Mars is about one-eighth the mass of the Earth and it may provide an analogue of what the Earth was like when it was at such an early stage of accretion. The fur ther growth of the Earth was sustained by major collisions with planetesimals and planets such as that which resulted in the formation ofthe Earth's moon (Hartmann and Davis, 1975; Cameron and Ward, 1976; Wetherill, 1986; Cameron and Benz, 1991). This late accretionary history, which lasted more than 50 Myr in the case of the Earth (Halliday, 2000a, b), appears to have been shorter and less catastrophic in the case of Mars (Harper et ai. , 1995; Lee and Halliday, 1997). In this article we review the basic differences between the bulk composition of Mars and the Earth and the manner in which this plays into our understanding of the timing and mechanisms of accretion and core formation. We highlight some of the evidence for early cessation of major collisional growth on Mars. Finally, we reevaluate the isotopic evidence that Mars differentiated quickly. Fundamental differences between the composition of Mars and that of other terrestrial planets are apparent from the planet's slightly lower density and from the compositions of Martian meteorites. The low density is partially explicable if there is a greater proportion of more volatile elements.

One of Springer’s Major Reference Works, this book gives the reader a truly global perspective. It is the first major reference work in its field. Paleoclimate topics covered in the encyclopedia give the reader the capability to place the observations of recent global warming in the context of longer-term natural climate fluctuations. Significant elements of the encyclopedia include recent developments in paleoclimate modeling, paleo-ocean circulation, as well as the influence of geological processes and biological feedbacks on global climate change. The encyclopedia gives the reader an entry point into the literature on these and many other groundbreaking topics.

In recent years, planetary science has seen a tremendous growth in new knowledge. Deposits of water ice exist at the Moon's poles. Discoveries on the surface of Mars point to an early warm wet climate, and perhaps conditions under which life could have emerged. Liquid methane rain falls on Saturn's moon Titan, creating rivers, lakes, and geologic landscapes with uncanny resemblances to Earth's. Vision and Voyages for Planetary Science in the Decade 2013-2022 surveys the current state of knowledge of the solar system and recommends a suite of planetary science flagship missions for the decade 2013-2022 that could provide a steady stream of important new discoveries about the solar system. Research priorities defined in the report were selected through a rigorous review that included input from five expert panels. NASA's highest priority large mission should be the Mars Astrobiology Explorer Cacher (MAX-C), a mission to Mars that could help determine whether the planet ever supported life and could also help answer questions about its geologic and climatic history. Other projects should include a mission to Jupiter's icy moon Europa and its subsurface ocean, and the Uranus Orbiter and Probe mission to investigate that planet's interior structure, atmosphere, and composition. For medium-size missions, Vision and Voyages for Planetary Science in the Decade 2013-2022 recommends that NASA select two new missions to be included in its New Frontiers program, which explores the solar system with frequent, mid-size spacecraft missions. If NASA cannot stay within budget for any of these proposed flagship projects, it should focus on smaller, less expensive missions first. Vision and Voyages for Planetary Science in the Decade 2013-2022 suggests that the National Science Foundation expand its funding for existing laboratories and establish new facilities as needed. It also recommends that the program enlist the participation of international partners. This report is a vital resource for government agencies supporting space science, the planetary science community, and the public.

A New York Times-bestselling author explains how the physical world shaped the history of our species When we talk about human history, we often focus on great leaders, population forces, and decisive wars. But how has the earth itself determined our destiny? Our planet wobbles, driving changes in climate that forced the transition from nomadism to farming. Mountainous terrain led to the development of democracy in Greece. Atmospheric circulation patterns later on shaped the progression of global exploration, colonization, and trade. Even today, voting behavior in the south-east United States ultimately follows the underlying pattern of 75 million-year-old sediments from an ancient sea. Everywhere is the deep imprint of the planetary on the human. From the cultivation of the first crops to the founding of modern states, Origins reveals the breathtaking impact of the earth beneath our feet on the shape of our human civilizations.

Perminov was the leading designer for Mars and Venus spacecraft at the Soviet Lavochkin design bureau in the early days of Martian exploration. In addition to competing with the U.S. to get to the Moon, the Soviets also struggled to beat the U.S. to Mars during the Cold War. Throughout the 1960s and 1970s, the Soviets attempted to send a number of robotic probes to Mars, but for a variety of reasons, most of these missions ended in failure. Despite these overall failures, the Soviets garnered a great deal of scientific and technical knowledge through these efforts. This monograph tells some fascinating, but little-known, stories.