A report on Light, Electromagnetic spectrum and Sun

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

A diagram of the electromagnetic spectrum, showing various properties across the range of frequencies and wavelengths

Illustration of the Sun's structure, in false color for contrast

Plot of Earth's atmospheric opacity to various wavelengths of electromagnetic radiation. This is the surface-to-space opacity, the atmosphere is transparent to longwave radio transmissions within the troposphere but opaque to space due to the ionosphere.

Illustration of a proton-proton reaction chain, from hydrogen forming deuterium, helium-3, and regular helium-4.

Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily

Plot of atmospheric opacity for terrestrial to terrestrial transmission showing the molecules responsible for some of the resonances

Illustration of different stars's internal structure, the Sun in the middle has an inner radiating zone and an outer convective zone.

$Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.$

The amount of penetration of UV relative to altitude in Earth's ozone

High-resolution image of the Sun's surface taken by the Daniel K. Inouye Solar Telescope (DKIST)

Hong Kong illuminated by colourful artificial lighting.

During a total solar eclipse, the solar corona can be seen with the naked eye, during the brief period of totality.

The Sun's transition region taken by Hinode's Solar Optical Telescope

Sunlight and glare seen overlooking from the International Space Station

$Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.$

Once outside the Sun's surface, neutrinos and photons travel at the speed of light

Measurements from 2005 of solar cycle variation during the previous 30 years

The size of the current Sun (now in the main sequence) compared to its estimated size during its red-giant phase in the future

The Solar System, with sizes of the Sun and planets to scale. The terrestrial planets are on the right, the gas and ice giants are on the left.

The Trundholm sun chariot pulled by a horse is a sculpture believed to be illustrating an important part of Nordic Bronze Age mythology.

Sol, the Sun, from a 1550 edition of Guido Bonatti's Liber astronomiae.

False-color image taken in 2010 as seen in 30.4-nanometer ultraviolet light wavelength

A false-color of a coronal hole on the Sun forming a question mark (22 December 2017)

A false-color solar prominence erupts in August 2012, as captured by the Solar Dynamics Observatory

The Sun seen from Earth, with glare from the lenses. The eye also see glare when looked towards the Sun directly.

Sun and Immortal Birds Gold Ornament by ancient Shu people. The center is a sun pattern with twelve points around which four birds fly in the same counterclockwise direction, Shang dynasty

Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye.

- Light

It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy mainly as light, ultraviolet, and infrared radiation.

- Sun

This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end.

- Electromagnetic spectrum

The main source of natural light on Earth is the Sun.

- Light

The Sun emits its peak power in the visible region, although integrating the entire emission power spectrum through all wavelengths shows that the Sun emits slightly more infrared than visible light.

- Electromagnetic spectrum

The transition region is not easily visible from Earth's surface, but is readily observable from space by instruments sensitive to the extreme ultraviolet portion of the spectrum.

- Sun

3 related topics with Alpha

Infrared

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This false-color infrared space telescope image has blue, green and red corresponding to 3.4, 4.6, and 12 μm wavelengths, respectively.

Plot of atmospheric transmittance in part of the infrared region

Materials with higher emissivity appear closer to their true temperature than materials that reflect more of their different-temperature surroundings. In this thermal image, the more reflective ceramic cylinder, reflecting the cooler surroundings, appears to be colder than its cubic container (made of more emissive silicon carbide), while in fact, they have the same temperature.

Active-infrared night vision: the camera illuminates the scene at infrared wavelengths invisible to the human eye. Despite a dark back-lit scene, active-infrared night vision delivers identifying details, as seen on the display monitor.

Hyperspectral thermal infrared emission measurement, an outdoor scan in winter conditions, ambient temperature −15 °C, image produced with a Specim LWIR hyperspectral imager. Relative radiance spectra from various targets in the image are shown with arrows. The infrared spectra of the different objects such as the watch clasp have clearly distinctive characteristics. The contrast level indicates the temperature of the object.

Infrared light from the LED of a remote control as recorded by a digital camera

Reflected light photograph in various infrared spectra to illustrate the appearance as the wavelength of light changes.

Infrared hair dryer for hair salons, c. 2010s

IR satellite picture of cumulonimbus clouds over the Great Plains of the United States.

The greenhouse effect with molecules of methane, water, and carbon dioxide re-radiating solar heat

Beta Pictoris with its planet Beta Pictoris b, the light-blue dot off-center, as seen in infrared. It combines two images, the inner disc is at 3.6 μm.

An infrared reflectogram of Mona Lisa by Leonardo da Vinci

Thermographic image of a snake eating a mouse

Infrared radiation was discovered in 1800 by William Herschel.

Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light.

Slightly more than half of the energy from the Sun was eventually found, through Herschel's studies, to arrive on Earth in the form of infrared.

Beyond infrared is the microwave portion of the electromagnetic spectrum.

Ultraviolet

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A 380 nanometer UV LED makes some common household items fluoresce.

Ultraviolet photons harm the DNA molecules of living organisms in different ways. In one common damage event, adjacent thymine bases bond with each other, instead of across the "ladder". This "thymine dimer" makes a bulge, and the distorted DNA molecule does not function properly.

Sunburn effect (as measured by the UV index) is the product of the sunlight spectrum (radiation intensity) and the erythemal action spectrum (skin sensitivity) across the range of UV wavelengths. Sunburn production per milliwatt of radiation intensity is increased by nearly a factor of 100 between the near UV‑B wavelengths of 315–295 nm

Demonstration of the effect of sunscreen. The man's face has sunscreen on his right side only. The left image is a regular photograph of his face; the right image is of reflected UV light. The side of the face with sunscreen is darker because the sunscreen absorbs the UV light.

Signs are often used to warn of the hazard of strong UV sources.

UV damaged polypropylene rope (left) and new rope (right)

IR spectrum showing carbonyl absorption due to UV degradation of polyethylene

A portrait taken using only UV light between the wavelengths of 335 and 365 nanometers.

Aurora at Jupiter's north pole as seen in ultraviolet light by the Hubble Space Telescope.

A bird appears on many Visa credit cards when they are held under a UV light source

After a training exercise involving fake body fluids, a healthcare worker's personal protective equipment is checked with ultraviolet light to find invisible drops of fluids. These fluids could contain deadly viruses or other contamination.

A collection of mineral samples brilliantly fluorescing at various wavelengths as seen while being irradiated by UV light.

Effects of UV on finished surfaces in 0, 20 and 43 hours.

A low-pressure mercury vapor discharge tube floods the inside of a hood with shortwave UV light when not in use, sterilizing microbiological contaminants from irradiated surfaces.

Entomologist using a UV light for collecting beetles in Chaco, Paraguay.

Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays.

The electromagnetic spectrum of ultraviolet radiation (UVR), defined most broadly as 10–400 nanometers, can be subdivided into a number of ranges recommended by the ISO standard ISO 21348:

The Sun emits ultraviolet radiation at all wavelengths, including the extreme ultraviolet where it crosses into X-rays at 10 nm.

Visible spectrum

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Newton's color circle, from Opticks of 1704, showing the colors he associated with musical notes. The spectral colors from red to violet are divided by the notes of the musical scale, starting at D. The circle completes a full octave, from D to D. Newton's circle places red, at one end of the spectrum, next to violet, at the other. This reflects the fact that non-spectral purple colors are observed when red and violet light are mixed.

Newton's observation of prismatic colors (David Brewster 1855)

How visible light interacts with objects to make them colorful

Approximation of spectral colors on a display results in somewhat distorted chromaticity

Earth's atmosphere partially or totally blocks some wavelengths of electromagnetic radiation, but in visible light it is mostly transparent

The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye.

Electromagnetic radiation in this range of wavelengths is called visible light or simply light.

For example, Helium was first detected by analysis of the spectrum of the sun.