Astronomy Chapter 30

Intelligent life is more likely to evolve on a planet orbiting a __________ star because __________

0.7 solar mass, a massive star will evolve off the main sequence too quickly

Place the Solar System bodies according to whether scientists think they currently have conditions that could support life. Venus Eris Europa Uranus Saturn Mars The Moon

Considered candidates to have conditions that could support life: Europa Mars Currently thought to be incapable of supporting life: Venus Eris Uranus Saturn The Moon

Classify the conditions as those that are absolutely essential for the existence of life as we know it and those that are not necessary for all forms of life. liquid water volcanic vents radiation levels greater than a nuclear explosion abundant and varied food sources a source of energy low levels of carbon dioxide a source of nutrients to build living cells

Essential for life: liquid water a source of energy a source of nutrients to build living cells Not essential for life: volcanic vents radiation levels greater than a nuclear explosion abundant and varied food sources

Which of these statements are true of "life as we know it" and which are false? Living organisms require temperatures warm enough for water to be liquid. Living organisms react to stimuli. Living things use energy to fuel their activities. Species evolve over time. Life is based on silicon molecules.

True: Living organisms react to stimuli. Living things use energy to fuel their activities. Species evolve over time. False: Living organisms require temperatures warm enough for water to be liquid. Life is based on silicon molecules.

Liquid water is important for the existence of life because a. water allows interactions between many important chemical components dissolved in it. b. living things require moderate temperatures, which happen to be the same temperatures where water is in its liquid phase. c. the human body is about 65%65% water. d. water is a strong base that enables important chemical reactions for life.

a. water allows interactions between many important chemical components dissolved in it.

Which of the elements serves as the foundation for all organic molecules on Earth? a. hydrogen b. silicon c. carbon d. boron

c. carbon

Which was directly necessary for the development of life as we know it to occur in the Milky Way Galaxy? a. the expansion of the Universe b. the concentration of dark matter between galaxies c. the formation of white dwarfs d. stellar nucleosynthesis in supernova explosions

d. stellar nucleosynthesis in supernova explosions

The search for extraterrestrial intelligence (SETI) is usually conducted at __________ wavelengths because __________

radio, these wavelengths can travel large interstellar distances with little attenuation and pass through Earth's atmosphere