Nature's Clocks: How Scientists Measure the Age of Almost Everything

by Doug Macdougall

"Radioactivity is like a clock that never needs adjusting," writes Doug Macdougall. "It would be hard to design a more reliable timekeeper." In Nature's Clocks, Macdougall tells how scientists who were seeking to understand the past arrived at the ingenious techniques they now use to determine the age of objects and organisms. By examining radiocarbon (C-14) dating―the best known of these methods―and several other techniques that geologists use to decode the distant past, Macdougall unwraps the last century's advances, explaining how they reveal the age of our fossil ancestors such as "Lucy," the timing of the dinosaurs' extinction, and the precise ages of tiny mineral grains that date from the beginning of the earth's history. In lively and accessible prose, he describes how the science of geochronology has developed and flourished. Relating these advances through the stories of the scientists themselves―James Hutton, William Smith, Arthur Holmes, Ernest Rutherford, Willard Libby, and Clair Patterson―Macdougall shows how they used ingenuity and inspiration to construct one of modern science's most significant a timescale for the earth's evolution and human prehistory.

Genres: Science, Geology, Nonfiction, History, Earth Sciences, Chemistry, Environment

284 pages, Hardcover

First published May 31, 2008

About the author

Doug Macdougall is a former Professor of Earth Sciences (now Emeritus) at the Scripps Institution of Oceanography, University of California, San Diego. Born in Toronto, he currently resides in Edinburgh, Scotland.

Reviews

[uosɯɐS · Rating 4 out of 5]

Good layman's overview of radiometric dating. Since my degree is in physics (and in fact I did some independent research with a professor who was involved with the radiocarbon dating of The Shroud of Turin), the basic theory of radiometric dating is not new to me. However, the history and detailed fieldwork behind actually dating anything (particularly non-C14 dating techniques) was all new to me.

However, I was disappointed that the scope did not go beyond radiometric dating, since that is the field of dating that was most familiar to me. Pollen grain dating and coral growth dating were also mentioned, but there was no discussion of those techniques. "Molecular clock" dating was not even mentioned.

[Daniel · Rating 5 out of 5]

The philosopher of science Mario Bunge listed several criteria for distinguishing a science from non-science. Among the most important is the steady accretion of knowledge by a science. Doug Macdougall's Nature's Clocks, a work of science history, describes the spectacular accretion of knowledge in geochronology. Macdougall largely sidesteps the conflict between science, with its ability to integrate seemingly unrelated bits of evidence to open a stunningly precise and fruitful window into Earth's actual past, versus religion, with its ancient holy books shown by science to be riddled with error and myth. Sadly, this conflict continues to rage today, with the enemies of science helping to elect America's least qualified President in 2016 - who is now waging war against science from the White House.

Science denial sppears to be easier when a person is unaware of science history. People who do read books such as Macdougall's can do little more than shake their heads in pity at those who, for religious or political reasons, must denounce a whole field of science as untrue. The history of science shows otherwise, as insights in one field continue to raise new questions and drive fruitful new inquiries in other fields, producing real benefits for us all. Macdougall traces the history of feedback that combined findings from physics, chemistry, geology, paleontology, archaeology, and the life sciences (including the forensic science so helpful to the politically conservative fans of law enforcement who deny large swathes of its scientific basis) into the science of geochronology - which in turn helped to revolutionize some of those other fields. One sees the interlocking nature of science playing out over time, as each new unexpected application of an insight in one field to some problem in a seemingly unrelated field adds another data point of confirmation. It's very hard for incorrect ideas to produce the same knowledge snowballing effect. Just as you can't cure illnesses with incorrect ideas about disease, or reach your destination with incorrect ideas about where it is, it's hard to produce useful results in any field when you're wildly off the mark.

Opinion surveys find that about 4 in 10 Americans believe Earth is no more than 10,000 years old. As you read and enjoy this book (Macdougall is a fine writer, who has clearly picked up some elements of creative nonfiction to keep the narrative breezing along), reflect on the many millions of my fellow Americans whose ideological blinders rob them of the same enjoyment - and even worse, cause them to vote for enemies of sound governance.

[Arvind Balasundaram · Rating 5 out of 5]

In Nature's Clocks, author and scientist Doug Macdougall takes his readers through a spellbinding tour of the science and art of geochronology. Tracing the roots of isotope chemistry to the accidental discovery of X-rays by Roentgen, followed by the work on radioactivity by Marie Curie and Henri Becquerel, this book introduces readers to how the science of radioactive dating matured from the popularly recognized carbon-14 to more elements like argon-potassium and zircon, and the use of complex technologies like mass spectrometry. We learn about pioneering researchers such as Willard Libby and Ernie Anderson, who through sheer grit and perseverance, established conclusively that historic radioactive patterns can be reliable predictors of the past. Macdougall does a marvelous job in balancing the science with the adventure, offering a very entertaining and factual read. We learn about the "curve of knowns" that led to firm proof of the principle of radiocarbon dating, and Patterson's famous age of the earth diagram, which first established our planet's age at 4.55 billion years.
Along the way, the author provides a detailed narrative on the many famous applications of radiocarbon technology and understanding - from Egyptian pharaohs, to the Iceman found buried in the snowy Alps, and the conclusive dismissal of the age of the Turin shroud. McDougall explains how our famous, hominid ancestor, Lucy was discovered (which made the Leakeys famous, and initially led scientists to proclaim they were still "dating" Lucy), and clarifies how notable geologic events such as the Santorini eruption and the Pacific Northwest tsunamis caused by the Cascadia subduction zones were firmly dated. When combined with tree ring evidence, sedimentary rock patterns, fossils, earth's magnetic polarity changes, or even zircon material trapped in rock, these insights provide a significantly clearer understanding of times and epochs in Earth's past, whether more recently or far back when the planet itself began. How do we know about the Cambrian explosion when multicellular animals suddenly appear in the geological timescales? Or, the potential causes of sudden, catastrophic events in our planet's history, referred to as the P-T boundary and the K-T boundary, when large animals like the dinosaurs were mysteriously wiped out? Much of this understanding rests on the simple chemistry of radioactive parent and daughter elements in the Periodic Table, with predictable half-lives, and the perseverance of a handful of scientists.
This book is a much-needed contribution for lay readers of science, passionately narrated by a scientist in love with his craft....

[Mark Isaak · Rating 4 out of 5]

Macdougall does an excellent job describing radiometric dating techniques, plus dendrochronology, ice cores, and a few other dating techniques. His telling of their history is particularly well done, but how they work is also described well. Three subjects were omitted that I wanted to see covered: coral clocks (how the length of the month, shorter in the distant past, can be read from fossil corals to give an indication of their age) are not terribly accurate but still interesting and fit well within the subject; isochrons, useful when initial concentrations are unknown, he might have decided are too difficult to explain without math; and varves have been used to extend the C14 calibration curve, but this might have been published after the book was written. The book is not as good as it could have been for lack of these subjects.

[Aadesh · Rating 4 out of 5]

Awesome presentation. First few chapters were breathtaking when the write was narrating about the development of x-rays and how radiation was discovered.
After finishing the book, it struck me so hard that one discovery that we do in a field impacts many others fields in an unexpected way. For example, using the techniques of measuring age, how the frequency of earthquakes were discovered near the pacific region.

Great work!

[Franz · Rating 5 out of 5]

Very well written and highly interesting book.

[Jonas Hadfield · Rating 3 out of 5]

Alot of the information is unecessarily spread out unevenly across the book it really needs to combine important things into a single chapter better

[Peter Tillman · Rating 3 out of 5]

3.5 stars, nice book. Read at Yavapai.

[Alan · Rating 5 out of 5]

We've all certainly read or heard of newspaper or magazine articles describing a new kind of fossil, maybe a dinosaur, and the article almost always includes a reference to the age of that fossil.

If you have ever wondered how scientists determine the ages of things then this is the book for you.

McDougall does a superb job of presenting and discussing the highly technical field of radiometric dating in a way that allows scientists and non-scientists alike to enjoy the ride. MacDougall hooked me in the first chapter...OK...imagine this, hikers are traversing a glacier and they come across what looks like a mummified(?) person with half of its body exposed to the air and the other half frozen into the glacier itself. The hikers don't know what to make of this situation. When the find is described and broadcast paleontologists descend on the site and discover an ancient human frozen into the ice, extremely well preserved, but now partially exposed to the elements. Questions soon arise: Who was this individual? How did s/he become frozen in the ice? When did s/he die? The stage is now set for MacDougall to explain how scientists determine the ages of things.

MacDougall does a masterful job of presenting scientifically complex ideas in clear, concise, and extremely readable prose. Not only that, but he pulls it off in a way that just about anyone can follow along and make sense of what there is to know about radiometric and other methods of determing the absolute ages of things.

I particularly enjoyed the historical context MacDougall provides when he introduces a new topic or method. For example, he starts by describing the discovery of radioactivity and progresses through early relatively inexact dating methods to the much more reliable and precise modern methods used today. And, since this book was publishd in 2008 he is able to include even cutting-edge methods.

The book is of particular interest to me since I teach a college-level course in the nature of science, and course topics include the origin and age of the universe, the origin and age of the earth, and the evolutionary origins of the human body. While I already had a general understanding of radiometric dating, this book opened my eyes to the simplicity and complexity of methods used in the past and today to the work it takes to determine the ages of things.

If you have ever wondered how scientists concluded that the earth is about 4.5 billion years old, or how they determine the ages of rocks, fossils, or pretty much anything else, then this book is for you.

MacDougall amazingly manages to address this topic in a comfortable 238 pp. of text, followed by some appendicies, and a glossary of terms, just in case you need to check something out.

This is a five-star read all the way! As soon as I finished I was sending out emails to colleagues telling them of my lucky find!

Thanks Doug! You've done a brilliant job!

[Brett Stortroen · Rating 5 out of 5]

"Nature's Clocks" covers in depth the history of how scientists discovered the technology of radiocarbon dating for biological carbon based life as well as the various radiometric dating for non-organic matter. The history of these great discoveries and the challenges overcome were quite compelling. In addition, this book lays out the case for the dating techniques and equipment employed in a logical well ordered format. The technical material was easy to follow and presented for the average layman to understand.

The author breaks down the different methods of dating for different age periods and explains in detail why.

Radiocarbon - up to 50,000 years.
Potassium-Argon - 1.25 billion yrs half-life.
Rubidium--Strontium - 48.8 billion years half-life.
Uranium-Lead 238 - 4.47 billion years half-life.
Uranium.Lead 235 - 704 million years half-life.

Even for those who follow a Creationist or Intelligent Design perspective, like myself, the dating techniques described in this book appear quite logical and useful for formulating one's own historical world-view.

I highly recommend this book to anyone interested in history,, paleontology, geology, physics, chemistry, archaeology, biblical studies, and theological studies.

[Sumeet Singh Sumo · Rating 5 out of 5]

For someone who is an earth scientist, he/ she must be familiar with the method of putting almost everything ( rocks, sediments, fossils, features, ice ages ...) on a time scale but it was relative to some reference before. What revolutionised this method was the discovery of x Ray's and then radioactivity, which give absolute ages with some uncertainty which kept on decreasing with time. This book also addresses the ingenuity and diligence of some scientists who painstakinly refined the process making this tool more effective and precise. A good read for someone who is learning isotope geochemistry or just geochronology.

[Craig Jorgensen · Rating 3 out of 5]

The oldest rocks are 4,567.2 million years old. The frozen "iceman" found in the alps is 5,200 years old. We know these timescales (and the ages of almost everything in between) with remarkable accuracy. In my opinion this is an amazing accomplishment of modern science. If you have even the slightest curiosity about how geologists, physicists, chemists, paleontologists and other scientists have figured this out then read this book. Pretty well written and engaging coverage of this subject matter.

[Janie · Rating 3 out of 5]

I gleaned fascinating inklings of chemistry and time-keeping.

Well-known, oft-bandied scientific methods (little "s", little "m"!) that before were fuzzy/magic to I now grasp with a basic understanding -- e.g., carbon14 dating; earthquake predictions.

The writing is engaging. Not too dry, not too sappy.

[Charles Ko · Rating 5 out of 5]

It has a lot of historical backgrounds that are quite enjoyable to read. The author is a geologist, so he has more things to say about it from that perspective than, say nuclear physics. It's probably okay for most readers. Overall, easy and fun to read.

[Tod Landis]

Reading it now and really enjoying it.

[Peter · Rating 4 out of 5]

Though a little obtuse at times, "Nature's Clocks" is a very informative book on the different methods of dating the universe.

[Dr Mona · Rating 4 out of 5]

Who was Lucy, and why is she so important to human evolution? How old was Lucy when she died. Keen?....I encourage you to read this book.

[Genti Mingla · Rating 5 out of 5]

A very informative book.