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- For a topic outline on this subject, see List of basic topics in science
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Scientists maintain that scientific investigation must adhere to the scientific method, a process for properly developing and evaluating natural explanations for observable phenomena based on empirical study and independent verification. Science therefore, avoids supernatural explanations until all other natural possibilities have been considered, and rejects arguments from authority.
Fields of science are commonly classified along two major lines: Natural sciences, which study natural phenomena; and Social sciences, which study human behavior and societies. Whether mathematics is a science is a matter of perspective.
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 knowledge in new ways.
The three major types of atomic line filters are absorption-re-emission ALFs, Faraday filters and Voigt filters. Absorption-re-emission filters were the first type developed, and so are commonly called simply "atomic line filters"; the other two types are usually referred to specifically as "Faraday filters" or "Voigt filters". Atomic line filters use different mechanisms and designs for different applications, but the same basic strategy is always employed: by taking advantage of the narrow lines of absorption or resonance in a metallic vapor, a specific frequency of light bypasses a series of filters that block all other light.
A plasma lamp is usually a clear glass orb, filled with a mixture of various inert gases at low pressure, and driven by high frequency alternating current at high voltage (approx. 35 kHz, 2–5 kV), generated by a high voltage transformer. A much smaller orb in its centre serves as an electrode. Beams or snakes of "light" (actually emergent patterns in ionized gas) extend from the inner electrode to the outer glass container, giving an appearance similar to multiple constant beams of coloured lightning. The beams first follow the electric field lines of the dipole, but move up due to convection.
Carl Edward Sagan (November 9, 1934 – December 20, 1996) was an American astronomer, astrobiologist, and highly successful science popularizer. He pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI). He is world-famous for writing popular science books and for co-writing and presenting the award-winning 1980 television series Cosmos: A Personal Voyage, which was the most-watched PBS program until Ken Burns' The Civil War in 1990. A book to accompany the program was also published. He also wrote the novel Contact, the basis for the 1997 film of the same name starring Jodie Foster. During his lifetime, Sagan published more than 600 scientific papers and popular articles and was author, co-author, or editor of more than 20 books. In his works, he frequently advocated scientific skepticism, humanism, and the scientific method.
- ...that the endangered golden lion tamarin (pictured) has a long, but not prehensile, tail?
- ...that the Witch's hat is the common name of a colourful orange-red toadstool?
- ...that Grandi's series 1 − 1 + 1 − 1 + • • • is divergent and appears to equal 0, yet in some sense "sums" to 1⁄2 — a paradox once linked to the creation ex nihilo of the universe?
- ...that Derek Freeman was an anthropologist whose refutation of Margaret Mead's work "ignited controversy of a scale, visibility, and ferocity never before seen in anthropology"?
- ...that the New Year's Eve snowstorm of 1963/1964 dropped over 17 inches of snow at Huntsville, Alabama, simultaneously setting new snowfall records for any day, week, or month in their history?
