0:21

As we approach a complex subject matter like the emergence of life,

Â we are immediately faced with a hurdle, a conceptual concept that is really hard

Â to get past, because it's something we don't think about much in our daily lives.

Â And that hurdle has to do with the concept of scale.

Â How large or how small is something.

Â And so the way that we want to approach scale in the emergence of life is to think

Â about the dimensions of two very important properties.

Â One of them is size, and one of them is time.

Â So, the properties of size we put into our category we call spatial, and so

Â spatial dimensions, how large or how small is something.

Â The spatial parameters are very important when we think about scale.

Â The other concept of scale is time, and we use the word temporal for

Â time, so, temporal dimensions.

Â So what we want to do now is how do we approach extremely broad

Â scales of spatial and temporal dimensions of space, size,

Â length versus how long or how short an amount of time something takes to

Â actually function and come to its completion or fruition.

Â So the way we do this in the emergence of life is that we have to recognize that our

Â spatial and temporal frameworks are incredibly large.

Â 1:50

In our everyday life, we're used to seeing things that,

Â obviously we use the human body as a good comparative standard.

Â We think about, say, a tree being three times as large as someone, or

Â we think about children being half or a third the size of an adult human being.

Â So we always start by kind of comparing, and that comparison we just described,

Â that's in this world of spatial dimensions and understanding how big or

Â how small something is.

Â But when we look at the emergence of life, we are talking about looking at dimensions

Â of length, length scales of spatial dimensions that are incredibly small.

Â The average diameter of a microorganism, especially bacteria, is about one micron.

Â Well one micron is one millionth of a meter.

Â And that one micron is one of the kind of functional units

Â of spatial dimensions that we want to consistently be able to access and

Â go to as we jump from one millionth of a meter to talk about human beings

Â that are one and a half to two meters in size to talking about meteor

Â impact craters that are 50 kilometers in size, right?

Â And each kilometer then of course is 1,000 meters.

Â So how do we describe these kind of tremendous differences in size,

Â when we want to go from a millionth or a billionth of something all the way up

Â to 1,000 or 1 million or 1 billion times larger?

Â We have the same kind of problem with the temporal concept of dimension.

Â We want to recognize and look at the lifetime of

Â a human being on average 60, 70, 80, 90, years in length.

Â But we also want to think about the time frame of which it takes a cell to divide,

Â which in many cases it can be within seconds.

Â Or some of the basic chemical reactions like when we breathe in oxygen and

Â then release CO2, those dimensions of time are in a fraction,

Â a tiny proportion of a second.

Â 3:50

Then we go to the age of the Earth, 4.7 billion years.

Â That's a tremendous increase over one second of time, so

Â these are enormous distances if you will of scale.

Â So how do we go about doing that for both space and time?

Â And the way we do that is first of all, we consider a critical conceptual benchmark.

Â 4:15

We say to ourselves, is something 10 times larger or 10 times smaller?

Â Is something 100 times larger or 100 times smaller?

Â Is something 1 million times larger or 1 million times smaller?

Â But that first functional unit of saying is something 10 times larger or

Â 10 times smaller, that is where we want to start

Â with understanding how to look at dimensions of time and space.

Â And by centering it around that template, is something ten times larger or

Â ten times smaller, we call the approach the powers of ten.

Â 4:49

If something is twice as large as something else, it catches our interest.

Â But if something is ten times larger than something else, it proves itself to be

Â fundamentally important, fundamentally different just because of the magnitude or

Â size of that scale change.

Â So the nice thing about the powers of ten approach and

Â centering the idea around ten times larger, ten times smaller to start with,

Â is that then, we can put the concept of describing length scales and

Â time scales, into a ten by ten by ten basis.

Â So we can say is something 10 times larger,

Â is it 100 times larger, is it 1000 times larger.

Â And if we go to the concept of something being 10 times larger,

Â then if we put the framework of 10 into exponential notation,

Â which goes to the point of saying that we put the number 10, and

Â then we make a small exponent that tells us how many 0's come after that 10,

Â is it 10, is it a 100, is it a 1,000?

Â 10 to the first is 10, 10 to the second is 100, and 10 to the third is 1000.

Â And by focusing on the exponent instead of saying

Â out all the zeros in terms of the number, like the word 1000,

Â then we can say that this microbial cell is ten to the third

Â larger than some of the molecules that make up the DNA of that microbial cell.

Â Then we can just drop off the ten part of the description, and

Â we can focus just on the exponent, which is three.

Â So if something is a 1000 times larger than something else,

Â then we say that object is three powers of ten greater.

Â So something that 10 times larger is one power of ten.

Â Something that's a 100 times larger is two powers of ten and so

Â forth, and we go in the opposite direction when something is two

Â powers of ten smaller than something else that means it's a 100 times smaller.

Â So this powers of 10 are conceptualization and framework is really powerful for us.

Â And another phrase that we're going to be using throughout the emergence of life

Â course is that we also say that one power of ten is one order of magnitude.

Â So, something, that's 10 times larger than something else is one power of ten larger,

Â and it also can be described as one order of magnitude larger.

Â 7:16

Let's say that the average child is one meter in height, and that we want

Â to understand then how that child fits into the framework of a kilometer, right?

Â So there are a thousand meters in a kilometer, and so

Â if we say well that meter scale,

Â let say that they were standing next to the front range of a mountain

Â that's a kilometer in size, and there's a child that's one meter in height.

Â Then we would say that that mountain,

Â that the child is standing in front of is three powers of ten larger than the child.

Â It's 1000 times larger than the child, and

Â we can also say that it's three orders of magnitude larger than that child.

Â