Life's cosmic origins: Carolyn Collins Petersen at TEDxFoCo
[Music] [Applause] pardon me yeah i just need to bring it down a little bit hi there everybody i really can't see you but i know you're out there yes i am carolyn collins-peterson i'll bring up my opening slide for you um yes i did interview a number of star trek captains and i'd be happy to talk to them talk to you about them after my talk when nick invited me to um come and talk today and he gave me the theme life worth living i had to think about that one for a while because i had originally intended to talk about astronomy and i decided that i'd spend my few minutes with you talking and focusing on the word life so now we're going to talk about life and discuss the cosmic origins of life so i want to start beginning with the question how did life get started that's an interesting question well we know it got started on this planet because here we are and astronomers are busy looking for other worlds where life has gotten started and we don't know that it's gotten started somewhere else but the nasa's kepler mission is out there looking for worlds it's looking for other worlds in a very tiny area of space and so far it's found about 20 more than 2700 exoplanets exoplanets or worlds around other stars and so far people when they hear that when when it they announced new uh discovery of new exoplanets they we asked the question are they earth-like and we asked that question because we just sort of seem to assume that earth-like means that it'll have conditions to form life and that those are the only places life can form well that may not be true i mean there could be a jupiter-like world out there we all know about jupiter big massive planet no life but there could be a jupiter-like world out there that does have life we just don't know so knowing that there are other worlds out there those 2 700 plus plus worlds it's very exciting but it doesn't really answer the question about where life came from so life think about it as a gift from the cosmos the cosmos supplies the raw materials for life and it does this using stars now astronomy and astrophysics tell us how stars live how they born how they work how they die but that's only part of the story of life the rest of the story of life comes from a science called astrobiology and that combines astronomy biology chemistry biochemistry planetary science life sciences and it tries to figure out what conditions are necessary for life and whether or not there are other worlds with life so think of astrobiology as a science that tries to determine where those worlds are and how they shape the life that arises on them well the story of life really begins with the big bang and these are the world i'm sorry i missed a slide these are the worlds that i wanted to show you about earth and many of the other worlds the story of life really begins with the big bang and we don't have a good picture of the big bang we kind of know what it is so i'm just going to show you darkness because anything i show you would look like an explosion that's not really what it was but the big bang was the founding event of the universe it was the beginning of space and time and interestingly the big bang created all the hydrogen in the universe hydrogen is the most elemental element that we have it also created some helium and some hydrogen i'm sorry lithium and hydrogen's very important it's part of water we need water for life it also bonds very easily with other elements that make the molecules that that life needs to exist and those elements are things like carbon nitrogen oxygen so where do all those other elements come from if all the hydrogen was made in the big bang well they come from stars now here's how stars form other elements they fuse hydrogen in their core and that creates helium the fusion process actually gives off heat and light which is how stars shine it's how the sun works when stars run out of hydrogen all of the hydrogen fuel in their cores they begin to fuse helium and that makes carbon another element that we need now the fusion process continues in some stars making more and heavier elements all the way up to iron actually but eventually all stars run out of fuel in their cores and when and that's in at that point the fusion stops and the stars die now stars die in different ways actually depending on their mass so a really massive star explodes as a supernova and that scatters all of the elements that it's been cooking up inside its core out to space now sun-like stars other stars like the sun they swell up to become red giants and they lose their outer atmospheres and they become what we call uh planetary nebulae and as they do this all of the material that they made in their cores is also scattered out to space now some of this material ends up floating out in space and it becomes the raw material for new generations of stars and planets now these are nebulae these are a very important part in the story of life think of them as interstellar chemical factories they're filled with elements that are created in stars but they also have water molecules they have bits of carbon they have sand grains ice chunks of rock and they're very busy places they move and they churn as they float through space they're elements mixed together they have magnetic fields threaded through them they get heated and stirred when new stars form inside them and occasionally you'll have a supernova that explodes near one of these nebulae and that tremendous explosion sends a shock wave through the cloud and it also infuses the cloud with new elements that were cooked up in the supernova in the star that blew up so what's important for life are the chemical reactions that take place in nebulae they create organic molecules especially amino acids now what's really amazing is today we're finding we're finding these prebiotics in many many nebulae in interstellar space in these clouds of gas and dust that are in interstellar space now the interesting part also is how we find them we use radio telescopes this is a the green bank telescope i'm sorry this is the green bank telescope okay where's the laser okay well never mind that thing down there in the corner is the green bank telescope in virginia um and a group of astronomers use this uh telescope to focus in on nebula not too far from our planet and and they found a whole slew of prebiotic molecules and the way they did that is they they sense the radio emissions from it there are little emissions that come out from these and what they found were all of these molecules and in particular the one down at the bottom called cyanomethanamine now that's really a precursor to something called adenine which is a a very important component of our dna they also found the amino acid alanine now all this material is out there floating around in space and it's available to seed planets with materials that are necessary for life the nebula where our solar system formed obviously had access to all this material because here we are astronomers are studying asteroids and comets and meteors that are left over from the formation of our solar system and they're sure enough they're finding uh traces of organic materials and prebiotics in those objects so here's what our early solar system looked like we had the sun in the center it's forming very young sun and it's surrounded by a rotating cloud of gas and dust and it has the seeds of planets forming inside it and let's skip forward to the formation of our own earth this is what early earth looked like as it was forming it was started out small and it was formed as planetesimals crashed into it now these planetesimals are these small rocks that are in in the picture here they're crashing into it and they're made out of bits of carbon they're made of rock so carbon and silicon they have prebiotic materials laced through them they have deposits of water and they helped build up the planet over hundreds of thousands of years now there were also comets crashing onto the surface of our early planet and they most certainly brought supplies of water and prebiotics now eventually the young earth cooled sorry i went too soon and as it did the oceans and an early atmosphere formed and so that set the stage for the formation of life now nobody really knows where the first life on earth on earth formed somewhere somehow it did a biochemical reaction took place and it needed a spot where conditions were just right it's kind of like goldilocks not too warm not too hot just right so it could have been a shallow lake somewhere or a a tidal pool or a deep ocean vent like we see down on the bottom of the deep ocean but wherever it happened prebiotic materials mixed and they warmed and eventually they assembled together to form the first single celled life now this is what our earliest ancestor probably looked like it's called a microbial mat so think of it as a colony of microbes now together they created oxygen through the process of photosynthesis and billions of years ago colonies of animals like this created the first free oxygen for earth's atmosphere so from this very simple beginning life on earth has experienced a tremendous explosion of life over 3.8 billion years from these small microbes life has evolved from these to complex organisms that inhabit an astonishingly diverse array of habitats so today for example we find microbes living in boiling hot water does anybody know where this is yeah yellowstone it's grand prismatic spring in yellowstone every one of the colors that you see here the yellows and the greens and the reds those are all different microbe colonies and they've adapted to different conditions chemical and temperature conditions in that pool now at the other end of the temperature spectrum we have these guys these are what i like these are basically little worms they nestle quite happily deep in the deep ocean surface and they live on deposits of methane ice so each environment on earth actually shapes the kind of life that can survive in it from the mountains here uh to the frigid conditions at the poles humans we actually live quite happily in a number of different habitats from the cities in the city of cairo down here to this little mountain village to farms out like like we have out here near fort collins um to the deserts to uh to the wilderness we pretty much can live we've lived on the moon briefly the deserts have their own well in three quarters of our planet is also covered with water and so the oceans the deep oceans and the coral reef everything in between support an incredible diversity of life and the deserts have their own sets of life and as do the as the forest so our planet is really an object lesson in how life has formed and how it adapted to an extreme number of conditions many different environments so you have to ask if life could get a foothold on our planet can it actually get a foothold on some other planet now remember remember i talked about the kepler mission it's found more than 2 700 potential worlds out there there are many more to be found it only looked in a very small area of space so there are many more worlds out there and so i'd say the odds for finding life somewhere else are pretty good in closing i'd like to like to end with a couple of thoughts first of all everything started with the big bang all life started with the big bang second of all we are all star stuff every single atom in your body came from some kind of star came from stars so think about it think about your eyes every atom in your eye was forged in a long dead star so when you go out tonight and you look up at the sky if it clears up you'll see stars and you're basically looking at the stars you're looking at the universe you are the universe looking back at itself and finally life is a big biochemistry experiment it began some 13.8 billion years ago in the big bang it continues on this planet and it's very likely working itself out on other planets as well and the conditions on every planet where life forms dictate the forms that that life will take they actually guide the evolution of life that's certainly been the case here on earth with all the diversity of life that we have so in a very real sense our planet was not made for us we were made for our planet it shaped what we are and it's very likely that somewhere else out there there are other planets doing the same thing for their collections of life thank you [Applause] you