The Solar System

North Pole Ellipse Ellipse Circle Hyberbola Parabola Center of mass NASANASA Closed orbits return the orbiting object to its sta ...

86 PART 1^ |^ EXPLORING THE SKY depends on how fast the planet moves, and the stored energy depends on the size of its orbit. Th ...

CHAPTER 5 | GRAVITY 87 they would collide in about two weeks except that they are orbit- ing around their common center of mass. ...

88 PART 1^ |^ EXPLORING THE SKY forces and recognize their surprising eff ects. For example, the moving water in tidal bulges ex ...

CHAPTER 5 | GRAVITY 89 Particles move according to three rules of motion and attract each other with a force called gravity. Th ...

90 PART 1^ |^ EXPLORING THE SKY Special Relativity Einstein began by thinking about how moving observers see events around them. ...

CHAPTER 5 | GRAVITY 91 Th e word accelerated is important. If either spaceship were to fi re its rockets, then its veloc- ity wo ...

92 PART 1^ |^ EXPLORING THE SKY the scope of this book, but you can have confi dence that these strange eff ects have been confi ...

CHAPTER 5 | GRAVITY 93 distance compared with the planet’s diameter of 4850 km that it could never have been detected had it not ...

94 PART 1^ |^ EXPLORING THE SKY Africa. Months before the eclipse, they photographed the part of the sky where the sun would be ...

CHAPTER 5CHAPTERCHAPTER 5 5 ||| GRAVITYGRAVITYGRAVITY 9595 Summary ▶ (^) Aristotle argued that the universe was composed of four ...

96 PART 1^ |^ EXPLORING THE SKY Review Questions Why wouldn’t Aristotle’s explanation of gravity work if Earth is not the cente ...

CHAPTER 5 | GRAVITY 97 Why is it a little bit misleading to say that this astronaut is weightless? Describe the orbit followed ...

98 Astronomers go to extremes to build giant telescopes atop high mountains, where they are above most of the distortion caused ...

CHAPTER 6 | LIGHT AND TELESCOPES 99 Radiation: Information from Space Just as a book on baking bread might begin with a discussi ...

100 PART 1^ |^ EXPLORING THE SKY thickness of a sheet of household plastic wrap. It is awkward to describe such short distances ...

CHAPTER 6 | LIGHT AND TELESCOPES 101 of Figure 6-3. Gamma rays, X-rays, and some radio waves are absorbed high in Earth’s atmosp ...

102 PART 1^ |^ EXPLORING THE SKY Focal length Focal length Light reflects from a metal film and does not enter the glass. Short- ...

CHAPTER 6 | LIGHT AND TELESCOPES 103 Its lens is 1 m (40 in.) in diameter and weighs half a ton. Larger refracting telescopes ar ...

104 PART 1^ |^ EXPLORING THE SKY objective. A lens or mirror with a large area gathers a large amount of light. Th e area of a c ...