Portal:Physics
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Physics is the scientific study of matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. Physics is one of the most fundamental scientific disciplines. A scientist who specializes in the field of physics is called a physicist.
Physics is one of the oldest academic disciplines. Over much of the past two millennia, physics, chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the Scientific Revolution in the 17th century, these natural sciences branched into separate research endeavors. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences and suggest new avenues of research in these and other academic disciplines such as mathematics and philosophy.
Advances in physics often enable new technologies. For example, advances in the understanding of electromagnetism, solid-state physics, and nuclear physics led directly to the development of technologies that have transformed modern society, such as television, computers, domestic appliances, and nuclear weapons; advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus. (Full article...)
The speed of light in vacuum, commonly denoted c, is a universal physical constant that is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour). According to the special theory of relativity, c is the upper limit for the speed at which conventional matter or energy (and thus any signal carrying information) can travel through space.
All forms of electromagnetic radiation, including visible light, travel at the speed of light. For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and very sensitive measurements, their finite speed has noticeable effects. Much starlight viewed on Earth is from the distant past, allowing humans to study the history of the universe by viewing distant objects. When communicating with distant space probes, it can take minutes to hours for signals to travel. In computing, the speed of light fixes the ultimate minimum communication delay. The speed of light can be used in time of flight measurements to measure large distances to extremely high precision. (Full article...)
Did you know -
- ...that Isaac Newton originally defined force as the rate of change of momentum with respect to time?
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November anniversaries
- 1952 - detonation of the first Hydrogen bomb, code named "Ivy Mike".
- 1947 - invention of the first transistor, between November 17 to December 23. APS.
- 1930 - Patent granted for Einstein-Szilard refrigerator designed by Albert Einstein and Leó Szilárd. APS.
- 1919 - Elmer Imes's published work presented the first accurate measurement of the distance between atoms in molecules with high resolution infrared spectroscopy. APS.
- 1915 – Einstein's presentation to the Prussian Academy of Science specifies how the geometry of space and time is influenced by whatever matter is present. (see: General relativity and APS)
- 1895 - Wilhelm Conrad Roentgen discovers X-rays.
- 1887 - Michelson–Morley experiment provided strong evidence against the luminiferous ether. APS.
- 1872 - death of Mary Somerville who gained an international reputation as a scientist in the intervals of raising a family of six children. APS
- 1783 - John Michell predicted the existence of black holes, and the possibility of a luminous twin to aid in detection. APS
- 1676 – using his first quantitative measurement of the speed of light, Ole Rømer accurately predicts the delay of eclipse of Io
Births
- 1934 – Carl Sagan
- 1932 - Melvin Schwartz
- 1929 - Richard E. Taylor
- 1925 - Simon van der Meer
- 1902 - Eugene Wigner
- 1837 - Johannes Diderik van der Waals
- 1867 - Marie Curie (Nov. 7)
- 1828 - Balfour Stewart
- 1878 - Lise Meitner (Nov. 7)
- 1887 - Henry Moseley
- 1888 - C V Raman (Nov. 7)
- 1892 - Dmitri Skobeltsyn (Nov. 24)
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Fundamentals: Concepts in physics | Constants | Physical quantities | Units of measure | Mass | Length | Time | Space | Energy | Matter | Force | Gravity | Electricity | Magnetism | Waves
Basic physics: Mechanics | Electromagnetism | Statistical mechanics | Thermodynamics | Quantum mechanics | Theory of relativity | Optics | Acoustics
Specific fields: Acoustics | Astrophysics | Atomic physics | Molecular physics | Optical physics | Computational physics | Condensed matter physics | Nuclear physics | Particle physics | Plasma physics
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Background: Physicists | History of physics | Philosophy of physics | Physics education | Physics journals | Physics organizations
Other: Physics in fiction | Physics lists | Physics software | Physics stubs
Physics topics
Classical physics traditionally includes the fields of mechanics, optics, electricity, magnetism, acoustics and thermodynamics. The term Modern physics is normally used for fields which rely heavily on quantum theory, including quantum mechanics, atomic physics, nuclear physics, particle physics and condensed matter physics. General and special relativity are usually considered to be part of modern physics as well.
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