[SOUND] [MUSIC] As we approach a complex subject matter like the emergence of life, we are immediately faced with a hurdle, a conceptual concept that is really hard to get past, because it's something we don't think about much in our daily lives. And that hurdle has to do with the concept of scale. How large or how small is something. And so the way that we want to approach scale in the emergence of life is to think about the dimensions of two very important properties. One of them is size, and one of them is time. So, the properties of size we put into our category we call spatial, and so spatial dimensions, how large or how small is something. The spatial parameters are very important when we think about scale. The other concept of scale is time, and we use the word temporal for time, so, temporal dimensions. So what we want to do now is how do we approach extremely broad scales of spatial and temporal dimensions of space, size, length versus how long or how short an amount of time something takes to actually function and come to its completion or fruition. So the way we do this in the emergence of life is that we have to recognize that our spatial and temporal frameworks are incredibly large. In our everyday life, we're used to seeing things that, obviously we use the human body as a good comparative standard. We think about, say, a tree being three times as large as someone, or we think about children being half or a third the size of an adult human being. So we always start by kind of comparing, and that comparison we just described, that's in this world of spatial dimensions and understanding how big or how small something is. But when we look at the emergence of life, we are talking about looking at dimensions of length, length scales of spatial dimensions that are incredibly small. The average diameter of a microorganism, especially bacteria, is about one micron. Well one micron is one millionth of a meter. And that one micron is one of the kind of functional units of spatial dimensions that we want to consistently be able to access and go to as we jump from one millionth of a meter to talk about human beings that are one and a half to two meters in size to talking about meteor impact craters that are 50 kilometers in size, right? And each kilometer then of course is 1,000 meters. So how do we describe these kind of tremendous differences in size, when we want to go from a millionth or a billionth of something all the way up to 1,000 or 1 million or 1 billion times larger? We have the same kind of problem with the temporal concept of dimension. We want to recognize and look at the lifetime of a human being on average 60, 70, 80, 90, years in length. But we also want to think about the time frame of which it takes a cell to divide, which in many cases it can be within seconds. Or some of the basic chemical reactions like when we breathe in oxygen and then release CO2, those dimensions of time are in a fraction, a tiny proportion of a second. Then we go to the age of the Earth, 4.7 billion years. That's a tremendous increase over one second of time, so these are enormous distances if you will of scale. So how do we go about doing that for both space and time? And the way we do that is first of all, we consider a critical conceptual benchmark. We say to ourselves, is something 10 times larger or 10 times smaller? Is something 100 times larger or 100 times smaller? Is something 1 million times larger or 1 million times smaller? But that first functional unit of saying is something 10 times larger or 10 times smaller, that is where we want to start with understanding how to look at dimensions of time and space. And by centering it around that template, is something ten times larger or ten times smaller, we call the approach the powers of ten. If something is twice as large as something else, it catches our interest. But if something is ten times larger than something else, it proves itself to be fundamentally important, fundamentally different just because of the magnitude or size of that scale change. So the nice thing about the powers of ten approach and centering the idea around ten times larger, ten times smaller to start with, is that then, we can put the concept of describing length scales and time scales, into a ten by ten by ten basis. So we can say is something 10 times larger, is it 100 times larger, is it 1000 times larger. And if we go to the concept of something being 10 times larger, then if we put the framework of 10 into exponential notation, which goes to the point of saying that we put the number 10, and then we make a small exponent that tells us how many 0's come after that 10, is it 10, is it a 100, is it a 1,000? 10 to the first is 10, 10 to the second is 100, and 10 to the third is 1000. And by focusing on the exponent instead of saying out all the zeros in terms of the number, like the word 1000, then we can say that this microbial cell is ten to the third larger than some of the molecules that make up the DNA of that microbial cell. Then we can just drop off the ten part of the description, and we can focus just on the exponent, which is three. So if something is a 1000 times larger than something else, then we say that object is three powers of ten greater. So something that 10 times larger is one power of ten. Something that's a 100 times larger is two powers of ten and so forth, and we go in the opposite direction when something is two powers of ten smaller than something else that means it's a 100 times smaller. So this powers of 10 are conceptualization and framework is really powerful for us. And another phrase that we're going to be using throughout the emergence of life course is that we also say that one power of ten is one order of magnitude. So, something, that's 10 times larger than something else is one power of ten larger, and it also can be described as one order of magnitude larger. Let's say that the average child is one meter in height, and that we want to understand then how that child fits into the framework of a kilometer, right? So there are a thousand meters in a kilometer, and so if we say well that meter scale, let say that they were standing next to the front range of a mountain that's a kilometer in size, and there's a child that's one meter in height. Then we would say that that mountain, that the child is standing in front of is three powers of ten larger than the child. It's 1000 times larger than the child, and we can also say that it's three orders of magnitude larger than that child. And this concept of how to approach these immense diameters of scale of time and space are what would give us the ability to communicate then about going from the evolution of early cells all the way up through fish, dinosaurs and now eventually human beings. [MUSIC]