Figure 17.1 Star Colors. This long time exposure shows the colors of the stars. The circular motion of the stars across the image is provided by Earth’s rotation. The various colors of the stars are caused by their different temperatures. (credit: modification of…
Sources of Sunshine: Thermal and Gravitational Energy The Sun produces an enormous amount of energy every second. Since Earth and the solar system are roughly 4.5 billion years old, this means that the Sun has been producing vast amounts for…
LEARNING OBJECTIVES By the end of this section, you will be able to: Recall that when we observe the Sun’s photosphere (the surface layer we see from the outside), we are not seeing very deeply into our star, certainly not into…
LEARNING OBJECTIVES By the end of this section, you will be able to: Fusion of protons can occur in the center of the Sun only if the temperature exceeds 12 million K. How do we know that the Sun is actually this…
LEARNING OBJECTIVES By the end of this section, you will be able to: As we have seen, energy cannot be created or destroyed, but only converted from one form to another. One of the remarkable conclusions derived by Albert Einstein (see Albert Einstein) when he…
LEARNING OBJECTIVES By the end of this section, you will be able to: Energy is a challenging concept to grasp because it exists in so many different forms that it defies any single simple explanation. In many ways, comprehending energy…
Figure 16.1 The Sun. It takes an incredible amount of energy for the Sun to shine, as it has and will continue to do for billions of years. (credit: modification of work by Ed Dunens) Chapter Outline 16.1 Sources of Sunshine: Thermal and Gravitational…
The Structure and Composition of the Sun The Sun, our star, has several layers beneath the visible surface: the core, radiative zone, and convective zone. These, in turn, are surrounded by a number of layers that make up the solar…
LEARNING OBJECTIVES By the end of this section, you will be able to: In the previous sections, we have seen that some of the particles coming off the Sun—either steadily as in the solar wind or in great bursts like CMEs—will…
LEARNING OBJECTIVES By the end of this section, you will be able to: Sunspots are not the only features that vary during a solar cycle. There are dramatic changes in the chromosphere and corona as well. To see what happens in…