Transcript 18. Life in the Universe: Are We Alone?

Astronomy
A BEGINNER’S GUIDE
TO THE UNIVERSE
EIGHTH EDITION
CHAPTER 18
Life in the Universe
Clickers
© 2017 Pearson Education, Inc.
Question 1
The Drake equation attempts to define the number of
a)
b)
c)
d)
e)
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.
© 2017 Pearson Education, Inc.
Question 1
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 2
In the Drake equation, a technical civilization is defined as
one that is able to
a)
b)
c)
d)
e)
explore space.
communicate over interstellar distances.
communicate using a written language.
construct metal tools.
travel at the speed of light.
© 2017 Pearson Education, Inc.
Question 2
In the Drake equation, a technical civilization is defined as
one that is able to
a)
b)
c)
d)
e)
explore space.
communicate over interstellar distances.
communicate using a written language.
construct metal tools.
travel at the speed of light.
© 2017 Pearson Education, Inc.
Question 3
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) water, rather than dry ice, at the south polar cap.
c) the spectral signature of chlorophyll.
d) the face on Mars.
e) volcanoes that are still active.
© 2017 Pearson Education, Inc.
Question 3
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) water, rather than dry ice, at the south polar cap.
c) the spectral signature of chlorophyll.
d) the face on Mars.
e) 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 4
The habitable zone is the area where
a) temperatures on a planet are reasonable.
b) terrestrial planets can form around a star.
c) terrestrial planets could have liquid water on their
surfaces.
d) liquid water can condense into rain in the atmosphere.
e) Sun-like stars can exist in the Milky Way Galaxy.
© 2017 Pearson Education, Inc.
Question 4
The habitable zone is the area where
a) temperatures on a planet are reasonable.
b) terrestrial planets can form around a star.
c) terrestrial planets could have liquid water on their
surfaces.
d) 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 5
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
© 2017 Pearson Education, Inc.
Question 5
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 6
The “water hole” is a region
a) in radio light where natural emissions from our Galaxy
are minimal.
b) on Mars where liquid water has been proven to exist in
the past.
c) 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.
© 2017 Pearson Education, Inc.
Question 6
The “water hole” is a region
a) in radio light where natural emissions from our
Galaxy are minimal.
b) on Mars where liquid water has been proven to exist in
the past.
c) 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 7
An extremophile is
a) an extremely unlikely place to search for life.
b) a planet that has very extreme temperatures.
c) 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.
Question 7
An extremophile is
a) an extremely unlikely place to search for life.
b) a planet that has very extreme temperatures.
c) 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.