Science (from the Latin word scientia, meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
The earliest roots of science can be traced to Ancient Egypt and Mesopotamia in around 3500 to 3000 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages but was preserved in the Muslim world during the Islamic Golden Age. The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived natural philosophy, which was later transformed by the Scientific Revolution that began in the 16th century as new ideas and discoveries departed from previous Greek conceptions and traditions. The scientific method soon played a greater role in knowledge creation and it was not until the 19th century that many of the institutional and professional features of science began to take shape.
Modern science is typically divided into three major branches that consist of the natural sciences (e.g., biology, chemistry, and physics), which study nature in the broadest sense; the social sciences (e.g., economics, psychology, and sociology), which study individuals and societies; and the formal sciences (e.g., logic, mathematics, and theoretical computer science), which study abstract concepts. There is disagreement, however, on whether the formal sciences actually constitute a science as they do not rely on empirical evidence. Disciplines that use existing scientific knowledge for practical purposes, such as engineering and medicine, are described as applied sciences.
Science is based on research, which is commonly conducted in academic and research institutions as well as in government agencies and companies. The practical impact of scientific research has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the development of commercial products, armaments, health care, and environmental protection.
is a NASA unmanned spacecraft
designed to fly by Pluto
and its moons
) and transmit images and data back to Earth. Mission planners hope that NASA will approve plans to continue the mission with a fly-by of a Kuiper Belt Object
and return further data. A consortium of organizations, led by Southwest Research Institute
and the Johns Hopkins Applied Physics Laboratory
, has built the craft. The mission's principal investigator is S. Alan Stern of Southwest Research. The probe successfully launched from Cape Canaveral
at 14:00 EST January 19, 2006 and flew past Jupiter on February 28, 2007 for a gravity assist
The primary scientific objectives are to characterize the global geology and morphology and map the surface composition of Pluto and Charon, and study the neutral atmosphere of Pluto and its escape rate. Other objectives include studying time variability of Pluto's surface and atmosphere; imaging and mapping areas of Pluto and Charon at high-resolution; characterizing Pluto's upper atmosphere, ionosphere, and energetic particle environment; searching for an atmosphere around Charon; refining bulk parameters of Pluto and Charon; and searching for additional satellites and rings.
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.
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