News tagged with speed of light
Through hardship to the stars
"Humanity's adventurous, stubborn, mad and glorious aspiration to reach the stars" is the subject of Physics World's lead feature in January.
Space & Earth / Space Exploration
Jan 04, 2012 |
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Physicist creates scale model of LHC ATLAS experiment of out LEGO blocks
(PhysOrg.com) -- The Large Hadron Collider at the European Organization for Nuclear Research (CERN) in Switzerland has generated a lot of news of late, e.g. the announcement that a team had found what it believes ...
Dec 30, 2011 |
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'Faster-than-light' particles spark science drama
Oh Albert. Did you get it wrong? In 2011, physics was shaken by an experiment which said the Universe's speed limit, enshrined by Einstein in his 1905 theory of special relativity, could be broken.
Dec 09, 2011 |
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Earth's outer core deprived of oxygen: study
The composition of the Earth's core remains a mystery. Scientists know that the liquid outer core consists mainly of iron, but it is believed that small amounts of some other elements are present as well. Oxygen ...
Space & Earth / Earth Sciences
Nov 23, 2011 |
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Cosmic particle accelerators get things going
(PhysOrg.com) -- ESA's Cluster satellites have discovered that cosmic particle accelerators are more efficient than previously thought. The discovery has revealed the initial stages of acceleration for the ...
Nov 17, 2011 |
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The secrets of tunneling through energy barriers
Electrons moving in graphene behave in an unusual way, as demonstrated by 2010 Nobel Prize laureates for physics Andre Geim and Konstantin Novoselov, who performed transport experiments on this one-carbon-atom-thick material. ...
Nov 07, 2011 |
5 / 5 (4) |
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Scientists take fresh look at 'faster-than-light' experiment
Scientists who threw down the gauntlet to physics by reporting particles that broke the Universe's speed limit said on Friday they were revisiting their contested experiment.
Oct 28, 2011 |
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Use your own computer to tame protons at CERN
Help to unravel the mysteries of the Universe! With the SixTrack project developed by EPFL, your computer can provide CERN with additional computing power.
Oct 24, 2011 |
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Special relativity may answer faster-than-light neutrino mystery
Oh, yeah. Moving faster than the speed of light has been the hot topic in the news and OPERA has been the key player. In case you didn’t know, the experiment unleashed some particles at CERN, close to ...
Oct 17, 2011 |
3.4 / 5 (9) |
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CERN and colliding theories
Findings that showed faster-than-light travel were released to the public too soon.
Oct 10, 2011 |
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New theories emerge to disprove OPERA faster-than-light neutrinos claim
(PhysOrg.com) -- It's been just two weeks since the Oscillation Project with Emulsion-tRacking Apparatus (OPERA) team released its announcement claiming that they have been measuring muon neutrinos moving faster t ...
Oct 06, 2011 |
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3 Questions: Faster than light?
The news media were abuzz this week with reports of experiments conducted at the Gran Sasso particle detector complex in Italy, apparently showing subatomic particles called neutrinos had traveled from th ...
Sep 26, 2011 |
4.7 / 5 (15) |
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Gee Whizzz! Basics on faster-than-light research
Some questions and answers about the experiment that appeared to show particles speeding faster than light.
Sep 23, 2011 |
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Physicists wary of junking light speed limit yet
(AP) -- Physicists on the team that measured particles traveling faster than light said Friday they were as surprised as their skeptics about the results, which appear to violate the laws of nature as we ...
Sep 23, 2011 |
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Scientists stunned, sceptical on faster-than-light particles
Physicists around the world expressed astonishment and scepticism in equal measure Friday after European scientists reported particles apparently travelling faster than light. ...
Sep 23, 2011 |
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Speed of light
The term speed of light generally refers to a fundamental physical constant of spacetime that limits the rate of transfer of matter or information. The speed of light is the speed of not just visible light, but of all electromagnetic radiation in vacuum (also called free space), and usually is denoted by the symbol c. Speeds faster than that of light are encountered in physics but, in all such cases, no matter or information is transmitted faster than c. The speed of light also plays a role in general relativity, and is believed to be the speed of gravitational waves.
In SI units, the magnitude of the speed of light in vacuum is exactly 299,792,458 metres per second (m/s) because of the way the metre is defined. More about this topic is found below in Speed of light set by definition.
For many practical purposes, the speed of light is so great that it can be regarded to travel instantaneously. An exception is where long distances or precise time measurements are involved. For example, in the Global Positioning System (GPS), a GPS receiver measures its distance to satellites based on how long it takes for a radio signal to arrive from the satellite. In astronomy, distances are often measured in light-years, the distance light travels in a year.
The speed of light when it passes through a transparent or translucent material medium, like glass or air, is less than its speed in vacuum. The speed is inversely proportional to the refractive index of the medium. In specially-prepared media, the speed can be tiny, or even zero.
For many years the speed of light was the subject of speculation, some believing it to be infinite. The first effective measurements of the speed of light were made in the seventeenth century, and these were progressively refined until, in 1983, the speed of light in vacuum was fixed by definition.
For more information about Speed of light, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
