The Sun is a 4.5 billion-year-old yellow dwarf star – a hot glowing bevery one of hydrogen and also helium – at the center of our solar mechanism. It’s about 93 million miles (150 million kilometers) from Planet and it’s our solar system’s only star. Without the Sun’s power, life as we understand it can not exist on our house planet.

From our vantage point on Planet, the Sun might appear prefer an unchanging source of light and warmth in the skies. But the Sun is a dynamic star, constantly altering and also sending power out into room. The scientific research of studying the Sun and also its influence throughout the solar mechanism is called heliophysics.

The Sun is the biggest object in our solar mechanism. Its diameter is about 865,000 miles (1.4 million kilometers). Its gravity holds the solar mechanism together, keeping every little thing from the best planets to the smallest bits of debris in orlittle bit roughly it.

You are watching: How do astronomers know what conditions exist inside the sun

Even though the Sun is the center of our solar mechanism and also vital to our survival, it’s only an average star in regards to its size. Stars up to 100 times bigger have actually been found. And many solar devices have more than one star. By studying our Sun, scientists have the right to much better understand also the woremperors of far-off stars.

The hottest component of the Sun is its core, wbelow temperatures optimal 27 million °F (15 million °C). The part of the Sun we call its surface – the photosphere – is a reasonably cool 10,000 °F (5,500 °C). In one of the Sun’s biggest mysteries, the Sun’s external atmosphere, the corona, gets hotter the farther it stretches from the surconfront. The corona reaches up to 3.5 million °F (2 million °C) – much, a lot hotter than the photospbelow.


Dec. 2, 2020, noted the 2fifth anniversary of the Solar and also Heliospheric Observatory, or SOHO. Because its launch, the mission has maintained watch on the Sun.Namesake

Namesake

The Sun has been called by many type of names. The Latin word for Sun is “sol,” which is the primary adjective for all points Sun-related: solar. Helios, the Sun god in primitive Greek mythology, lends his name to many type of Sun-related terms as well, such as heliospbelow and helioseismology.

Potential for Life

Potential for Life

The Sun might not harbor life as we recognize it bereason of its too much temperatures and radiation. Yet life on Earth is only feasible bereason of the Sun’s light and power.

Size and also Distance

Size and Distance

Our Sun is a medium-sized star via a radius of about 435,000 miles (700,000 kilometers). Many kind of stars are a lot larger – yet the Sun is far even more enormous than our house planet: it would certainly take even more than 330,000 Earths to complement the mass of the Sun, and it would take 1.3 million Earths to fill the Sun's volume.

The Sun is around 93 million miles (150 million kilometers) from Earth. Its nearest stellar neighbor is the Alpha Centauri triple star system: red dwarf star Proxima Centauri is 4.24 light-years ameans, and also Alpha Centauri A and B – 2 sunprefer stars orbiting each various other – are 4.37 light-years away. A light-year is the distance light travels in one year, which amounts to about 6 trillion miles (9.5 trillion kilometers).

Orlittle and Rotation

Orlittle bit and also Rotation

The Sun is situated in the Milky Way galaxy in a spiral arm dubbed the Orion Spur that exoften tends outside from the Sagittarius arm.


*

This illustration mirrors the spiral arms of our Milky Way galaxy. Our Sun is in the Orion Spur. Credit: muzic-ivan.info/Adler/U. Chicago/Wesleyan/JPL-Caltech | Full inscription and image

The Sun orbits the center of the Milky Way, bringing via it the planets, asteroids, comets, and also other objects in our solar mechanism. Our solar mechanism is moving with an average velocity of 450,000 miles per hour (720,000 kilometers per hour). But even at this speed, it takes about 230 million years for the Sun to make one complete trip roughly the Milky Way.

The Sun rotates on its axis as it revolves around the galaxy. Its spin has actually a tilt of 7.25 degrees via respect to the airplane of the planets’ orbits. Since the Sun is not solid, various parts revolve at different prices. At the equator, the Sun spins about once about eincredibly 25 Earth days, however at its poles, the Sun rotates once on its axis eexceptionally 36 Planet days.

Moons

As a star, the Sun doesn’t have any moons, yet the planets and their moons orbit the Sun.

Rings

Rings

The Sun would certainly have actually been surrounded by a disk of gas and also dust beforehand in its history as soon as the solar device was initially forming, around 4.6 billion years earlier. Several of that dust is still around now, in several dust rings that circle the Sun. They trace the orbits of planets, whose gravity tugs dust into place approximately the Sun.

Formation

Formation

The Sun developed around 4.6 billion years earlier in a huge, spinning cloud of gas and also dust referred to as the solar nebula. As the nebula collapsed under its own gravity, it spun much faster and also flattened into a disk. Most of the nebula's material was pulled toward the facility to develop our Sun, which accounts for 99.8% of our solar system’s mass. Much of the continuing to be material developed the planets and various other objects that currently orlittle bit the Sun. (The rest of the leftover gas and also dust was blown away by the young Sun's beforehand solar wind.)

Like all stars, our Sun will eventually run out of energy. When it starts to die, the Sun will expand into a red giant star, ending up being so large that it will engulf Mercury and also Venus, and also probably Planet also. Scientists predict the Sun is a tiny less than halfmethod via its life time and also will certainly last one more 5 billion years or so before it becomes a white dwarf.


A 3D version of the Sun, our star. Credit: muzic-ivan.info Visualization Technology Applications and also Growth (VTAD)› Downfill Options
Structure

Structure

The Sun is a huge bevery one of hydrogen and also helium organized together by its own gravity.

The Sun has several areas. The internal regions incorporate the core, the radiative zone, and the convection zone. Moving outside – the visible surconfront or photospright here is next, then the chromosphere, complied with by the change zone, and also then the corona – the Sun’s expansive outer setting.

Once material leaves the corona at supersonic speeds, it becomes the solar wind, which develops a vast magnetic "bubble" approximately the Sun, dubbed the heliosphere. The heliospbelow exoften tends beyond the orbit of the planets in our solar system. Therefore, Planet exists inside the Sun’s atmosphere. Outside the heliosphere is interstellar area.

The core is the hottest part of the Sun. Nuclear reactions right here – wright here hydrogen is fused to form helium – power the Sun’s warm and also light. Temperatures height 27 million °F (15 million °C) and it’s about 86,000 miles (138,000 kilometers) thick. The density of the Sun’s core is about 150 grams per cubic centimeter (g/cm³). That is roughly 8 times the thickness of gold (19.3 g/cm³) or 13 times the thickness of lead (11.3 g/cm³).

Energy from the core is brought exterior by radiation. This radiation bounces about the radiative zone, taking about 170,000 years to gain from the core to the top of the convection zone. Moving outward, in the convection zone, the temperature drops listed below 3.5 million °F (2 million °C). Here, huge bubbles of warm plasma (a soup of ionized atoms) relocate upward toward the photospright here, which is the layer we think of as the Sun's surchallenge.

Surface

Surface

The Sun doesn’t have actually a solid surface choose Earth and the other rocky planets and also moons. The part of the Sun typically referred to as its surchallenge is the photospbelow. The word photosphere implies "light sphere" – which is apt bereason this is the layer that emits the the majority of visible light. It’s what we see from Planet with our eyes. (Hopetotally, it goes without saying – however never before look directly at the Sun without protecting your eyes.)

Although we speak to it the surface, the photospright here is actually the first layer of the solar environment. It's about 250 miles thick, with temperatures getting to about 10,000 levels Fahrenheit (5,500 levels Celsius). That's much cooler than the blazing core, yet it's still warm enough to make carbon – like diamonds and graphite – not simply melt, but boil. Most of the Sun's radiation escapes outward from the photospright here right into area.

Atmosphere

Atmosphere

Above the photospright here is the chromospright here, the transition zone, and also the corona. Not all researchers refer to the change zone as its own area – it is sindicate the thin layer wbelow the chromospbelow rapidly heats and also becomes the corona. The photospright here, chromospright here, and also corona are all part of the Sun’s setting. (The corona is occasionally casually described as “the Sun’s setting,” however it is actually the Sun’s upper atmosphere.)

The Sun’s environment is wright here we watch features such as sunspots, coronal holes, and solar flares.

Key Sun Features


Visible light from these top regions of the Sun is usually also weak to be watched against the brighter photospbelow, yet throughout total solar eclipses, as soon as the Moon covers the photospbelow, the chromospbelow looks favor a fine, red rim roughly the Sun, while the corona creates a beautiful white crown ("corona" implies crvery own in Latin and Spanish) with plasma streamers narrowing external, developing forms that look choose flower petals.

In among the Sun’s best mysteries, the corona is much hotter than the layers automatically below it. (Imagine walking away from a bonfire only to gain warmer.) The resource of coronal heating is a significant unfixed puzzle in the research of the Sun.

Magnetosphere

Magnetosphere

The Sun generates magnetic fields that extend out into area to develop the interplanetary magnetic field – the magnetic field that pervades our solar device. The area is brought via the solar system by the solar wind – a stream of electrically charged gas blowing outside from the Sun in all directions. The large bubble of area dominated by the Sun’s magnetic area is dubbed the heliosphere. Due to the fact that the Sun rotates, the magnetic area spins out right into a huge rotating spiral, well-known as the Parker spiral. This spiral has a shape something choose the pattern of water from a rotating garden sprinkler.

The Sun doesn't behave the same way all the moment. It goes through phases of high and low task, which consist of the solar cycle. Approximately eextremely 11 years, the Sun’s geographic poles readjust their magnetic polarity – that is, the north and also southern magnetic poles swap. Throughout this cycle, the Sun's photospbelow, chromospright here, and also corona adjust from quiet and calm to violently energetic.

The elevation of the Sun’s task cycle, well-known as solar maximum, is a time of substantially enhanced solar storm task. Sunspots, eruptions referred to as solar flares, and also coronal mass ejections are prevalent at solar maximum. The latest solar cycle – Solar Cycle 25 – started in December 2019 as soon as solar minimum developed, according to the Solar Cycle 25 Prediction Panel, an worldwide group of professionals co-sponsored by muzic-ivan.info and NOAA. Scientists currently suppose the Sun’s activity to ramp up towards the next predicted maximum in July 2025.

Solar task deserve to release huge quantities of energy and also pshort articles, some of which affect us here on Earth. Much favor weather on Earth, conditions in space – well-known as room weather – are always transforming via the Sun’s task. "Gap weather" can interfere through satellites, GENERAL PRACTITIONERS, and radio communications. It additionally deserve to cripple power grids, and also corrode pipelines that carry oil and gas.

The strongest geomagnetic storm on record is the Carrington Event, called for British astronomer Rictough Carrington that oboffered the Sept. 1, 1859, solar flare that triggered the event. Telegraph units international went haywire. Spark discharges shocked telegraph operators and collection their telegraph paper on fire. Just before dawn the next day, skies almost everywhere Earth erupted in red, green, and purple auroras – the result of energy and pposts from the Sun interacting through Earth’s environment. Reportedly, the auroras were so brilliant that newsrecords could be review as quickly as in daylight. The auroras, or Northern Lights, were visible as far south as Cuba, the Bahamas, Jamaica, El Salvador, and Hawaii.

Another solar flare on March 13, 1989, resulted in geomagnetic storms that disrupted electric power transmission from the Hydro Québec generating terminal in Canada, plunging 6 million human being right into darkness for 9 hrs. The 1989 flare additionally led to power surges that melted power transformers in New Jersey.

In December 2005, X-rays from a solar storm disrupted satellite-to-ground communications and also Global Positioning System (GPS) navigation signals for about 10 minutes.

NOAA’s Space Weather Prediction Center monitors active areas on the Sun and issues watches, warnings, and alerts for hazardous area weather events.

Resources

Resources


Length of day 25 Planet days at the equator and also 36 Earth days at the poles.

See more: Fin A Short Term Creditor Would Be Most Interested In Terest To The Short

Length of year The Sun doesn't have actually a "year," per se. But the Sun orbits the center of the Milky Way about eextremely 230 million Earth years, bringing the planets, asteroids, comets, and other objects via it.

Star type G2 V, yellow dwarf main-sequence star

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

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