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) nine D) ten 6 A) Uranus and Neptune B) Jupiter and Saturn C) Neptune and Pluto D) Earth and Venus 7 A) large and wet B) solid and rocky C) small and soupy D) gaseous and large 8 A) Alpha Centauri B) the Sun C) the Moon D) Ursa Major 9 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. 10 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 11 A) three B) four C) two D) one 12 A) Earth, Sun, Moon B) Moon, Sun, Earth C) Sun, Earth, Moon D) Sun, Moon, Earth 13 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 14 A) 24 h B) 1 month C) 365 days D) 1 year 15 A) 1 AU B) 100,000 light-years C) 1 light-year D) 100,000 AUs 16 A) black hole B) supernova C) white dwarf D) black dwarf 17 A) dimmer the star is B) dimmer the star looks from Earth C) brighter the star looks from Earth D) brighter the star is 18 A) astronomical unit B) miles C) kilometer D) light-year 19 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 20 A) kilometer B) light-year C) miles D) astronomical unit
.
