The Solar Cycle
LEARNING OBJECTIVES By the end of this section, you will be able to: Before the invention of the telescope, the Sun was thought to be an unchanging and perfect sphere. We now know that the Sun is in a perpetual state of…
The Structure and Composition of the Sun
LEARNING OBJECTIVES By the end of this section, you will be able to: The Sun, like all stars, is an enormous ball of extremely hot, largely ionized gas, shining under its own power. And we do mean enormous. The Sun could…
Thinking Ahead
Figure 15.1 Our Star. The Sun—our local star—is quite average in many ways. However, that does not stop it from being a fascinating object to study. From solar flares and coronal mass ejections, like the one seen coming from the Sun in the…
Summary
Meteors When a fragment of interplanetary dust strikes Earth’s atmosphere, it burns up to create a meteor. Streams of dust particles traveling through space together produce meteor showers, in which we see meteors diverging from a spot in the sky…
Planetary Evolution
LEARNING OBJECTIVES By the end of this section, you will be able to: While we await more discoveries and better understanding of other planetary systems, let us look again at the early history of our own solar system, after the…
Comparison with Other Planetary Systems
LEARNING OBJECTIVES By the end of this section, you will be able to: Until the middle 1990s, the practical study of the origin of planets focused on our single known example—the solar system. Although there had been a great deal…
Formation of the Solar System
LEARNING OBJECTIVES By the end of this section, you will be able to: As we have seen, the comets, asteroids, and meteorites are surviving remnants from the processes that formed the solar system. The planets, moons, and the Sun, of course, also…
Meteorites: Stones from Heaven
LEARNING OBJECTIVES By the end of this section, you will be able to: Any fragment of interplanetary debris that survives its fiery plunge through Earth’s atmosphere is called a meteorite. Meteorites fall only very rarely in any one locality, but over…
Meteors
LEARNING OBJECTIVES By the end of this section, you will be able to: As we saw in Comets and Asteroids: Debris of the Solar System, the ices in comets evaporate when they get close to the Sun, together spraying millions of…
Thinking Ahead
Figure 14.1 Planetesimals. This illustration depicts a disk of dust and gas around a new star. Material in this disk comes together to form planetesimals. (credit: modification of work by University of Copenhagen/Lars Buchhave, NASA) Chapter Outline 14.1 Meteors 14.2 Meteorites: Stones from Heaven 14.3 Formation…