Planets Ours And Others

What is a planet? The answer may seem obvious; still, the definition of a planet has continuously evolved over the centuries, and their number has changed following successive discoveries. In 2006, the decision endorsed by the International Astronomical Union to remove Pluto from the list of planets has well illustrated the difficulty associated with their definition. The recent discovery of hundreds of exoplanets around nearby stars of our Galaxy opens a new and spectacular dimension to astrophysics. We presently know very little about the physical nature of exoplanets. In contrast, our knowledge on solar system planets has made huge progress over the past decades, thanks, especially, to space planetary exploration. The purpose of this book is first to characterize what planets are, in their global properties and in their diversity. Then, this knowledge is used to try to imagine the physical nature of exoplanets, starting from the few parameters we know about them. Throughout, we keep in mind the ultimate question of the search for possible extraterrestrial life: Could life exist or have existed in the solar system and beyond? Thérèse Encrenaz is Emeritus Senior Scientist at the Centre National de la Recherche Scientifique. She works at the Observatoire de Paris, at the Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique (LESIA). She is a specialist of the study of planetary atmospheres, and has been involved in several space missions.

Discover Earth and the other inner planets through engaging text, vibrant photography, and powerful infographics. It's time to go where no human and few robots have gone before. It's time for Deep Space Discovery. This series explores everything from the sun and other stars to the vast galaxies they make up. With up-to-date content, infographics, and closely leveled text, this series will have reluctant readers reaching for more.

Building on the eighteenth-century fascination with the possibility of life on other worlds and with traveler's tales of other cultures, this work describes life on other planets in our solar system and elsewhere in the universe. Swedenborg undertook this work specifically to demonstrate that Jesus is God not just of planet Earth but also of the universe as a whole.

An insider's look at the cutting-edge science of today's planet hunters In Strange New Worlds, renowned astronomer Ray Jayawardhana brings news from the front lines of the epic quest to find planets—and alien life—beyond our solar system. Only in the past two decades, after millennia of speculation, have astronomers begun to discover planets around other stars—thousands in fact. Now they are closer than ever to unraveling distant twins of the Earth. In this book, Jayawardhana vividly recounts the stories of the scientists and the remarkable breakthroughs that have ushered in this extraordinary age of exploration. He describes the latest findings--including his own—that are challenging our view of the cosmos and casting new light on the origins and evolution of planets and planetary systems. He reveals how technology is rapidly advancing to support direct observations of Jupiter-like gas giants and super-Earths—rocky planets with several times the mass of our own planet—and how astronomers use biomarkers to seek possible life on other worlds. Strange New Worlds provides an insider's look at the cutting-edge science of today's planet hunters, our prospects for discovering alien life, and the debates and controversies at the forefront of extrasolar-planet research. In a new afterword, Jayawardhana explains some of the most recent developments as we search for the first clues of life on other planets.

"Tender and illuminating. A beautiful debut." --Rebecca Stead, Newbery Medal-winning author of When You Reach Me A heartrending and hopeful story about a nonverbal girl and her passion for space exploration, for fans of See You in the Cosmos, Mockingbird, and The Thing About Jellyfish. Twelve-year-old Nova is eagerly awaiting the launch of the space shuttle Challenger--it's the first time a teacher is going into space, and kids across America will watch the event on live TV in their classrooms. Nova and her big sister, Bridget, share a love of astronomy and the space program. They planned to watch the launch together. But Bridget has disappeared, and Nova is in a new foster home. While foster families and teachers dismiss Nova as severely autistic and nonverbal, Bridget understands how intelligent and special Nova is, and all that she can't express. As the liftoff draws closer, Nova's new foster family and teachers begin to see her potential, and for the first time, she is making friends without Bridget. But every day, she's counting down to the launch, and to the moment when she'll see Bridget again. Because as Bridget said, "No matter what, I'll be there. I promise."

The captivating possibilities of extraterrestrial life on exoplanets, based on current scientific knowledge of existing worlds and forms of life It is now known that we live in a galaxy with more planets than stars. The Milky Way alone encompasses 30 trillion potential home planets. Scientists Trefil and Summers bring readers on a marvelous experimental voyage through the possibilities of life--unlike anything we have experienced so far--that could exist on planets outside our own solar system. Life could be out there in many forms: on frozen worlds, living in liquid oceans beneath ice and communicating (and even battling) with bubbles; on super-dense planets, where they would have evolved body types capable of dealing with extreme gravity; on tidally locked planets with one side turned eternally toward a star; and even on "rogue worlds," which have no star at all. Yet this is no fictional flight of fancy: the authors take what we know about exoplanets and life on our own world and use that data to hypothesize about how, where, and which sorts of life might develop. Imagined Life is a must-have for anyone wanting to learn how the realities of our universe may turn out to be far stranger than fiction.

Winner of the 2019 Phi Beta Kappa Award for Science "A valuable perspective on the most important problem of our time." —Adam Becker, NPR Light of the Stars tells the story of humanity’s coming of age as we realize we might not be alone in this universe. Astrophysicist Adam Frank traces the question of alien life from the ancient Greeks to modern thinkers, and he demonstrates that recognizing the possibility of its existence might be the key to save us from climate change. With clarity and conviction, Light of the Stars asks the consequential question: What can the likely presence of life on other planets tell us about our own fate?