Science

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 qualified research.
Scientists maintain that scientific investigation must adhere to the scientific method, a rigorous process for properly developing and evaluating natural explanations for observable phenomena based on reliable empirical evidence and neutral, unbiased independent verification, and not on arguments from authority or popular preferences. Science therefore bypasses supernatural explanations, it instead only considers natural explanations that may be falsifiable.
Fields of science are 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 practical applications. Applied science is principally involved with the application of existing knowledge in new ways.
Mathematics is the language in which scientific information is best presented, often it is the only way to formulate and present scientific knowledge. Therefore whether mathematics is a science in itself or the framework of science is a matter of perspective.

In physical cosmology, the Big Bang is the scientific theory that the universe emerged from a tremendously dense and hot state about 13.7 billion years ago. The theory is based on the observations indicating the expansion of space (in accord with the Robertson-Walker model of general relativity) as indicated by the Hubble redshift of distant galaxies taken together with the cosmological principle. Extrapolated into the past, these observations show that the universe has expanded from a state in which all the matter and energy in the universe was at an immense temperature and density. Physicists do not widely agree on what happened before this, although general relativity predicts a gravitational singularity (for reporting on some of the more notable speculation on this issue, see cosmogony).
The term Big Bang is used both in a narrow sense to refer to a point in time when the observed expansion of the universe (Hubble's law) began — calculated to be 13.7 billion (1.37 × 10¹⁰) years ago (±2%) — and in a more general sense to refer to the prevailing cosmological paradigm explaining the origin and expansion of the universe, as well as the composition of primordial matter through nucleosynthesis as predicted by the Alpher-Bethe-Gamow theory.


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.

A Tesla coil is a category of disruptive discharge transformer coils, named after their inventor, Nikola Tesla. Tesla coils are composed of coupled resonant electric circuits. Nikola Tesla actually experimented with a large variety of coils and configurations, so it is difficult to describe a specific mode of construction that will meet the wants of those who ask about "Tesla" coils. "Early coils" and "later coils" vary in configuration and setup. Tesla coils in general are very popular devices among high-voltage enthusiasts.

Did you know...

• ...that silica aerogel (pictured) 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?
• ...that the genus Entomocorus includes a catfish species that lives only one year?
• ...that a successful experimental system must be stable and reproducible enough for scientists to make sense of the system's behavior, but unpredictable enough that it can produce useful results?
• ...that Abbott Lawrence Rotch established the Blue Hill Meteorological Observatory in 1885, which maintains the longest-running meteorological record of any observation site in the United States?