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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.

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.

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This long range RADAR antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll.
RADAR is a system that uses radio waves to determine and map the location, direction, and/or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations and terrain. A transmitter emits radio waves, which are reflected by the target and detected by a receiver, typically in the same location as the transmitter. Although the radio signal returned is usually very weak, radio signals can easily be amplified, so radar can detect objects at ranges where other emissions, such as sound or visible light, would be too weak to detect. Radar is used in many contexts, including meteorological detection of precipitation, air traffic control, police detection of speeding traffic, and by the military.

The term RADAR was coined in 1941 as an acronym for Radio Detection and Ranging. This acronym of American origin replaced the previously used British abbreviation RDF (Radio Direction Finding). The term has since entered the English language as a standard word, radar, losing the capitalization in the process.

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The Hubble Space Telescope as seen from the Space Shuttle Discovery on mission STS-82.
Credit: NASA

The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble for his discovery of galaxies outside the Milky Way and his creation of Hubble's Law, which calculates the rate at which the universe is expanding. Its position outside the Earth's atmosphere allows it to take sharp optical images of very faint objects, and since its launch in 1990, it has become one of the most important instruments in the history of astronomy. It has been responsible for many ground-breaking observations and has helped astronomers achieve a better understanding of many fundamental problems in astrophysics. Hubble's Ultra Deep Field is the deepest (most sensitive) astronomical optical image ever taken.

It also has very large satellite mirrors which are so precise that even a star 100 light years away can be seen easily.

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Selected biography

Francis Crick, (1916 – 2004) was a British physicist, molecular biologist and neuroscientist, most noted for being one of the co-discoverers of the structure of the DNA molecule in 1953. He, James D. Watson, and Maurice Wilkins were jointly awarded the 1962 Nobel Prize for Physiology or Medicine for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material. His later work at the MRC Laboratory of Molecular Biology until 1977 has not received as much formal recognition. His remaining career as the J.W. Kieckhefer Distinguished Research Professor at the Salk Institute for Biological Studies was spent in La Jolla, California, until his death; "He was editing a manuscript on his death bed, a scientist until the bitter end" (a quote from his close associate Christof Koch).

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