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Goddard Space Flight Center, Greenbelt, Maryland 20771

ENGINEERING COLLOQUIUM

Monday, April 4, 2005 / 3:30 PM, Building 3 Auditorium

Dana Mackenzie

"The Big Splat, or How Our Moon Came to Be"

ABSTRACT -- When the Apollo astronauts went to the Moon from 1969 to 1972, one of their objectives was to discover how the Moon was created, and in particular to decide among three principal theories (the fission theory, the capture theory, and the co-accretion theory). What no one expected was that the Moon rocks would point towards a fourth answer -- none of the above! In the lecture, Dr. Mackenzie will discuss the history of the theories of the Moon's origins, the ways in which all three of the pre-Apollo theories failed to pass physical tests, and how a fourth theory -- the giant impact theory -- has superseded them. The giant impact theory, in which the Moon was formed in the aftermath of a collision between Earth and a Mars-sized planet named Theia, fits in very well with our current understanding of the dynamics of the early solar system, which was a much more chaotic place than the theorists of previous generations realized.

At the end of the lecture, Dr. Mackenzie will talk about our "unfinished business" on the Moon, which could be on the agenda for further manned exploration as part of the Moon, Mars and Beyond initiative.

SPEAKER -- Dana Mackenzie is a science writer based in Santa Cruz, California. He received a doctorate in mathematics from Princeton University, and taught for thirteen years at Duke University and Kenyon College before heeding a friend's advice to "think about what you wanted to do as a child, and try to make that happen." That was easy -- as a child, he always wanted to be a writer. After learning the ropes of journalism in the Science Communication Program at the University of California at Santa Cruz, he has been a free-lance writer for nearly eight years. His articles have appeared in Science, New Scientist, Discover, and Smithsonian. The Big Splat, or How Our Moon Came to Be, published by John Wiley & Sons, is his first book.




Engineering Colloquium home page: https://ecolloq.gsfc.nasa.gov