How do we know how old things are? That’s a straightforward and very scientific question, and exactly the kind of thing students ought to ask; it’s also the kind of question that has been muddled up by lots of bad information (blame the creationists), and can be difficult for a teacher to answer. There are a great many dating methods, and you may need to be a specialist to understand many of them…and heck, I’m a biologist, not a geologist or physicist. I’ve sort of vaguely understood the principles of measuring isotope ratios, but try to pin me down on all the details and I’d have to scurry off and dig through a pile of books.
I understand it better now, though. I’ve been reading Bones, Rocks and Stars : The Science of When Things Happened(amzn/b&n/abe/pwll) by Chris Turney.
It’s a slim volume, written by a specialist specifically for the non-specialist, and it is highly focused on that one question: how do we date objects and events? I consider that a virtue. At the same time that Turney is exploring a subject in depth, he’s also able to keep the discussion general enough that anyone with an interest can read it. That’s also clearly his goal, to make his specialty approachable by the general public.
When I started this book, I was concerned that science wasn’t being effectively communicated. It seemed to me a real danger that society was enjoying the benefits of knowledge without understanding how it was gathered. I still feel this is a very real problem. You often hear folk bemoaning that science is ‘too hard’ or ‘too difficult’. This is a great pity. Science is terribly exciting and I hope that by writing this book, I’ve given a few insights into this exhilaration. Science has a tremendous amount to offer to improve the quality of life for all of us on this piece of rock we call home. The need is an urgent one.
Another pleasant surprise to this liberal-artsy reader is that the book isn’t all about physics. It’s organized in chronological order, sensibly enough, working backward through time and explaining how each progressively older problem is puzzled out. The first chapter is on calendar systems: when a historian has a date from a primary source that uses their calendar, how does she work out when it happened in our calendar, or by relative dating? Let me tell you, if you think science is hard, wait until you see all the special cases and dropped dates and finagled season-fitting and combinations of calendars that historians have to work over. It was a relief when he moved on to the simple clarity of mere geochemistry.
It’s not as if he abandons the wide-ranging approach in subsequent chapters, though. The penultimate chapter is on dating the age of the earth, and there we get a history lesson, discussing Ussher and Hutton and Lyell and Kelvin, before learning about radioactive decay and isotope series.
The final chapter is on creationism, and really, he doesn’t have to work too hard at that point. Everything else in the book has built up so well to documenting the evidence for an old earth that bringing out the young earth creationists is almost an example of comic relief. He neatly dismisses the YEC idea that the speed of light has been changing by pointing out that E=mc2: so “a small change in the speed of light can have a disproportionately large effect on the amount of energy produced from radioactive decay,” and that compressing 13.7 billion years into 6000 would mean so much energy would be released that the earth would be vaporized.
The audience for Bones, Rocks and Stars(amzn/b&n/abe/pwll) is, I think, anyone with an interest in the subject. You do not need a college degree to read the book; you don’t even need to have taken freshman chemistry. The focus is on context and concepts and comprehension, not the nit-picky details, and it is illustrated with concrete examples (When would King Arthur have lived? How old is the Shroud of Turin? When did the Ice Ages occur? How do we date the meteor strike that killed the dinosaurs?) Another key audience, I think, are high school teachers. If you’re teaching earth science or biology, and aren’t already thoroughly comfortable with the principles of geological dating, this book is an excellent survey of the topic. It will definitely help answer those pesky questions the creationists like to poke into kids’ brains in Sunday school, and even better, several of the chapters are outlines of good lesson plans in themselves.
What I like best about the book, though, is that it’s an example of a genre I’d like to see more often. It’s a scientist clearly and simply explaining what he does for a living, at a level that any literate person can understand, and explaining why it is important. That’s not an easy accomplishment.
Thanks – I now know the first thing I’ll use my customary Barnes&Noble gift certificate that I’ll get for Father’s Day on. I may get a second copy for the high-school library….
Keith Douglas says
Sounds like yet another thing I should read. [sigh]
(OT: How do those home glucose meters work?)
PZ Myers says
That is OT!
The test strips have an enzyme embedded in them that reacts with glucose to produce products that change the conductivity or reflectance at specific wavelengths of the blood sample. The meter either shines a light on or runs a current through the sample to get a measure of how much glucose was present.
As a geologist, I’m glad that somebody out there is pointing out our usefulness.
There are a great many dating methods, and you may need to be a specialist to understand many of them
LOL. Is this why I can’t get past second base?
Am I missing something here. Both amazon and bn seem to indicate the book isn’t out yet. Where can I get it from?
PZ Myers says
It isn’t out yet — a few more weeks, though.
I’m just special, and the author sent me an advance copy.
I’ve been beating myself senseless against a brick wall on the Crosswalk forums trying to convince a couple of people that these so-simple-that-any-idiot-can-understand dating methods (varves, tree rings, coral deposits, radiocarbon dating, et al) conclusively prove that the Earth is at least much older than 6,000 years.
Doesn’t work. They can’t argue against the logic so they go running to Answers In Genesis and faithfully trot out the “well, it all depends upon your presuppositions–old Earth or the Bible–so my interpretation could be just as easily be right”. They swallow the dishonest AIG line than if you can cast the smallest amount of doubt on something, then it cannot be trusted.
These people have been innoculated against the truth (ironically by something they think of as “Truth”). I swear, if we ever invent a time machine, I’m going to hunt these people down and drag them all kicking and screaming into the dark and distant past.
Thanks PZ, this is one High School Bio Teach that will buy and read this book; and it will be on my desk should any student want to read it as well.
“He neatly dismisses the YEC idea that the speed of light has been changing by pointing out that E=mc2: so “a small change in the speed of light can have a disproportionately large effect on the amount of energy produced from radioactive decay,” and that compressing 13.7 billion years into 6000 would mean so much energy would be released that the earth would be vaporized.”
Yeah, this one I’ve never gotten. The only way for the “radioactive-dating assumes a constant rate but it could have been much much faster” to work is if so much radiation was at one time shooting out of nearly every rock formation that it would be like a constant stream of shotgun blasts from every direction, everywhere. And yet, that wouldn’t leave any evidence?
It’s the same thing with the idea that maybe the continents moved really fast. Think about the amount of energy that would be required to make them move that faster (in the order of miles per year) and what that would do to the surface of the earth and everything on it. Heck, we have devastating earthquakes when they move just a TINY bit faster than their usual glacial pace, which is often less than a centimeter a year at the fastest.
Thanks PZ! I also really like books like that, I’ll have to get my hands on it. The non-fiction section of my bookshelves at home includes several examples of the type, including another one with a good discussion of one particular dating method: deep ice cores from big, old glaciers.
Alley, Richard B. “The Two-Mile Time Machine” Princeton University Press, Princeton, New Jersey.
And, it seems to be on sale at Amazon: http://www.amazon.com/gp/product/0691102961/qid=1147709766/sr=1-1/ref=sr_1_1/102-8707699-1890519?s=books&v=glance&n=283155
Plunge, been there, done that. The response: “Well obviously, God would have protected the Earth from such deadly heat and radiation.” Doh!
When they say that I simply tell them that I’m not going to argue miracles with them so long as they don’t claim them to be part of science.
So… you get free stuff ahead of time? Man, am I jealous.
Doesn’t work. They can’t argue against the logic so they go running to Answers In Genesis and faithfully trot out the “well, it all depends upon your presuppositions–old Earth or the Bible–so my interpretation could be just as easily be right”.
It’s really amazing how post-modernism was embraced by the religious right.
Definitely getting this book. But curse you, PZ, for igniting the desire to have it before it is available. Buddhists are right; desire is the source of suffering…
Ed Darrell says
Plunge, you’ll never convince them.
But just for fun, and to drag along any honest observers with you, do some homework, and then innocently ask what these guys know about Jericho. Get them involved in a discussion of the archaeological digs at that site, and what occurred when. Let them introduce the discussion on whether the walls at Jericho fell at a time propitious to the Bible’s explanation of Joshua’s assault, and don’t make too much of it — just get them introduced to the idea that archaeologists know what they’re talking about with regard to Jericho, and that all scholars accept their conclusions (except the really dishonest non-scholars, like Kent Hovind).
Then, at some point, note that Jericho is 800 feet below sea level, and ask about the evidence for a flood of Noachic proportions at the site.
There is no evidence of any flood there. Certainly, at 800 feet below sea level, that site would have been flooded had there been a Noachic flood.
And make sure in your homework that you find the stuff that shows the site has been continuously inhabited for 12,000 to 15,000 years.
Let them draw their own conclusions. Like I say, you won’t persuade any of the hard-core know-nothings, but others will come along.
TorbjÃ¶rn Larsson says
“”There are a great many dating methods, and you may need to be a specialist to understand many of them”
LOL. Is this why I can’t get past second base?”
That is easy if you remember that you have to collect the active (or “hot”) samples.
“I swear, if we ever invent a time machine, I’m going to hunt these people down and drag them all kicking and screaming into the dark and distant past.”
So like me, you want to go medieval on them?!
I initially misread the title as “Bones and Rocks Stars.” When I saw the first line, “How do we know how old things are?” I immediately thought of the Rolling Stones. What dating method would be appropriate for them? Radiocarbon? Counting rings?
I’m adding this book the the long list of “Must Buy” books.
To make up for seducing me into getting Bones, Rocks and Stars, have you got anything bad to say to keep me from getting ‘Life on a Young Planet: The First Three Billion Years of Evolution on Earth’ by Andrew Knoll?
PZ Myers says
I haven’t read Knoll, curse you. Now I’m going to have to!
Andrew Wade says
‘Life on a Young Planet’ is definitely recommended reading. The chapter about the origin of eukaryotes is great.
shane h says
…discussing Ussher and Hutton and Lyell and Kelvin… The Celts have must have a on obsession with the age of the universe: Two Irishmen and two Scots!
Corey P says
While I agree that you will probably never convince most creationists of their error, there are some that actually desire their beliefs to resemble reality and are just on the wrong side of the issue due to ignorance. I know because I was in this latter categoy. I had decided I wanted to study up on creationism so I could defend my faith to the educated types, however I found creationism was not based on science and I could not use it for this purpose with a clear concience. After further reading and consideration I no longer believe in a young earth or the flood or special creation. While I don’t believe it to be a necessary conclusion for someone who rejects creationism, for me personally it has taken my faith to the edge of extinction (I’m not saying that is good or bad, it just is). It’s not easy to overcome beliefs that have been fed to you since childhood, but in the end I will choose truth and honest investigation over deceit and propaganda. It is clear, concise, science books (like this one appears to be) that make the science understandable to someone without a degree that I believe are most effective in convincing people of the truth.