Age of the Earth research. Most geological samples from Earth are unable to give a direct date of the formation of Earth from the solar nebula because Earth has undergone differentiation into the core, mantle, and crust, and this has then undergone a long history of mixing and unmixing of these sample reservoirs by plate tectonics, weathering and hydrothermal circulation. All of these processes may adversely affect isotopic dating mechanisms because the sample cannot always be assumed to have remained as a closed system, by which it is meant that either the parent or daughter nuclide (a species of atom characterised by the number
Do Not Ask What Good We Do Do Not Ask What Good We Do Do Not Ask What Good We Do: Inside the U.S. House of Representatives is a 2012 book by the author Robert Draper and published by Free Press. It details the activities of Republicans and Democrats in the United States House of Representatives and the Senate during the first term of Barack Obama's presidency. The book was republished under the title When the Tea Party Came to Town. In order to research the activities and politics within the House of Representatives, Draper "embedded with new and senior House members" that had been elected in