How is the Sun?
Sun It is a yellow dwarf star at the center of our Solar System. All the planets in the Solar System orbit around the Sun.
Sun and the Solar System orbit around the center of our Galaxy, the Milky Way.
Although the Sun is a relatively small star in the universe, it is huge relative to our solar system.
Even with massive gas planets like Jupiter and Saturn, the Sun contains 99.8% of all the mass in the solar system.
The sun is made of hydrogen superheated and helium gas. Hydrogen makes up about 74% of the mass of the Sun.
At the center of the Sun, hydrogen atoms, under intense pressure from gravity, go through a process called nuclear fusion and become helium atoms.
The nuclear fusion process generates a tremendous amount of heat causing radiation and eventually sunlight to reach Earth.
The sun is at the heart of the solar system, where it is by far the largest object.
How does the sun sound?
The biggest
It contains 99.8 percent of the mass of the solar system and is approximately 109 times the diameter of Earth – about a million Earths could fit inside the sun.
The visible part of the sun is about 10,000 degrees Fahrenheit (5,500 degrees Celsius), while temperatures in the core reach more than 27 million F (15 million C), driven by nuclear reactions.
One would need to explode 100 billion tons of dynamite every second to equal the energy produced by the sun, according to NASA.
The sun is one of the most 100 billion stars of the Milky Way. It orbits about 25,000 light-years from the galactic nucleus, completing one revolution approximately every 250 million years.
The sun is relatively young, part of a generation of stars known as Population I, which are relatively rich in elements heavier than helium.
An older generation of stars is called Population II, and an earlier Population III generation may have existed, although no members of this generation are yet known.
The End of the Sun PodCast
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Formation and evolution of the Sun
The sun was born about 4.6 billion years ago. Many scientists think that the sun and the rest of the solar system formed from a giant, spinning cloud of gas and dust known as the solar nebula.
As the nebula collapsed due to its gravity, it spun faster and flattened into a disk. Most of the material was pulled towards the center to form the sun.
The sun has enough nuclear fuel to stay that way for another 5 billion years.
After that, it will swell up to become a red giant. Eventually, it will shed the outer layers of it, and the remaining core will collapse to become a white dwarf.
Gradually this will fade away, to enter its final phase as a cold, dark theoretical object, sometimes known as a black dwarf.
sun size
The size of the Sun compared to the largest known stars (red giants) is not very large.
However, when compared to the most common type of star in the universe, the red dwarf, the Sun is considerably larger.
Thus, the Sun is not the largest type of star in the universe, but it is definitely larger than most.
In terms of the mass of the Sun compared to other bodies found in our solar system, the Sun is easily the most massive. The Sun alone contains 99.8% of the total mass of the Solar System.
In terms of size, the Sun has a diameter of about 1.4 million kilometers (870,000 miles).
To put this in perspective, it is almost 110 times the diameter of the Earth. What this means is that about a million Earths could fit inside the Sun.
Internal structure and atmosphere of the Sun
The sun and its atmosphere are divided into several zones and layers. The solar interior, from the inside out, is made up of the core, the radiative zone, and the convective zone.
The solar atmosphere above consisting of the photosphere, chromosphere, a transition region, and the corona.
Beyond is the solar wind, an outflow of coronal gas.
The core extends from the center of the sun to about a quarter of the way to its surface.
Although it only makes up about 2 percent of the sun’s volume, it is nearly 15 times the density of lead and contains almost half the solar mass.
Then there is the radiative zone, which extends from the core to 70 percent of the sun’s surface, making up 32 percent of the sun’s volume and 48 percent of its mass.
The nucleus
Light from the nucleus is scattered in this area, so that a single photon can often take a million years to pass.
The convection zone reaches down to the surface of the sun, making up 66 percent of the sun’s volume, but only a little more than 2 percent of its mass.
Coiled gas «convection cells» dominate this zone. There are two main types of solar convection cells: granulation cells about 1,000 kilometers wide and supergranulation cells about 30,000 kilometers in diameter.
the photosphere
The photosphere is the lowest layer of the sun’s atmosphere and emits the light we see. It is about 500 km thick, although most of the light comes from its lower third.
Temperatures in the photosphere vary from 6125C (11,000F) at the bottom to 4,125 C (7,460 F) at the top.
Next is the chromosphere, which is hotter, up to 35,500 F (19,725 C), and apparently made up entirely of spiky structures known as spicules, typically about 600 miles (1,000 km) in diameter and up to 6,000 miles (10,000 km) high.
After that is the transition region a few hundred to a few thousand kilometers thick, which is heated by the corona above it and sheds most of its light as ultraviolet rays.
At the top is the super-hot corona, which is made of structures such as loops and streams of ionized gas.
The corona typically ranges from 900,000 F (500,000 C) to 10.8 million F (6 million C) and can even reach tens of millions of degrees when a solar flare occurs. The matter of the corona is blown like the solar wind.
The Sun from Space
Sun’s magnetic field
The strength of the sun’s magnetic field is typically only twice as strong as Earth’s field. However, it becomes highly concentrated in small areas, becoming up to 3,000 times stronger than normal.
These kinks and kinks in the magnetic field develop because the sun spins faster at the equator than at higher latitudes and because the inner parts of the sun spin faster than the surface.
These distortions create features ranging from sunspots to spectacular eruptions known as flares and coronal mass ejections.
Flares are the most violent eruptions in the solar system, while coronal mass ejections are less violent but involve extraordinary amounts of matter – a single ejection can eject an estimated 20 billion tons (18 billion metric tons) of matter into space.
Chemical Composition of the Sun
Like most other stars, the sun is made mostly of hydrogen, followed by helium.
Almost all of the remaining matter consists of seven other elements: oxygen, carbon, neon, nitrogen, magnesium, iron, and silicon.
For every million hydrogen atoms in the sun, there are 98,000 helium, 850 oxygen, 360 carbon, 120 neon, 110 nitrogen, 40 magnesium, 35 iron, and 35 silicon.
Still, hydrogen is the lightest of all the elements, making up only about 72 percent of the sun’s mass, while helium makes up about 26 percent.
Sunspots and solar cycles
Sunspots are relatively cool, dark features on the sun’s surface that are often roughly circular.
They emerge where dense bundles of magnetic field lines from the interior of the sun pierce the surface.
The number of sunspots varies as does solar magnetic activity – the change in this number, from a minimum of none to a maximum of about 250 sunspots or sunspot groups and then back to the minimum, is known as the solar cycle , and has an average duration of about 11 years.
At the end of a cycle, the magnetic field quickly reverses its polarity.
Observation and history of the Sun
Ancient cultures often modified natural rock formations or built stone monuments to mark the movements of the sun and moon, charting the seasons, creating calendars, and monitoring eclipses.
Many believed that the sun revolved around the Earth, with the ancient Greek scholar Ptolemy formalizing this «geocentric» model in 150 BC Later.
In 1543, Nicholas Copernicus described a sun-centered, heliocentric model of the solar system, and in 1610, Galileo Galilei’s discovery of Jupiter’s moons revealed that not all celestial bodies circled the Earth.
To learn more about how the sun and other stars work, after the first rocket observations, scientists began studying the sun from Earth’s orbit.
The NASA
NASA launched a series of eight orbiting observatories known as the Orbiting Solar Observatory between 1962 and 1971. Seven of them were successful, analyzing the sun at ultraviolet and X-ray wavelengths and photographing the super-hot corona, among other accomplishments. .
In 1990, NASA and the European Space Agency launched the Ulysses probe to make the first observations of their polar regions.
Also, in 2004, NASA’s Genesis spacecraft returned samples of the solar wind to Earth for study.
In 2007, NASA’s Solar and Terrestrial Relations Observatory (STEREO) mission returned the first three-dimensional images of the sun.
NASA lost contact with STEREO-B in 2014, which remains out of contact except for a brief period in 2016. STEREO-A remains fully functional.
SOHO
One of the most important solar missions to date has been the Solar and Heliospheric Observatory (SOHO), which was designed to study the solar wind as well as the outer layers and inner structure of the sun.
It has imagined the structure of sunspots below the surface, measured the acceleration of the solar wind, discovered coronal waves and solar tornadoes, found more than 1,000 comets, and revolutionized our ability to forecast space weather.
The observatory
Recently, NASA’s Solar Dynamics Observatory (SDO), the most advanced spacecraft designed to study the sun, has returned never-before-seen detail of material flowing out and away from sunspots.
As well as close-ups of activity on the sun’s surface and the first high-resolution measurements of solar flares in a…