Sun: Difference between revisions

Sun
	The Sun, viewed through a clear solar filter
Type	G-type main-sequence star
Spectral Class	G2V
Mass	1.989 × 10^30 kg
Radius	696,340 km
Luminosity	3.828 × 10^26 W
Surface Temperature	5,778 K
Distance from Earth	0 light-years (center of Solar System)
Age	4.6 billion years
Gravity	274 m/s² (at surface)
Composition	74% hydrogen, 24% helium, 2% heavier elements
Constellation	Leo
Discovery	Known since antiquity

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Latest revision as of 10:41, 13 January 2025

The Sun is the star at the center of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies. It is by far the most important source of energy for life on Earth. The Sun has been an object of veneration in many cultures. It has been a central subject for astronomical research since antiquity.

The Sun orbits the Galactic Center at a distance of 24,000 to 28,000 light-years. From Earth, it is astronomical unit (1.496×108 km) or about 8 light-minutes away. Its diameter is about 1,391,400 km (864,600 mi), 109 times that of Earth. Its mass is about 330,000 times that of Earth, making up about 99.86% of the total mass of the Solar System. 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.

The Sun is a G-type main-sequence star (G2V), informally called a yellow dwarf, though its light is actually white. It formed approximately 4.6 billion^{[lower-alpha 1]} years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core. Every second, the Sun's core fuses about 600 billion kilograms (kg) of hydrogen into helium and converts 4 billion kg of matter into energy.

About 4 to 7 billion years from now, when hydrogen fusion in the Sun's core diminishes to the point where the Sun is no longer in hydrostatic equilibrium, its core will undergo a marked increase in density and temperature which will cause its outer layers to expand, eventually transforming the Sun into a red giant. This process will make the Sun large enough to render Earth uninhabitable approximately five billion years from the present. After the red giant phase, models suggest the Sun will shed its outer layers and become a dense type of cooling star (a white dwarf), and no longer produce energy by fusion, but will still glow and give off heat from its previous fusion for perhaps trillions of years. After that, it is theorized to become a super dense black dwarf, giving off negligible energy.

Etymology[edit]

The English word sun developed from Old English sunne. Cognates appear in other Germanic languages, including West Frisian sinne, Dutch zon, Low German Sünn, Standard German Sonne, Bavarian Sunna, Old Norse sunna, and Gothic sunnō. All these words stem from Proto-Germanic *sunnōn.^[1]^[2] This is ultimately related to the word for sun in other branches of the Indo-European language family, though in most cases a nominative stem with an l is found, rather than the genitive stem in n, as for example in Latin sōl, ancient Greek ἥλιος (hēlios), Welsh haul and Czech slunce, as well as (with *l > r) Sanskrit स्वर् (svár) and Persian خور (xvar). Indeed, the l-stem survived in Proto-Germanic as well, as *sōwelan,, which gave rise to Gothic sauil (alongside sunnō) and Old Norse prosaic sól (alongside poetic sunna), and through it the words for sun in the modern Scandinavian languages: Swedish and Danish sol,, Icelandic sól,, etc.^[2]

The principal adjectives for the Sun in English are sunny for sunlight and, in technical contexts, solar (/ˈsoʊlər/),^[3] from Latin .^[4] From the Greek helios comes the rare adjective heliac (/ˈhiːliæk/). In English, the Greek and Latin words occur in poetry as personifications of the Sun, Helios (/ˈhiːliəs/) and Sol (/ˈsɒl/),^[5]^[6] while in science fiction Sol may be used to distinguish the Sun from other stars. The term sol with a lowercase s is used by planetary astronomers for the duration of a solar day on another planet such as Mars.^[7]

The astronomical symbol for the Sun is a circle with a center dot, .^[8] It is used for such units as M_☉ (Solar mass), R_☉ (Solar radius) and L_☉ (Solar luminosity).^[9]^[10] The scientific study of the Sun is called heliology.^[11]

Sun[edit]

The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy mainly as visible light and infrared radiation, and driving the solar wind, a stream of charged particles that blow outward through the Solar System.

Physical Characteristics[edit]

The Sun is composed mostly of hydrogen (about 74%) and helium (about 24%), with trace amounts of heavier elements such as oxygen, carbon, neon, and iron. It has a diameter of approximately 1.4 million kilometers (870,000 miles), about 109 times that of Earth, and its mass is about 330,000 times that of Earth, making it about 99.86% of the total mass of the Solar System.

Structure[edit]

The Sun is divided into several layers, each with distinct characteristics:

Core: The innermost layer, where nuclear fusion occurs, producing energy.
Radiative zone: Surrounds the core; energy from the core is transported outward by radiation.
Convective zone: The outer layer of the Sun, where energy is transported by convection.
Corona: The outermost part of the Sun's atmosphere, visible during a solar eclipse.

Solar Activity[edit]

The Sun undergoes various cycles of activity, including the solar cycle, which is an approximately 11-year cycle during which the frequency of solar storms, such as sunspots and solar flares, fluctuates. The Sun's magnetic field is responsible for these phenomena, and during periods of high activity, the number of sunspots increases, leading to more solar flares and coronal mass ejections.

Solar Wind[edit]

The solar wind is a continuous stream of charged particles, primarily electrons and protons, that flow outward from the Sun. The solar wind shapes the heliosphere, a bubble-like region of space dominated by the Sun’s magnetic field and solar wind. The solar wind interacts with the magnetic fields of planets, creating phenomena such as the auroras on Earth.

Importance for Life on Earth[edit]

The Sun is crucial for sustaining life on Earth. It provides light and warmth, enabling photosynthesis in plants and regulating Earth's climate. Its energy is essential for maintaining the Earth's water cycle and supporting the overall ecosystem. However, solar activity can also affect Earth, as large solar storms have the potential to disrupt satellite communications and power grids.

Observation and Study[edit]

Humans have been observing the Sun for millennia. Ancient civilizations such as the Egyptians and Greeks studied its movements, and it played a significant role in various mythologies. Modern astronomy and space exploration have significantly expanded our understanding of the Sun. Instruments like the Solar and Heliospheric Observatory (SOHO) and the Parker Solar Probe have provided invaluable data on the Sun's behavior.

Solar System Formation[edit]

The Sun formed approximately 4.6 billion years ago from the gravitational collapse of a region within a large molecular cloud. This collapse triggered nuclear fusion in the core, marking the birth of the Sun. The surrounding material formed a rotating disk that eventually coalesced into the planets, moons, and other objects in the Solar System.

References[edit]

The Sun. Nasa.gov. Retrieved on December 24, 2024.
Template:Cite encyclopedia

Cite error: <ref> tags exist for a group named "lower-alpha", but no corresponding <references group="lower-alpha"/> tag was found

↑ The Barnhart Concise Dictionary of Etymology. HarperCollins,1995.ISBN 978-0-06-270084-1.
↑ ^2.0 ^2.1 A Handbook of Germanic Etymology. Brill,2003.ISBN 978-9-00-412875-0.
↑ Error on call to Template:cite web: Parameters url and title must be specified. Oxford University Press.
↑ Template:Cite dictionary
↑ Template:Cite dictionary
↑ Error on call to Template:cite web: Parameters url and title must be specified. Oxford University Press.
↑ Opportunity's View, Sol 959 (Vertical). NASA (15 November 2006).
↑ Allen's Astrophysical Quantities(4th ed.). Springer,2000.ISBN 978-0-38-798746-0.
↑ Template:Cite dictionary
↑ Encyclopedia of the Solar System. Academic Press,ISBN 978-0-08-057313-7.
↑ Template:Cite dictionary

[BARNHART776-2] The Barnhart Concise Dictionary of Etymology. HarperCollins,1995.ISBN 978-0-06-270084-1.

[Orel-3] 2.0 ^2.1 A Handbook of Germanic Etymology. Brill,2003.ISBN 978-9-00-412875-0.

[OED2-4] Error on call to Template:cite web: Parameters url and title must be specified. Oxford University Press.

[5] Template:Cite dictionary

[Lexico-6] Template:Cite dictionary

[OED-7] Error on call to Template:cite web: Parameters url and title must be specified. Oxford University Press.

[8] Opportunity's View, Sol 959 (Vertical). NASA (15 November 2006).

[9] Allen's Astrophysical Quantities(4th ed.). Springer,2000.ISBN 978-0-38-798746-0.

[10] Template:Cite dictionary

[11] Encyclopedia of the Solar System. Academic Press,ISBN 978-0-08-057313-7.

[12] Template:Cite dictionary

[lower-alpha 1]

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

@@ Line 1: / Line 1: @@
+{{SHORTDESC: Star at the center of the Solar System}}
 {{Infobox star
 | name             = Sun
@@ Line 20: / Line 21: @@
 | discovered       = Known since antiquity
 }}
+The '''Sun''' is the [[star]] at the center of the [[Solar System]]. It is a massive, nearly perfect [[sphere]] of hot [[Plasma (physics)|plasma]], heated to [[incandescence]] by [[nuclear fusion]] reactions in its core, radiating the energy from its [[surface]] mainly as [[visible light]] and [[infrared radiation]] with 10% at [[ultraviolet]] energies. It is by far the most important source of energy for [[life]] on [[Earth]]. The Sun has been an [[The Sun in culture|object of veneration]] in many cultures. It has been a central subject for astronomical research since [[Ancient history|antiquity]].
+The Sun orbits the [[Galactic Center]] at a distance of 24,000 to 28,000 [[light-year]]s. From Earth, it is [[astronomical unit]] (1.496×108 km)  or about 8 [[light-minute]]s away. [[Solar radius|Its diameter]] is about 1,391,400 km (864,600 mi), 109 times that of Earth. [[solar mass|Its mass]] is about 330,000 times that of Earth, making up about 99.86% of the total mass of the Solar System. 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]].
+The Sun is a [[G-type main-sequence star]] (G2V), informally called a yellow dwarf, though its light is actually white. It formed approximately 4.6&nbsp;billion<ref group=lower-alpha name=short>All numbers in this article are [[short scale]]. One billion is 10<sup>9</sup>, or 1,000,000,000.</ref> years ago from the [[gravitational collapse]] of matter within a region of a large [[molecular cloud]]. Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that [[formation and evolution of the Solar System|became the Solar System]]. The central mass became so hot and dense that it eventually initiated [[nuclear fusion]] in its [[solar core|core]]. Every second, the Sun's core fuses about 600&nbsp;billion [[kilograms]] (kg) of hydrogen into helium and converts 4&nbsp;billion kg of [[mass–energy equivalence|matter into energy]].
+About 4 to 7 billion years from now, when [[hydrogen fusion]] in the Sun's core diminishes to the point where the Sun is no longer in [[hydrostatic equilibrium]], its core will undergo a marked increase in density and temperature which will cause its outer layers to expand, eventually transforming the Sun into a [[red giant]]. This process will make the Sun large enough to render Earth uninhabitable approximately five billion years from the present. After the red giant phase, models suggest the Sun will shed its outer layers and become a dense type of cooling star (a [[white dwarf]]), and no longer produce energy by fusion, but will still glow and give off heat from its previous fusion for perhaps trillions of years. After that, it is theorized to become a super dense [[black dwarf]], giving off negligible energy.
+== Etymology ==
+The English word ''sun'' developed from [[Old English]] sunne. Cognates appear in other [[Germanic languages]], including [[West Frisian language|West Frisian]] sinne, [[Dutch language|Dutch]] zon, [[Low German]] Sünn, [[Standard German]] Sonne, [[Bavarian language|Bavarian]] Sunna, [[Old Norse]] sunna, and [[Gothic language|Gothic]] sunnō. All these words stem from [[Proto-Germanic]] *sunnōn.<ref name="BARNHART776">{{Cite book |last=Barnhart |first=R. K. |title=The Barnhart Concise Dictionary of Etymology |year=1995 |publisher=[[HarperCollins]] |isbn=978-0-06-270084-1 |page=776}}</ref><ref name="Orel">{{cite book|last=Orel|first=Vladimir|author-link=Vladimir Orel|year=2003|title=A Handbook of Germanic Etymology|page=[https://archive.org/details/Orel-AHandbookOfGermanicEtymology/mode/2up/search/sun 41]|url=https://archive.org/details/Orel-AHandbookOfGermanicEtymology/mode/2up|via=[[Internet Archive]]|publisher=Brill|place=Leiden|isbn=978-9-00-412875-0}}</ref> This is ultimately related to the word for ''sun'' in other branches of the [[Indo-European language]] family, though in most cases a [[nominative]] stem with an ''l'' is found, rather than the [[genitive]] stem in ''n'', as for example in [[Latin]] sōl, [[ancient Greek]] ἥλιος (hēlios), [[Welsh language|Welsh]] haul and [[Czech language|Czech]] slunce, as well as (with *l > ''r'') Sanskrit स्वर् (svár) and [[Persian language|Persian]] خور (xvar). Indeed, the ''l''-stem survived in Proto-Germanic as well, as *sōwelan,, which gave rise to Gothic sauil (alongside sunnō) and Old Norse prosaic sól (alongside poetic sunna), and through it the words for ''sun'' in the modern Scandinavian languages: [[Swedish language|Swedish]] and [[Danish language|Danish]] sol,, [[Icelandic language|Icelandic]] sól,, etc.<ref name=Orel />
+The principal adjectives for the Sun in English are ''sunny'' for sunlight and, in technical contexts, ''solar'' (/ˈsoʊlər/),<ref name="OED2">{{OED|solar}}</ref> from Latin .<ref>{{cite dictionary |last1=Little |first1=William |dictionary=Oxford Universal Dictionary on Historical Principles |last2=Fowler |first2=H. W. |last3=Coulson |first3=J. |year=1955 |edition=3rd |title=Sol |asin=B000QS3QVQ |url=https://archive.org/details/oxforduniversald07litt |url-access=registration}}</ref> From the Greek helios comes the rare adjective ''heliac'' (/ˈhiːliæk/). In English, the Greek and Latin words occur in poetry as personifications of the Sun, [[Helios]] (/ˈhiːliəs/) and [[Sol (Roman mythology)|Sol]] (/ˈsɒl/),<ref name="Lexico">{{Cite dictionary |title=Helios |dictionary=[[Lexico]] UK English Dictionary |publisher=[[Oxford University Press]] |url=http://www.lexico.com/definition/Helios |archive-url=https://web.archive.org/web/20200327234645/https://www.lexico.com/definition/helios |archive-date=27 March 2020 |url-status=dead}}</ref><ref name="OED">{{OED|Sol}}</ref> while in science fiction ''Sol'' may be used to distinguish the Sun from other stars. The term ''[[Sol (day on Mars)|sol]]'' with a lowercase ''s'' is used by planetary astronomers for the duration of a [[solar day]] on another planet such as [[Mars]].<ref>{{Cite web |date=15 November 2006 |title=Opportunity's View, Sol 959 (Vertical) |url=http://www.nasa.gov/mission_pages/mer/images/pia01892.html |url-status=live |archive-url=https://web.archive.org/web/20121022155351/http://www.nasa.gov/mission_pages/mer/images/pia01892.html |archive-date=22 October 2012 |access-date=1 August 2007 |publisher=[[NASA]]}}</ref>
+The [[astronomical symbol]] for the Sun is a circle with a center dot, [[File:Sun symbol (fixed width).svg|16px|☉]].<ref>{{cite book |last1=Allen |first1=Clabon W. |author-link1=Clabon Allen |last2=Cox |first2=Arthur N. |editor-last=Cox |editor-first=Arthur N. |year=2000 |title=Allen's Astrophysical Quantities |page=2 |publisher=Springer |edition=4th |isbn=978-0-38-798746-0 |url=https://books.google.com/books?id=w8PK2XFLLH8C|via=[[Google Books]]}}</ref> It is used for such units as ''M''<sub>☉</sub> ([[Solar mass]]), ''R''<sub>☉</sub> ([[Solar radius]]) and ''L''<sub>☉</sub> ([[Solar luminosity]]).<ref>{{Cite dictionary |title=solar mass |url=https://www.oxfordreference.com/display/10.1093/oi/authority.20110803100516843 |access-date=2024-05-26 |dictionary=Oxford Reference }}</ref><ref>{{Cite book |last1=Weissman |first1=Paul |url=https://books.google.com/books?id=4gmSOrXIQUEC&dq=%22solar+radius%22&pg=PA349 |title=Encyclopedia of the Solar System |last2=McFadden |first2=Lucy-Ann |last3=Johnson |first3=Torrence |date=1998-09-18 |publisher=Academic Press |isbn=978-0-08-057313-7 |pages=349, 820}}</ref>
+The scientific study of the Sun is called ''heliology''.<ref>{{cite dictionary |url=https://www.collinsdictionary.com/dictionary/english/heliology |title=heliology |publisher=Collins |dictionary=Collins Dictionary |access-date=24 November 2024 }}</ref>
 == Sun ==
 The '''Sun''' is the star at the center of the [[Solar System]]. It is a nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy mainly as visible light and infrared radiation, and driving the [[solar wind]], a stream of charged particles that blow outward through the [[Solar System]].
-=== Physical Characteristics ===
+==Physical Characteristics ==
 The Sun is composed mostly of [[hydrogen]] (about 74%) and [[helium]] (about 24%), with trace amounts of heavier elements such as oxygen, carbon, neon, and iron. It has a diameter of approximately 1.4 million kilometers (870,000 miles), about 109 times that of Earth, and its mass is about 330,000 times that of Earth, making it about 99.86% of the total mass of the [[Solar System]].
-=== Structure ===
+== Structure ==
 The Sun is divided into several layers, each with distinct characteristics:
@@ Line 35: / Line 53: @@
 * '''Corona''': The outermost part of the Sun's atmosphere, visible during a solar eclipse.
-=== Solar Activity ===
+== Solar Activity ==
 The Sun undergoes various cycles of activity, including the [[solar cycle]], which is an approximately 11-year cycle during which the frequency of solar storms, such as sunspots and solar flares, fluctuates. The Sun's magnetic field is responsible for these phenomena, and during periods of high activity, the number of sunspots increases, leading to more solar flares and coronal mass ejections.
-==== Solar Wind ====
+=== Solar Wind ===
 The [[solar wind]] is a continuous stream of charged particles, primarily electrons and protons, that flow outward from the Sun. The solar wind shapes the [[heliosphere]], a bubble-like region of space dominated by the Sun’s magnetic field and solar wind. The solar wind interacts with the magnetic fields of planets, creating phenomena such as the [[auroras]] on Earth.
-=== Importance for Life on Earth ===
+== Importance for Life on Earth ==
 The Sun is crucial for sustaining life on Earth. It provides light and warmth, enabling photosynthesis in plants and regulating Earth's climate. Its energy is essential for maintaining the Earth's [[water cycle]] and supporting the overall ecosystem. However, solar activity can also affect Earth, as large solar storms have the potential to disrupt [[satellite]] communications and [[power grid]]s.
-=== Observation and Study ===
+== Observation and Study ==
 Humans have been observing the Sun for millennia. Ancient civilizations such as the [[Egyptians]] and [[Greeks]] studied its movements, and it played a significant role in various mythologies. Modern astronomy and space exploration have significantly expanded our understanding of the Sun. Instruments like the [[Solar and Heliospheric Observatory]] (SOHO) and the [[Parker Solar Probe]] have provided invaluable data on the Sun's behavior.
-=== Solar System Formation ===
+== Solar System Formation ==
 The Sun formed approximately 4.6 billion years ago from the gravitational collapse of a region within a large molecular cloud. This collapse triggered nuclear fusion in the core, marking the birth of the Sun. The surrounding material formed a rotating disk that eventually coalesced into the planets, moons, and other objects in the [[Solar System]].
-=== See Also ===
+== See Also ==
 * [[Solar System]]
 * [[Solar Cycle]]
@@ Line 58: / Line 76: @@
 * [[Earth]]
-=== References ===
+== References ==
 * {{cite web |url=https://www.nasa.gov/sun |title=The Sun |publisher=Nasa.gov |accessdate=2024-12-24}}
 * {{cite encyclopedia |last=Brown |first=James |title=The Sun |encyclopedia=[[Encyclopædia Britannica]] |year=2024 |url=https://www.britannica.com/sun}}