 So right now you're looking at an image in the website, it's really diagramming everything that can happen when light is interacting with matter, with surfaces, with molecules. What happens in that process in the lifetime of the photon? And what I like about this diagram is it's actually diagramming everything happening at once, which is more realistic of what's actually happening. Remember that when we say incident radiation, what we're talking about, light is directional and so we have a language for light that's being emitted from surfaces, that's radiant extents, radiance, radiation. And we have the language, the terminology for the light that is incident upon a surface. And so what we would call this, we would probably correct this to call this irradiance, right, NCE, or irradiation as well, right? So either one of these is talking about light incident upon a surface. And so again, what we're seeing is light coming in to a surface. This is really meant to be indicative of what's happening in the atmosphere. And so we have light that is absorbed by this material, and this could be the atmosphere. We have, or it could be clouds, could be water molecules for that matter. We have scattering happening in it, and the scattering events are basically reflections. So backscattering is really indicating reflection. Absorption is indicated by alpha. So we have scattering events on a surface, even though that surface in our case is a single dot. And the scattering in our case could be backscattering. It could also be forward scattering happening. And that's why you have these two different arrows. And the last that you have is transmission. And that's really like that nothing was absorbed. So we're going to diagram that with a circle. That's going to be a tau equal to or say a tau approaching one. Something that is very transparent is going to have a coefficient, a fractional value closer to one. Something that is very dark, very opaque is going to have a fractional value close to one for alpha. And somewhere in between this, all of these things happening, we have to recognize that all this light coming in, right, is going to be equal to one in a fractional sense. And then the three different things that can be happening is it could be absorbed, it could be reflected, and it could be transmitted. But the balance of all of that energy is still going to add up back into one. So we can have a very opaque material, which will have a high absorption coefficient and a transparency that will go towards zero, in which case will have basically just absorption and reflection happening. And that reflection and absorption process happening is called a gray body. So it's an opaque material that reflects some of the light and absorbs the rest of the light that is incident upon that surface. And if you think about it, when we want to call something a black body, what a black body means is that the absorption is all one, okay? It's absorbing perfectly, it's not reflecting any of that light, it's not transmitting any of that light, that is a black body. And a black body like the sun, which is a very close approximation of the black body, is also going to be used Kirchhoff's law. So you'll have absorptance equal to emittance. And so the emittance is going to be equal to one as well. So we've got some pretty interesting stuff going on that's really demonstrating everything that we've learned about light so far. And we've demonstrated that we've got a few diagramming techniques that will tie this together.