Science, in the broadest sense of the term, refers to any system of knowledge attained by verifiable means. In a more restricted sense, science refers to a system of acquiring knowledge based on empiricism, experimentation, and methodological naturalism, as well as to the organized body of knowledge humans have gained by such research.
Fields of science can be further distinguished as pure science or applied science. Pure science is principally involved with the discovery of new truths with less (or no) regard to their applications. Applied science is principally involved with the application of existing truths in new ways.
Erosion is the displacement of solids (soil, mud, rock and other particles) by the agents of wind, water or ice, by downward or down-slope movement in response to gravity or by living organisms (in the case of bioerosion). Erosion is distinguished from weathering, which is the decomposition of rock and particles through processes where no movement is involved, although the two processes may be concurrent.
Erosion is an intrinsic natural process but in many places it is increased by human land use. Poor land use practices include deforestation, overgrazing, unmanaged construction activity and road or trail building. However, improved land use practices can limit erosion, using techniques like terrace-building and tree planting.
A certain amount of erosion is natural and, in fact, healthy for the ecosystem. For example, gravels continually move downstream in watercourses. Excessive erosion, however, can cause problems, such as receiving water sedimentation, ecosystem damage (including fish kills) and outright loss of soil.
Her parents were Quakers who, unconventionally for their time, insisted on giving her the same quality of education that boys received. She worked as a librarian and also pursued astronomy at her father's observatory.
Using a telescope, she discovered "Miss Mitchell's Comet" (Comet 1847 VI, modern designation is C/1847 T1) in the autumn of 1847. Some years previously, King Frederick VI of Denmark had established gold medal prizes to each discoverer of a "telescopic comet" (too faint to be seen with the naked eye). The prize was to be awarded to the "first discoverer" of each such comet (note that comets are often independently discovered by more than one person). She duly won one of these prizes, and this gave her worldwide fame, since the only previous woman to discover a comet had been Caroline Herschel.
...that silica aerogel holds 15 entries in the Guinness Book of Records for material properties, including best insulator and lowest-density solid?
...that acoustic levitation is a method for suspending matter in a fluid by using acoustic radiation pressure from intense sound waves in the medium?
...Necrotizing fasciitis is a rare infection of subcutaneous tissues that results in the necrosis of the flesh?
...Napalm-B used in the Vietnam War was synthesized with only three ingredients: polystyrene, gasoline, and benzene?
...that a laser harp is an electronic musical instrument consisting of several laser beams that are blocked to produce sound?
December 6: A study by the Institute of Cancer Epidemiology in Denmark does not produce any statistically significant link between cancer and cell phone use. It is based on about 400,000 cell phone users. (Reuters)
December 5: NASA announces that it plans to build a permanently occupied station on the Moon, and shuttle persons to it regularly by 2020. (BBCNews)(Reuters)
