The sun is a 4.5 billion-year-old yellow dwarf star – a warm glowing sphere of hydrogen and helium – in ~ the center of our solar system. It’s around 93 million miles (150 million kilometers) native Earth and also it’s ours solar system’s only star. Without the Sun’s energy, life as we recognize it could not exist ~ above our house planet.

From ours vantage point on Earth, the sun may show up like one unchanging resource of light and heat in the sky. However the sun is a dynamic star, constantly transforming and sending power out right into space. The science of researching the Sun and its affect throughout the solar device is referred to as heliophysics.

The sun is the biggest object in our solar system. The diameter is around 865,000 mile (1.4 million kilometers). Its gravity holds the solar system together, keeping whatever from the biggest planets come the the smallest bits of debris in orbit approximately it.

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Even though the sun is the center of our solar system and essential come our survival, it’s only an average star in terms of its size. Stars up to 100 time larger have actually been found. And many solar equipment have much more than one star. By studying our Sun, researchers can far better understand the workings of far-off stars.

The hottest part of the sun is the core, wherein temperatures optimal 27 million °F (15 million °C). The component of the sunlight we call its surface – the photosphere – is a fairly cool 10,000 °F (5,500 °C). In one of the Sun’s biggest mysteries, the Sun’s outer atmosphere, the corona, it s okay hotter the furthermore it stretches from the surface. The corona reaches as much as 3.5 million °F (2 million °C) – much, lot hotter than the photosphere.

Dec. 2, 2020, significant the 25th anniversary that the Solar and Heliospheric Observatory, or SOHO. Since its launch, the mission has kept clock on the Sun.Namesake


The Sun has been dubbed by many names. The Latin word for sun is “sol,” which is the key adjective for all things Sun-related: solar. Helios, the sunlight god in old Greek mythology, lends his surname to plenty of Sun-related terms as well, such together heliosphere and helioseismology.

Potential because that Life

Potential because that Life

The Sun could not port life as we understand it since of its too much temperatures and also radiation. Yet life on planet is only feasible because of the Sun’s light and also energy.

Size and also Distance

Size and also Distance

Our sunlight is a medium-sized star through a radius of around 435,000 miles (700,000 kilometers). Countless stars room much larger – however the sunlight is far much more massive 보다 our residence planet: it would certainly take much more than 330,000 Earths to complement the mass of the Sun, and also it would certainly take 1.3 million Earths to to fill the Sun's volume.

The sunlight is around 93 million miles (150 million kilometers) native Earth. The nearest stellar neighbor is the Alpha Centauri triple star system: red dwarf star Proxima Centauri is 4.24 light-years away, and Alpha Centauri A and also B – 2 sunlike stars orbiting each other – are 4.37 light-years away. A light-year is the street light travel in one year, i beg your pardon equals around 6 sunshine miles (9.5 trillion kilometers).

Orbit and also Rotation

Orbit and Rotation

The sun is situated in the Milky means galaxy in a spiral arm referred to as the Orion Spur the extends external from the Sagittarius arm.


This illustration reflects the spiral eight of our Milky way galaxy. Our sun is in the Orion Spur. Credit: Chicago/Wesleyan/JPL-Caltech | full caption and image

The sun orbits the center of the Milky Way, bringing with it the planets, asteroids, comets, and also other objects in our solar system. Our solar mechanism is relocating with an average velocity of 450,000 miles per hour (720,000 kilometers per hour). Yet even in ~ this speed, the takes around 230 million years because that the sun to make one finish trip around the Milky Way.

The sun rotates top top its axis as it revolves around the galaxy. That spin has a tilt that 7.25 levels with respect to the aircraft of the planets’ orbits. Since the sun is not solid, different parts revolve at different rates. In ~ the equator, the sun spins around once about every 25 planet days, yet at its poles, the sun rotates as soon as on the axis every 36 planet days.


As a star, the sun doesn’t have any type of moons, but the planets and their moons orbit the Sun.



The sun would have actually been surrounded by a decaying of gas and also dust beforehand in its background when the solar system was an initial forming, about 4.6 billion years ago. Several of that dust is still roughly today, in numerous dust rings that circle the Sun. They map the orbits the planets, whose heaviness tugs dust right into place around the Sun.



The sunlight formed around 4.6 billion years earlier in a giant, spinning cloud that gas and also dust referred to as the solar nebula. As the nebula fell down under its very own gravity, it be crazy faster and flattened into a disk. Many of the nebula's product was pulled towards the center to form our Sun, i beg your pardon accounts for 99.8% of ours solar system’s mass. Lot of the continuing to be material formed the planets and also other objects that now orbit the Sun. (The remainder of the leftover gas and also dust to be blown far by the young Sun's early on solar wind.)

Like every stars, our sunlight will ultimately run the end of energy. As soon as it starts come die, the sunlight will increase into a red large star, coming to be so large that it will certainly engulf Mercury and also Venus, and also possibly planet as well. Researchers predict the sunlight is a little less 보다 halfway v its lifetime and also will last another 5 billion year or so before it becomes a white dwarf.

A 3D version of the Sun, ours star. Credit: Visualization modern technology Applications and breakthrough (VTAD)› Download Options


The sun is a substantial ball of hydrogen and helium organized together by its own gravity.

The Sun has actually several regions. The interior regions encompass the core, the radiative zone, and the convection zone. Moving outward – the visible surface or photosphere is next, then the chromosphere, complied with by the change zone, and then the corona – the Sun’s expansive external atmosphere.

Once product leaves the corona in ~ supersonic speeds, it i do not care the solar wind, which forms a huge magnetic "bubble" around the Sun, called the heliosphere. The heliosphere extends beyond the orbit the the planets in ours solar system. Thus, planet exists inside the Sun’s atmosphere. Exterior the heliosphere is interstellar space.

The main point is the hottest part of the Sun. Atom reactions below – wherein hydrogen is fused to type helium – strength the Sun’s heat and light. Temperatures height 27 million °F (15 million °C) and also it’s around 86,000 miles (138,000 kilometers) thick. The thickness of the Sun’s core is about 150 grams per cubic centimeter (g/cm³). The is about 8 time the density of yellow (19.3 g/cm³) or 13 time the thickness of lead (11.3 g/cm³).

Energy indigenous the main point is carried outward through radiation. This radiation bounces roughly the radiative zone, taking about 170,000 years to gain from the main point to the top of the convection zone. Moving outward, in the convection zone, the temperature drops below 3.5 million °F (2 million °C). Here, huge bubbles of warm plasma (a soup of ionized atoms) relocate upward toward the photosphere, i beg your pardon is the layer us think of together the Sun's surface.



The sunlight doesn’t have actually a hard surface prefer Earth and also the other rocky planets and moons. The part of the Sun commonly called its surface ar is the photosphere. The word photosphere method "light sphere" – i m sorry is apt due to the fact that this is the layer the emits the most visible light. It’s what we view from earth with ours eyes. (Hopefully, the goes without speak – yet never look directly at the sun without protecting your eyes.)

Although we contact it the surface, the photosphere is in reality the very first layer the the solar atmosphere. It's around 250 miles thick, with temperatures reaching around 10,000 levels Fahrenheit (5,500 degrees Celsius). That's lot cooler than the blazing core, however it's tho hot enough to make carbon – like diamonds and graphite – not just melt, but boil. Most of the Sun's radiation escapes exterior from the photosphere right into space.



Above the photosphere is the chromosphere, the transition zone, and also the corona. No all scientists refer to the shift zone as its own an ar – that is simply the thin layer where the chromosphere quickly heats and also becomes the corona. The photosphere, chromosphere, and also corona room all component of the Sun’s atmosphere. (The corona is periodically casually referred to as “the Sun’s atmosphere,” yet it is actually the Sun’s upper atmosphere.)

The Sun’s atmosphere is whereby we see attributes such as sunspots, coronal holes, and also solar flares.

Visible irradiate from these height regions that the sunlight is usually also weak to be seen against the brighter photosphere, but during complete solar eclipses, when the Moon consists the photosphere, the chromosphere looks like a fine, red rim approximately the Sun, if the corona forms a beautiful white crown ("corona" means crown in Latin and Spanish) v plasma streamers narrowing outward, developing shapes that look like flower petals.

In one of the Sun’s biggest mysteries, the corona is much hotter than the layers automatically below it. (Imagine walking away from a bonfire only to get warmer.) The source of coronal heating is a major unsolved puzzle in the study of the Sun.



The sunlight generates magnetic areas that expand out into an are to type the interplanetary magnetic field – the magnetic field that pervades ours solar system. The field is lugged through the solar device by the solar wind – a stream of electrically charged gas blowing exterior from the sun in every directions. The huge bubble of room dominated by the Sun’s magnetic field is dubbed the heliosphere. Since the sun rotates, the magnetic ar spins out into a large rotating spiral, well-known as the Parker spiral. This spiral has a form something like the sample of water native a rotating garden sprinkler.

The sun doesn't law the same means all the time. It goes through phases that high and also low activity, which make up the solar cycle. Roughly every 11 years, the Sun’s geographical poles adjust their magnetic polarity – that is, the north and also south magnetic poles swap. During this cycle, the Sun's photosphere, chromosphere, and corona change from quiet and also calm to violently active.

The elevation of the Sun’s task cycle, known as solar maximum, is a time of substantially increased solar storm activity. Sunspots, eruptions dubbed solar flares, and also coronal massive ejections are usual at solar maximum. The latest solar bike – Solar bicycle 25 – began in December 2019 once solar minimum occurred, follow to the Solar cycle 25 forecast Panel, an international group of specialists co-sponsored by and NOAA. Scientists now expect the Sun’s activity to ramp up towards the following predicted maximum in July 2025.

Solar task can release huge amounts that energy and particles, several of which affect us below on Earth. Lot like weather on Earth, problems in space – well-known as room weather – room always an altering with the Sun’s activity. "Space weather" deserve to interfere through satellites, GPS, and also radio communications. It likewise can cripple power grids, and corrode pipelines that lug oil and gas.

The the strongest geomagnetic storm on record is the Carrington Event, named for brother astronomer Richard Carrington that observed the Sept. 1, 1859, solar flare that triggered the event. Telegraph systems global went haywire. Spark discharges shocked telegraph operator and collection their telegraph document on fire. Just prior to dawn the next day, skies every over earth erupted in red, green, and also purple auroras – the an outcome of energy and particles native the Sun connecting with Earth’s atmosphere. Reportedly, the auroras were so brilliant the newspapers might be check out as conveniently as in daylight. The auroras, or north Lights, were visible as much south together Cuba, the Bahamas, Jamaica, El Salvador, and Hawaii.

Another solar flare on in march 13, 1989, led to geomagnetic storms that disrupted electric power transmission from the Hydro Québec generating station in Canada, plunging 6 million people into darkness because that 9 hours. The 1989 flare also caused strength surges the melted strength transformers in new Jersey.

In December 2005, X-rays native a solar storm disrupted satellite-to-ground interactions and worldwide Positioning device (GPS) navigation signals for about 10 minutes.

NOAA’s an are Weather Prediction center monitors energetic regions ~ above the Sun and issues watches, warnings, and alerts for hazardous space weather events.



Diameter 865,000 miles | 1.4 million kilometers

Length of day 25 earth days in ~ the equator and 36 planet days in ~ the poles.

See more: Why Are Metals Able To Conduct Electricity ? Why Do Metals Conduct Electricity

Length that year The sun doesn't have a "year," per se. However the sun orbits the center of the Milky way about every 230 million earth years, pass the planets, asteroids, comets, and other objects with it.

Volume 338,100,000,000,000,000 miles3 (1,409,000,000,000,000,000 km3), or 3.381 x 1017 miles3 (1.409 x 1018km3)

Mass 1.99 × 1030 kg, or 333,000 earth masses

Star type G2 V, yellow dwarf main-sequence star

Surface temperature (Photosphere) 10,000 levels Fahrenheit (5,500 degrees Celsius)

Corona (solar atmosphere) temperature approximately 3.5 million °F (2 million °C)