8 LOOKING BACK KEY CONCEPTS SUMMARY CHAPTER 8 KEY CONCEPTS SUMMARY Careful observation of the night sky can offer clues about the motion of celestial objects. The stars appear to move across the night sky from east to west, except for the North Star (Polaris), which appears stationary. The Moon rises in the east and sets in the west. Sometimes the Moon is visible in the daytime. Different constellations are visible at different times of year. Lunar and solar eclipses sometimes occur. They are due to the alignment of Earth and the Moon with respect to the Sun.

8 LOOKING BACK KEY CONCEPTS SUMMARY CHAPTER 8 KEY CONCEPTS SUMMARY Celestial objects in the Solar System have unique properties. There are eight planets in the Solar System. The physical properties of the four terrestrial planets are distinct from the physical properties of the four gas giant planets. The planets all orbit the Sun in ellipses, in the same direction but at different distances. Asteroids, meteoroids, comets, and dwarf planets all orbit the Sun but are smaller and have properties that distinguish them from the planets.

8 LOOKING BACK KEY CONCEPTS SUMMARY CHAPTER 8 KEY CONCEPTS SUMMARY Some celestial objects can be seen with the unaided eye and can be identified by their motion. Mars, Venus, Saturn, and Jupiter can be easily seen in the night sky without a telescope. They move eastward from night to night. The positions of the objects in the night sky can be specified by their altitude and azimuth. The planets that are farther from the Sun than Earth sometimes exhibit retrograde motion. Artificial satellites orbitting Earth have different uses, such as communications, weather monitoring, and military applications.

8 LOOKING BACK KEY CONCEPTS SUMMARY CHAPTER 8 KEY CONCEPTS SUMMARY The Sun emits light and other forms of radiant energy that are necessary for life on Earth to exist. Solar weather interacts with Earth’s magnetic field, causing auroras around the North and South Poles. Satellites in Earth orbit can be damaged by solar wind. Various types of radiation from the Sun bring light and warmth to the surface of Earth, providing support for life on Earth.

8 LOOKING BACK KEY CONCEPTS SUMMARY CHAPTER 8 KEY CONCEPTS SUMMARY Satellites have useful applications for technologies on Earth. Galileo Galilei first observed the Moon and the planets in the night sky with a telescope, obtaining evidence to support the heliocentric model of the Solar System. RADARSAT-1 and RADARSAT-2 are successful Canadian satellites that observe the surface of Earth. Astronomers gather information on the Sun with special observatories like SOHO and STEREO. LOOKING BACK

8 LOOKING BACK KEY CONCEPTS SUMMARY CHAPTER 8 KEY CONCEPTS SUMMARY The study of the night sky has influenced the culture and lifestyles of many civilizations. Patterns of stars can be used for navigation. Aboriginal peoples in Canada have a long history of observing patterns in the night sky for navigational and cultural purposes. Cultures across the globe have legends and stories specific to their culture based on patterns of the stars in the night sky. Sometimes they built structures that aligned with the positions of certain stars. LOOKING BACK

QUIZ CHAPTER 8 MULTIPLE CHOICE For each question, select the best answer from the four alternatives. 1. Which of the following celestial objects are luminous? a) planets b) stars c) the Moon d) Earth 2. In 2006, the new definition of “planet” excluded Pluto because a) it does not orbit the Sun. b) it doesn’t have enough mass to be spherical. c) it does not dominate its orbit. d) its orbit is not circular.

QUIZ CHAPTER 8 MULTIPLE CHOICE For each question, select the best answer from the four alternatives. 3. Jupiter, Uranus, and Neptune are known as a) gas giants. b) inner planets. c) terrestrial planets. d) dwarf planets. 4. Which of the following result in the seasons on Earth? a) proximity to the Sun during Earth’s orbit b) the amount of energy released by the Sun at certain times c) Earth’s rotation d) the tilt of Earth’s axis

QUIZ CHAPTER 8 FILL IN THE BLANKS Fill in the blanks with a that correctly completes the sentence. 5. The Sun is composed of many layers of ___________. 6. High _____________ and _____________ within the Sun’s _____________ cause particles to collide and join together in a process called nuclear fusion. 7. Aurora borealis occur when solar winds come into contact with Earth’s ______________. 8. The Sun’s atmosphere is divided into two layers: the ___________ and the ____________. corona; magnetic field; core; gas; temperatures; chromosphere; pressures

QUIZ CHAPTER 8 SHORT ANSWER 9. In your notebook, copy this diagram and identify which positions of Earth correspond to the vernal equinox, autumnal equinox, summer solstice, and winter solstice for the northern hemisphere. N N N N

8 QUIZ ANSWERS MULTIPLE CHOICE CHAPTER 8 MULTIPLE CHOICE For each question, select the best answer from the four alternatives. 1. Which of the following celestial objects are luminous? a) planets b) stars c) the Moon d) Earth 2. In 2006, the new definition of “planet” excluded Pluto because a) it does not orbit the Sun. b) it doesn’t have enough mass to be spherical. c) it does not dominate its orbit. d) its orbit is not circular.

8 QUIZ ANSWERS MULTIPLE CHOICE CHAPTER 8 MULTIPLE CHOICE For each question, select the best answer from the four alternatives. 3. Jupiter, Uranus, and Neptune are known as a) gas giants. b) inner planets. c) terrestrial planets. d) dwarf planets. 4. Which of the following result in the seasons on Earth? a) proximity to the Sun during Earth’s orbit b) the amount of energy released by the Sun at certain times c) Earth’s rotation d) the tilt of Earth’s axis

QUIZ CHAPTER 8 FILL IN THE BLANKS Fill in the blanks with a that correctly completes the sentence. 5. The Sun is composed of many layers of gas. 6. High temperatures and pressures within the Sun’s core cause particles to collide and join together in a process called nuclear fusion. 7. Aurora borealis occur when solar winds come into contact with Earth’s magnetic field. 8. The Sun’s atmosphere is divided into two layers: the chromosphere and the corona.

QUIZ CHAPTER 8 SHORT ANSWER 9. In your notebook, copy this diagram and identify which positions of Earth correspond to the vernal equinox, autumnal equinox, summer solstice, and winter solstice for the northern hemisphere. N N N N