Our Sun is just one of multitude of Stars


Imagine that our Sun is the size of a one grain of sand. In fact, our Sun is just one of multitude of Stars. It's surrounded by over 200 billion Stars in our Milky Way Galaxy. It's just a speck in a vast beach of Stars. Milky Way Galaxy is just one of 100 billion Galaxies scattered in the Universe. It is estimated that there are more Stars in the Universe than are grains of sand on all the beaches in all the world...

The occurrence of the Sun took place so that one or more of Supernova should happen close to where our Star is formed. The shock wave from a nearby Supernova would trigger the creation of the Star by compression substances in the molecular cloud, generating the particular region to collapse under it's own gravity. As one part of the cloud collapsed, also started to turn to because to conserve angular momentum and heating under increasing pressure.

Much of the mass has become concentrated in the center. The rest is remained flattened out in the disc, from which will appear Planets and other bodies of the Solar System. Gravity and pressure inside the core of the cloud generates a lot of heat, as it accumulated more substance than the surrounding disk. Finally starts nuclear fusion and the Sun was born. From the present time, the end of Star is predicted for 5 billion years.

The process of fusion and energy production will stop when it runs out of hydrogen. It will grow and convert into a Red Giant and surely will swallow Mercury. After that it will be reduced to a White Dwarf and it is assumed when will spent all fuel it will remain a Black Dwarf. So far it has not been recorded. In order to reach this state needs more time than is the age of the Universe (13.8 billion years).

There are several types of Stars:

White Dwarf is a small Star. It is composed mostly of matter that does not contain electrons in it. The mass of White Dwarfs is similar to the mass of the Sun and the volume of the Earth. These stars are very dense. They shine due to the heat being stuck in them. Slowly radiate the heat into the surrounding space and thus cooling. When the White Dwarf cools, then it's called the Black Dwarf.

Red Dwarf Star is 2 to 10 times less mass than the Sun. Surface temperature is 2.500 to 3.800 K. Slowly consumes it's nuclear fuel. Radiates 10 to 10.000 times less and can last much longer compared to our Star. In Star, which is a mass of 0.3 solar masses, for a billion years in the nuclear conversion is involved only 1% of the mass.

Supernova is catastrophic explosion of the Star. It releases enough energy to Supernova, with it's brilliance, overshadowed the rest of the Galaxy. It happens when a massive Star runs out of nuclear fuel, while the core becomes unstable and collapse. From this Stars remains only Neutron Star (fast spinning Pulsar) or Black Hole.

Neutron Star is a mass of between 1.5 and 3 mass of the Sun. Due to it's own gravity is collapsed to such an extent that most of the protons and electrons enter into neutrons. They are formed in a Supernova explosion. Neutron Stars are the smallest and most densely Stars known to exist. Greater than 3 mass of the Sun does not stop it's collapse in the phase of Neutron Stars, but they become a Black Hole.

Our Sun is Yellow Dwarf

There are Stars from Red and Yellow Dwarf (later White), to the Neutron Star. Our Star is in the center of the Solar System. Average distance between the Sun and the Earth is 149.6 million kilometers (1 AU - astronomical unit, the distance from Earth to the Sun). The energy transmitted light gives almost all life on Earth, thanks to photosynthesis. It also launches weather and climate on Earth. It is almost a perfect sphere. It consists of hot gas and plasma interwoven with magnetic fields.

The diameter is about 1.392.000 kilometers and is 109 times larger than Earth. It consists of ionized gas. The chemical composition of Stars, ¾ weight makes hydrogen (about 74.9%), while the rest is mostly helium (about 23.8%). Less than 2% consists of heavier elements such as oxygen, carbon, neon, iron and others. In the center, where is energy source, hydrogen is less than helium. Temperatures reaching 15 million K and on surface area is ​​around 6.000 Kelvin.

It belongs to the spectral class G2V, or we can call it Yellow Dwarf. Visible light is most pronounced in the greenish part of the spectrum. The Star generates energy by nuclear fusion reactions, converting hydrogen into helium.

At the core of every second burn 4.3 billion kg of hydrogen. Corona is the outer part of the atmosphere and constantly emits a part of plasma into space in the form of wind. It's like a stream of electrically charged particles. It spreads to about 100 astronomical units. Balloon interstellar matter generated by the wind is called the heliosphere. The whole system rotate around the center of the Milky Way. Distance is 24.000 to 26.000 light-years. One full circle make for 225 - 250 million years and this period is called the galactic year.

Data about the Sun:
 
Diameter - 1,392,000 km
Volume - 1.3 million times bigger than Earth
Weight - 1.9891 ∙ 1030 kg, 330.000 times more than the Earth, 99.86% of the mass of the entire Solar System
The average density - 1.411kg/m3, about 1/4 the density of the Earth
Surface temperature - 5504.85°C (5.778 K)
During the tour around the center of the Galaxy - 2.2 ∙ 108 years