Light

Cosma Home > Communication > Knowledge > Realm > Physical > Light

Spotlight


Related

Pages

Physical Realm
Physical Laws (Constants) Relativity
Matter Molecule, Atom (Periodic Table), Particle
Force Gravity, Electromagnetism (Light, Color)

Resources

These are organized by a classification scheme developed exclusively for Cosma. More…

General

Portal

Exploring the Science of Light! (Optical Society of America)

Dictionary

light : electromagnetic radiation of any wavelength that travels in a vacuum with a speed of 299,792,458 meters (about 186,000 miles) per second; specifically : such radiation that is visible to the human eye. — Webster

OneLook, Free Dictionary, Wiktionary, Urban Dictionary

Thesaurus

Roget’s II (Thesaurus.com), Merriam-Webster Thesaurus, Visuwords

Encyclopedia

Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to visible light, which is the visible spectrum that is visible to the human eye and is responsible for the sense of sight. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), or 4.00 × 10−7 to 7.00 × 10−7 m, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). This wavelength means a frequency range of roughly 430–750 terahertz (THz).

The main source of light on Earth is the Sun. Sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the energy used by living things. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight. Some species of animals generate their own light, a process called bioluminescence. For example, fireflies use light to locate mates, and vampire squids use it to hide themselves from prey.

The primary properties of visible light are intensity, propagation direction, frequency or wavelength spectrum, and polarization, while its speed in a vacuum, 299,792,458 metres per second, is one of the fundamental constants of nature. Visible light, as with all types of electromagnetic radiation (EMR), is experimentally found to always move at this speed in a vacuum.

In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. Like all types of electromagnetic radiation, visible light propagates as waves. However, the energy imparted by the waves is absorbed at single locations the way particles are absorbed. The absorbed energy of the EM waves is called a photon, and represents the quanta of light. When a wave of light is transformed and absorbed as a photon, the energy of the wave instantly collapses to a single location, and this location is where the photon “arrives.” This is what is called the wave function collapse. This dual wave-like and particle-like nature of light is known as the wave–particle duality. The study of light, known as optics, is an important research area in modern physics. — Wikipedia

Optics (Eric Weisstein’s World of Physics, Wolfram Research)
Encyclopædia Britannica

Introduction


Search

Light (WolframAlpha), Optics (WolframAlpha)

Innovation

Science

Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.

Most optical phenomena can be accounted for using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be accounted for in geometric optics. Historically, the ray-based model of light was developed first, followed by the wave model of light. Progress in electromagnetic theory in the 19th century led to the discovery that light waves were in fact electromagnetic radiation.

Some phenomena depend on the fact that light has both wave-like and particle-like properties. Explanation of these effects requires quantum mechanics. When considering light’s particle-like properties, the light is modeled as a collection of particles called “photons”. Quantum optics deals with the application of quantum mechanics to optical systems.

Optical science is relevant to and studied in many related disciplines including astronomy, various engineering fields, photography, and medicine (particularly ophthalmology and optometry). Practical applications of optics are found in a variety of technologies and everyday objects, including mirrors, lenses, telescopes, microscopes, lasers, and fiber optics. — Wikipedia

Encyclopædia Britannica




Discovery

Scientists & Discovery, Light (Museum Victoria Australia)

Technology


How Light Works (HowStuffWorks)

Preservation

History






Optics Timeline (Optical Society of America)
A History of Light and Lighting (Bill Williams)

Quotation

Quotations Page Bartlett’s

Museum

The Museum of Optics (University of Arizona)

Library

WorldCat, Library of Congress, UPenn Online Books, Open Library

Participation

Education

Course






OER Commons: Open Educational Resources

Community

Occupation


Careers in Optics and Photonics (Optical Society of America)

Organization

International Society for Optics and Phontonics (SPIE)
Optical Society of America

News

International Society for Optics and Phontonics (SPIE)
Nature of Light (Science Daily)
Optics and Photonics News (Phys.org), Optics (Science 2.0), NPR Archives

Book

ISBNdb

Government

Document

USA.gov

Expression

Fun



We Are One Step Closer to a Lightsaber (Darren Orf, Popular Mechanics
Scientists Catch Up With Jedi in Understanding Light (Richard Adhikari, TechNewsWorld)

Poem

OEDILF: The Omnificent English Dictionary In Limerick Form

Music

Song Lyrics

returntotop

More…

Optics.org News latest News from Optics.org


Optics News -- ScienceDaily Optics. Can light go backwards? Researchers push the limits of our understanding of light. Also see amazing new applications of light energy. Full-text, images, free.

  • Tiny vibration-powered robots are the size of the...
    on July 18, 2019 at 3:25 pm

    Researchers have created a new type of tiny 3D-printed robot that moves by harnessing vibration from piezoelectric actuators, ultrasound sources or even tiny speakers. Swarms of these 'micro-bristle-bots' might work together to sense environmental changes, move materials -- or perhaps one day repair injuries inside the human body. […]

  • First-ever visualizations of electrical gating...
    on July 17, 2019 at 5:28 pm

    Scientists have visualized the electronic structure in a microelectronic device for the first time, opening up opportunities for finely-tuned high performance electronic devices. […]

  • Fiber-optic vibration sensors could prevent train...
    on July 17, 2019 at 4:26 pm

    Researchers have developed new sensors for measuring acceleration and vibration on trains. The technology could be integrated with artificial intelligence to prevent railway accidents and catastrophic train derailments. […]

  • Ultrasound-assisted optical imaging to replace...
    on July 17, 2019 at 1:03 pm

    New research introduces a novel technique which uses ultrasound to noninvasively take optical images through a turbid medium such as biological tissue to image body's organs. This new method has the potential to eliminate the need for invasive visual exams using endoscopic cameras. […]

  • Researchers build transistor-like gate for...
    on July 16, 2019 at 9:41 pm

    Researchers have built what could be a quantum version of a transistor -- with qudits. […]


Optics & Photonics News - Optics, Photonics, Physics News Phys.org provides the latest news on Optics and Photonics

  • Researchers use nano-particles to increase power,...
    on July 17, 2019 at 5:23 pm

    Scientists at the U.S. Naval Research Laboratory have devised a new process for using nano-particles to build powerful lasers that are more efficient and safer for your eyes. […]

  • Ultrasound-assisted optical imaging to replace...
    on July 17, 2019 at 3:19 pm

    Carnegie Mellon University's Assistant Professor of Electrical and Computer Engineering (ECE) Maysam Chamanzar and ECE Ph.D. student Matteo Giuseppe Scopelliti today published research that introduces a novel technique which uses ultrasound to noninvasively take optical images through a turbid medium such as biological tissue to image body's organs. This new method has the potential to eliminate the need for invasive visual exams using endoscopic cameras. […]

  • Quantum photonics by serendipity
    on July 17, 2019 at 2:14 pm

    A photonic chip with no less than 128 tunable components proves to be a true computing "Swiss army knife" with a variety of applications. During her research on measuring light wavelengths using this photonic chip, Caterina Taballione of the University of Twente came across yet another application serendipitously—by sending single photons through the system instead of continuous light, the optical components can perform quantum operations, as well. The same chip works as a photonic […]

  • Coupled exploration of light and matter
    on July 15, 2019 at 4:21 pm

    n quasiparticles known as polaritons, states of light and matter are strongly coupled. The group of Prof. Ataç İmamoğlu has now developed a new approach to study nonlinear optical properties of polaritons in strongly correlated electronic states. In doing so, they opened up fresh perspectives for exploring both ingredients of the polariton: novel functionalities for photonic devices and fundamental insight into exotic states of matter. […]

  • SLAC makes 'electron camera,' a world-class tool...
    on July 11, 2019 at 4:29 pm

    Over the past few years, the Department of Energy's SLAC National Accelerator Laboratory has developed a new tool to visualize physical and chemical processes with outstanding clarity: an ultra-high-speed "electron camera" capable of tracking atomic motions in a broad range of materials in real time. Starting this week, the lab has made this tool available to researchers worldwide. […]