The sun is the greatest object in the solar system, and it is located in the center of it.
It contains 99.8% of the mass of the solar system and has a diameter of around 109 times that of the Earth; one million Earths could fit within the sun.
The sun’s surface is roughly 10,000 degrees Fahrenheit (5,500 degrees Celsius) heated. While nuclear reactions raise temperatures in the core to almost 27 million degrees Fahrenheit (15 million degrees Celsius).
According to NASA, to duplicate the energy produced by the sun, 100 billion tonnes of dynamite would have to explode every second.
The Milky Way contains around 100 billion stars, including the sun. It orbits the galactic core at a distance of around 25,000 light-years, turning once every 250 million years or so. The sun is a young star, belonging to a population of stars known as Population I. This is rich in heavier elements than helium.
Population II is an older generation of stars, and Population III may have occurred as well. However, no members of this generation have yet been discovered.
THE FORMATION OF THE SUN
The sun was created approximately 4.6 billion years ago. The sun and the rest of the solar system thought to have arisen from a massive revolving cloud of gas and dust known as the solar nebula, according to many astronomers. The nebula whirled faster and flattened into a disc as it collapsed due to gravity. To build the sun, the majority of the material drawn toward the center.
The sun has enough nuclear fuel to last another 5 billion years in its current state. It will then swell to the size of a crimson giant. It will eventually shed its outer layers, with the remaining core collapsing to form a white dwarf. The white dwarf will gradually fade, eventually transforming into a dim, cool theoretical entity known as a black dwarf.
THE SUN’S INTERNAL STRUCTURE AND ATMOSPHERE
The sun, as well as its atmosphere, separated into various zones and layers. The core, radiative zone, and convection zone make up the solar interior from the inside out. The photosphere, chromosphere, transition area, and corona make up the solar atmosphere above that. The solar wind, a gas outflow from the corona, lies beyond that.
From the sun’s center to roughly a quarter of the way to its surface, the core extends.
Although it only accounts for around 2% of the sun’s volume. It has a density approximately 15 times that of lead and holds nearly half of the sun’s mass.
The radiative zone, which spans from the core to 70% of the way to the sun’s surface and accounts for 32% of the sun’s volume and 48% of its mass, is next.
In this zone, light from the core is dispersed, and a single photon can take a million years to travel through.
The convective zone extends up to the sun’s surface and accounts for 66 percent of the sun’s volume
but only about 2% of its mass. This zone dominates by roiling “convection cells” of gas.
There are two types of solar convection cells: granulation cells, which are about 600 miles (1,000 kilometers) broad, and supergranulation cells, which are around 20,000 miles (30,000 kilometers) wide.
The photosphere is the lowest layer of the sun’s atmosphere, and it is this layer that produces visible light.
Although most of the light originates from the bottom third, it is around 300 miles (500 kilometers) thick.
Temperatures in the photosphere range from 11,000 degrees Fahrenheit (6,125 degrees Celsius)
at the bottom to 7,460 degrees Fahrenheit (4,125 degrees Celsius) at the top.
The hotter chromosphere formed completely of spiky structures known as spicules. Which are typically 600 miles (1,000 kilometers) across and 6,000 miles (10,000 kilometers) high.
THE MAGNETIC FIELD OF THE SUN
The transition region, which is a few hundred to a few thousand miles deep and heated by the corona above it,
emits the majority of its light as ultraviolet rays follow. The super-hot corona, which made up of structures like loops and streams of ionized gas, is at the very top.
When a solar flare occurs, the corona can reach temperatures of tens of millions of degrees,
ranging from 900,000 degrees Fahrenheit (500,000 degrees Celsius) to 10.8 million degrees Fahrenheit (6 million degrees Celsius). The solar wind blows matter from the corona away.
The magnetic field of the sun is normally only about twice as strong as the magnetic field of the Earth. However, it gets extremely concentrated in limited locations, reaching a strength of up to 3,000 times that of normal. Because the sun spins faster at the equator than at higher latitudes and because the core sections of the sun rotate faster than the surface, the magnetic field kinks, and twists.
Sunspots to dramatic eruptions known as flares and coronal mass ejections are all caused by these aberrations.
Flares are the most explosive eruptions in the solar system,
whereas coronal mass ejections are less violent but spew massive amounts of stuff into space
a single ejection can spit out nearly 20 billion tonnes (18 billion metric tonnes) of materials.
THE SUN’S CHEMICAL COMPOSITION
The sun, like most other stars, primarily composed of hydrogen, followed by helium. The remaining substance almost entirely made up of seven different elements: oxygen, carbon, neon, nitrogen, magnesium, iron, and silicon. In the sun, there are 98,000 helium atoms for every million hydrogen atoms, 850 oxygen atoms, 360 carbon atoms, 120 neon atoms, 110 nitrogen atoms, 40 magnesium atoms, 35 iron atoms, and 35 silicon atoms.
Despite this, because hydrogen is the lightest of all elements,
it only makes up around 72 percent of the sun’s mass, while helium makes up about 26%.
SOLAR CYCLES AND SUNSPOTS
Sunspots are dark, cold spots on the sun’s surface that are frequently roughly round in shape. They appear like the sun’s internal magnetic field lines break through the surface in dense bundles.
The number of sunspots varies with solar magnetic activity; the fluctuation in this number, from zero to around 250 sunspots or clusters,
and back to zero, is known as the solar cycle, which lasts about 11 years. The magnetic field rapidly switches polarity at the end of a cycle.
To record the seasons, create calendars, and watch eclipses, ancient cultures typically manipulated natural rock formations or created stone monuments to mark the motions of the sun and moon.
In 150 B.C., the ancient Greek philosopher Ptolemy formalized the “geocentric” paradigm,
which held that the sun revolved around the Earth. Then, in 1543, Nicolaus Copernicus proposed a heliocentric (sun-centered) model of the solar system,
HISTORY OF SUN OBSERVATION
and Galileo Galilei’s discovery of Jupiter’s moons in 1610 revealed that not all celestial bodies revolved around the Earth.
After early studies with rockets, astronomers began studying the sun from Earth’s orbit to learn more about how the sun and other stars work. Between 1962 and 1971, NASA launched the Orbiting Solar Observatory, a series of eight orbiting observatories. Seven of them were successful and among other things,
they investigated the sun at ultraviolet and X-ray wavelengths and captured the super-hot corona.
The Ulysses mission was launched by NASA and the European Space Agency in 1990 to make the first measurements of the planet’s polar regions. The Genesis spacecraft of NASA delivered samples of the solar wind to Earth in 2004 for study. The Solar Terrestrial Relations Observatory (STEREO) mission, which consisted of two spacecraft,
returned the first three-dimensional images of the sun in 2007. In 2014, NASA lost contact with STEREO-B, which remained inactive until a brief period in 2016. STEREO-A is still operational.
One of the most important solar missions to date is the Solar and Heliospheric Observatory (SOHO),
which celebrated its 25th-anniversary last year. It has imaged the structure of sunspots below the surface, measured the acceleration of the solar wind, discovered coronal waves and solar tornadoes,
discovered more than 1,000 comets, and revolutionized our ability to forecast space weather.
Since its launch in 2010, the Solar Dynamics Observatory (SDO) has returned never-before-seen details of material streaming outward and away from sunspots, as well as extreme close-ups of activity on the sun’s surface and the first high-resolution measurements of solar flares in a wide range of extreme ultraviolet wavelengths.
NASA’s Parker Solar Probe launched in 2018, and the ESA/NASA Solar Orbiter,
launched in 2020, are the most recent additions to the sun-observing fleet.
SUN IN CLOSER
Both of these spacecraft orbit the sun at a closer distance than any previous mission.
The Parker Solar Probe dips into the sun’s outer atmosphere, the corona, during its near approaches.
Also, The Parker Solar Probe will come within 4 million miles (6.5 million kilometers) of the sun’s surface
at its closest approach (the distance between the sun and Earth is 93 million miles (150 million kilometers).
Scientists are learning more about how energy moves through the sun
the structure of the solar wind, and how energetic particles are propelled and transported thanks to the measurements it takes.
Solar Orbiter is outfitted with high-tech cameras and telescopes that snap photographs of the sun’s surface from the closest distance ever.
The Parker Solar Probe could not carry a camera that could gaze straight at the sun’s surface due to technical constraints.
Solar Orbiter will pass around 26 million miles (43 million kilometers) from the star at its closest approach, which is about 25% closer than Mercury. The spacecraft approached the sun to nearly half its distance from Earth during its first perihelion, the point in its elliptical orbit closest to the sun. The photographs collected during the first perihelion, which were released in June of last year, were the closest images of the sun ever recorded and revealed previously unseen characteristics on the star’s surface – small flares known as campfires.
After a few close approaches, mission controllers will begin boosting Solar Orbiter’s orbit out of the ecliptic plane, which is where planets circle, to allow the spacecraft’s cameras to capture the first-ever close-up photographs of the sun’s poles. Scientists will gain a better understanding of the sun’s magnetic field, which governs the 11-year solar cycle, by mapping activity in the polar regions.
