Chapter 18 Life in the Universe – Flashcards

question
Cosmic Evolution
answer
Continuous transformation of matter and energy that has led to the appearance of life on Earth - 7 phases
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Cosmic Evolution Phases
answer
- Particulate - primal energy into elementary particles - Galactic - atoms into galaxies and stars - Stellar - stars into heavy elements - Planetary - elements into solid, rocky planets - Chemical - elements into building blocks of life - Biological - molecules into life itself - Cultural - advanced life forms into intelligence
question
Big Bang -> Intelligent __________ & _________ Simplicity -> _________________
answer
Life & Culture Complexity
question
What is life?
answer
1) Living organisms can react to their environment and often can heal themselves when damaged 2) They can grow by taking in nourishment from their surroundings 3) They can reproduce, passing along some of their own characteristics to their offspring 4) They have the capacity for genetic change and can therefore evolve from generation to generation to adapt to a changing environment
question
Assumption of Mediocrity Against:
answer
If - life on Earth depends on just a few basic molecules - elements that make up these molecules are common to all stars - laws of science apply to the entire universe Then - Given sufficient time, life must have originated elsewhere in the cosmos Against: If -intelligent life on Earth is a product of extremely fortunate series of astronomical, geological, chemical, and biological events Then - life is unlikely to have occurred elsewhere in the universe
question
Amino Acids and Nucleotides
answer
- Organic (carbon based) molecules - Building blocks of life - Amino Acids -> maintains life -- Build proteins which controls metabolism - Nucleotides -> masterminds life -- Form genes
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Urey-Miller Experiment
answer
- 1953 - Harold Urey and Stanley Miller - showed that building blocks of life form easily and spontaneously under early Earth conditions
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Life in the Solar System
answer
- Mars - Jupiter's moon Europa
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Extremophiles
answer
- Life forms that have adapted to live in extreme environments - Suggests life may be able to survive on harsh conditions of Mars, Europa or Titan
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What must we ask to know if life exists in the Galaxy?
answer
- Must ask HOW LIKELY life is to exist
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The Drake Equation
answer
Number of Intelligent Civilizations in the Galaxy N(comm) = R* x f(planets) x n(earthlike) x f(life) x f(int) x f(civ) x L(comm)
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Drake Equation Estimates
answer
Rate of star Formation = 10/year Fraction of Stars w/Planetary Systems = 1 Number of Habitable Planets/Planetary System = 1/10 Fraction of Habitable Planets in Which Life Arises = 1 Fraction of Life-bearing planets on which intelligence arises = 1 Fraction of Life-bearing planets on which intelligence arises and uses technology = 1 **Average lifetime of a technological civilization = Unknown
question
If length of technological society is 100 years, there should be ____ civilizations to communicate with!
answer
100
question
Communication Issue
answer
- Size of galaxy represents huge communication hurdle - distances of light years - Sending signal and receiving reply in our lifetime is not possible
question
Expanding Bubble of Radio Signals
answer
- Earth has expanding 'bubble' of manmade radio signals expanding outward at speed of light - Receiving a reply i the lifetime of our civilization is not possible
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SETI
answer
- Search for Extraterrestrial Intelligence - Look for deliberate signals from et civilizations
question
Active SETI
answer
- after decades of searching, scientists have found no trace of extraterrestrial intelligence - now, some of them hope to make contact by broadcasting messages to the stars
question
Summary of Chapter 18
answer
- Cosmic evolution is the continuous process that has led to the appearance of galaxies, stars, planets, and life on Earth - Living organisms are characterized by 4 traits - Amino acids and nucleotide bases are the building blocks of life - Life may have formed on Earth or been brought here by comets and meteors - Life in our solar system is most likely to be found on Mars and Europa - Life forms that have adapted to live in extreme environments are called extremophiles - Drake equation estimates the probability of other intelligent life in galaxy - Number of technologically advanced civilizations is approximately equal to the lifetime of typical civilization expressed in years - SETI listens for extraterrestrial broadcasts in electromagnetic spectrum
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question
Cosmic Evolution
answer
Continuous transformation of matter and energy that has led to the appearance of life on Earth - 7 phases
question
Cosmic Evolution Phases
answer
- Particulate - primal energy into elementary particles - Galactic - atoms into galaxies and stars - Stellar - stars into heavy elements - Planetary - elements into solid, rocky planets - Chemical - elements into building blocks of life - Biological - molecules into life itself - Cultural - advanced life forms into intelligence
question
Big Bang -> Intelligent __________ & _________ Simplicity -> _________________
answer
Life & Culture Complexity
question
What is life?
answer
1) Living organisms can react to their environment and often can heal themselves when damaged 2) They can grow by taking in nourishment from their surroundings 3) They can reproduce, passing along some of their own characteristics to their offspring 4) They have the capacity for genetic change and can therefore evolve from generation to generation to adapt to a changing environment
question
Assumption of Mediocrity Against:
answer
If - life on Earth depends on just a few basic molecules - elements that make up these molecules are common to all stars - laws of science apply to the entire universe Then - Given sufficient time, life must have originated elsewhere in the cosmos Against: If -intelligent life on Earth is a product of extremely fortunate series of astronomical, geological, chemical, and biological events Then - life is unlikely to have occurred elsewhere in the universe
question
Amino Acids and Nucleotides
answer
- Organic (carbon based) molecules - Building blocks of life - Amino Acids -> maintains life -- Build proteins which controls metabolism - Nucleotides -> masterminds life -- Form genes
question
Urey-Miller Experiment
answer
- 1953 - Harold Urey and Stanley Miller - showed that building blocks of life form easily and spontaneously under early Earth conditions
question
Life in the Solar System
answer
- Mars - Jupiter's moon Europa
question
Extremophiles
answer
- Life forms that have adapted to live in extreme environments - Suggests life may be able to survive on harsh conditions of Mars, Europa or Titan
question
What must we ask to know if life exists in the Galaxy?
answer
- Must ask HOW LIKELY life is to exist
question
The Drake Equation
answer
Number of Intelligent Civilizations in the Galaxy N(comm) = R* x f(planets) x n(earthlike) x f(life) x f(int) x f(civ) x L(comm)
question
Drake Equation Estimates
answer
Rate of star Formation = 10/year Fraction of Stars w/Planetary Systems = 1 Number of Habitable Planets/Planetary System = 1/10 Fraction of Habitable Planets in Which Life Arises = 1 Fraction of Life-bearing planets on which intelligence arises = 1 Fraction of Life-bearing planets on which intelligence arises and uses technology = 1 **Average lifetime of a technological civilization = Unknown
question
If length of technological society is 100 years, there should be ____ civilizations to communicate with!
answer
100
question
Communication Issue
answer
- Size of galaxy represents huge communication hurdle - distances of light years - Sending signal and receiving reply in our lifetime is not possible
question
Expanding Bubble of Radio Signals
answer
- Earth has expanding 'bubble' of manmade radio signals expanding outward at speed of light - Receiving a reply i the lifetime of our civilization is not possible
question
SETI
answer
- Search for Extraterrestrial Intelligence - Look for deliberate signals from et civilizations
question
Active SETI
answer
- after decades of searching, scientists have found no trace of extraterrestrial intelligence - now, some of them hope to make contact by broadcasting messages to the stars
question
Summary of Chapter 18
answer
- Cosmic evolution is the continuous process that has led to the appearance of galaxies, stars, planets, and life on Earth - Living organisms are characterized by 4 traits - Amino acids and nucleotide bases are the building blocks of life - Life may have formed on Earth or been brought here by comets and meteors - Life in our solar system is most likely to be found on Mars and Europa - Life forms that have adapted to live in extreme environments are called extremophiles - Drake equation estimates the probability of other intelligent life in galaxy - Number of technologically advanced civilizations is approximately equal to the lifetime of typical civilization expressed in years - SETI listens for extraterrestrial broadcasts in electromagnetic spectrum
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