Water Worlds in the Solar System

Front cover
Half title
Full title
Copyright
Dedication
Contents
Foreword
Preface
Acknowledgments
Chapter 1 - Solar/planetary formation and evolution
	1.1 Planet formation
		1.1.1 Terrestrial planet formation
		1.1.2 Giant planet formation
	1.2 Asteroids, meteorites, and chondrites
	1.3 Giant-impact theory on the origin of Earth’s Moon
		1.3.1 Single giant impact theory
		1.3.2 Multiple giant impact theory
		1.3.3 The concept of lunar magma ocean (LMO) of global dimensions
	1.4 Influence of Moon-forming impacts on the environmental conditions on the early Earth
	1.5 Earth’s internal structure, development, orbit, and rotation
		1.5.1 Influence of collisions
		1.5.2 Features of Earth’s core
		1.5.3 Earth’s paleo-rotation and revolution—day: ∼21 h; year: ∼13 months and ∼400 days
		1.5.4 Earth’s inclination and orbit
	1.6 Water and frost line in the astrophysical environments
		1.6.1 Water in the protoplanetary disk of the Sun
		1.6.2 Frost line
		1.6.3 Water stored on the surface and in the ground of modern Earth
	1.7 Water-abundant celestial bodies in the Solar System—brief overview
	1.8 Importance of understanding Earth’s oceans in the search for life in extraterrestrial ocean worlds—NASA’s ocean worlds ...
	1.9 Importance of radiogenic heating and tidal dissipation in the generation and sustenance of extraterrestrial subsurface ...
	1.10 Shedding light on extraterrestrial bodies—role of astronomical research
	References
	Bibliography
Chapter 2 - Geological timeline of significant events on Earth
	2.1 An era from 4.5 to 4 billion years ago when the entire Earth was a “Fire Ball”
	2.2 Importance of greenhouse gases in the atmosphere of the early Earth
	2.3 Genesis of water on Earth
		2.3.1 Water on Earth through mantle evolution
		2.3.2 Water brought to Earth by comets and asteroids
	2.4 Indispensability of water, biologically important chemical elements, and energy to sustain life as we know it
	2.5 Formation of liquid water oceans on Earth about 3.8 billion years ago
	2.6 Importance of deuterium to hydrogen ratio of water
	2.7 Roles of Earth’s Moon and Sun in generating tides—influences of local bathymetry and shoreline boundary on modifying t ...
		2.7.1 General characteristics of tidal oscillations
		2.7.2 Topographical influences on tidal range and tidal pattern
		2.7.3 Tidal bore—wall of tumbling and foaming water waves in some geometrically special water bodies during a spring tide  ...
		2.7.4 Tidal currents—their role in mixing of ocean waters
		2.7.5 Implications of coastal tides and tidal bores
	2.8 Appearance of microbes on Earth about 3.7 billion years ago
	2.9 Stromatolites appearing on Earth about 3.5 billion years ago
	2.10 Initiation of plate tectonics on Earth between 3.5 and 3.3 billion years ago
	2.11 The great oxidation event ∼2.4–2.0 billion years ago—an event that led to the banded iron formations and the rise of  ...
	2.12 An era when the entire Earth became fully covered with thick ice ∼750–635 million years ago—“Snowball Earth” hypothesis
	2.13 Multiple mass extinction events on Earth—important for understanding life
		2.13.1 Ordovician–Silurian extinction: ∼440 million years ago
		2.13.2 Late Devonian extinction: ∼365 million years ago
		2.13.3 Permian–Triassic extinction: ∼253 million years ago
		2.13.4 Triassic–Jurassic extinction: ∼201 million years ago
		2.13.5 The K–Pg extinction: ∼66 million years ago: extinction of dinosaurs from Earth and subsequent appearance of modern  ...
	2.14 Carbonate–silicate cycle and its role as a dynamic climate buffer
	2.15 Occurrence of a sharp global warming ∼56 million years ago
		2.15.1 Consequences
		2.15.2 Causes
			2.15.2.1 Volcanic eruptions and seaquakes ∼56 million years ago—Greenland and North America drifting away from Europe, res ...
			2.15.2.2 Methane hydrates emission
			2.15.2.3 Orbitally triggered (Milankovitch cycles) decomposition of soil organic carbon in polar permafrost
	2.16 Volcano eruptions on land causing atmospheric cooling and those happening underwater causing abnormal atmospheric warming
	2.17 Synthesis of marine proxy temperature data across the Paleocene–Eocene thermal maximum
	2.18 Fate of excess carbon released during the Paleocene–Eocene thermal maximum event
	References
		Bibliography
Chapter 3 - Beginnings of life on Earth
	3.1 Origins of life and potential environments—multiple hypotheses on chemical evolution preceding biological evolution
		3.1.1 Lightning in the early atmosphere and the consequent production of amino acids—Miller–Urey “prebiotic soup” experiment
		3.1.2 Chemical processes at submarine hydrothermal vents
			3.1.2.1 Significance of hydrothermal vents in the origin of life
			3.1.2.2 Functional resemblance of iron‐sulfide membrane in alkaline hydrothermal
		3.1.3 Life brought to Earth from elsewhere in space
	3.2 Biological evolution
		3.2.1 Discovery of DNA and its sequencing—the intriguing story of combined efforts by a group of scientists from different ...
			3.2.1.1 Isolating nucleic acid—Johannes Friedrich Miescher: the first scientist
			3.2.1.2 DNA sequencing—contributions of Frederick Sanger, Francis Crick, and James D. Watson
		3.2.2 Role of National Human Genome Research Institute (NHGRI) in supporting development of new technologies for DNA seque ...
		3.2.3 Discovery of RNA and its sequencing— a combined effort by a group of researchers
			3.2.3.1 mRNA
			3.2.3.2 tRNA
			3.2.3.3 rRNA
			3.2.3.4 Sequencing RNA
		3.2.4 Genome sequencing
		3.2.5 Dark DNA
		3.2.6 Categorization of all living organisms into two major divisions: the cellular and the viral “empires” and three prim ...
			3.2.6.1 Cells, viruses, and the classification of organisms
			3.2.6.2 The cellular domains: archaea, bacteria, and eukarya
			3.2.6.3 Viruses
	3.3 Origins of life on Earth—importance of organic molecules
	3.4 Life and living systems—interpretations
	3.5 Why do a few million years or more are necessary for evolution from prebiotic chemical phase to biological phase?
	3.6 Understanding the evolution of life
	3.7 Influence of thermodynamic disequilibrium on life
	3.8 Extraterrestrial life in the Solar System—implications of Kumar’s hypothesis
	3.9 Looking for possibility of extraterrestrial life in the Solar System—deriving clues from early Earth’s conducive atmos ...
	References
		Bibliography
Chapter 4 - Biosignatures—The prime targets in the search for life beyond Earth
	4.1 Life
	4.2 Use of fossil lipids for life-detection
	4.3 Biosignatures
		4.3.1 Biosignatures of microorganisms
		4.3.2 Chemical biosignatures
		4.3.3 Morphological biosignatures
	4.4 Serpentinization—implications for the search for biosignatures
	4.5 Biosignatures versus bioindicators
	4.6 Life and biomarkers
		4.6.1 Biomarker
		4.6.2 The search for life on Mars
		4.6.3 A potential biomarker identified on Venus
	4.7 Identification of biosignature in Antarctic rocks
	4.8 Existence of biosignatures under diverse environmental conditions
	4.9 Characterizing extraterrestrial biospheres through absorption features in their spectra
	4.10 Means of studying biosignatures
		4.10.1 Identification of stromatolites using portable network graphics analysis of layered structures captured in digital  ...
		4.10.2 Characterization of molecular biosignatures using time-of-flight secondary ion mass spectrometry
			4.10.2.1 Advantage of time-of-flight secondary ion mass spectrometry over other techniques for obtaining biomarker information
			4.10.2.2 Generic scheme of a time-of-flight secondary ion mass spectrometry experiment
			4.10.2.3 Demonstration of potential of time-of-flight secondary ion mass spectrometry for biomarker research
	4.11 Detecting biosignature gases on extrasolar terrestrial planets
	4.12 False positives and false negatives
	4.13 Potential biosignatures—molecules that can be produced under both biological and nonbiological mechanisms but selecti ...
	4.14 Atmospheric chemical disequilibrium (a generalized biosignature)—a proposed method for detecting extraterrestrial bio ...
	4.15 Identification of amino acids in Murchison meteorite and Atarctic micrometeorites
	4.16 Major challenges lurking in the study of extrasolar biosignature gases
	References
		Bibliography
Chapter 5 - Extremophiles—Organisms that survive and thrive in extreme environmental conditions
	5.1 Relevance of astrobiology
	5.2 Habitability
	5.3 Importance of liquid water in maintaining habitability on celestial bodies
	5.4 Habitability of extremophilic and extremotolerant bacteria under extreme environmental conditions
	5.5 Why do extremophiles survive in extreme environments? Application of exopolymers derived from extremophiles in the foo ...
	5.6 Microbial life on and inside rocks
	5.7 Microbial life beneath the seafloor
	5.8 Microbial life in Antarctic ice sheet
	5.9 The year-2021 discovery of sessile benthic community far beneath an Antarctic ice shelf
	5.10 Microbial life at the driest desert in the world
	5.11 Tardigrades—Important extremophiles useful for investigating life’s tolerance limit beyond earth
		5.11.1 Temperature tolerance in tardigrades
		5.11.2 Desiccation tolerance in tardigrades
		5.11.3 Radiation tolerance in tardigrades
		5.11.4 Dormancy strategies in tardigrades
		5.11.5 Ability of tardigrades to cope with high hydrostatic pressure
		5.11.6 Effect of extreme environmental stresses on tardigrades’ DNA
	5.12 Role of tardigrades as potential model organisms in space research
	5.13 Discovery of a living Bdelloid Rotifer from 24,000-year-old Arctic permafrost
	5.14 Archaea—single-celled microorganisms with no distinct nucleus—constituting a third domain in the phylogenetic tree of ...
		5.14.1 The intriguing history of the discovery of archaea
		5.14.2 General features of archaea
		5.14.3 Unique feature of archaea
		5.14.4 Diverse sizes and shapes exhibited by archaea
		5.14.5 Extremophile archaea—halophiles, thermophiles, alkaliphiles, and acidophiles
		5.14.6 Extreme halophilic and hyperthermophilic archaea
		5.14.7 Implications of studies on archaea for the search for life on extraterrestrial worlds
	5.15 How do extremophiles survive and thrive in extreme environmental conditions—clues from study of the DNA
	5.16 Revival of panspermia concept encouraged by the discovery of survival limits of tardigrades in high-speed impacts
		5.16.1 Panspermia concept
		5.16.2 Ability of tardigrades to survive high-speed impact shocks
	References
		Bibliography
Chapter 6 - Salinity tolerance of inhabitants in thalassic and athalassic saline and hypersaline waters & salt flats
	6.1 Salinities in thalassic and athalassic water bodies—survival and growth of living organisms in saline and hypersaline  ...
	6.2 Classification of organisms as osmo-regulators and osmo-conformers
	6.3 Life in thalassic water bodies
		6.3.1 Life in the oceans, seas, gulfs, and bays
			6.3.1.1 Phytoplankton & algae
			6.3.1.2 Cephalopods, crustaceans, & other shellfish
			6.3.1.3 Ocean fishes
			6.3.1.4 Sea turtles & reptiles
			6.3.1.5 Marine mammals
			6.3.1.6 Sharks & rays
			6.3.1.7 Corals—reef builders in the oceans
			6.3.1.8 Starfish, jellyfish, & sea slugs
			6.3.1.9 Seabirds
			6.3.1.10 Microbes living in subseafloor sediment layers
		6.3.2 Life in thalassic brackish water bodies
			6.3.2.1 Fauna in the Baltic sea—world’s largest inland brackish sea & an arm of the Atlantic ocean
			6.3.2.2 Flora and fauna of the Bay of Bengal-connected Chilika Lake—a lake with a delicate salinity gradient between its d ...
	6.4 Life in athalassic brackish water bodies
		6.4.1 Life in the Caspian Sea
			6.4.1.1 Caspian seal
			6.4.1.2 Caspian sturgeon—the world’s largest freshwater fish
		6.4.2 Life in lake texoma
	6.5 Life in athalassic hypersaline water bodies
		6.5.1 Life in the Dead Sea—situated between Israel and Jordan
			6.5.1.1 High density of archaea in the spring waters in the lake bed
			6.5.1.2 Dense biofilms of diatoms, bacteria, and cyanobacteria surrounding underwater springs in the lake bed
		6.5.2 Life in Great Salt Lake in the state of Utah in the United States
			6.5.2.1 Algae, bacteria, protozoa, and brine flies
			6.5.2.2 Brine shrimp
			6.5.2.3 Migratory birds
		6.5.3 Meagre microbial life in the hypersaline Don Juan Pond in Antarctica—the most saline water body on Earth
		6.5.4 The fauna of Athalassic salt lake at Sutton & Saline Pond at Patearoa in New Zealand
		6.5.5 Importance of the genus bacillus
		6.5.6 Microbial life in the hypersaline lake Assal in Djibouti in the Horn of Africa—the most saline hypersaline lake outs ...
	6.6 Life in lithium chloride-dominated hypersaline salt flats & ponds belonging to the lithium triangle zone (Argentina, B ...
		6.6.1 Effects of lithium on microbial cells
		6.6.2 Microbial diversity with the presence of fungi, algae, and bacteria in the lithium-rich hypersaline environment of S ...
		6.6.3 Presence of bacteria and archaea in the lithium-rich hypersaline environment of Salar de Uyuni, Bolivia—the largest  ...
		6.6.4 Life in lithium chloride-dominated hypersaline environments of Atacama hypersaline lakes & salt flats in Chile
		6.6.5 Importance of Atacama desert in astrobiological study of Mars
	References
		Bibliography
Chapter 7 - Terrestrial analogs & submarine hydrothermal vents—their roles in exploring ocean worlds, habitability, and li ...
	7.1 Terrestrial analogs—their importance in understanding the secrets of extraterrestrial worlds
		7.1.1 Ice on Earth—analog for possible microbial life on extraterrestrial icy ocean worlds
		7.1.2 The NASA OCEAN project—an ocean-space analog
		7.1.3 Microbial communities colonizing on terrestrial submarine hydrothermal vents and volcanic rocks—analogs for life on  ...
		7.1.4 Terrestrial lava tubes—analogs of underground tunnels on Earth’s moon and Mars
		7.1.5 Ukrainian rocks—terrestrial analogs for botanical studies in simulation experiments involving possible growth of pla ...
		7.1.6 Atacama desert in Chile—a terrestrial analog of Mars to examine its habitability conditions
		7.1.7 International efforts to map the distribution of extremophiles across the globe
		7.1.8 Extreme acidic environment of Rio Tinto basin—terrestrial analog of Mars to understand its microbial survival during ...
		7.1.9 Antarctic Ross Desert—terrestrial analog of Mars to understand its ecosystem and habitability conditions for differe ...
		7.1.10 Pingos on Earth—tools for understanding permafrost geomorphology on Mars
			7.1.10.1 General features of terrestrial pingos
			7.1.10.2 Pingo-like forms (PLFs) identified on Mars
		7.1.11 Spotted Lake (a hypersaline sulfate lake), British Columbia, Canada—a terrestrial analog of saline water bodies of  ...
		7.1.12 Hypersaline springs on Axel Heiberg Island, Canadian High Arctic—a unique analog to putative subsurface aquifers on ...
		7.1.13 Subglacial Lake Vostok in Antarctica and Mariana Trench in the Pacific Ocean—terrestrial analogs of Jupiter’s Moon  ...
		7.1.14 Methanogens and ecosystems in terrestrial volcanic rocks—terrestrial analogs to assess the plausibility of life on  ...
		7.1.15 Bubbles bursting in Earth’s oceans—terrestrial analogs in studying the transport of organics from Enceladus’s sub ...
		7.1.16 Haughton Crater in the Canadian Arctic Desert—a terrestrial analog for the study of craters on Mars and Saturn’s  ...
		7.1.17 Terrestrial Salt Diapirs & Dust Devils—terrestrial analogs to study cantaloupe terrain & geyser-like plumes on the  ...
		7.1.18 Earth’s biosphere—terrestrial analog in the search for life on Exoplanets
	7.2 Role of submarine hydrothermal vents in the emergence and persistence of life on Earth—their astrobiological implications
		7.2.1 General features of terrestrial submarine hydrothermal vents
			7.2.1.1 Magma-chambers-fed black smoker vents & white smoker vents
			7.2.1.2 Serpentinite-hosted carbonate chimneys—Lost City carbonate structures
		7.2.2 Rich microbial and faunal ecosystems harbored by submarine hydrothermal vents
			7.2.2.1 Fascinating life supported by magma-chambers-fed vents
			7.2.2.2 Organisms supported by Lost City and Lost City-Type hydrothermal systems
		7.2.3 Role of geothermal energy in driving deep-sea hydrothermal vent ecosystem
	7.3 Discovery of indications of hydrothermal vents adorning the subsurface seafloors of Enceladus and Europa—possibili ...
		7.3.1 Direct evidence for submarine hydrothermal vents on Enceladus
		7.3.2 Submarine hydrothermal activity on Europa—inferences gleaned from telescopic observations and laboratory experiments
	References
		Bibliography
Chapter 8 - Surface environment evolution for Venus, Earth, and Mars—the planets which began with the same inventory of el ...
	8.1 Relevance of examining the surface environment evolution for Venus, Earth, and Mars
	8.2 Specialties in the geologic activities of the three planets—Stagnant, Episodic, and Mobile Lid Regimes
	8.3 Size and composition of Venus, Earth, and Mars
		8.3.1 Earth’s size and composition & differences with Mars
		8.3.2 Venus and Earth—twins in terms of size & composition
		8.3.3 How large is Mars & what is it made of?
	8.4 Atmospheres of Venus, Earth, and Mars
		8.4.1 Earth’s atmosphere
		8.4.2 Venus’ atmosphere and clouds
		8.4.3 Atmospheric composition—Mars versus Earth
		8.4.4 Influence of mineral dust on Martian weather
	8.5 Dust devils and vortices
		8.5.1 Dust devil on Earth
		8.5.2 Dust devil on Mars
		8.5.3 Vortex on Venus
	8.6 Distances of Venus, Earth, and Mars from Sun, and their current surface temperatures
		8.6.1 Gradually growing distance between Earth and Sun over time
		8.6.2 Distance of Mars from Sun and Earth & temperature differences
		8.6.3 Venus’ distance from Sun & its brightness and temperature profile
	8.7 Volcanism and surface features of Venus, Earth, and Mars
		8.7.1 Volcanism of Venus
		8.7.2 Earth’s volcanism
		8.7.3 Volcanism on Mars—differences with terrestrial volcanic styles
	8.8 Lava tubes on Earth and Mars
	8.9 History of water on Mars and Venus
		8.9.1 Water once flowed on Mars—indications of hydrated minerals and clay, possible ocean, and vast river plains on martia ...
			8.9.1.1 Hydrated minerals and clay on Martian surface
			8.9.1.2 Mars once possessed a Primordial ocean—Indications
			8.9.1.3 Vast river plains on Martian surface
			8.9.1.4 Open-lake systems on ancient Mars
			8.9.1.5 Evidence of tsunami waves striking in the primordial Martian ocean—caused by asteroids hitting Mars millions of ye ...
		8.9.2 Venus’ dry surface
	8.10 Magnetic fields of Earth, Venus, and Mars—intrinsic & induced magnetic fields
		8.10.1 Earth’s magnetic field—intrinsic magnetic field
		8.10.2 Venus’ unusual magnetic field—induced magnetosphere
		8.10.3 Induced magnetosphere of Mars—comparison with Venus and Titan
	References
		Bibliography
Chapter 9 - Lunar explorations—Discovering water, minerals, and underground caves and tunnel complexes
	9.1 Orbiter- and lander-based explorations of Earth’s Moon
	9.2 A peep into the early history of the study of the origin of Earth’s Moon
	9.3 Origin of Earth’s Moon—evidences from lunar observations
	9.4 Differing preliminary views on the existence of water on Earth’s Moon
	9.5 Experimental search for clues to the existence of water on Earth’s Moon
	9.6 United States’ Apollo missions culminating in the landing of Man on Earth’s Moon
	9.7 The year-2007 discovery of water molecules trapped/chemically bound in lunar rock samples
	9.8 Discovery of adsorbed hydrogen and hydroxyl in volatile content of lunar volcanic glasses—additional clues to the pres ...
	9.9 Identifying presence of water on Earth’s Moon through spacecraft-borne spectroscopic measurements
	9.10 The year-2009 confirmation of the presence of water on Earth’s Moon by India’s Moon Impact Probe (MIP) and America’s  ...
		9.10.1 Providing complete coverage of the Moon’s polar regions—acquiring images of peaks and craters and conducting chemic ...
		9.10.2 Probing the poles in search of ice and water and providing confirmation of regolith hydration everywhere across the ...
	9.11 Permanently shadowed regions (cold traps) of the lunar poles—initial inferences
	9.12 Role of NASA’s LRO and LCROSS in confirming presence of water in the southern lunar crater Cabeus
	9.13 Discovery of frozen water in permanently shadowed craters and poles of Earth’s Moon
	9.14 Water in the lunar interior
		9.14.1 Detection of water existing deeper within the lunar crust and mantle through analyses of melt inclusions that origi ...
		9.14.2 Indications of past presence of water in the lunar interior (within the lunar mantle) from lunar convective core dy ...
		9.14.3 Identification of water in the lunar interior through remote sensing of impact crater Bullialdus
	9.15 Origin of water on Earth’s Moon
	9.16 The last phase of Chandrayaan-1 mission—the lunar probe lost and found
	9.17 Discovery of subsurface empty lava tubes and caves on Earth’s Moon—potential shelters for human settlement?
		9.17.1 Sinuous lunar rilles
		9.17.2 Underground caves and lava tubes on Earth’s Moon—formation processes, strength, and durability
		9.17.3 Underground caves and tunnel complexes as potential shelters for lunar habitats
		9.17.4 Technical considerations in planning the use of lava tubes to house manned lunar bases
	9.18 Lunar samples—what all tales do they tell the world about Earth’s Moon?
		9.18.1 Protection of returned lunar samples from terrestrial contamination
		9.18.2 Fine-tuning the models for the origin of Earth’s Moon
		9.18.3 First proposing and then disproving the “Dry Moon Paradigm”
		9.18.4 Understanding how and when large basins on the near side of the Earth’s Moon were created
		9.18.5 Application of Apollo lunar samples in plant biology experiments
	9.19 China’s year-2019 landmark success in placing a lander and rover on Earth’s Moon’s far side for scientific data colle ...
		9.19.1 Importance of exploring lunar far side
		9.19.2 Establishing a relay satellite at the “halo orbit” around Lagrange point 2 of the Earth–Moon system—the first step  ...
		9.19.3 The Chang’e-4 mission lander and rover
		9.19.4 Unveiling of Earth’s Moon’s far side shallow subsurface structure by China’s Chang’E-4 lunar penetrating radar
	9.20 Cotton seeds carried to Earth’s Moon by China’s Chang’e-4 probe—the first-ever to sprout on Earth’s nearest neighbor
	References
		Bibliography
Chapter 10 - Liquid water lake under ice in Mars’s southern hemisphere—Possibility of subsurface biosphere and life
	10.1 Mars’ glorious past
	10.2 Mars—once a water-rich planet whose surface dried later
	10.3 Favorable position of Mars in Sun’s habitable zone
	10.4 Water-bearing minerals on Mars, its hydrologic history, and its potential for hosting life
	10.5 Evidence for hydrated sulfates on Martian surface—Biological implication
	10.6 Day–night variations in liquid interfacial water in Martian surface
	10.7 Clues leading to existence of water at Mars’ subsurface
	10.8 Searching for presence of liquid water at the base of the Martian polar caps using ground-penetrating radar on Mars  ...
	10.9 The year-2018 discovery of an underground liquid water lake in Mars’ southern hemisphere
	10.10 Indications suggestive of Mars’ subsurface harboring a vast microbial biosphere
		10.10.1 Prokaryotic life in Earth’s deep subsurface offers clues to Mars’ subsurface microbial biosphere
		10.10.2 Model studies suggestive of subsurface Martian biosphere
		10.10.3 Arguments in support of a deep biosphere on Mars
		10.10.4 Early Mars’ potential as a better place for the origin of life compared to early Earth
	10.11 Search for biosignatures and habitability on early Mars—ExoMars mission
		10.11.1 ExoMars mission to Mars—An astrobiology program of the European Space Agency (ESA) and the Russian Space Agency  ...
		10.11.2 Prospects of lava tube caves on Mars as an extant habitable environment
		10.11.3 Mars’ anticipated habitability potential
		10.11.4 Mars landing site selection criteria
	10.12 When could life have probably arisen on early Mars? Clues from early Earth environments and biosignatures
	10.13 Search for life on Mars under the first NASA Mars Scout mission—The Phoenix mission
	10.14 Search for traces of life on Mars—NASA’s biology experiments
	10.15 Exploring Mars under United States’ Viking Lander missions—Discovering volcanoes, lava plains, giant canyons, crater ...
	10.16 Looking for signs of primitive life on Mars
		10.16.1 Arguments favoring possibility of life on Mars
		10.16.2 Probable ancient life on Mars: Chemical arguments and clues from Martian meteorites
		10.16.3 UV is not always fatal—Examples from studies of haloarchaea and spore-forming bacteria
			10.16.3.1 Survival of some haloarchaea under simulated Martian UV radiation
			10.16.3.2 Survival of spores of Bacillus subtilis bacteria under simulated Martian UV radiation
	10.17 Exploring Mars under Rover mission to assess past environmental conditions for suitability for life
	10.18 Mangalyaan—India’s Mars Orbiter Mission (MOM) spacecraft—Exploring Mars’ surface features, morphology, mineralogy, a ...
	10.19 Imaging of Mars’ surface, its dynamical events, and its Moons Phobos and Deimos using Mars Color Camera (MCC) on ...
		10.19.1 Atmospheric optical depth estimation in Valles Marineris—A huge canyon system
		10.19.2 Imaging of Mars’ twin Moons—Phobos and the far side of Deimos
		10.19.3 Morphology study of Ophir Chasma canyon
		10.19.4 Automatic extraction, monitoring, and change detection of area under polar ice caps on Mars
		10.19.5 Application of reflectance data derived from a differential radiometer and the MCC on-board MOM in studying the mi ...
	10.20 Solar forcing on the Martian atmosphere and exosphere
	10.21 Emission of thermal infrared radiation from Mars
	10.22 D/H ratio estimation of Martian atmosphere/exosphere
	10.23 Success achieved by MOM
	10.24 Perchlorates on Mars
		10.24.1 Use of perchlorates as an energy source—Example by Antarctic microbes
		10.24.2 Effects of perchlorate salts on the function of a cold-adapted extreme halophile from Antarctica—No significant in ...
		10.24.3 Bacteriocidal effect of UV-irradiated perchlorate
		10.24.4 Bacteriocidal effect of perchlorate salts under Martian analog conditions
		10.24.5 Interactions of other Martian soil components
		10.24.6 Implications of perchlorate detection on Mars
	10.25 Hydrogen peroxide—Negatively impacting the habitability of Mars?
	10.26 Exploring organic substances in the Martian soil
	10.27 A ray of hope in Mars’ horizon—Possibility of halophilic life on Mars
	References
		Bibliography
Chapter 11 - Could near-Earth watery asteroid Ceres be a likely ocean world and habitable?
	11.1 Near-Earth asteroids Ceres and Vesta—why did they become targets of NASA discovery-class mission, Dawn?
	11.2 An overview of the dwarf planet Ceres
	11.3 Indications favoring the presence of water on Ceres
	11.4 Application of reflectance spectroscopy for remote detection of water molecules on Ceres
	11.5 Clues leading to the presence of water on the surface of Ceres
	11.6 Inferring presence of water in the subsurface of Ceres
	11.7 The year-2018 discovery of a seasonal water cycle on Ceres
	11.8 Hint of an ocean hiding below the surface of Ceres
	11.9 Possibility of hydrothermal geochemistry to take place on Ceres
	11.10 Presence of organics on and inside Ceres
	11.11 Ceres—a candidate ocean world in the asteroid belt
	11.12 Habitability potential of Ceres
	References
	Bibliography
Chapter 12 - An ocean and volcanic seafloor hiding below the icy crust of Jupiter’s Moon Europa—Plumes of water vapor ri ...
	12.1 Planet Jupiter and its water-bearing moons
		12.1.1 Jupiter—the largest and the most massive planet in the solar system
		12.1.2 NASA’s Galileo mission to Jupiter and its mysterious moons
		12.1.3 Searching for water vapor in Jupiter’s atmosphere
		12.1.4 Magnetic field production and surface topography of Ganymede
		12.1.5 Water and oxygen exospheres of Ganymede
	12.2 An overview of Europa
	12.3 Jupiter’s icy moons Europa, Ganymede, and Callisto containing vast quantities of liquid water
	12.4 Oxygen, water, and sodium chloride on Europa
	12.5 Understanding the mysteries of Europa
	12.6 An approx. 100 km deep subsurface salty ocean hiding beneath Europa’s ice shell
	12.7 Indirect methods for detecting an ocean hidden within Europa
		12.7.1 Radar-based active detection—practical constraint
		12.7.2 Radar-based passive detection—an ingenious method
	12.8 Direct methods for detecting Europa’s Ocean—plans in the pipeline
	12.9 Lakes & layer of liquid water in & beneath Europa’s hard icy outer shell
	12.10 Europa adorning a volcanic seafloor—the year 2021 numerical model prediction
	12.11 Plumes of water vapor erupting from Europa’s surface
	12.12 Saucer-shaped sills of liquid water in Europa’s ice shell
	12.13 Europa Clipper Mission aimed at Europa’s exploration
	12.14 Prospects of extant life on Europa
	12.15 Future exploration of Europa in the pipeline
	References
Chapter 13 - Salty ocean and submarine hydrothermal vents on Saturn’s Moon Enceladus—Tall plume of gas, jets of water va ...
	13.1 Saturn and its glaring similarities and dissimilarities with Earth
	13.2 Exploring Saturn and its two major moons (Enceladus and Titan)—importance of Cassini spacecraft mission
	13.3 Presence of a global subsurface ocean on Enceladus—inferences from gravitational field measurements and forced phys ...
	13.4 Liquid water ocean hiding below the icy crust of Enceladus—inference drawn from plumes of water vapor & salty ice g ...
	13.5 Maintaining liquid oceans inside cold planets and moons—role of tidal heating
	13.6 Eruptions in the vicinity of Enceladus’ south pole—role of tidally driven lateral fault motion at its south polar rifts
	13.7 Presence of macromolecular organic compounds in the subglacial water-ocean of Enceladus
	13.8 Mechanisms driving the cryovolcanic plume emission from the warm fractures in Enceladus
	13.9 Hydrothermal vents on the seafloor of Enceladus—possibility for harboring an ecosystem based on microbial populations
	13.10 Resemblance of Enceladus’s organics-rich ocean to earth’s primitive prebiotic ocean—a favorable scenario for life’ ...
	13.11 Science goals and mission concept for future exploration of Enceladus
	13.12 Implementable mission concepts to further explore Enceladus in the near future—Enceladus life finder (ELF) mission
	References
	Bibliography
Chapter 14 - Hydrocarbon lakes and seas & internal ocean on Titan—Resemblance with primitive earth’s prebiotic chemistry
	14.1 Titan—an earth-like system in some ways
	14.2 Pre-Cassini mission knowledge of Titan
		14.2.1 Titan’s dense atmosphere
		14.2.2 Size and shape of aerosol particles in Titan’s atmosphere—results from voyager 1 and 2 missions
		14.2.3 Understanding the mechanisms of aerosol particle building in Titan’s atmosphere
		14.2.4 Chemical transition of simple organic molecules into aerosol particles in Titan’s atmosphere
		14.2.5 Understanding particle size distribution in Titan’s hazy atmosphere
		14.2.6 Gaining Insight on the vertical distribution of Titan’s atmospheric haze
		14.2.7 Greenhouse and antigreenhouse effects on Titan
		14.2.8 Inferring clues on Titan’s surface
	14.3 Role of Cassini spacecraft and Cassini–Huygens probe in understanding Titan better
		14.3.1 Cassini spacecraft mission to explore planet Saturn and some of its icy moons
		14.3.2 The European space agency’s Huygens probe to explore Titan’s hazy atmosphere and its surface
		14.3.3 Landing of Huygens probe on Titan’s surface
	14.4 Gaining better understanding of Titan based on data gleaned from Cassini spacecraft mission
		14.4.1 Titan’s clouds, storms, and rain
		14.4.2 Detection of tall sand dunes in the equatorial regions of Titan
		14.4.3 Understanding Titan’s ionosphere using Cassini plasma spectrometer (CAPS)
		14.4.4 Confirming the existence of strong winds in Titan’s atmosphere
		14.4.5 Knowing more on an unusual atmosphere surrounding Titan
		14.4.6 Making the first direct identification of bulk atmospheric nitrogen and its abundance on Titan
		14.4.7 Obtaining evidence for formation of Tholins in Titan’s upper atmosphere and understanding the process
		14.4.8 Detection of benzene (C6H6) in Titan’s atmosphere
		14.4.9 Direct measurements of carbon-based aerosols in Titan’s atmosphere and deciphering their chemical composition
		14.4.10 Understanding the role of nitrogen and methane in generating the orange blanket of haze in Titan’s atmosphere
		14.4.11 Examining the contribution of polycyclic aromatic hydrocarbons (PAHs) in producing organic haze layers in Titan’s  ...
		14.4.12 Deciphering the particle size distribution in Titan’s hazy atmosphere
		14.4.13 Investigating the role of organic haze in Titan’s atmospheric chemistry
		14.4.14 Understanding the processes responsible for the evolution of aerosols in Titan’s atmosphere
	14.5 Organic compounds on Titan’s surface
	14.6 Hydrocarbon reservoirs, seas, lakes, and rivers on Titan
		14.6.1 Hydrocarbon seas on Titan’s surface
		14.6.2 Likelihood of finding transient liquid water environments on Titan’s surface
		14.6.3 Subsurface hydrocarbon reservoirs on Titan
		14.6.4 Hydrocarbon lakes on Titan and their astrobiological significance
		14.6.5 Ammonia-enriched salty liquid–water inner-ocean hiding far beneath Titan’s frozen surface
		14.6.6 Rivers and drainage networks on Titan—comparison and contrast with those on Earth and Mars
	14.7 Presence of a salty liquid water inner ocean hiding far beneath Titan’s frozen surface—evidence gleaned from a deform ...
	14.8 Gaining insight into Titan’s overall similarities and dissimilarities to Earth
	14.9 Titan’s resemblance to prebiotic Earth
	14.10 Possibility of finding biomolecules on Titan
	14.11 Practicability of photosynthesis on Titan’s surface
	14.12 Active cycling of liquid methane and ethane on Titan
	14.13 Cassini spacecraft’s retirement in September 2017 after successful 13 years’ orbiting around the Saturn system
	14.14 Is existence of life on Titan possible? Significance of carbon-rich and oxygen-loaded fullerenes in introducing oxyg ...
	14.15 Viability of a nonwater liquid capable of sustaining life on Titan
	14.16 Science goals and mission concept for future exploration of Titan
	References
Chapter 15 - A likely ocean world fostering a rare mixing of CO and N2 ice molecules on Neptune’s Moon Triton
	15.1 General features of Triton
	15.2 Origin of Triton—its uniqueness among all large moons in the solar system
	15.3 Triton’s surface temperature and pressure
	15.4 Chemical composition of Triton’s atmosphere & surface
	15.5 Triton’s nitrogen deposits—interesting consequences
	15.6 Triton’s surface—among the youngest surfaces in the solar system
	15.7 Spectral features of Triton’s water–ice
	15.8 Ridges on Triton
	15.9 Dust devils-like tall plumes of gas and dark material rising through Triton’s atmosphere
	15.10 Likely existence of a 135–190 km thick inner ocean at a depth of ∼20–30 km beneath Triton’s icy surface
	15.11 The Year-2019 discovery of Triton fostering a rare mixing of CO and N2 ice molecules—shedding more light on Trit ...
	15.12 Triton in the limelight as a high-priority target under NASA’s “Ocean Worlds” program
	15.13 Forthcoming mission to map Triton, characterize its active processes, and determine the existence of the predicted ...
	References
		Bibliography
Chapter 16 - Subsurface ocean of liquid water on Pluto
	16.1 Pluto and its five moons
	16.2 Pluto’s highly eccentric orbit—an oddity in the general scheme
	16.3 Long-period perturbations in the chaotic motion of Pluto
	16.4 Pluto’s complex crater morphology
	16.5 Controversy over Pluto’s planetary status—recent arguments
	16.6 Studies on Pluto system and Pluto’s physical and geological features prior to the launch of “New Horizons” spacecraft
		16.6.1 Dynamics of Pluto and its largest moon Charon
		16.6.2 Three-body orbital resonant interactions among Pluto’s small moons Styx, Nix, and Hydra
		16.6.3 Insolation and reflectance changes on Pluto
			16.6.3.1 Insolation changes on Pluto caused by orbital element variations
			16.6.3.2 Latitudinal variations of Pluto’s insolation and reflectance
		16.6.4 Pluto’s atmosphere
		16.6.5 Presence of a subsurface ocean on Pluto—inference based on numerical studies
	16.7 “New Horizons”—the spacecraft that brilliantly probed the distant Pluto from close quarters
		16.7.1 Powering the New Horizons spacecraft
		16.7.2 New Horizons spacecraft and its science payloads
		16.7.3 Discoveries by New Horizons during its long travel to Pluto and beyond
		16.7.4 New Horizons spacecraft performing the first ever flyby of Pluto
	16.8 Understanding Pluto and its moons through the eyes of New Horizons spacecraft
		16.8.1 Shedding light on the consequences of Pluto’s high orbital eccentricity and high obliquity
		16.8.2 Achieving confirmation on Pluto’s small Moons’ rotation, obliquity, shapes, and color & the absence of a predicted  ...
		16.8.3 Runaway Albedo effect on Pluto
		16.8.4 Knowing more on Pluto’s insolation and reflectance in the light of new data from New Horizons mission
		16.8.5 Ice-laden “Heart-Shaped” region on Pluto’s surface—formation and stability of Sputnik Planitia crater
		16.8.6 Gaining insights on Pluto’s SP crater basin and its surroundings
		16.8.7 Subtle topography of ice domes and troughs of cellular plains within Sputnik Planitia crater
		16.8.8 Latitudinal variations of solar energy flux on Pluto—theoretical investigations
	16.9 The current state of Pluto’s atmosphere
	16.10 Indirect detection of subsurface ocean of liquid water inside Pluto—in support of pre-New Horizons numerical studies
	16.11 Distinct topographic signatures on Pluto’s “Near-Side” and “Far-Side”
		16.11.1 Deep depression enclosing Sputnik Planitia ice sheet & north-south running complex ridge-trough system along 155°  ...
		16.11.2 Bladed terrain on Pluto’s “Near-Side”
		16.11.3 Bladed terrain on Pluto’s “Far-Side”
	16.12 Is life possible on Pluto?
	16.13 Expectations from future explorations of Pluto
	References
		Bibliography
Chapter 17 - Hunting for environments favorable to life on planets, moons, dwarf planets, and meteorites
	17.1 A new frontier in planetary simulation
	17.2 Role of tidally heated oceans of giant planets’ moons in supporting an environment favorable to life
	17.3 Prospects of life on Mars and Jupiter’s Moon Europa
		17.3.1 Role of biomineralization in providing bacteria with an effective UV screen on Mars
		17.3.2 Redox gradients may support life and habitability on Mars
		17.3.3 Probable life on Mars—speculations driven by biochemistry
		17.3.4 Best possible hideout on Mars—a string of lava tubes in the low-lying Hellas Planitia
		17.3.5 Europa—one of most promising places in the solar system where possible extra-terrestrial life forms could exist
	17.4 In the hope of finding evidence of past life on Mars—arrival of NASA’s “Mars 2020 Perseverance Rover” at Mars
	17.5 Looking for signs of primitive life on Jupiter & Saturn and their Moons
		17.5.1 Prospects of life on Europa
		17.5.2 Strategies for detection of life on Europa
		17.5.3 Anticipation of an Earth-like chemical balance of Europa’s ocean
		17.5.4 Proposal for probing subglacial ocean of enceladus in search of life—orbiter and lander missions
		17.5.5 Possibility of life on Enceladus
		17.5.6 The anticipated nature of life on Saturn’s Moon Titan
		17.5.7 Possibility of amino acids production in Titan’s haze particles
	17.6 Astrobiological potential of the dwarf planet Pluto
	17.7 Is there a prospect for life to arise on the asteroid belt resident dwarf planet ceres?
	17.8 Recent and upcoming missions to the extraterrestrial worlds in the solar system in search of ingredients for life
		17.8.1 Upcoming missions to Earth’s Moon
			17.8.1.1 America’s plans to explore the far-side of Earth’s Moon in search of water and other sustaining minerals
			17.8.1.2 ESA’s “Moonlight Initiative”—raising a network of satellites around Earth’s Moon to enhance telecommunications an ...
			17.8.1.3 Turkey’s plans to send a rover to Earth’s Moon by the Year 2030
		17.8.2 New missions to Mars initiated in 2021
			17.8.2.1 United Arab Emirates (UAE)’s “Hope Mission” to Mars
			17.8.2.2 China’s Tianwen-1 Mission to Mars
			17.8.2.3 India’s Mars Orbiter Mission 2
		17.8.3 Titan’s exploration planned to launch in 2026—NASA’s dragonfly mission
	17.9 Astrobiologists’ thoughts on collection of samples from plumes emitted by Enceladus and Europa
	References
		Bibliography
Appendix - Chemical names and their chemical formulae
Water Worlds in the Solar System: Exploring Prospects of Extraterrestrial Habitability & Life
Definition/Meaning
Index
Back cover