an abstract description. And then, you can built it in any different way. Probably, in your own lifetime, some of you will have seen radio sets evolve from being big, heavy devices with vacuum tubes and so on, to small devices built out of transistors. They're all the same thing. They all pick up radio stations, but they use completely different technology. So, we need a description of life that is independent of the technology of life. Independent of the molecules of life. And so, that's what universal biology is. Now, my institute, the Institute for Universal Biology, is attempting to understand life as a phenomenon in this universal way. And we're trying to do many different things. We're trying to understand, if you have living objects, living systems, what must they all share in common? What must they all do? Now, one of the things is, obviously, that they must evolve. But perhaps one of the other things is that they must evolve along a similar trajectory. Another thing that we're interested in doing is understanding how life responds to environments. When life evolved, it evolved within a particular environment. And in our case, the Earth's environment. How does the fluctuating environment affect the rate of evolution? How does it affect the way that organisms can evolve and interact and grow communities and so on and so forth? Well, those are questions that actually can be understood at a very fundamental level by doing laboratory experiments, taking cells, subjecting them to stress. See if they evolve faster in some sense. Those are some of the things that we're trying to do at the Institute for Universal Biology. [MUSIC]