In public debate, much noise is sometimes made about the inherent uncertainty of scientific conclusions. For decades, creationists have bleated about the potential for error using dating methods based upon the radioactive decay of carbon-14.

More recently, climate change deniers have used the uncertainty inherent in the work of the U.N. Intergovernmental Panel on Climate Change to confuse, and sometimes mislead, the general public.

The Age of Everything provides an explanation of some of the important ways that scientists are able to establish the age of objects, from archaeological artefacts to the universe itself. Hedman's account of carbon-14 dating makes it clear that researchers are usually far more aware than their critics of error margins and uncertainties in their measurements and methods.

There are numerous potential sources of error using radioactive dating, usually because of contamination of samples from outside sources. Scientists are aware of these issues and as a result of careful analysis they can often provide corrections to otherwise inaccurate results.

Other isotopes besides carbon-14 can also be used for radioactive dating including those of potassium, rubidium, magnesium and thorium. Each has its own characteristics, which determine the timescale that it can acccurately measure and the circumstances in which it can be used.

In biology, the rate of mutation of genetic DNA can be used to estimate timescales. As with radioactive dating, there are influences that can decrease the accuracy of results obtained with this method. Scientists have studied these influences closely and are often able to compensate for their effects.

Other methods of dating include measuring the age of stars by determining their place in the 'main sequence' that describes the evolution of most stars, establishing the age of distant galaxies by measuring their electromagnetic redshift and dating the entire universe by studying the cosmic microwave background radiation.

The Age of Everything is informative, well written and easy to read. The ingenuity of those who have uncovered ways to figure out the age of things is clear. This book should be compulsory reading for anyone
wishing to publicly comment on the uncertainties of scientific measurements and methods.