Customer Reviews

The Age of the Earth

5 star:		(8)
4 star:		(2)
3 star:		(2)
2 star:		(0)
1 star:		(2)

 

 

Chapters 1 to 3 were great. I'm a mathematician myself, but I do think Dalrymple presented the math simply enough that most readers can understand or just skip it without serious damage. The "isochron" methods depict the solution of complex problems in comparatively simple graphical terms, and the underlying radiochemistry is clear enough, although the details are beyond a non-specialist (as they should be).

Chapter 4, on the other hand, was far too laden down with terminology. There must be 50 words for different igneous rocks alone, and a neophyte will see no method (or reason) to distinguish between them. I kept wanting to hear verbs to go with the nouns and adjectives. The word "metamorphic" (and various synonyms) appeared a thousand times, with very few clues on what HAPPENED to cause metamorphism. Nevertheless, I was able to learn a great deal, despite these frustrations.

I was fascinated to hear in Chapter 5 that, by 1975, over 30 thousand pages of scientific research had already been published on moon rocks. That's a lot of serious study for 382 kg of rocks -- which is quite a bit more than I thought, at that.

The chief "problem" with the book is also its great virtue. Dozens of radiometric methods and the analysis (in some detail) of hundreds of rocks are discussed, when a few examples would suffice for most readers. This gets very soporific after a while.

But the many, many examples and the exhaustive chronology reveal how imaginative but sometimes wrong researchers have been, and how tirelessly other researchers have triple-checked their work until finding the errors and developing more trustworthy methods. It is also clear that reliable methods have been checked copiously against the results of other methods, until there can be little doubt about the general results. One cannot read this book honestly, I think, and go away believing a few scientists conspired to come up with false answers just to please themselves.

In the Preface, Dalrymple makes the point that geochemists and geophysicists (for example) can barely read each other's specialty literature, despite the close connections. It takes experts in those areas and many others, working together, to seriously evaluate details of the models and results presented in this book.

That being so, it's incredible that so many non-scientists (or sometimes scientists in very unconnected fields) have the unmitigated gall to attack the findings of professionals for any reason, but especially when motivated by their interpretation of the writings of unwashed, uneducated, long-dead "prophets".

It truly boggles the mind.

On one hand, yes I know radiometric dating is a fairly complex topic and perhaps can only be "dumbed-down" so far. I guess I am in the minority opionion compared to the other reviewers, but I didn't feel that that author met his stated goal in his preface - where he stated his intention was to be understandable by anyone with even a rusty knowledge of algerbra. I didn't feel he met this level of clarity, though I understand he tried valiently.

Some of the other reviewers felt that the author was too anti-religion. And I'd agree that the author does ridicule "young-earthers". But if the author was intending to convince young-earthers the error of their ways, I'm not sure he is successful. Frankly, I don't think many young-earthers would be able to follow his discussion of radiometric dating.

I'm not current with what claims young-earthers are currently making to attempt to discredit radiometric dating, but I thought that there were some criticisms that at least superfically seem plausible that perhaps the author could have specifically addressed. Perhaps I'm mistaken on this point - I guess I'd have to ask a young-earther what they think is wrong with radiometric dating.

I'm not saying it is a bad book, it has its good points. And certainly most people with a science background should be able to understand and appreciate it. I'm just not sure you can give it to a young-earther and they'll go, "of course, how silly of me to have thought otherwise!"

Dalrymple presents the overwhelming evidence for the age of the Earth, Moon, and Solar system in such well documented and critical manner, that it leaves NO room for doubt about the validity of radiometric dating. Contrary to young earth creationist's childish ravings, he builds a case that leaves no avenues for any other conclusion. When creationists say you must have read the "relevant" literature, they mean the writings of such people as Morris and Hovind. Unfortunately for them the relevant literature is all referenced in Dalrympl's book and he has done a OUTSTANDING job at simplifying it for both scientist and layperson. He gives sufficient references that anyone who wishes can pursue any topic on their own.

He chronicles the early attempts and a variety of approaches used to date. He goes on to clearly explain how modern radiometric methods work and some of the problems that have been overcome. He then shows the direct evidence for the ages of the Earth from a plethora of independent studies over the past and the consistent, and reliable dates they provide. He then goes on to the dating of the Moon rocks and their concordance with those of the Earth. Next he discusses meteorites, the use of the lead isotope method, the evidence from the distribution of elements in the universe, and finally wraps it up with a chapter on what we know and don't know.

The conclusion after reading this book is undeniable. There is no doubt that the Earth is at least about 4.5 billion years old. This book is a must read for anyone who wants to argue credibly about the age of the Earth.

Dalrymple's book provides a good summary of earlier failed attempts to date the Earth with non-radiometric methods and the later successful development of radiometric dating. The book has a strong emphasis on the dating of Moon rocks and meteorites, which are relatively simple systems. Because the intended audience is laypeople, the book is non-technical and does not discuss complicated situations. For individuals that desire more technical discussions, there are a number of good textbooks and available journals that demonstrate that even complicated rocks may be successfully dated with radiometric methods.

Dalrymple's "Age of the Earth" was a classic when it was published, and now that it is in paperback, it will be more accessible to the general reader or the student. It is simply the best compilation of information on the wide variety of methods that scientists use to determine the age of the Earth. Because the author is a specialist in radiometric dating, there appropriately is much emphasis on this topic. One of the impressive facts to emerge is that several different radiometric methods all converge on the same approximate number for the age of the Earth: surely a persuasive internal control for this conclusion!

Dalrymple writes that he became interested in the need for the public to understand these basic geological ideas when he was called upon in the early 1980's to testify in a trial concerning an Arkansas law requiring "equal time" for evolution and creation "science". Much of the latter consists of arguments that the Earth is young (corresponding to a biblical literalist view of Genesis), but as Dalrymple shows, the view is scientifically unsupportable.

It makes one reflect that the same principles of physics and chemistry -- the nature of matter itself -- that put men and women in space are the same ones that allow us to establish principles like radiometric dating, which is at the heart of the argument that the Earth is about 4.5 billion years old. If geologists like Dalrymple are wrong about the age of the Earth, don't tell those guys up there in the Shuttle!

I had long known that rocks were dated by measuring the levels of radioactive elements and their decay products, but I had also realized that that by itself couldn't determine an age -- how do we know that the rock wasn't created yesterday with the elemental ratios we observe now? Dalrymple describes the methods by which this so-called "initial daughter" problem is solved. He also gives the data for various rocks from the earth, the moon, and meteorites. Anyone who can follow a logical argument and isn't scared off by a few logarithms will finish this book convinced that the earth is, indeed, about 4.5 billion years old. (Or else he must conclude that God is malicious and has done His damnedest to make it *look* as though the earth is that old.)

If you've ever wondered how geologists can confidently state that a rock solidified from lava 1000 times longer ago than any human could have observed, this is the book for you.

I am a Christian, and I have a high view of the Bible. I also have a high view of nature, as it is God's creation. God made the rocks, just as He wrote the Bible. They should both agree. Dalrymple summarizes in this book what the rocks have to say. To ignore this massive and consistent set of data is unreasonable. The only option is to conclude that the days of Genesis are not 24 hours long. (This is not a modern view; Augustine taught it in 400 AD in The Literal Meaning of Genesis.) The book would benefit from some more color graphics and specific responses to creationist arguments such as the notion of apparent age. The author says he wrote it 'for himself'. It might have been better if it were focused on the objections and misconceptions of others.

How old is the Earth? Dalrymple gives the answer, 4.54 billion years, in the Preface. The rest of the book is a patient, thorough, clear, and utterly compelling account of how Science has arrived at this answer. To determine the age of the Earth, one must determine the ages of rocks. The basic idea in dating a rock is to measure the ratio of a radioactive "parent" isotope and a "daughter" isotope the parent decays into. Plug this data into a simple exponential equation, and solve for t. The basic problem with this idea is that in order to write down the correct exponential equation, you need to know how much of the daughter isotope was present when the rock was formed. If there was some daughter isotope present, and you assume there wasn't, your computed age could be far older than the rock's actual age. Intuitively, this seems like an insoluble problem: how could you possibly measure how much daughter isotope was present when a rock was formed billions of years ago? There is a stunningly beautiful variation of the basic idea, called the "isochron method", which can tell you the age of a rock, regardless of how much daughter isotope was present originally! The isochron method also *tells* you how much daughter isotope there was at formation! As if that weren't spectacular enough, the isochron method *also* tells you how reliable your answers are: the closer the data points for a rock are to a straight line, the more confident you can be about the rock's age. The book begins with descriptions of early attempts to find the age of the Earth. Each theory is carefully explained and put in historical context, and the fatal flaws pointed out. Next is a survey of experimental evidence indicating that the radioactive decay rates used in radiometric dating are virtually constant over time. The isochron method is then explained, along with some of its variations. Then comes the real meat of the book: a sampling of how these techniques have been used to date rocks from the Earth, the Moon, and meteorites. Literally hundreds of these computations are discussed (thoroughly referenced to scientific literature, of course). Finally, Dalrymple gives a summary of indirect corroborating evidence. For example, the age of the universe is currently thought to be 10-20 billion years-- a figure which fits nicely with the age of the Earth, but which was arrived at by different scientists, using completely different methods. One thing that struck me repeatedly as I read this book was how fair Dalrymple is. This is clearly a scientist in search of Truth, not a man with an ax to grind. For example, one experiment he discusses arrived at exactly 4.54 billion years as the age of some meteorite; but Dalrymple dismisses that particular computation as unreliable, for various technical reasons. This is quite possibly the single best book I have ever read, period. When I finished, I felt like I was holding a couple of pounds of pure distilled Knowledge. This book is just plain beautiful. Read it.

G. Dalrymple has done a wonderful job in writing such a technical work on the history and direct data for the current estimate of the age of the Earth being 4.5 Billion years old and the Universe being 7 - 20 Billion years old.

The history of chronological methods used to date the earth are documented well from: the use of the Bible Genealogies by Lightfoot and Ussher (which were excellent scholars that even Dalrymple complements because for their time and limited data, they were very rigorous), De Maillet's rate of sea declination after the Noahic Flood, Lord Kelvin's estimate of the age of the sun and the earth by it's cooling rate using Newton's Law of Cooling (Heat Transfer anyone?) and assuming conduction of heat from the Sun, George Darwin's Orbital Estimate of the Age of the Moon, Salt (NaCl and other _Cl's) Accumulation of Oceans, Sediment Accumulation with sample calculations, and finally Radiometric Dating Methods.

The principles and basics of Radiometric Dating Methods are discussed, along with half-lives. Decay rate fluctuations are dealt with and addressed by both "Isochron Method" and "U-Pb Concordia-Discordia Method", and multiple sample calculations, and graphs are given as well. Along with this Dalrymple mentions the Problems, Limits, Difficulties, and Plausible Contradictions via sample impurities (by virtue of tectonic plate shifts, cross contamination, erosion, and stuff that diminishes originality of the original earth core) of relevant dating methods like Rb-Sr Method, Lu-Hf Method, K-Ar Method, Ar-Ar Method, U-Th-Pb Method and others used to date really old substances.

Carbon Dating and other shorter decay rated methods are not discussed in this book at all because of their low half-lives and the absence of any of these isotopes in old sediments renders them irrelevant for the scope of the book.

Finally, Dalrymple discusses and has assembled excellent data tables and Isochron graphs showing results from a good chunk of sources and samples of rock and mineral samples from Earth rocks(the oldest age from earth rocks ever obtained via current dating methods is 3.8-3.9 Billion, after this there is a bit of conjecture that make up for the 600 million to get the 4.5 Billion). Thus, there is no direct empirical evidence from Earth that Earth is 4.5 Billion years old per se, only 3.8-3.9 Billion.

He assembled excellent data tables and graphs showing results from a good chunk of sources and samples of rock and mineral samples from Moon rocks (the oldest age estimates obtained from moon rocks via current dating methods are 4.5 Billion).

He assembled excellent data tables and graphs showing results from a good chunk of sources and samples of rock and mineral samples from Meteorites (the oldest age estimates obtained from meteorites via current dating methods is 4.6 Billion).

He then discusses the two assumptions of claiming the Earth to be 4.5 Billion years old (making up for the 600 million for which there is no empirical support from Earthen rocks or strata):

1) the earth probably had a beginning similar to meteorites (earth's crust contains lead)
2) Single-Stage Model of lead isotope evolution has occurred and is assumed to be relevant to earth's designing.

Finally, he discusses evidences from the universe implying Earth's age and also discusses the age of the universe and the wide discrepancies (7-20 Billion Years is a HUGE discrepancy! Dalrymple discusses why 13.5-16.5 Billion is presumed to best represent the current estimate of the age of the Universe), difficulties, and uncertainties of dating both the actual Universe and the Earth are discussed.

Here are the ALL Chapter Titles and a FEW subsection titles:

1. "Introduction"

2. "Early Attempts: A Variety of Approaches" (I named them at the top of this review. Beginning with Biblical chronologies.)

3. "Modern Radiometric Methods: How They Work" - Is Decay Constant?, Simple Accumulation Clocks, Age-Diagnostic Diagrams, The Accuracy of Radiometric Dating

4. "Earth's Oldest Rocks"- Archean Rocks, North Atlantic Craton, Superior Province, Pilbara Block, The Record and Missing Record

5. "Moon Rocks: Samples From a Sister Planet" - Hypotheses For the Origin of the Moon, The Nature of Moon Rocks, The Geologic History of the Moon, The Ages of the Moon Rocks

6. "Meteorites: Visitors From Space" - Types of Meteorites, Where Do Meteorites Come From?, The Ages of Meteorites, Formation Intervals

7. "Isotopes of Lead: The Hourglass of the Solar System" - The Growth of Lead Isotopes, The Age of the Crust, Patterson and the Meteoritic Lead Isochron, Pb-Pb Ages of Meteorites, The Terrestrial Connection

8. "The Universe and the Elements: The Indirect Evidence"

9. "What We Know and Do Not Know"

Overall, It's very technical and pretty dense. It maybe difficult for people with little chemistry, physics, and algebra, but people should still buy it for the data he assembles. It's pretty objective and he rarely ridicules Young Earthers (which is good since pointless ridicule distracts the reader and may even push them away from really evaluating anything the author claims). He simply stays focused on his goal of providing a complete history of the attempts to age the earth and to document the current evidences, conjectures, and reasons leading some to believe the current estimate of 4.5 Billion years to be the age of the Earth.

Even if some don't believe the earth to be this old, at least the reasons some have used for the 4.5 billion will be brought to light. Ridiculously few scientists can justify this number, by the way. Most scientists believe it without investigating it at all and are essentially just bandwagoning the number since they generally can't even personally muster up one specific piece of evidence that leads to the number 4.5 Billion for Earth and are pretty much clueless as to any particular evidence that contributes to the 13.5 Billion for the Universe. I say this and know this because I have asked many fellow students, scientists, and professors on this at my University and this seems to be true. Not many study in any detail geology since most scientists are not geologists. These numbers are essentially taken for granted.

I am just reporting my experiences here. People should be informed about this research and decide on the reliability of these values for themselves.

(Well... I just lost 33% of positive votes for this review just by being honest and saying the last paragraph)

Bravo for Dalrymple's book! It fills in people on evidences, conjectures, and inferences on the age of the earth.

If anyone wants to read in depth books on radiometric dating methods: how they work, are they trustworthy, and so on, then please read Quaternary Dating Methods and Isotopes: Principles and Applications. A softer version of this book (without calculations and formulas) is Ancient Earth, Ancient Skies: The Age of Earth and its Cosmic Surroundings. This one looks interesting too Radioisotopes and the Age of the Earth: Creationist Research.

I looked and looked for the methods explained and the data summarized in one place that leads scientists to confidence in the age of the earth. This book exceeded my expectations, with in-depth explanations of dating techniques and pages upon pages of actual tables and graphs showing the results of various analyses of moon rocks, meteorites, and earth rocks and minerals from all over the world, as well as lengthy sections on dating the universe and the galaxy.

If you really want the details on why we can be so confident in the age of the earth, or just a good primer on dating techniques in general, this is definitely the book to buy.