Honors 228 Astrobiology w/ Dr. H. Geller Meeting #2 Physical Origins

Presented 31 August 2011 1

The Phase Diagram

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iClicker Question

• What is the name of the phase change from liquid to gas?

– A Vaporization – B – C Condensation Deposition – D – E Sublimation None of the above 3

iClicker Question

• What is the name of the phase change from solid to gas?

– A Vaporization – B – C Condensation Deposition – D – E Sublimation None of the above 4

iClicker Question

• What is the name of the phase change from gas to liquid?

– A Vaporization – B – C Condensation Deposition – D – E Sublimation None of the above 5

iClicker Question

• What is the name of the phase change from gas to solid?

– A Vaporization – B – C Condensation Deposition – D – E Sublimation None of the above 6

iClicker Question

• What is the name of the phase change from liquid to solid?

– A Vaporization – B – C Condensation Deposition – D – E Sublimation None of the above 7

Recall Unique Properties of Water Density vs. Temperature

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iClicker Question

• The density of liquid water is greater than the density of solid water (ice).

– A True – B False 9

iClicker Question

• There is always more to an iceberg beneath the water’s surface than above the water’s surface – A because liquid water is less dense than ice – B – C – D – E because liquid water is more dense than ice because ice is more dense than liquid water because water and ice are two different molecules This is a false statement because there’s always more of an iceberg above the surface than beneath the surface 10

Overview of Chapter 1

• 1.1 The Possibility of Life Beyond Earth – Some discussion in 1st meeting • What life are scientists searching for?

• Is it reasonable to expect life elsewhere in the universe?

• 1.2 The Scientific Context of the Search – Usefulness of astronomy in search for life – Utility of planetary science in search for life – Earth’s biology and its usefulness for search for life • 1.3 Places to Search – Where should we search?

• In our solar system • In our galaxy 11

iClicker Question

• An extrasolar planet (aka exoplanet) is – A a planet that is larger than our Sun – B – C a planet that orbits a star other than our Sun a planet located in another galaxy 12

iClicker Question

• A habitable planet is – A a planet that has oceans like the Earth – B – C a planet that has life of some kind a planet that may or may not have life, but that has environmental conditions under which it seems that life could arise or survive 13

iClicker Question

• By a geocentric view of the universe, we mean – A the idea that Earth resides at the center of the universe – B – C the idea that Earth is the only planet with life in the universe a view of the universe shaped by current understanding of geological science 14

iClicker Question

• According to current scientific understanding, life on Earth – A was exceedingly improbable – B arose quite soon after conditions allowed it – C may have been inevitable, but took billions of years to arrive 15

iClicker Question

• The correct order of the eight official planets in our Solar System, from closest to farthest from the Sun is – A – B – C Mercury, Venus, Earth, Mars, Saturn, Jupiter, Uranus, Neptune, Uranus Mercury, Venus, Earth, Mars, Jupiter, Uranus, Saturn, Neptune Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune 16

iClicker Question

• Today, the research known as SETI is conducted primarily by – A scanning the skies for signals from alien civilizations – B sending spacecraft to the planets – C using telescope to observe extrasolar planets 17

iClicker Question

• If we sent one of our current spacecraft to a nearby star (besides the Sun), the trip would take about – A 10 years – B – C – D – D 100 years 1000 years 10,000 years 100,000 years 18

iClicker Question

• Scientists today are interested in searching for life on Mars because – A – B – C past.

we see clear evidence of a past civilization on Mars.

Mars contains frozen water ice at its polar caps.

evidence suggests that Mars had liquid water on its surface in the distant 19

iClicker Question

• Based on current evidence, the object in our Solar System most likely to have a deep, subsurface ocean of liquid water is – A Mars – B Titan – C – D – E Venus Europa Io 20

iClicker Question

• Based on the way scientists view the study of astrobiology, failure to find life on any other world would mean – A the whole subject has been a waste of time.

– B has to exist beyond Earth – C we must have done something wrong, since life we have learned important lessons about the conditions that made life on Earth possible 21

Overview of Chapter 1

• 1.4 The New Science of Astrobiology – New, are you kidding?

• Bio-astronomy, exobiology • Even Galileo and Kepler considered where else in our solar system we might find life • IAU conference on bioastronomy in 1959!

– Astrobiology according to Geller • ODDS – origins – development – distribution – search 22

Some Words on In-Class Discussion Groups

• Three to four persons in a group • To start – Determine leader and recorder (writer) • This will alternate each meeting • Write the answer to discussion questions the question correctly • Use complete sentences • Answer in terms that address scientific 23

Discussion Questions

• Question #1: – A) Can life exist in places that never receive sunlight? • If Yes » What types of life forms could exist?

• If No » Cite the physical reasons why life cannot exist without sunlight. – B) What elements are the most important for the existence of life? Explain your reasoning.

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Discussion Questions

• Question #2: – A) Consider the following statement: • "For a life form to exist, liquid water must be present in

the local environment in at least small amounts or for short time periods."

• Do you agree or disagree with this statement.

• If You Agree » Explain why liquid water is necessary.

• If You Disagree » What type of life could exist and what would the environment be like? – B) We know that there are 9 planets orbiting the Sun in our solar system. Would you expect there to be other planets orbiting other stars outside our solar system? Explain why or why not.

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Discussion Questions

• Question #3: – A) Can any forms of life exist in environments with temperatures much greater than 100°C (the boiling point of water) or much less than 0°C (the freezing point of water)? • If Yes » What types of life forms could exist at either of these temperatures? State the form of life and the corresponding temperature.

• If No » Cite the physical reasons why life cannot exist at either of these temperatures. – B) Which of the following elements must be present for life to exist. Explain your reasoning for each choice. (consider hydrogen, potassium, zinc, oxygen, calcium, uranium, magnesium, sulfur, carbon, nitrogen, iron, and sodium) 26

Discussion Questions

• Question #4: – A) Describe an environment on Earth that would not allow any form of life to exist. Cite specific examples and explain why these environments cannot support life.

– B) Do scientists have evidence that indicates whether life exists anywhere other than Earth? Explain your reasoning.

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For Next Meeting

• Read Chapter 2 in textbook – In general you should be reading ahead for the upcoming classes 28