[DB 1507 (29); OAB 68] The reference given for this claim is literally a single paragraph, without cited references, in the "news digest" section of Chemical and Engineering News (v.49, no.39, p.29 (20 Sept 1971)). The paragraph reports the detection of plutonium-244 in a natural ore sample by a group of American researchers. Noting the relatively short half-life of plutonium-244 (80 million years), the C&EN report wonders about production of plutonium by nuclear processes early in the history of the Solar System. The claim by young-Earth advocates that this report places an 80-million-year limit on the age of the Solar System is flawed in several ways. Firstly, a half-life of 80 Myr is very different from an age limit of 80 Myr. Since radioactive decay is not linear but exponential, small remnants of an element remain even after the half-life has expired many times over. In this case, the amount of plutonium left after 4.5 billion years (4500 Myr) would be about 10⁻¹⁷ of the original sample [to be precise, the calculation is (1/2)^4500/80 = 10⁻¹⁷]. This is an exceedingly small amount, but not too small to detect in a sample that was initially very enriched. Secondly, the young-Earth advocates completely ignored the actual scientific paper referred to in the C&EN news item, which is by D.C. Hoffman et al (Nature, v.234, pp.132-134 (19 Nov 1971)). The very first paragraph of Hoffman's paper makes it clear that the detection of natural plutonium is not a challenge to mainstream cosmology. Calculations based on the abundance of thorium-232, a long-lived radioisotope with similar origins to plutonium-244, indicate that the global abundance of natural plutonium should be extremely low, but just high enough to still be detected in enriched ores. The final section of the paper also discusses at length the plutonium's origin. Indeed, it has become clear in the 30 years since Hoffman's article that natural plutonium is exceedingly rare, if it actually does exists at all. No one has ever duplicated Hoffman's measurement, and no one has ever reported another detection of natural plutonium. Not only does the existence of natural plutonium pose no challenge to an old Earth, it also brings up the question of why, if the young-Earth paradigm is correct, are there no genuine examples of this argument? Plutonium-244 is in the extreme with its short half-life among elements found in nature, and indeed its natural abundance is extremely low. No elements with half-lives shorter than plutonium-244's are found in nature at all, although many are observed in young stars and in man-made particle accelerators. On the other hand, every single known element with a half-lifelonger than plutonium-244's is found in nature. The obvious explanation for this phenomenon is that the Earth has been around long enough for the shorter-lived isotopes to decay away, leaving only the longer-lived ones. However, if the young-Earth hypothesis is correct, then this phenomenon is nothing more than a bizarre coincidence.