Astronomy A BEGINNER’S GUIDE TO THE UNIVERSE EIGHTH EDITION CHAPTER 18 Life in the Universe Clickers © 2017 Pearson Education, Inc Question The Drake equation attempts to define the number of a) b) c) d) e) © 2017 Pearson Education, Inc planets in the Milky Way Galaxy planets with life in the universe stars with planets like Earth civilizations in our Galaxy terrestrial planets with water Question The Drake equation attempts to define the number of a) b) c) d) planets in the Milky Way Galaxy planets with life in the universe stars with planets like Earth civilizations in our Galaxy e) terrestrial planets with water © 2017 Pearson Education, Inc Question In the Drake equation, a technical civilization is defined as one that is able to a) b) c) d) e) © 2017 Pearson Education, Inc explore space communicate over interstellar distances communicate using a written language construct metal tools travel at the speed of light Question In the Drake equation, a technical civilization is defined as one that is able to a) b) c) d) e) © 2017 Pearson Education, Inc explore space communicate over interstellar distances communicate using a written language construct metal tools travel at the speed of light Question The possibility of life once existing on Mars was supported by the discovery of a) mudflows and bodies of liquid water existing in the past b) c) d) e) © 2017 Pearson Education, Inc water, rather than dry ice, at the south polar cap the spectral signature of chlorophyll the face on Mars volcanoes that are still active Question The possibility of life once existing on Mars was supported by the discovery of a) mudflows and bodies of liquid water existing in the past b) c) d) e) water, rather than dry ice, at the south polar cap the spectral signature of chlorophyll the face on Mars volcanoes that are still active Explanation: The exploration of the Mars rovers Spirit and Opportunity, as well as the Global Surveyor mission, have provided evidence that water did exist on Mars in the past © 2017 Pearson Education, Inc Question The habitable zone is the area where a) b) c) d) e) © 2017 Pearson Education, Inc temperatures on a planet are reasonable terrestrial planets can form around a star terrestrial planets could have liquid water on their surfaces liquid water can condense into rain in the atmosphere Sun-like stars can exist in the Milky Way Galaxy Question The habitable zone is the area where a) b) c) d) temperatures on a planet are reasonable terrestrial planets can form around a star terrestrial planets could have liquid water on their surfaces liquid water can condense into rain in the atmosphere e) Sun-like stars can exist in the Milky Way Galaxy Explanation: Habitable zones have the right temperature for life—neither too hot nor too cold Habitable zones must be smaller and closer to a cool star like the Sun because such a star emits less warming radiation © 2017 Pearson Education, Inc Question Which star is the best candidate for seeking extraterrestrial life? a) b) c) d) e) © 2017 Pearson Education, Inc Spica, a B-type main-sequence star 61 Cygni, a K-type main-sequence star Sirius B, a white dwarf Antares, an M-type supergiant Barnard’s star, an M-type red dwarf Question Which star is the best candidate for seeking extraterrestrial life? a) b) c) d) e) Spica, a B-type main-sequence star 61 Cygni, a K-type main-sequence star Sirius B, a white dwarf Antares, an M-type supergiant Barnard’s star, an M-type red dwarf Explanation: In the OBAFGKM spectral ranking scale, K-type main-sequence stars are cooler than the Sun, but will shine long enough with nonlethal radiation to allow life to form and evolve © 2017 Pearson Education, Inc Question The “water hole” is a region a) b) c) in radio light where natural emissions from our Galaxy are minimal on Mars where liquid water has been proven to exist in the past on the Moon where water is believed to exist under ice in a deep crater d) © 2017 Pearson Education, Inc in the Oort cloud where comets rich in water are formed Question The “water hole” is a region a) b) c) in radio light where natural emissions from our Galaxy are minimal on Mars where liquid water has been proven to exist in the past on the Moon where water is believed to exist under ice in a deep crater d) in the Oort cloud where comets rich in water are formed Explanation: The “water hole” may be the best part of the electromagnetic spectrum for intelligent civilizations to communicate across the vast reaches of space © 2017 Pearson Education, Inc Question An extremophile is a) b) c) d) © 2017 Pearson Education, Inc an extremely unlikely place to search for life a planet that has very extreme temperatures a planet whose orbit lies beyond Pluto in the most distant regions of our solar system a life-form adapted to very extreme environments Question An extremophile is a) b) c) an extremely unlikely place to search for life a planet that has very extreme temperatures a planet whose orbit lies beyond Pluto in the most distant regions of our solar system d) a life-form adapted to very extreme environments © 2017 Pearson Education, Inc  ... into rain in the atmosphere Sun-like stars can exist in the Milky Way Galaxy Question The habitable zone is the area where a) b) c) d) temperatures on a planet are reasonable terrestrial planets... at the south polar cap the spectral signature of chlorophyll the face on Mars volcanoes that are still active Explanation: The exploration of the Mars rovers Spirit and Opportunity, as well as... 2017 Pearson Education, Inc temperatures on a planet are reasonable terrestrial planets can form around a star terrestrial planets could have liquid water on their surfaces liquid water can condense