The Formation and Evolution of the Solar System began 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud.
It is a Planetary system lying within the Milky Way Galaxy.
99% of Matter that formed our Solar System was pulled towards the center. It ignited into a self-sustaining process of thermonuclear fusion, The Sun.

 

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he Sun is roughly middle-aged; it has not changed dramatically for more than four billion[a] years, and will remain fairly stable for more than another five billion years. After hydrogen fusion in its core has diminished to the point at which it is no longer in hydrostatic equilibrium, the core of the Sun will experience a marked increase in density and temperature while its outer layers expand to eventually become a red giant. It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury and Venus, and render Earth uninhabitable.

The enormous effect of the Sun on Earth has been recognized since prehistoric times, and the Sun has been regarded by some cultures as a deity. The synodic rotation of Earth and its orbit around the Sun are the basis of solar calendars, one of which is the predominant calendar in use today.The Sun is a G-type main-sequence star (G2V) based on its spectral class. As such, it is informally referred to as a yellow dwarf. It formed approximately 4.6 billion[a][10][19] 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. It is thought that almost all stars form by this process.

 

 

It is a nearly perfect sphere of hot plasmawith internal convective motion that generates a magnetic field via a dynamo process.

It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometers, i.e. 109 times that of Earth, and its mass is about 330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System.

About 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.

 It is a nearly perfect sphere of hot plasma with internal convective motion that generates a magnetic field via a dynamo process.

The Sun is 99.86% of the total mass of the Solar System.  Its diameter is c. 1.39 million kilometers, i.e. 100 Earth Dia; its mass is c.330,000 X Earth
About 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 iro
The Sun is roughly middle-aged; it has not changed dramatically for more than four billion[a] years, and will remain fairly stable for more than another five billion years.

After hydrogen fusion in its core has diminished to the point at which it is no longer in hydrostatic equilibrium, the core of the Sun will experience a marked increase in density and temperature while its outer layers expand to eventually become a red giant. It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury and Venus, and render Earth uninhabitable.
The enormous effect of the Sun on Earth has been recognized since prehistoric times, and the Sun has been regarded by some cultures as a deity. The synodic rotation of Earth and its orbit around the Sun are the basis of solar calendars, one of which is the predominant calendar in use today.

➡️ The Sun – BURNT SIENNA

The Sun is 1,390,000 km in diameter. That compares with 12,756 km for diameter of the Earth. In other words, the diameter of the Sun is over 100 times the diameter of the Earth.

The mass of the Sun is about 2 x 1030 kilograms (2 followed by 30 zeros). It is one of the larger stars in our Milky Way galaxy. The median size of stars in our galaxy is less than half the mass of the Sun. In comparison, the Earth is 6 x 1024 kg. This means that the mass of the Sun is over 300,000 times greater than that of the Earth.

The Sun is 149,600,000 km (92 million miles) from the Earth. Since the speed of light is 303,000 km/sec (186,000 miles/second), it takes the light slightly over 8 minutes to get from the Sun to the Earth.

The distance of the Sun to the Earth is called an Astronomical Unit (AU) and is sometimes used to denote large distances that are less than a light year.

The Sun consists of about 70% Hydrogen, 28% Helium and 2% of metals such as iron. Other characteristics are its rotation, temperature, and radiation.

The Sun rotates on its axis, which is approximately the same axis that most of the planets revolved around the Sun. Since the Sun is primarily very hot gas, the surface at the equator rotates once every 25.4 days. The rotation near the poles is around 36 days. Also the surface swirls in high and low pressure areas, similar to those that occur on Earth.

The rotation of the Sun and the inclusion of iron in its core cause it to have a magnetic field, which is considerably more than the Earth’s magnetic field.

Its temperature is extremely hot, with the surface being about 5000° C and the center core at 15,600,000° C. The high temperature in the core, along with extreme pressure from the Sun’s mass, result in nuclear fusion reactions. Two Hydrogen nuclei (protons) combine with two neutrons to form a Helium nucleus plus a release of energy.

The energy released from the fusion reactions near the Sun’s core is in the form of very high frequency electromagnetic waves called gamma rays.

As this radiation moves towards the Sun’s surface, it is absorbed by atoms in the Sun’s interior, increasing their kinetic energy. After absorption, the rays are then re-emitted at lower frequencies. This process continues until the radiation reaches the Sun’s surface. By that time it is primarily visible light.

The surface of the Sun is called the photosphere. Some areas of the Sun’s surface are hotter than the average 5000° C temperature and some are cooler. The cool areas look dark in comparison with the surrounding regions. They are called sunspots and are at about 3800° C.

The chromospheres lie above the photosphere. Above that is the corona which extends millions of kilometers into space and is visible only during a total solar eclipse.

Stormy surface of the Sun, with jets of material

Stormy surface of the Sun, with jets of material

The Sun continually emits a stream of charged particles consisting mostly of electrons and protons. This is called the solar wind. Most of these particles are blocked by the Earth’s upper atmosphere or attracted to the magnetic poles. The solar wind is the reason that the tails of comets always face away from the Sun.

Occasionally, solar flares on the Sun’s surface shoot out streams of high energy particles. They can cause such problems as power line surges and radio interference. They also result in the Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights), where the charged particles cause the atoms in the atmosphere to give off a glow.

 

 

 

 

 
Sun white.jpg

Sun with sunspots and limb darkening as seen in visible light with solar filter.
Observation data
Mean distance
from Earth
1 au1.496×108 km
8 min 19 s at light speed