"What if?" questions stimulate people to think in new ways, to refresh old ideas, and to make new discoveries. In What If the Earth Had Two Moons, Neil Comins leads us on a fascinating ten-world journey as we explore what our planet would be like under alternative astronomical conditions. In each case, the Earth would be different, often in surprising ways. The title chapter, for example, gives us a second moon orbiting closer to Earth than the one we have now. The night sky is a lot brighter, but that won't last forever. Eventually the moons collide, with one extra-massive moon emerging after a period during which Earth sports a Saturn-like ring. This and nine and other speculative essays provide us with insights into the Earth as it exists today, while shedding new light on the burgeoning search for life on planets orbiting other stars. Appealing to adult and young adult alike, this book is a fascinating journey through physics and astronomy, and follows on the author's previous bestseller, What if the Moon Didn't Exist?, with completely new scenarios backed by the latest astronomical research.

An astonishing exploration of planet formation and the origins of life by one of the world’s most innovative planetary geologists. In 1959, the Soviet probe Luna 3 took the first photos of the far side of the moon. Even in their poor resolution, the images stunned scientists: the far side is an enormous mountainous expanse, not the vast lava-plains seen from Earth. Subsequent missions have confirmed this in much greater detail. How could this be, and what might it tell us about our own place in the universe? As it turns out, quite a lot. Fourteen billion years ago, the universe exploded into being, creating galaxies and stars. Planets formed out of the leftover dust and gas that coalesced into larger and larger bodies orbiting around each star. In a sort of heavenly survival of the fittest, planetary bodies smashed into each other until solar systems emerged. Curiously, instead of being relatively similar in terms of composition, the planets in our solar system, and the comets, asteroids, satellites and rings, are bewitchingly distinct. So, too, the halves of our moon. In When the Earth Had Two Moons, esteemed planetary geologist Erik Asphaug takes us on an exhilarating tour through the farthest reaches of time and our galaxy to find out why. Beautifully written and provocatively argued, When the Earth Had Two Moons is not only a mind-blowing astronomical tour but a profound inquiry into the nature of life here—and billions of miles from home.

Demonstrates how ten hypothetical situations would affect our planet and life on it. Topics include: what if the moon didn't exist, what if earth were tilted like Uranus, what if a black hole passed through earth, and so on.

An astronomer and author explores ten examples of what Earth would be like if conditions in the universe were slightly altered, in a fascinating journey into scientific scenarios.

What if Earth had several moons or massive rings like Saturn? What if the Sun were but one star in a double-star or triple-star system? What if Earth were the only planet circling the Sun? These and other imaginative scenarios are the subject of Arthur Upgren's inventive book Many Skies: Alternative Histories of the Sun, Moon, Planets, and Stars. Although the night sky as we know it seems eternal and inevitable, Upgren reminds us that, just as easily, it could have been very different. Had the solar sytem happened to be in the midst of a star cluster, we might have many more bright stars in the sky. Yet had it been located beyond the edge of the Milky Way galaxy, we might have no stars at all. If Venus or Mars had a moon as large as ours, we would be able to view it easily with the unaided eye. Given these or other alternative skies, what might Ptolemy or Copernicus have concluded about the center of the solar sytem and the Sun? This book not only examines the changes in science that these alternative solar, stellar, and galactic arrangements would have brought, it also explores the different theologies, astrologies, and methods of tracking time that would have developed to reflect them. Our perception of our surroundings, the number of gods we worship, the symbols we use in art and literature, even the way we form nations and empires are all closely tied to our particular (and accidental) placement in the universe. Many Skies, however, is not merely a fanciful play on what might have been. Upgren also explores the actual ways that human interferences such as light pollution are changing the night sky. Our atmosphere, he warns, will appear very different if we have belt of debris circling the globe and blotting out the stars, as will happen if advertisers one day pollute space with brilliant satellites displaying their products. From fanciful to foreboding, the scenarios in Many Skies will both delight and inspire reflection, reminding us that ours is but one of many worldviews based on our experience of a universe that is as much a product of accident as it is of intention.

Contains 250 questions and answers about astronomy, particular for the amateur astronomer.

Advance praise for Philip Plait s Bad Astronomy "Bad Astronomy is just plain good! Philip Plait clears up everymisconception on astronomy and space you never knew you sufferedfrom." --Stephen Maran, Author of Astronomy for Dummies and editorof The Astronomy and Astrophysics Encyclopedia "Thank the cosmos for the bundle of star stuff named Philip Plait,who is the world s leading consumer advocate for quality science inspace and on Earth. This important contribution to science willrest firmly on my reference library shelf, ready for easy accessthe next time an astrologer calls." --Dr. Michael Shermer,Publisher of Skeptic magazine, monthly columnist for ScientificAmerican, and author of The Borderlands of Science "Philip Plait has given us a readable, erudite, informative,useful, and entertaining book. Bad Astronomy is Good Science. Verygood science..." --James "The Amazing" Randi, President, JamesRandi Educational Foundation, and author of An Encyclopedia ofClaims, Frauds, and Hoaxes of the Occult and Supernatural "Bad Astronomy is a fun read. Plait is wonderfully witty andeducational as he debunks the myths, legends, and 'conspiraciesthat abound in our society. 'The Truth Is Out There' and it's inthis book. I loved it!" --Mike Mullane, Space Shuttle astronaut andauthor of Do Your Ears Pop in Space?

Lunar Abundance is a beautiful and practical guide for today's women on cultivating peace, purpose, and abundance in both their personal and professional lives, guided by the phases of the moon. In a world in which women feel increasingly disconnected-from their inner selves, each other, and the world, Lunar Abundance offers a path to reconnection, with results that you can actually see. It shows how by tuning into the natural rhythm of lunar ebbs and flows, you can connect with work, relationships, your body, and surroundings on a higher level than ever before, becoming more productive and self-aware in the process. Filled with inspirational photography and interactive features, it's also a practical guide to self-care that will help you summon your true potential and create a better life for you and for those in your orbit. This beautiful book is perfect for any woman seeking holistic wellness and unique inspiration to feed mind, body, and soul.

From writer Stacy McAnulty and illustrator Stevie Lewis, Moon! Earth's Best Friend is a light-hearted nonfiction picture book about the formation and history of the moon—told from the perspective of the moon itself. Meet Moon! She's more than just a rock—she’s Earth’s rock, her best friend she can always count on. Moon never turns her back on her friend (literally: she's always facing Earth with the same side!). These two will stick together forever. With characteristic humor and charm, Stacy McAnulty channels the voice of Moon in this next celestial "autobiography" in the Our Universe series. Rich with kid-friendly facts and beautifully brought to life by Stevie Lewis, this is an equally charming and irresistible companion to Earth! My First 4.54 Billion Years and Sun! One in a Billion.

In her own singularly beautiful style, Newbery Medal winner Sharon Creech intricately weaves together two tales, one funny, one bittersweet, to create a heartwarming, compelling, and utterly moving story of love, loss, and the complexity of human emotion. Thirteen-year-old Salamanca Tree Hiddle, proud of her country roots and the "Indian-ness in her blood," travels from Ohio to Idaho with her eccentric grandparents. Along the way, she tells them of the story of Phoebe Winterbottom, who received mysterious messages, who met a "potential lunatic," and whose mother disappeared. As Sal entertains her grandparents with Phoebe's outrageous story, her own story begins to unfold—the story of a thirteen-year-old girl whose only wish is to be reunited with her missing mother.