Buch, Englisch, 360 Seiten, Format (B × H): 154 mm x 233 mm, Gewicht: 605 g
Reihe: Science Essentials
Buch, Englisch, 360 Seiten, Format (B × H): 154 mm x 233 mm, Gewicht: 605 g
Reihe: Science Essentials
ISBN: 978-0-691-15627-9
Verlag: Princeton University Press
Ever since Carl Sagan first predicted that extraterrestrial civilizations must number in the millions, the search for life on other planets has gripped our imagination. Is Earth so rare that advanced life forms like us--or even the simplest biological organisms--are unique to the universe? How to Find a Habitable Planet describes how scientists are testing Sagan's prediction, and demonstrates why Earth may not be so rare after all. James Kasting has worked closely with NASA in its mission to detect habitable worlds outside our solar system, and in this book he introduces readers to the advanced methodologies being used in this extraordinary quest. He addresses the compelling questions that planetary scientists grapple with today: What exactly makes a planet habitable? What are the signatures of life astronomers should look for when they scan the heavens for habitable worlds? In providing answers, Kasting explains why Earth has remained habitable despite a substantial rise in solar luminosity over time, and why our neighbors, Venus and Mars, haven't. If other Earth-sized planets endowed with enough water and carbon are out there, he argues, chances are good that some of those planets sustain life. Kasting describes the efforts under way to find them, and predicts that future discoveries will profoundly alter our view of the universe and our place in it. This book is a must-read for anyone who has ever dreamed of finding other planets like ours--and perhaps even life like ours--in the cosmos. In a new afterword, Kasting presents some recent breakthroughs in the search for exoplanets and discusses the challenges facing space programs in the near future.
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Weitere Infos & Material
Preface xi
Part I: Introduction 1
Chapter 1: Past Thinking about Earth-Like Planets and Life 3
The Habitable Zone and the Importance of Liquid Water 5
Carl Sagan and the Drake Equation 9
Other Perspectives on Planetary Habitability: Rare Earth and Gaia 11
Part II: Our Habitable Planet Earth 15
Chapter 2: Critical Updates on How Planets Are Built 17
The Conventional Wisdom regarding Planet Formation 18
Where Did Earth's Water Come From? 21
New Models for Planetary Accretion and Delivery of Water 23
Could Earth's Water Have Come from Comets? 25
An Up-to-Date Simulation of Planetary Accretion 28
Chapter 3: Long-Term Climate Stability 32
Solar Evolution Theory 32
Solar Mass Loss? 36
Electromagnetic Radiation and the Greenhouse Effect 37
Planetary Energy Balance 41
The Faint Young Sun Problem 42
Possible Solutions to the Problem 45
The Carbonate- Silicate Cycle and Controls on Atmospheric CO2 49
The CO2-Climate Feedback Loop 53
Chapter 4: More Wrinkles in Earth's Climate History 57
The Phanerozoic Climate Record 58
Precambrian Climate 63
Geologic Evidence for the Rise of Atmospheric O2 65
Cause of the O2 Rise: Cyanobacteria 68
Methane, Methanogens, and the Universal Tree of Life 71
The Archean Methane Greenhouse 75
The Paleoproterozoic Glaciation 77
Chapter 5: Runaway Glaciation and "Snowball Earth" 80
Milankovitch Cycles and the Recent Ice Ages 81
Ice Albedo Feedback and Climatic Instability 86
Evidence for Low- Latitude Glaciation 88
Mechanisms for Explaining Low- Latitude Glaciation 90
Snowball Earth 92
Part III: Limits to Planetary Habitability 97
Chapter 6: Runaway Greenhouses and the Evolution of Venus' Atmosphere 99
The History of Water on Venus 100
The Classical Runaway Greenhouse Effect 103
An Alternative Runaway Greenhouse Model 106
Evolution of Venus'Atmosphere 111
Chapter 7: The Future Evolution of Earth 116
High- CO2 Atmospheres and Temperature Limits for Life 116
Future Solar Evolution and Lifetime of the Biosphere 118
A Geoengineering Solution to Solar Luminosity Increases 121
Chapter 8: The Martian Climate Puzzle 125
Evidence for Liquid Water near Mars'Surface 126
CH4 in Mars'Atmosphere? 130
Evidence That Water Flowed in Mars'Distant Past 131
When Did the Martian Valleys Form? 135
How Warm Was Early Mars? 136
Mechanisms for Warming Early Mars 138
Where Are the Carbonates? 144
Chapter 9: Is the Earth Rare? 147
Planetary Size / Magnetic Fields 147
Ozone and Ultraviolet Radiation 152
Availability of Nitrogen and the Importance of N2 155
Is Plate Tectonics Common? 157
A Planet's Impact Environment 161
Stabilization of Earth's Obliquity by the Moon 164
Chapter 10: Habitable Zones around Stars 171
Historical Attempts to Defi ne the Habitable Zone 171
A More Modern Model for the Habitable Zone around the Sun 176
Hertzsprung- Russell Diagrams and Main Sequence Stars 179
Habitable Zones around Other Stars 181
Problems for Planets Orbiting Early- Type Stars 185
Problems for Planets Orbiting Late- Type Stars 188
Further Extensions of the Habitable Zone Concept 191
The Galactic Habitable Zone 192
Part IV: How to Find Another Earth 195
Chapter 11: Indirect Detection of Planets around Other Stars 197
Barnard's Star 198
The Astrometric Method 199
Pulsar Planets 205
The Doppler Effect 207
The Radial Velocity Method 210
Gravitational Microlensing 216
Chapter 12: Finding and Characterizing Planets by Using Transits 221
Transits of Mercury and Venus 221
Transits of Extrasolar "Hot Jupiters" 222
Space- Based Transit Searches: CoRoT and Kepler 227
Observing Exoplanet Atmospheres during Transits 229
Secondary Transit Spectroscopy 233
Characterizing Earth- Like Planets around M Stars 235
Chapter 13: Direct Detection of Extrasolar Planets 239
What Wavelength Region Should We Choose? 240
Infrared Interferometers: TPF- I and Darwin 245
Searching for Planets at Visible Wavelengths TPF- C 248
The Visible Occulter: TPF- O 253
Nearby Target Stars 254
Chapter 14: The Spectroscopic Search for Life 258
Spectral Resolution 259
The Visible / Near- IR Region: TPF- C or -O 260
The Thermal- IR Region: TPF- I or Darwin 266
Looking for Life on Early Earth- Type Planets 269
Possible False Positives for Life 271
Polarization Measurements: Looking for the Glint of Surface Water 274
The Holy Grail: Simultaneous Detection of O and Reduced Gases 276
Chapter 15: Prospects for the More Distant Future 284
NASA's Life Finder Mission 284
Using the Sun as a Gravitational Lens 287
The Drake Equation Revisited: The Search for Extraterrestrial Intelligence 290
Notes 299
Index 317
