The study by Edwards, Chen, and Wasserburg presents a method for measuring the abundance of thorium-230 (²³⁰Th) in corals using isotope dilution mass spectrometry, which significantly reduces analytical errors in uranium-238 (²³⁸U)-uranium-234 (²³⁴U)-thorium-230 (²³⁰Th) dating. This technique allows for precise measurements of ²³⁰Th, enabling age determinations of corals over the past 500,000 years. The study shows that 6×10⁸ atoms of ²³⁰Th can be measured with ±30% error, and 2×10¹⁰ atoms with ±2% error. The age uncertainty for corals ranges from ±5 years for a 180-year-old coral to ±1.1 ky for a 123.1 ky-old coral. The study also reports lower ²³²Th concentrations in corals than previously measured, and determines precise ages for corals that grew during high sea level stands around 120 ky ago, supporting the Milankovitch theory of climate change. The study develops techniques for measuring ²³⁴U, ²³⁸U, and ²³²Th in corals, enabling high-precision dating. The results show that the ²³⁰Th/²³⁸U ratio in corals is extremely low, similar to that in seawater. The study also demonstrates that the age of corals can be calculated using the ²³⁸U-²³⁴U-²³⁰Th age equation, which accounts for the initial ²³⁴U/²³⁸U ratio and the decay constants of the isotopes. The study confirms that the ²³⁰Th/²³⁸U ratio in corals is negligible, and that the age of a coral can be determined if the initial ²³⁴U/²³⁸U ratio and the decay constants are known. The study also shows that the age of corals can be resolved with high precision, with differences of 2 ky for corals 120 ky old and 17 years for corals 200 years old. The study concludes that the ²³⁸U-²³⁴U-²³⁰Th systematics are valuable for dating geological materials and understanding the chronology of events in the late Pleistocene and Holocene.The study by Edwards, Chen, and Wasserburg presents a method for measuring the abundance of thorium-230 (²³⁰Th) in corals using isotope dilution mass spectrometry, which significantly reduces analytical errors in uranium-238 (²³⁸U)-uranium-234 (²³⁴U)-thorium-230 (²³⁰Th) dating. This technique allows for precise measurements of ²³⁰Th, enabling age determinations of corals over the past 500,000 years. The study shows that 6×10⁸ atoms of ²³⁰Th can be measured with ±30% error, and 2×10¹⁰ atoms with ±2% error. The age uncertainty for corals ranges from ±5 years for a 180-year-old coral to ±1.1 ky for a 123.1 ky-old coral. The study also reports lower ²³²Th concentrations in corals than previously measured, and determines precise ages for corals that grew during high sea level stands around 120 ky ago, supporting the Milankovitch theory of climate change. The study develops techniques for measuring ²³⁴U, ²³⁸U, and ²³²Th in corals, enabling high-precision dating. The results show that the ²³⁰Th/²³⁸U ratio in corals is extremely low, similar to that in seawater. The study also demonstrates that the age of corals can be calculated using the ²³⁸U-²³⁴U-²³⁰Th age equation, which accounts for the initial ²³⁴U/²³⁸U ratio and the decay constants of the isotopes. The study confirms that the ²³⁰Th/²³⁸U ratio in corals is negligible, and that the age of a coral can be determined if the initial ²³⁴U/²³⁸U ratio and the decay constants are known. The study also shows that the age of corals can be resolved with high precision, with differences of 2 ky for corals 120 ky old and 17 years for corals 200 years old. The study concludes that the ²³⁸U-²³⁴U-²³⁰Th systematics are valuable for dating geological materials and understanding the chronology of events in the late Pleistocene and Holocene.