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
What the Bleep Do We Know!? "What the Bleep Do We Know!?" have described distinct assertions made in the film as pseudoscience. Lisa Randall refers to the film as "the bane of scientists". Amongst the assertions in the film that have been challenged are that water molecules can be influenced by thought (as popularized by Masaru Emoto), that meditation can reduce violent crime rates, and that quantum physics implies that "consciousness is the ground of all being." The film was also discussed in a letter published in "Physics Today" that challenges how physics is taught, saying teaching fails to "expose the mysteries physics has encountered [and]