New York Times Bestseller | Wall Street Journal Bestseller | Publishers Weekly Bestseller | Publishers Marketplace 2020 Buzz Book | Amazon Best Book of the Year | Longlisted for the 2022 PEN/E.O. Wilson Literary Science Writing Award Harvard's top astronomer lays out his controversial theory that our solar system was recently visited by advanced alien technology from a distant star. "Provocative and thrilling ... Loeb asks us to think big and to expect the unexpected."--Alan Lightman, New York Times bestselling author of Einstein's Dreams and Searching for Stars on an Island in Maine In late 2017, scientists at a Hawaiian observatory glimpsed an object soaring through our inner solar system, moving so quickly that it could only have come from another star. Avi Loeb, Harvard's top astronomer, showed it was not an asteroid; it was moving too fast along a strange orbit, and left no trail of gas or debris in its wake. There was only one conceivable explanation: the object was a piece of advanced technology created by a distant alien civilization. In Extraterrestrial, Loeb takes readers inside the thrilling story of the first interstellar visitor to be spotted in our solar system. He outlines his controversial theory and its profound implications: for science, for religion, and for the future of our species and our planet. A mind-bending journey through the furthest reaches of science, space-time, and the human imagination, Extraterrestrial challenges readers to aim for the stars--and to think critically about what's out there, no matter how strange it seems.

"The world's leading alien hunter" -- New York Times Magazine From acclaimed Harvard astrophysicist and bestselling author of Extraterrestrial comes a mind-expanding new book explaining why becoming an interstellar species is imperative for humanity's survival and detailing a game plan for how we can settle among the stars. In the New York Times bestseller Extraterrestrial, Avi Loeb, the longest serving Chair of Harvard's Astronomy Department, presented a theory that shook the scientific community: our solar system, Loeb claimed, had likely been visited by a piece of advanced alien technology from a distant star. This provocative and persuasive argument opened millions of minds internationally to the vast possibilities of our universe and the existence of intelligent life beyond Earth. But a crucial question remained: now that we are aware of the existence of extraterrestrial life, what do we do next? How do we prepare ourselves for interaction with interstellar extraterrestrial civilization? How can our species become interstellar? Now Loeb tackles these questions in a revelatory, powerful call to arms that reimagines the idea of contact with extraterrestrial civilizations. Dismantling our science-fiction fueled visions of a human and alien life encounter, Interstellar provides a realistic and practical blueprint for how such an interaction might actually occur, resetting our cultural understanding and expectation of what it means to identify an extraterrestrial object. From awe-inspiring searches for extraterrestrial technology, to the heated debate of the existence of Unidentified Aerial Phenomena, Loeb provides a thrilling, front-row view of the monumental progress in science and technology currently preparing us for contact. He also lays out the profound implications of becoming--or not becoming--interstellar; in an urgent, eloquent appeal for more proactive engagement with the world beyond ours, he powerfully contends why we must seek out other life forms, and in the process, choose who and what we are within the universe. Combining cutting edge science, physics, and philosophy, Interstellar revolutionizes the approach to our search for extraterrestrial life and our preparation for its discovery. In this eye-opening, necessary look at our future, Avi Loeb artfully and expertly raises some of the most important questions facing us as humans, and proves, once again, that scientific curiosity is the key to our survival.

David Lasser stands as one of the least-known but extraordinary pioneers of spaceflight. In 1930 he founded the American Interplanetary Society (AIAA) -- the same year he wrote this book -- the first book ever written in the English language to address the notion of spaceflight as a serious possibility. The book has not been in print since 1931 and yet it still stands up to scrutiny. The lucid style with which Lasser explains the basic concepts of rocketry make it a delight for anyone to read.

This volume explains the dramatic effect of cross-correlations in forming the structural response of aircraft in turbulent excitation, ships in rough seas, cars on irregular roads, and other dynamic regimes. It brings into sharp focus the dramatic effect of cross correlations often neglected due to the analytical difficulty of their evaluation. Veteran author Professor Isaac Elishakoff illustrates how neglect of cross correlations could result in underestimation of the response by tens or hundreds of percentages the effect of the random vibrations of structures' main elements, including beams, plates, and shells. Clarifies the common misconception that natural frequencies of structures are well apart from each other; Illustrates that the interaction of associated modes in plates can dramatically alter the random response due to presence of coinciding frequencies; Demonstrates that natural frequencies in beams on elastic foundation, as well as cylindrical or spherical shells, might cluster together resulting in substantial percentage error if cross-correlations are ignored.