About the Author Springer author/artist Michael Carroll received the AAS Division of Planetary Science’s Jonathan Eberhart Award for the best planetary science feature article of 2012, an article based on his Springer book D rifting on Alien Winds . He lectures extensively in concert with his various books and has done invited talks at science museums, aerospace facilities, and NASA centers. His two decades as a science journalist have left him well con- nected in the planetary science community. He is a Fellow of the International Association for the Astronomical Arts and has written arti- cles and books on topics ranging from space to archaeology. His articles have appeared in Popular Science , Astronomy , Sky & Telescope , Astronomy Now (UK), and a host of children’s magazines. His 20-some titles also include Alien Volcanoes (Johns Hopkins University Press), S pace Art (Watson Guptill), The Seventh Landing (Springer 2009), and D rifting on Alien Winds (Springer 2011). His latest coauthored book is Springer’s A lien Seas: Oceans in Space (2013). Carroll has done commissioned artwork for NASA, the Jet Propulsion Laboratory, and several hundred magazines throughout the world, includ- ing National Geographic , T ime , S mithsonian , A stronomy , and others. One of his paintings is on the surface of Mars – in digital form – aboard the Phoenix lander. Carroll is the 2006 recipient of the Lucien Rudaux Award for lifetime achievement in the astronomical arts. xiii.
A Note About the Paintings Living Among the Giants has a dozen or so original paintings done speciﬁ - cally for the project. Almost all are traditionally done on canvas. We live in a digital world, and this book is about technologically advanced things, so I decided that traditional paintings would bring a visual softness to the subject. Some are “tradigital,” such as the painting of the astronaut on Titan. In this case, I began with a traditional painting on board and then added digital touches in Photoshop and Terragen. I hope my readers will enjoy the results! xv.
Acknowledgments My artistic thanks goes to Carolyn Porco of the Space Science Institute and Joe Spitale of the Planetary Science Institute for their patience and wisdom on Saturn’s ring “spikes.” A special shoutout goes to Rob Callison for ideas on submarine psychology. For translations of Lucien Rudaux’s work, I am indebted to Jenna Khazoyan and Caroline Carroll. Bill Higgins was of tre- mendous help in providing material and insights into the history of sci- ence ﬁ ction. Thanks to Wes Patterson and Chris Paranicas at Johns Hopkins Applied Physics Laboratory for use of their Europa sputtering diagram (if you don’t know what that is, you’ll ﬁ nd out in Chap. 5 ). Ted Stryk gener- ously lent his digital magic to images of various planets and moons. Thanks to Keith Cooper and the team at A stronomy Now , and to Dave Eicher and the gang at Astronomy , for letting me borrow from articles written for them. Cynthia Rodriguez and Princess Cruise Lines generously gave per- mission for me to use their logo and beautiful ships as reference for our own cosmic cruise ship in Chap. 1 0 . Aldo Spadoni brought life to the Iapetus Ridge Resort, aka “New Santorini,” and Edie Carroll (my very own Mom), Marilyn Flynn (special commendation for last-minute frenzy), and Bill Gerrish made my words look intelligent, more or less (there’s only so much one can do). My talented daughter Alexandra helped transcribe interviews, a critical part of any book like this. Thanks to Alice Salvage, Chris White, and Matt Levin at Magnolia Pictures and Wayfare Entertainment for the cool scene from E uropa Report . And many thanks to Maury Solomon – fearless editor at Springer – for her years of support. xvii.
Contents Preface . ix Part I The Backdrop 1 Early Ideas . 2 2 How They Got Here . 16 3 How We Got There . 26 Part II Destinations 4 The Gas and Ice Giants . 46 5 The Galilean Moons . 68 6 Saturn’s Ice Moons: Dione, Tethys, Rhea, Hyperion, Iapetus, Phoebe and Enceladus . 102 7 Titan, the Other Mars . 1 28 8 Ariel, Miranda and Triton – Moons of Uranus and Neptune . 152 Part III A New Frontier 9 Technology and Living Among the Giants . 172 10 Frolicking in the Outer Darkness: The Cultural Side of Living Among the Giants . 200 Index . 223 xix.
Fig. 1.1 The Flemish painter Garrit Dou (1613–1675) crafted this masterpiece of an astronomer working by candlelight. The scholar’s tools include a liquid-ﬁ lled beaker, an hourglass, a huge book, and a celestial globe showing the constellations of the night sky. Although telescopes were invented at the opening of the seventeenth century, most early astronomers did not have access to them; the objects in the painting were the tools of their trade. At the end of the day, the ancient student of the sky could only dream of what travelers might discover out there (Painting by Garrit Dou, ca. 1658) Chapter 1 Early Ideas 2.
9 EARLY IDEAS THE TERRESTRIAL PLANETS The inner planets are called terrestrials because of their similarities to Earth. Unlike the outer giant worlds, the terrestrials all have solid surfaces. And while the inner planets may differ fundamentally from the gas and ice giants, we will ﬁ nd some spooky echoes of them in the moons of the outer Solar System. Understanding the hot, rocky worlds will lend insight into understanding the outer worlds of rock and ice, our ultimate destinations. The surface of Earth, stable and solid as it may seem, displays tatters and scars from a long succession of assaults. One of the most important of these assaults comes in the form of tectonics. Earth’s crust is not of one piece. The continents rest upon plates that drift and pirouette about at the rate of the growth of a human ﬁ ngernail. Although many geologists remarked on the fact that the continents seem to have shifted through time, the real force behind the modern view of plate tectonics was the German scientist Alfred Wegener. While recover- ing from a neck wound sustained on the battleﬁ elds of World War I, Wegener came upon the idea that Africa and South America, along with all the other landmasses of the world, had once formed a supercontinent that he called Pangaea ( Pan meaning “all,” and g aia meaning “Earth”). He searched the world over for proof of his model. He matched the proﬁ les of mountain ranges in South Africa and Argentina. He linked a plateau in Brazil with another on the Ivory Coast of Africa. He demonstrated geo- graphic links of the fossil fern Glossopteris. Its locations line up perfectly with the coastlines of the two continents. Wegener wrote that, “It is just as if we were to reﬁ t the torn pieces of a newspaper by matching their edges and then check whether the lines of print run smoothly across … there is nothing left but to conclude that the pieces were in fact joined…” Wegener’s shifting continents were a bit like Copernicus’ hurtling Earth; the idea went against the senses. Despite his proofs, there were skep- tics. The idea, when ﬁ rst proposed, was met with widespread derision. The scientiﬁ c community saw Wegener’s evidence as largely circumstantial. One reviewer of his book on the subject said, “If we are to believe Wegener’s hypothesis, we must forget everything which has been learned in the last 70 years and start over again.” As it turns out, the critic was absolutely right. But it was the science of the past 70 years that had been mistaken. By the 1960s, the scientiﬁ c community was beginning to assemble a picture of the ocean ﬂ oor. Long thought to be a lifeless desert of rolling plains and a few seamounts (underwater mountains), the sea ﬂ oor was turning out to be bizarre and unlike conventional mountains and deserts. Sonar maps of the Mid-Atlantic Ridge revealed an undersea mountain chain unlike anything seen before. The long ridge rose 6,000–10,000 ft from the sea ﬂ oor, and had a deep cleft or valley along its top. Unlike the mountain ranges of the continents, which seemed to have been pushed up .
14 LIVING AMONG GIANTS THE GIANTS The outer planets had strikingly different childhoods than their terrestrial siblings. While the young Sun was busily stripping the atmospheres from the inner planets, Jupiter, Saturn, Uranus and Neptune kept themselves at a distance. In the cold outer system, they were able to retain atmospheres similar to the earliest primordial cloud surrounding the Sun. Their atmo- spheres are dominated by hydrogen, a building block of all other gases, and helium. In addition to these major gases, Jupiter and Saturn have an abun- dance of ammonia, while the skies of Uranus and Neptune are seasoned by more methane. These poisonous brews rest above dense cores, but the giant planets have no solid surface. They are worlds of weather, spheres of tempest and thunderbolt, cyclone and rainstorm. Jupiter and Saturn, the gas giants, are large enough that their interiors differ substantially from the other two giants. At their cores, pressures rise to the point where hydrogen becomes an electriﬁ ed liquid metal. Densities in the lower regions of these behemoths are so great that laboratory studies of their conditions are practically impossible.1 2 The cores of the other two giants, Uranus and Neptune, have lower pressures and are primarily water ice (hence their label of “Ice Giants”). The hearts of these outer worlds generate intense magnetospheres unlike those seen in the inner Solar System. Although the giant planets are fascinating, human exploration will undoubtedly focus on the dozens of moons circling them. Many of these moons are as complex geologically as the terrestrials, with their own features echoing landscapes we have seen on the terrestrial worlds. Some are the size of planets, and one has more of an atmosphere than Earth. This “new” Solar System, populated by planets the size of Mercury and smaller, begs the question: What about life out there on the moons? In the early 1960s, the planetary landscape looked fairly forbidding, as described by Patrick Moore: To sum up: in the Solar System, there are only two planets apart from the Earth which might possibly support life. On Mars there seems to be ‘vegetation,’ but intel- ligent beings are improbable. (Whether a Martian civilization used to exist and has now died out we do not know, but the evidence is rather against it.) Venus seems unsuitable for anything except, possibly, very lowly single-celled marine creatures. Yet can there be planetary systems circling other stars? The Picture History of Astronomy by Patrick Moore (Grosset & Dunlap 1961). Back then, Moore and his colleagues didn’t even consider the outer 12. Sandia Laboratories in New Mexico use their famous Solar System. But discoveries of extremophiles in deadly environments of Z machine, a 130-ft-diameter Earth, along with the detection of subsurface oceans on several moons of torus X-ray generator, to the outer planets, have changed the game (see Chaps. 5 and 6 ). simulate these horriﬁ c conditions, but the machine Will human exploration be limited to the satellites of the outer can only hold these pressures worlds? Perhaps not. The outer planets themselves are currently beyond for fractions of a second at a time. our technical capability to explore using manned ships, but eventually .
Fig. 2.1 Extended primordial rings encircle both Saturn and Neptune in this view of planetary migration in the early Solar System. According to the “Nice” theory, Neptune may have had several close encounters with Jupiter and/ or Saturn. In the process, wandering asteroids such as Saturn’s outer moon Phoebe may have been captured, or even exchanged, from one planet to another. These captures would have been violent, perhaps causing internal pressures leading to volcanic eruptions, differentiation and surface collapse (Painting © Michael Carroll, original iteration courtesy Astronomy magazine) Chapter 2 How They Got Here 16.