1 A) chunks of ice and rock B) asteroids C) comets D) gas giants 2 A) the carbon dioxide layer B) the ozone layer C) space between Earth and the Sun D) the asteroid belt 3 A) nebulae B) supernovas C) galaxies D) black holes 4 A) the same as the Sun B) hot C) cool D) medium for a star 5 A) hundreds B) three C) eight D) ten 6 A) large and wet B) solid and rocky C) small and soupy D) gaseous and large 7 A) Alpha Centauri B) the Sun C) the Moon D) Ursa Major 8 A) when fusion begins in gas clouds in space B) when white dwarfs start generating light again C) when other stars become supernovae and shoot off smaller stars D) They emerge from black holes. 9 A) the distance between Earth and the Sun B) the rotation of Earth C) the phases of the Moon D) the tilt of Earth's axis 10 A) three B) four C) two D) one 11 A) Earth, Sun, Moon B) Moon, Sun, Earth C) Sun, Earth, Moon D) Sun, Moon, Earth 12 A) Earth's shadow on the Moon B) the Moon's shadow on Earth C) the Sun's shadow on Earth D) Earth's shadow on the Sun 13 A) 24 h B) 1 month C) 365 days D) 1 year 14 A) 1 AU B) 100,000 light-years C) 1 light-year D) 100,000 AUs 15 A) black hole B) supernova C) white dwarf D) black dwarf 16 A) dimmer the star is B) dimmer the star looks from Earth C) brighter the star looks from Earth D) brighter the star is 17 A) astronomical unit B) miles C) kilometer D) light-year 18 A) several miles in diameter B) smaller than pebbles C) 1 AU wide D) They can be as small as a pebble as large as several tons 19 A) kilometer B) light-year C) miles D) astronomical unit
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