Astrobiology: The Semester in Review

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A Universe of Life Astrobiology: The Semester in Review Honors 228 with Dr.

distance Stars and the origins of chemicals Formation of planets Defining astrobiology the science 1 2 The

Sun. A Jovian planets B metals and metal oxides C silicates D ices of water, methane, and ammonia E low

Copernicus, Galileo, Kepler, Newton Pseudoscience and nonsense 4 The Nature of Life What is it?

1 A Universe of Life Astrobiology: The Semester in Review Honors 228 with Dr. Harold Geller Searching for life everywhere Planets, stars, galaxies, Big Bang Conception of size and distance Stars and the origins of chemicals Formation of planets Defining astrobiology the science 1 2 The nebular condensation model of the formation of the solar system suggests that should condense closest to the Sun. A Jovian planets B metals and metal oxides C silicates D ices of water, methane, and ammonia E low density materials 3 The Science of Life in the Universe Ancient cosmologies Science as a way of knowing Copernicus, Galileo, Kepler, Newton Pseudoscience and nonsense 4 The Nature of Life What is it? Cells Metabolism DNA Extremophiles Life on Earth is based on A silicon chemistry. B helium chemistry. C carbon chemistry. D oxygen chemistry. E nitrogen chemistry

The chemical building blocks of life are found throughout space All life on Earth, and

occur naturally throughout interstellar space Organic molecules needed for life to originate

Earth The Geological History of the Earth Geologic Timescale Plate Tectonics Solid Earth

dioxide is transparent to visible light and opaque to infrared radiation.

C ozone is transparent to ultraviolet radiation and opaque to infrared radiation.

E the sun emits more infrared radiation than ultraviolet radiation.

Air Impacts & Extinctions Human Evolution 9 10 Searching for Life in the Solar System

2 The chemical building blocks of life are found throughout space All life on Earth, and presumably on other worlds, depends on organic (carbon-based) molecules These molecules occur naturally throughout interstellar space Organic molecules needed for life to originate were possibly brought to the young Earth by comets or asteroids, as well as being formed on Earth The Geological History of the Earth Geologic Timescale Plate Tectonics Solid Earth Greenhouse Effect Relative/Absolute Dating 7 8 The greenhouse effect occurs because A carbon dioxide is transparent to visible light and opaque to infrared radiation. B carbon dioxide is transparent to infrared radiation and opaque to ultraviolet radiation. C ozone is transparent to ultraviolet radiation and opaque to infrared radiation. D methane is transparent to infrared radiation and opaque to visible light. E the sun emits more infrared radiation than ultraviolet radiation. The Origin and Evolution of Life on Earth Origin of Life Prokaryotes Eukaryotes Oxygen in Air Impacts & Extinctions Human Evolution 9 10 Searching for Life in the Solar System Another likely source for organic molecules is chemical reactions in the Earth s primitive atmosphere Similar processes may occur on other worlds Environmental Needs In the Solar System

3 Mars NASA rovers that reached Mars in 2004 landed at locations that may once have been covered in water Science Fiction Search for Life Martian Meteorites Exploration 13 The unsuccessful Beagle 2 mission to Mars was to carry out a different set of biological experiments on samples taken from the interiors of rocks 14 The Viking Lander spacecraft searched for microorganisms on the Martian surface, but found no conclusive sign of their presence A so-called Face on Mars Meteorites from Mars have been scrutinized for life-forms An ancient Martian rock that came to Earth as a meteorite was examined for evidence that microorganisms once existed on Mars This has not been corroborated

Life on Jovian Moons Europa Titan Others Europa and

Besides Earth, only two worlds in our solar system

have had the right conditions for the origin of

though it has none today Life may have originated

to have extensive liquid water beneath its icy

of life 19 20 The Nature and Evolution of

Future The Search for Habitable Worlds Planet

new generation of orbiting telescopes may be able

4 Life on Jovian Moons Europa Titan Others Europa and Mars best potential for life to have evolved Besides Earth, only two worlds in our solar system the planet Mars and Jupiter s satellite Europa may have had the right conditions for the origin of life Mars once had liquid water on its surface, though it has none today Life may have originated on Mars during the liquid water era Europa appears to have extensive liquid water beneath its icy surface Future missions may search for the presence of life The Nature and Evolution of Habitability Habitability Zone Past, Present, Future The Search for Habitable Worlds Planet Formation Extrasolar Planets Detection Earth-like Planets? Infrared telescopes in space began searching for Earthlike planets The Search for Extraterrestrial Intelligence SETI Drake Equation A new generation of orbiting telescopes may be able to detect terrestrial planets around nearby stars If such planets are found, their infrared spectra may reveal the presence or absence of life

The Drake equation helps scientists estimate how many civilizations may

intelligent civilizations in our galaxy.

D the lifespan of a civilization. E the lifespan of a species.

travel, round trip, between stars? I. Fuel requirements II.

The finite speed at which objects can travel How realistic?

5 The Drake equation helps scientists estimate how many civilizations may inhabit our Galaxy The Drake equation allows us to estimate A the number of intelligent civilizations in our galaxy. B the number of stars in our galaxy. C the number of people on the Earth. D the lifespan of a civilization. E the lifespan of a species Interstellar Travel What limitation(s) make it close to impossible to travel, round trip, between stars? I. Fuel requirements II. The tremendous distances between stars III. The finite speed at which objects can travel How realistic? Engineering Limited by c Relativity and time dilation Wormholes and hyperspace? 27 A B C D E I I and II III II and III I, II and III 28 The Fermi Paradox Where are the aliens? Galactic colonization Resolving the paradox Contact Implications of the Search and Discovery Can we make contact Which kind 1 st, 2 nd, 3 rd Contact implications

Radio searches for alien civilizations are under way If an alien civilization were someday to find this message, which of the features on the plaque do you think would be easily understandable to

there is little noise and little absorption by the Earth s atmosphere scientists suggest that this noise-free region would be well suited for interstellar communication 31 32 Astrobiology in One

6 Radio searches for alien civilizations are under way If an alien civilization were someday to find this message, which of the features on the plaque do you think would be easily understandable to them? No signs of intelligent life have yet been detected searches are continuing and using increasingly sophisticated techniques The so-called water hole is a range of radio frequencies in which there is little noise and little absorption by the Earth s atmosphere scientists suggest that this noise-free region would be well suited for interstellar communication Astrobiology in One Sentence The universe is unimaginably large, and alive; you are not at the center of the universe; and, the way to know the universe is through science Dr. Harold Geller HAVE A GREAT SUMMER 33 6

ACTIVITY 6 Using Spectra to Search for an Earth-like Planet

Name: Class: SOLIDS & Visual Quantum Mechanics LIGHT ACTIVITY 6 Using Spectra to Search for an Earth-like Planet Goal Now that we can explain why gas lamps emit their characteristic spectra and how absorption