 Starting again with the image of the sun and interacting with the atmosphere and the earth. The atmosphere is a cover, it's a transparent cover relative to some wavelengths. And we'd like to use that as our quick diagram in case study. So we've got the sun that is emitting shortwave light. It is transparent in the shortwave, for the large part. That sunlight ultimately interacts with the earth's surface where it is absorbed. A portion of it is absorbed, and a portion of that light is reflected, and that reflected light ultimately is going to leave the atmosphere. What we find out is that that amount of light that's leaving the atmosphere, whether it's reflected off of the ground, or let's say, for example, it's sunlight that is being reflected off of clouds, we're still assessing that these total are going to be on the order of 70 to 75% of light. And that would be evaluated with a row of 0.7. We'd have, from the balance, because the earth is opaque, we'd have an alpha value of 0.3, so alpha of 0.3 for the surface of the earth. And that would make the transparency approximately 1 for the earth's atmosphere. Now that's part of the balance, and that's all the shortwave, right? But the earth itself, in this case study, again, has a given temperature, the temperature of the sun, and the temperature of the earth, and the temperature of the atmosphere are all going to come to play into this. Shortwave is coming from the source of the sun, because the sun's surface temperature is that 5,777 degrees Kelvin, or approximated as such, and the earth is going to be emitting long wave light. The atmosphere is going to be emitting long wave light, only the atmosphere will emit is actually two surfaces, a top surface and effectively a bottom surface, and will be emitting up and down long wave radiation. However, the earth itself, let's grab this guy and simplify it again, the earth itself is going to be emitting this long wave light, and a large part of that long wave light is going to be absorbed by the atmosphere. Some of that light, however, emitted by the earth, is going to make its way through the atmosphere, and it's going to have a very low transparency, I will say approximately 0.1, but some of that makes its way out, and it makes its way out through what we call the sky window, or the atmospheric window, and that sky window is occurring in a specific band, this is a selective surface of its own, where from 8 to 13 micrometers, we have a gap, a leaky window, where long wave radiation can escape, so if I were to grab this image that we've been looking at before, you're going to see a range, and we're going to kind of dial into where is that sky window happening. So somewhere right in here is a range that's lining up over in this area, and that range, if we look closely, is going to be down here, and carry that down, that's going to be at about 10, 9, 8 nanometers, and the next one is going to be right here, alright, let's grab that guy, and he is going to be at about, that's about 20, so half of that's 15, and approximately, right there is about 13 or 14 micrometers. So again, from 8 to 13 micrometers, we have in this range, right here, and here is our window where we're getting a percentage, actually it looks like a higher percentage, 15 to 30 percent of light transmitted through the Earth's atmosphere. On this side over here, we see that whole spectrum, that is the solar spectrum from the Sun, and it's in the small percentage in the UV, a bigger percentage in the visible band, and a very large percentage of light that's coming through the atmosphere that is in the infrared band. But ultimately, it all cuts off at about 1, 2, 3,000 nanometers, and actually if we were to look closely, the atmosphere actually cuts off to about 25. Now, the other thing that we can look at in this diagram is what are the sources of the walls of this atmosphere? If I draw that arrow down, I see that one of the absorbing gases is carbon dioxide, and on the other side of this, the main absorbing gas is going to be water vapor, water vapor and oxygen. So essentially I have water vapor on this side, I have CO2 on this side that are limiting the leakiness of the atmosphere to lose energy, to leak energy into the interspace, and that's actually the valve mechanism that we tie into the greenhouse effect. So you increase CO2, you start moving the valve tighter, you heat up the atmosphere, you increase the water content, you squeeze things a little tighter, and you actually lose your leakiness, and you dry the atmosphere warmer and warmer. Okay, that's the end of our case study. Let's move on to the next.