Although researchers have determined the ages of rocks from other planetary bodies, the actual experiments -- like analyzing meteorites and moon rocks -- have always been done on Earth. Now, for the first time, researchers have successfully determined the age of a Martian rock -- with experiments performed on Mars. The work, led by geochemist Ken Farley of the California Institute of Technology Caltech , could not only help in understanding the geologic history of Mars but also aid in the search for evidence of ancient life on the planet. However, shortly before the rover left Earth in , NASA's participating scientist program asked researchers from all over the world to submit new ideas for experiments that could be performed with the MSL's already-designed instruments. Farley, W.
(K/Ar) Potassium Argon Dating Techniques I
Comparisons between the observed abundance of certain naturally occurring radioactive isotopes and their decay products, using known decay rates, can be used to measure timescales ranging from before the birth of the Earth to the present. For example measuring the ratio of stable and radioactive isotopes in meteorites can give us information on their history and provenance. Radiometric dating techiques were pioneered by Bertram Boltwood in , when he was the first to establish the age of rocks by measuring the decay products of the uranium to lead. Carbon is the basic building block of organic compounds and is therefore an essential part of life on earth.
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In this section we will explore the use of carbon dating to determine the age of fossil remains. Carbon is a key element in biologically important molecules. During the lifetime of an organism, carbon is brought into the cell from the environment in the form of either carbon dioxide or carbon-based food molecules such as glucose; then used to build biologically important molecules such as sugars, proteins, fats, and nucleic acids.
Absolute dating is the process of determining a specific date for an archaeological or palaeontological site or artifact. Some archaeologists prefer the terms chronometric or calendar dating, as use of the word "absolute" implies a certainty and precision that is rarely possible in archaeology. Absolute dating is usually based on the physical or chemical properties of the materials of artifacts, buildings, or other items that have been modified by humans. Absolute dates do not necessarily tell us when a particular cultural event happened, but when taken as part of the overall archaeological record they are invaluable in constructing a more specific sequence of events.