Time
hideTime is a component of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify the motions of objects. Time has been a major subject of religion, philosophy, and science, but defining it in a non-controversial manner applicable to all fields of study has consistently eluded the greatest scholars.
In physics as well as in other sciences, time is considered one of the few fundamental quantities. Time is used to define other quantities – such as velocity – and defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime brings the nature of time into association with related questions into the nature of space, questions that have their roots in the works of early students of natural philosophy.
Among prominent philosophers, there are two distinct viewpoints on time. One view is that time is part of the fundamental structure of the universe, a dimension in which events occur in sequence. Time travel, in this view, becomes a possibility as other "times" persist like frames of a film strip, spread out across the time line. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time. The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.
Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined in terms of radiation emitted by caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.
For more information about Time, read the full article at
Wikipedia.
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News tagged with time
AOL offers buyouts to over a third of work force
Nov 19, 2009 |
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(AP) -- The struggling Internet company AOL plans to shed up to 2,500 jobs - more than a third of its work force - as it prepares to separate from Time Warner and finally sever their ill-fated marriage.
Time Warner Cable asks help on rising program fees
Nov 25, 2009 |
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(AP) -- Time Warner Cable Inc. is asking the public for help as it tries to curtail increases in the programming fees it has to pay to carry cable channels and broadcast stations on its systems.
Earthquakes actually aftershocks of 19th century quakes
Space & Earth / Earth Sciences
Nov 04, 2009 |
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(PhysOrg.com) -- When small earthquakes shake the central U.S., citizens often fear the rumbles are signs a big earthquake is coming. Fortunately, new research instead shows that most of these earthquakes ...
Study: Can meditation sharpen our attention?
Medicine & Health / Neuroscience
Nov 13, 2009 |
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(PhysOrg.com) -- A new study at the University of Wisconsin-Madison suggests that people can train their minds to stay focused.
Physicist Proposes Solution to Arrow-of-Time Paradox
Aug 27, 2009 |
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(PhysOrg.com) -- Entropy can decrease, according to a new proposal - but the process would destroy any evidence of its existence, and erase any memory an observer might have of it. It sounds like the plot ...
Could Exotic Matter Provide an Infinite Source of Energy?
Sep 15, 2009 |
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(PhysOrg.com) -- Generally, scientists prefer to avoid the concept of perpetual motion. The idea of a machine that could produce movement that goes on forever, and using that movement to generate an endless ...
In Twin Paradox Twist, the Accelerated Twin is Older
Jun 09, 2009 |
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Just when you thought you were beginning to understand the twin paradox (maybe), scientists have found something new to ponder. In the original version of the famous thought experiment on time dilation, one ...
Major advance in organic solar cells
Oct 19, 2009 |
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Professor Guillermo Bazan and a team of postgraduate researchers at UC Santa Barbara's Center for Polymers and Organic Solids (CPOS) today announced a major advance in the synthesis of organic polymers for plastic solar cells. ...
Ion trap quantum computing
May 12, 2009 |
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(PhysOrg.com) -- “Right now, classical computers are faster than quantum computers,” René Stock tells PhysOrg.com. “The goal of quantum computing is to eventually speed up the time scale of solving certain important proble ...
Nanocomposite material provides photonic switching
Feb 09, 2009 |
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(PhysOrg.com) -- Integrated photonic devices represent the wave of future technology. These devices will be extremely small, making use of photons on the nanoscale, and (hopefully) be very efficient in terms of power use. ...
Time Lens Speeds Up Optical Data Transmission
Sep 28, 2009 |
4.8 / 5 (15) |
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(PhysOrg.com) -- Researchers at Cornell University have developed a device called a "time lens" which is a silicon device for speeding up optical data. The basic components of this device are an optical-fiber ...
AOL to log additional $200M in restructuring costs
Nov 12, 2009 |
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(AP) -- New regulatory filings suggest many more layoffs could be coming at AOL LLC as it separates from Time Warner Inc. by the end of the year.
'Rosetta Stone' of supervolcanoes discovered in Italian Alps
Space & Earth / Earth Sciences
Sep 21, 2009 |
4.3 / 5 (29) |
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Scientists have found the "Rosetta Stone" of supervolcanoes, those giant pockmarks in the Earth's surface produced by rare and massive explosive eruptions that rank among nature's most violent events. The eruptions produce ...
Study Shows Thousands of Consumer Internet Connectivity Devices Are Vulnerable to Attack
Technology / Computer Sciences
Oct 26, 2009 |
5 / 5 (1) |
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(PhysOrg.com) -- Following news reports that 65,000 modems and wireless routers used by Time Warner Cable customers are vulnerable to attack by hackers, a Columbia University expert on computer security and ...
Counterintuitive physics may help everyone drive home quicker
Oct 02, 2008 |
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If you're trying to drive to a destination as quickly as possible, you might think that knowing the traffic conditions would help you choose the quickest route for yourself. Traffic reports and new GPS technologies ...
