The Big Splat, or How Our Moon Came to Be

by Dana Mackenzie

Book Overview

The first popular book to explain the dramatic theory behind the Moon's genesis This lively science history relates one of the great recent breakthroughs in planetary astronomy-a successful theory of the birth of the Moon. Science journalist Dana Mackenzie traces the evolution of this theory, one little known outside the scientific community: a Mars-sized object collided with Earth some four billion years ago, and the remains of this colossal explosion-the...

• Format: Hardcover
• Language: English
• ISBN: 0471150576
• ISBN13: 9780471150572
• Release Date: March 2003
• Publisher: Wiley (TP)
• Length: 240 Pages
• Weight: 1.16 lbs.
• Dimensions: 0.9" x 6.3" x 9.3"

Customer Reviews

Excellent Account of a Complex Scientific Story of Lunar Origins

If there is one dramatic moment--as opposed to myriad important but mundane events--in the history of lunar science it is the 1984 conference in Kona, Hawaii, in which scientists around the world presented papers on the sole topic of how the Moon originated. What made this conference so remarkable, however, was that a new consensus on the subject emerged through this process of presentation and discussion. Usually, positions are well known prior to any scientific meeting and few scientists change their minds right away. As the author of this outstanding popular history phrased it, "other specialists have to go home and process the new information. Old theories have to be sifted through and reappraised. More papers come out in favor of the new hypothesis, and others come out against it. Eventually, sometimes after many years, a new consensus emerges" (p. 167). Not so at Kona. The consensus on the origins of the Moon that came about there has enjoyed remarkable exceptional staying power since. "The Big Splat: Or How Our Moon Came to Be" by Dana Mackenzie is a concise and exceptionally readable account of how a significant but divisive scientific question came to be settled through the investigation of the Moon made possible by sending human and robotic missions there in the 1960s and 1970s. The Kona conference established a consensus in favor of a theory of origins known as the "big whack," or "big splat." Two scientists working independently, William Hartmann and Alastair Cameron, first advanced the theory in 1974 that the Moon had been formed by debris from a massive collision with the Earth about 4.6 billion years ago. This theory was predicated on the study of lunar rock and soil samples returned from the Moon by the Apollo astronauts, and over the course of the next decade further analysis allowed scientists to resolve most of the questions plaguing other theories of lunar origin by applying the "big splat" hypothesis. So contentious had the question of lunar origins been prior to the Apollo program, as Mackenzie shows, that many scientists just threw up their hands in frustration at ever being able to develop a reasonable hypothesis. Confusion ruled among scientists about the Moon's origin as competing schools battled among themselves for dominance of their particular viewpoint in the textbooks. Indeed, some expressed concern that determining the Moon's origins should be the single most significant scientific objective of Project Apollo, thinking of it as a hopeless objective. Their concern was legitimate based on what had gone before. Prior to the Apollo missions the origin of the Moon had been a subject of considerable scientific debate and careers had risen and fallen on championing one or another theory. Prior to the 1960s there had been three principal theories: 1. Co-accretion--a theory which asserted that the Moon and the Earth formed at the same time from the Solar Nebula. 2. Fission--a theory that asserted that the Moon split off

Moonies, meteors and tidal mechanics

There's no greater reading pleasure than good science writing. By combining ingredients from history, stirring in good data, adding some spice of characterisation, a recipe of adventure and inquiry becomes a delicious result. Dana Mackenzie has produced a confection suited to any reader's taste in this account of thinking about our neighbour in space. Tracing the history of thought on our satellite, he travels down the centuries to reach an earth-shaking conclusion.It's difficult today to view the Moon as the ancients did. Once, it was considered a disc. Even whether its light came from the sun or originated from the lunar surface was disputed. The nature of the markings, Mackenzie explains, was equally contentious. The dark areas were finally deemed "seas" and the Latin "maria" remains with us today. After Galileo determined the moon was cratered, the origins of these enigmatic forms opened new discussion. Volcanoes held sway as their origin, although no Earth vulcanism had produced caldera of such size. Meteor impact was viewed with suspicion in an age when catastrophic events were looked on with cautious scorn. The moon's effect on the oceans was realised in ancient times, brought strongly to further awareness as Europe sent ships to far shores. Tidal predictability became a normal calculation, but much about tidal forces remained mysterious, Mackenzie reminds us. Examining tidal action would help lay the foundation for the most likely mechanism of the Moon's formation.Although Mackenzie introduces us to many thinkers on the lunar phenomenon, the key figure is Ralph Baldwin. In the midst of growing debate about the lunar craters, Baldwin had the temerity to suggest that one impact had formed a significant part of the lunar surface. The debate was resolved, of course, by the Apollo landings. Among the rocky souvenirs brought back from those explorations were some green, glassy samples. These objects can only be formed by high speed impact of solid bodies. Deep in the past, The Moon had bombarded by meteors. Some of the bolides had been large, and their origin remained in question. One object had far greater impact than anything the lunar surface implies. It was the body that had led to the formation of the Moon itself. Mackenzie's "great splat" is the analysis of lunar material that revealed the Moon is made up of Earth-like surface material. The Moon doesn't have the iron core typical of rocky planets. The reason for this is that the Moon didn't co-form when the Earth did. The Moon was the result of a Mars-size planetoid striking the Earth shortly after its formation. The impact drove a mass of material into space which coalesced to form our satellite.Mackenzie's lively account is an excellent read and highly informative. He deals ably with some tough questions and cantankerous characters. Scientific dispute is often entertaining, particularly when the reader has little stake in the outcome. Yet, anything that advan

Fascinating!

In this fascinating book, author and scientist Dr. Dana Mackenzie traces man's "scientific" study of the Moon from the Greek philosopher Anaxagoras, through the Pythagoreans, Aristotle, Kepler, Newton, and on to the present. Along the way, you get to see the flowering of modern science, and how advances helped and hindered the various explanations for how the Moon came into being. In the final chapters, the author examines the newest theory, and that is that the Moon was created by a collision between the Earth and another planet (which some have tentatively named Theia).This is a book that really exercises the mind. It is highly informative, and brings the reader right up-to-date on the latest thinking on the nature and origin of the Moon. If you are at all interested in the Moon or the history of our solar system, then I highly recommend that you get this book.As an added bonus, the book has an appendix that seeks to refute the theory that the lunar landings were merely a hoax, perpetrated by NASA. Overall, I thought that this was a well-written piece, but feel that anyone who believes in such a conspiracy theory probably wouldn't read this book anyway. That said, it gives you an interesting little thing to read when done with the book.

Highly recommended

While the Apollo astronauts collected rocks from the lunar surface, their mentors on Earth debate whether the moon originated as the Earth's `daughter', `sister' or `spouse' - each of which theories had its eminent advocates, its good points and its faults. At first, it seemed that the moonrocks had not resolved the issue, but in the mid-1980s, out of left field, came the `giant impact' theory (the Big Splat of Mackenzie's title) which combined all the good points of the earlier theories without their faults. If you wish to know how scientists came to realise how the moon formed, then this delightful and eminently readable book is for you.

A wonderful book about the moon and its genesis

Dana Mackenzie has created that rare combination of a book both consistently entertaining and scientifically excellent. His theme is the evolution of theories about the origins of the moon. He sweeps the reader from Anaxagoras and Pythagoras to Newton to modern times. Explanation of the moon's creation was only recently made possible in part through powerful computer modeling and the Apollo space program's physical recovery and analysis of moon rocks. The story is fascinating and enlivened throughout by scientific mini-biographies, pithy discussions about the history of astronomy, and highly intelligent explanations of relevant principles of geology, celestial mechanics, physics, chemistry, and related sciences. The "Big Splat" refers to the overwhelming event which much evidence indicates really did create the moon - the oblique collision of another planet (the impactor) with the earth over 4 billion years ago, shortly after the genesis of the solar system. The evidence in support of this interpretation is compellingly presented, and the event itself summarized clearly and dramatically. Those interested in science, astronomy, and the history of thought should place this book high on their reading list. It is hard to put down until finished. After reading this volume, few of us will ever again look at the moon without greater interest, understanding, and awe.