A report on Light

A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) are separated.
The electromagnetic spectrum, with the visible portion highlighted
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Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily
Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.
Hong Kong illuminated by colourful artificial lighting.
Pierre Gassendi.
Christiaan Huygens.
Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.
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Electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye.

- Light
A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) are separated.

81 related topics with Alpha

Overall

Photopic (daytime-adapted, black curve) and scotopic (darkness-adapted, green curve) luminosity functions. The photopic includes the CIE 1931 standard (solid), the Judd-Vos 1978 modified data  (dashed), and the Sharpe, Stockman, Jagla & Jägle 2005 data  (dotted). The horizontal axis is wavelength in nm.

Photometry (optics)

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Photopic (daytime-adapted, black curve) and scotopic (darkness-adapted, green curve) luminosity functions. The photopic includes the CIE 1931 standard (solid), the Judd-Vos 1978 modified data  (dashed), and the Sharpe, Stockman, Jagla & Jägle 2005 data  (dotted). The horizontal axis is wavelength in nm.

Photometry is the science of the measurement of light, in terms of its perceived brightness to the human eye.

Aurora at Alaska showing light created by charged particles and magnetism, fundamental concepts to electromagnetism study

Electromagnetism

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Branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles.

Branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles.

Aurora at Alaska showing light created by charged particles and magnetism, fundamental concepts to electromagnetism study
Hans Christian Ørsted
André-Marie Ampère
James Clerk Maxwell
Representation of the electric field vector of a wave of circularly polarized electromagnetic radiation.
Magnetic reconnection in the solar plasma gives rise to solar flares, a complex magnetohydrodynamical phenomenon.

The electromagnetic force is carried by electromagnetic fields composed of electric fields and magnetic fields, and it is responsible for electromagnetic radiation such as light.

Triboluminescence of Nicotine-L salicylate

Triboluminescence

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Triboluminescence of Nicotine-L salicylate
An Uncompahgre Ute Buffalo rawhide ceremonial rattle filled with quartz crystals. Flashes of light are visible when the quartz crystals are subjected to mechanical stress in darkness.

Triboluminescence is a phenomenon in which light is generated when a material is mechanically pulled apart, ripped, scratched, crushed, or rubbed (see tribology).

Pencils shown in various colors

Color

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Visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes.

Visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes.

Pencils shown in various colors
Continuous optical spectrum rendered into the sRGB color space.
The upper disk and the lower disk have exactly the same objective color, and are in identical gray surroundings; based on context differences, humans perceive the squares as having different reflectances, and may interpret the colors as different color categories; see checker shadow illusion.
Normalized typical human cone cell responses (S, M, and L types) to monochromatic spectral stimuli
The visual dorsal stream (green) and ventral stream (purple) are shown. The ventral stream is responsible for color perception.
This picture contains one million pixels, each one a different color
The CIE 1931 color space xy chromaticity diagram with the visual locus plotted using the CIE (2006) physiologically-relevant LMS fundamental color matching functions transformed into the CIE 1931 xy color space and converted into Adobe RGB. The triangle shows the gamut of Adobe RGB. The Planckian locus is shown with color temperatures labeled in Kelvins. The outer curved boundary is the spectral (or monochromatic) locus, with wavelengths shown in nanometers. Note that the colors in this file are being specified using Adobe RGB. Areas outside the triangle cannot be accurately rendered since they are outside the gamut of Adobe RGB, therefore they have been interpreted. Note that the colors depicted depend on the gamut and color accuracy of your display.
Additive color mixing: combining red and green yields yellow; combining all three primary colors together yields white.
Subtractive color mixing: combining yellow and magenta yields red; combining all three primary colors together yields black
Twelve main pigment colors

It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what is commonly referred to simply as light).

π-electronic energy levels of an organic molecule. S0 is the ground state. S1, S2, S3 are excited singlet states. T1, T2, T3 are excited triplet states. S00, S01, S10, S11 etc. are vibrational sublevels.

Scintillation (physics)

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π-electronic energy levels of an organic molecule. S0 is the ground state. S1, S2, S3 are excited singlet states. T1, T2, T3 are excited triplet states. S00, S01, S10, S11 etc. are vibrational sublevels.

Scintillation is a flash of light produced in a transparent material by the passage of a particle (an electron, an alpha particle, an ion, or a high-energy photon).

Ibn al-Haytham

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Arab mathematician, astronomer, and physicist of the Islamic Golden Age.

Arab mathematician, astronomer, and physicist of the Islamic Golden Age.

Front page of the Opticae Thesaurus, which included the first printed Latin translation of Alhazen's Book of Optics. The illustration incorporates many examples of optical phenomena including perspective effects, the rainbow, mirrors, and refraction.
The structure of the human eye according to Ibn al-Haytham. Note the depiction of the optic chiasm. —Manuscript copy of his Kitāb al-Manāẓir (MS Fatih 3212, vol. 1, fol. 81b, Süleymaniye Mosque Library, Istanbul)
The theorem of Ibn Haytham
Hevelius's Selenographia, showing Alhasen [sic] representing reason, and Galileo representing the senses.
Alhazen's geometrically proven summation formula
The lunes of Alhazen. The two blue lunes together have the same area as the green right triangle.
Cover page of the Latin translation of Kitāb al-Manāẓir

The first theory, the emission theory, was supported by such thinkers as Euclid and Ptolemy, who believed that sight worked by the eye emitting rays of light.

The luminiferous aether: it was hypothesised that the Earth moves through a "medium" of aether that carries light

Luminiferous aether

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The luminiferous aether: it was hypothesised that the Earth moves through a "medium" of aether that carries light
The Michelson–Morley experiment compared the time for light to reflect from mirrors in two orthogonal directions.

Luminiferous aether or ether ("luminiferous", meaning "light-bearing") was the postulated medium for the propagation of light.

Laser light is a type of stimulated emission of radiation.

Stimulated emission

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Process by which an incoming photon of a specific frequency can interact with an excited atomic electron , causing it to drop to a lower energy level.

Process by which an incoming photon of a specific frequency can interact with an excited atomic electron , causing it to drop to a lower energy level.

Laser light is a type of stimulated emission of radiation.
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When an electron absorbs energy either from light (photons) or heat (phonons), it receives that incident quantum of energy.

The reflection of Mount Hood in Mirror Lake.

Reflection (physics)

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Change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.

Change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.

The reflection of Mount Hood in Mirror Lake.
Diagram of specular reflection
Refraction of light at the interface between two media.
An example of the law of reflection
General scattering mechanism which gives diffuse reflection by a solid surface
Working principle of a corner reflector
Multiple reflections in two plane mirrors at a 60° angle.
Sound diffusion panel for high frequencies

Common examples include the reflection of light, sound and water waves.

Direct image of a supermassive black hole at the core of Messier 87

Black hole

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Direct image of a supermassive black hole at the core of Messier 87
Animated simulation of a Schwarzschild black hole with a galaxy passing behind. Around the time of alignment, extreme gravitational lensing of the galaxy is observed.
Simulated view of a black hole in front of the Large Magellanic Cloud. Note the gravitational lensing effect, which produces two enlarged but highly distorted views of the Cloud. Across the top, the Milky Way disk appears distorted into an arc. Published in 2019.
Gravitational time dilation around a black hole
The ergosphere is a region outside of the event horizon, where objects cannot remain in place.
Gas cloud being ripped apart by black hole at the centre of the Milky Way (observations from 2006, 2010 and 2013 are shown in blue, green and red, respectively).
Artist's impression of supermassive black hole seed
Simulated event in the CMS detector: a collision in which a micro black hole may be created
This artist's impression depicts the paths of photons in the vicinity of a black hole. The gravitational bending and capture of light by the event horizon is the cause of the shadow captured by the Event Horizon Telescope.
Predicted appearance of a non-rotating black hole with toroidal ring of ionised matter, such as has been proposed as a model for Sagittarius A*. The asymmetry is due to the Doppler effect resulting from the enormous orbital speed needed for centrifugal balance of the powerful gravitational attraction of the hole.
Black hole with corona, X-ray source (artist's concept)
NASA simulated view from outside the horizon of a Schwarzschild black hole lit by a thin accretion disk.
Blurring of X-rays near black hole (NuSTAR; 12 August 2014)
A Chandra X-Ray Observatory image of Cygnus X-1, which was the first strong black hole candidate discovered
Magnetic waves, called Alfvén S-waves, flow from the base of black hole jets.
Detection of unusually bright X-Ray flare from Sagittarius A*, a black hole in the centre of the Milky Way galaxy on 5January 2015
Simulation of gas cloud after close approach to the black hole at the centre of the Milky Way.
An infographic explaining in detail the appearance of a black hole. The photon sphere surrounds the black hole's shadow.

A black hole is a region of spacetime where gravity is so strong that nothing – no particles or even electromagnetic radiation such as light – can escape from it.