[SOUND] [MUSIC] I don't know if you've thought about this, but on a daily basis when I look up at the sky, or get up and see what's going on around me, I'm constantly amazed at the combination of events that have actually come together to allow our every day life to be as it is. Planet Earth was a very difficult place. In fact, it was an impossible place for organisms like ourself to live in for the vast majority of Earth history. But then as Earth and life evolved together, the planet changed. And the whole idea that life could even get a foothold on planet Earth is a truly remarkable combination of events and one of the best ways to describe this is really this phrase, the perfect storm. There were many things that came together that were unexpected and quite rare and unique but all these factors came together to allow a window of opportunity for life to begin and initiate in planet Earth. So, I'd like to run through what this perfect storm is and the perfect storm in this case is actually positive, right? It's a combination of events that allowed a remarkable thing to happen, which is the genesis and synthesis of life on planet earth. So when earth was first being formed, it was coming together as a combination of rock and dust and water that was cooling out of small particles that were swirling through the universe. And so, it was a very dynamic process of matter coming together within the universe. Well soon after that we had a collision and it created through time, again, this dust, this water, these rock particles that coalesced, stuck together, and made the moon. And so the moon was actually a product of meteor impact on the early earth. Well, in that stage then, of the earth, and recovering from that impact, then the earth slowly went through cooling and chemical changes. And some of those chemical changes were profound. Now, one of those major changes that took place was, as the core of the Earth was formed, and again, in that core, we had an inner core that was solid and an outer core. Those bodies of material that were molten and solid, they would rotate past each other constantly. And they're metallic and so that rotation actually generated the Earth's magnetic field. Now, we're going into all these details because of the fact that we needed to have a magnetic field to protect the outer crust of the earth, and the surface of the earth from incoming cosmic rays, that were generated by the sun. Ultraviolet radiation among others, and so until the Earth had generated it's magnetic field, which if you will, acts as a safety umbrella. To protect the Earth from this incoming cosmic radiation, the Earth's crust, the outer part of the crust would could not sustain life. So, at just the right series of events again, the Earth cooled, differentiated, went through chemical changes and established this protective umbrella called the Earth's magnetic field. And that protected the outer surface from the cosmic radiation but also at the same time, the early Earth had been bombarded very heavily by meteors, these incoming bodies of rock and ice that come in from outerspace and slam into the planet. And the frequency at which that happened was dramatic, it was very, very high. Now the Earth and Mars were not so dissimilar in that they both were planets, now we know, with water on the surface and they had atmospheres. But Mars got unlucky compared to Earth. And Mars simply had many more meteor impacts that lasted a lot longer, and we call that the period of heavy early bombardment. While the Earth got lucky, the early bombardment, it was intense at first and then it died off and it got to be in a relative sense, very low frequency, the number of times it was. And so at the same time the earth's magnetic field was set up to protect us from radiation, also the frequency in the number of meteor bombardments decreased at just the right time. There are some hypotheses that suggest that during the early stages of early bombardment, when we did have a magnetic field, that Earth tried to get a foot hold, in terms of life, and life couldn't do it. And it wasn't because of the radiation. It was because it was basically blasted to pieces by these incoming meteors. But as soon as you decrease the frequency of meteor impacts and you have your safety shield up, then life can get a foot hold. That was also the early Earth environment where we had no oxygen. It was a very sulfur rich environment in which sulfur to us is toxic, but oxygen to these early organisms was equally toxic as sulfur is to us. And this whole confluence of dramatic circumstance came together to create an ability to have life start, and survive, on the outer crust of the earth. So, that's how we need to see the initial kickstart, the template for the evolutionary biology, of planet Earth, is that, the Earth configured itself perfectly, in the perfect storm, to allow the genesis of life, and then the radiation of life across the planet. [MUSIC]
