Sun

solarSolThe Sunsolar magnetic fieldsolar astronomysolar atmospheresolar diametersolar masseslocal starsolar photosphere
The Sun is the star at the center of the Solar System.wikipedia
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Solar System

outer Solar Systeminner Solar SystemSol system
The Sun is the star at the center of the Solar System. The related word solar is the usual adjectival term used for the Sun, in terms such as solar day, solar eclipse, and Solar System.
The Solar System is the gravitationally bound system of the Sun and the objects that orbit it, either directly or indirectly.

Earth

terrestrialworldGlobal
It is by far the most important source of energy for life on Earth. It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury and Venus, and render Earth uninhabitable.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.

Venus

Morning Starevening starCytherocentric
It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury and Venus, and render Earth uninhabitable.
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days.

Helium

Hesuperfluid heliumhelium II
Roughly three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron. In 1868, Norman Lockyer hypothesized that these absorption lines were caused by a new element that he dubbed helium, after the Greek Sun god Helios.
Its abundance is similar to this figure in the Sun and in Jupiter.

Formation and evolution of the Solar System

solar nebulaformation of the Solar Systemoutward
Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that became the Solar System.
Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and other small Solar System bodies formed.

Plasma (physics)

plasmaplasma physicsplasmas
It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process.
The interior of the Sun is an example of fully ionized plasma, along with the solar corona and stars.

White dwarf

white dwarfswhite dwarf starcentral star
After this, it will shed its outer layers and become a dense type of cooling star known as a white dwarf, and no longer produce energy by fusion, but still glow and give off heat from its previous fusion.
A white dwarf is very dense: its mass is comparable to that of the Sun, while its volume is comparable to that of Earth.

Mars

Martianplanet MarsRed Planet
Sol is also used by planetary astronomers to refer to the duration of a solar day on another planet, such as Mars.
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury.

The Sun in culture

regarded by some culturesSunThe rising sun
The enormous effect of the Sun on Earth has been recognized since prehistoric times, and the Sun has been regarded by some cultures as a deity.
The Sun, as the source of energy and light for life on earth has been a central object in culture and religion since prehistory.

Solar dynamo

dynamodynamo processmagnetic field of the sun
It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process.
The solar dynamo is the physical process that generates the Sun's magnetic field.

Solar core

coreSun's corecore of the Sun
The central mass became so hot and dense that it eventually initiated nuclear fusion in its core.
It is the hottest part of the Sun and of the Solar System.

Solar eclipse

solar eclipsessolareclipse
The related word solar is the usual adjectival term used for the Sun, in terms such as solar day, solar eclipse, and Solar System. Atmosphere – a gaseous 'halo' surrounding the Sun, comprising the chromosphere, solar transition region, corona and heliosphere. These can be seen when the main part of the Sun is hidden, for example, during a solar eclipse.
A solar eclipse occurs when an observer (on Earth) passes through the shadow cast by the Moon which fully or partially blocks ("occults") the Sun.

Stellar classification

spectral typeK-typeG-type
The Sun is a G-type main-sequence star (G2V) based on its spectral class.
The full spectral class for the Sun is then G2V, indicating a main-sequence star with a temperature around 5,800 K.

Surya

SunSun GodRavi
In Proto-Indo-European religion, the Sun was personified as the goddess *Seh 2 ul. Derivatives of this goddess in Indo-European languages include the Old Norse Sól, Sanskrit Surya, Gaulish Sulis, Lithuanian Saulė, and Slavic Solntse.
Surya (सूर्य, IAST: ‘'Sūrya’') is a Sanskrit word that means the Sun.

Sunday

Suday of the sunfirst day of each week
The English weekday name Sunday stems from Old English (Sunnandæg; "Sun's day", from before 700) and is ultimately a result of a Germanic interpretation of Latin dies solis, itself a translation of the Greek ἡμέρα ἡλίου (hēméra hēlíou).
The name "Sunday", the day of the Sun, is derived from Hellenistic astrology, where the seven planets, known in English as Saturn, Jupiter, Mars, the Sun, Venus, Mercury and the Moon, each had an hour of the day assigned to them, and the planet which was regent during the first hour of any day of the week gave its name to that day.

Helios

TitanHeliusSun
In 1868, Norman Lockyer hypothesized that these absorption lines were caused by a new element that he dubbed helium, after the Greek Sun god Helios. In ancient Greek religion, the sun deity was the male god Helios, but traces of an earlier female solar deity are preserved in Helen of Troy.
Helios ( Hēlios; Latinized as Helius; Ἠέλιος in Homeric Greek) is the god and personification of the Sun in Greek mythology.

Solar mass

mass of the SunSun's masssolar masses
Its diameter is about 1.39 million kilometers (864,000 miles), or 109 times that of Earth, and its mass is about 330,000 times that of Earth.
It is equal to the mass of the Sun (denoted by the solar symbol ⊙︎).

Carbon

Ccarbonaceouscarbon atom
Roughly three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron.
Carbon compounds form the basis of all known life on Earth, and the carbon–nitrogen cycle provides some of the energy produced by the Sun and other stars.

Sunlight

sunshinesolar radiationnatural light
The energy of this sunlight supports almost all life on Earth by photosynthesis, and drives Earth's climate and weather.
Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light.

Proto-Indo-European mythology

Indo-EuropeanProto-Indo-EuropeanIndo-European myth
In Proto-Indo-European religion, the Sun was personified as the goddess *Seh 2 ul. Derivatives of this goddess in Indo-European languages include the Old Norse Sól, Sanskrit Surya, Gaulish Sulis, Lithuanian Saulė, and Slavic Solntse.
The Meteorological School holds that Proto-Indo-European mythology was largely centered around deified natural phenomena such as the sky, the Sun, the Moon, and the dawn.

Astronomical unit

AUastronomical unitsAUs
The solar constant is equal to approximately 1368 W/m2 (watts per square meter) at a distance of one astronomical unit (AU) from the Sun (that is, on or near Earth).
The astronomical unit (symbol: au, ua, or AU) is a unit of length, roughly the distance from Earth to the Sun.

Solar constant

energy from the starheatintensity at Earth orbit
The solar constant is the amount of power that the Sun deposits per unit area that is directly exposed to sunlight.
The solar constant (G SC ) is a flux density measuring mean solar electromagnetic radiation (solar irradiance) per unit area.

Ancient Greek religion

Greek PolytheismGreek religionGreek
In ancient Greek religion, the sun deity was the male god Helios, but traces of an earlier female solar deity are preserved in Helen of Troy.
For instance, Zeus was the sky-god, sending thunder and lightning, Poseidon ruled over the sea and earthquakes, Hades projected his remarkable power throughout the realms of death and the Underworld, and Helios controlled the sun.

Limb darkening

limblimb-darkenedsolar limb
The average luminance of the Sun is about 1.88 giga candela per square metre, but as viewed through Earth's atmosphere, this is lowered to about 1.44 Gcd/m 2 . However, the luminance is not constant across the disk of the Sun (limb darkening).
Limb darkening is an optical effect seen in stars (including the Sun), where the center part of the disk appears brighter than the edge or limb of the image.

Corona

solar coronacoronal heating problemcoronae
Atmosphere – a gaseous 'halo' surrounding the Sun, comprising the chromosphere, solar transition region, corona and heliosphere. These can be seen when the main part of the Sun is hidden, for example, during a solar eclipse.
A corona (Latin, 'crown') is an aura of plasma that surrounds the Sun and other stars.