Greetings and welcome to the Introduction to Astronomy. One of the things that I like to do in each of my introductory astronomy classes is to begin the class with the Astronomy Picture of the Day. From the NASA website that is APOD.nasa.gov slash APOD. And today's picture for February 3rd of 2020, while it is titled Solar granules at Record High Resolution. So what do we see here? Well this is one of the earliest images taken by the new NOA telescope in Hawaii. And it is a telescope dedicated to studying the sun and learning more about the sun, which is of course the closest star to us here on Earth. And here we look at a small portion of the sun, and this is actually a time lapse video that will show 10 minutes worth of time compressed into about 5 seconds. And during the video, which actually lasts about 15 seconds and plays this several times, so you get a chance to look at a very close up area of the sun's surface. And as we play the video, what you will see is that the sun's surface is not as quiet, quiet and calm as you might think just looking at it. When we look at it up close, it is constantly changing. And what we are looking at here are what we call granules on the sun. Now granules are something we see on the surface, and that actually are a cause of convection in the sun down below the surface. Radiation and energy can be transferred in a couple of different ways, and they can be transferred by convection, conduction, or radiation. Now the sun uses two of these, which are radiation, which are used deep inside the sun, and also after the sun's surface as the radiation travels from the sun to the earth. But in between those, it travels by convection. And that is much like a boiling pot or a convection oven, where the material is heated down below and the hot air rises up to the top. And that's what you're seeing are the top of the convection cells here. So the hotter areas in the middle are where material has risen up from the bottom, a warmer material from deeper in the sun, and is releasing that energy, and then the edges are the cooler areas where it is sinking back down. So again, as you watch the video, you will see that kind of bubbling almost, so that we associate with boiling, that is occurring on the surface of the sun. Now it is a very rapid process for the sun. It changes very quickly, and you can see that the granules do not look the same. Even after just about 10 minutes, they look a little bit different than they had. The other interesting thing is the size of these granules are not small, but actually very, very large in the size of a good size state in the United States, or even a decent size country. So they're actually quite large granules over the surface of the sun, and we're seeing only a tiny portion of the sun's surface here. So hopefully over the coming years, we will begin to learn even more about this, the one star that we can come up, can study up close, which is of course our own sun. And learning more about our sun tells us in more detail about how stars work, and we can then hide and apply that knowledge to other stars that are much more distant. We would never be able to see this kind of detail on another star. In fact, we really cannot even see any other stars as anything other than a single point of light in the sky. Only a few of the nearest and biggest stars can actually be seen to have a small disc. Everything else just looks like a dot even through the most powerful telescopes. So a chance to study one example of a star in great detail up close with the new NOA telescope. So that was our picture of the day for February 3rd of 2020. It was titled Solar granules at Record High Resolution. We'll be back again tomorrow for the next picture, previewed to be Grand Canyon Night Sky. So we'll see what that is about tomorrow. And until then, have a great day everyone, and I will see you in class.