An analysis of the irregular rotation of the Earth and the geophysical mechanisms responsible for it.

This book is intended for geophysicists, astronomers (especially those with an interest in history), historians and orientalists. The culmination of many years of research, it discusses, in depth, ancient and medieval eclipse observations and their importance in studying Earth's past rotation. This was the first major book on this subject to appear in the last twenty years. The author has specialised in the interpretation of early astronomical records and their application to problems in modern astronomy for many years. The book contains an in-depth discussion of numerous eclipse records from Babylon, China, Europe and the Arab lands. Translations of almost every record studied are given. It is shown that although tides play a dominant long-term role in producing variations in Earth's rate of rotation - causing a gradual increase in the length of the day - there are significant, and variable non-tidal changes in opposition to the main trend.

Long before Galileo published his discoveries about Jupiter, lunar craters, and the Milky Way in the Starry Messenger in 1610, people were fascinated with the planets and stars around them. That interest continues today, and scientists are making new discoveries at an astounding rate. Ancient lake beds on Mars, robotic spacecraft missions, and new definitions of planets now dominate the news. How can you take it all in? Start with the new Encyclopedia of the Solar System, Second Edition.This self-contained reference follows the trail blazed by the bestselling first edition. It provides a framework for understanding the origin and evolution of the solar system, historical discoveries, and details about planetary bodies and how they interact—and has jumped light years ahead in terms of new information and visual impact. Offering more than 50% new material, the Encyclopedia includes the latest explorations and observations, hundreds of new color digital images and illustrations, and more than 1,000 pages. It stands alone as the definitive work in this field, and will serve as a modern messenger of scientific discovery and provide a look into the future of our solar system.· Forty-seven chapters from 75+ eminent authors review fundamental topics as well as new models, theories, and discussions· Each entry is detailed and scientifically rigorous, yet accessible to undergraduate students and amateur astronomers· More than 700 full-color digital images and diagrams from current space missions and observatories amplify the chapters· Thematic chapters provide up-to-date coverage, including a discussion on the new International Astronomical Union (IAU) vote on the definition of a planet· Information is easily accessible with numerous cross-references and a full glossary and index

Each book in 8143--TIME For Kids Nonfiction Readers: Fluent Plus Kit is available in a set of six.For add-on purchases, each 6-pack includes 6 copies of this title and a lesson plan, packaged in a self-sealing vinyl bag.Word Count: 1147TCM (Teacher Created Materials) Level: 3.6Guided Reading Level: PEarly Intervention Level: 22DRA (Developmental Reading Assessment) Level: 38

Here are teacher demonstrations, student hands-on activities, and student journals, plus a two-sided poster in each book that presents information on one side, and a learning game on the other. It is science education at its best, balancing process and content.

The family from Secrets of the Garden are back in a new book about backyard science that explains why the seasons change. Alice and her friend Zack explore the reasons for the seasons. Alice's narrative is all about noticing the changes as fall turns into winter, spring, and then summer. She explains how the earth's yearlong journey around the sun, combined with the tilt in the earth's axis, makes the seasons happen. Alice's text is clear and simple, and experiential. Two very helpful—and very funny—chickens give more science details and further explanation through charts, diagrams, and sidebars. Packed with sensory details, humor, and solid science, this book makes a complicated concept completely clear for young readers—and also for the many parents who struggle to answer their kids' questions! "Several adults of my acquaintance . . . would find Secrets of the Seasons to be an eye-popping revelation." —John Lithgow, The New York Times Book Review

This accessible reference presents the evolution of concepts of time and methods of time keeping, for historians, scientists, engineers, and educators. The second edition has been updated throughout to describe twentieth- and twenty-first-century advances, progress in devices, time and cosmology, the redefinition of SI units, and the future of UTC.