Hydrogen Clouds

Image Source

We already known the hydrogen is a chemical element with lightest mass, hydrogen also abundant element in the universe and the main constituent of stars and planets in the universe. The star is a large gas ball formed from a clump of dust and gas generally it form of hydrogen gas and helium has a cold temperature (about 10^oK), the clouds of dust and gas who exist among the stars in a galaxy caused by a waves shock from supernova explosions or gravitational disturbances from nearby stars, or we may mention stars as spheres of ionized gas, the main star elements consisting of hydrogen and helium. To more easily understand which energy source of a star, we should know first about nuclear fusion.^[1]

We can say the star is a natural fusion reactor that derives its energy from hydrogen fusion to helium, then it forms another heavier element. To be more clear explanation, we should understand the hydrogen fusion with combustion. Hydrogen combustion is an endothermic chemical reaction that generates heating, but the energy produced by hydrogen fusion is more due of this process involving of nuclear fusion as a helium nucleus^[2]. For more details let we study the cycle life of the star, The thing we should to know are:

Combustion of Giant Fusion Reactor,
The Birth of a Star,
The Star Death

The cycle life of a star is called as star's evolution and its composition change constantly cause it evolves through several stages, the star located in the main part of burn the hydrogen to be helium through a gigantic fusion process. The big stars have higher core temperatures than smaller stars, therefore, the large stars will burn hydrogen faster in the core, while the smaller stars encounter slow combustion, the require time to stay in the main part depend on hydrogen fuel speed, therefore, the massive stars have a shorter life span, for example the sun will burn its hydrogen in 10 billion years.^[3]

Stars

Image source

The galaxy has a large cloud composed of hydrogen atoms and molecules that are at temperatures above 0^oC, each part of universe material drawn by gravity force, the cold clouds begin to receive a pressure under gravity then the clouds will heat up, this happened cause changing of gravitational potential energy to kinetic energy, for the great cloud undergoes a shrinking, thereby become a small proton-gas ball composed of hydrogen and helium to other fractions of heavy elements.

When the clump protostar gas was compressed and heats up, during this compression process the entire temperature of the gas rises from some degree above zero absolute (about 7 million kelvins), since hydrogen was warmed up (hot plasma), the hydrogen core begin to fuse and form the helium nucleus inside of proton core, the difference mass convert to energy. This process called as the source energy of the star. The star fusion produces thermal stress to heats the core, and balances the moving of gravitational pressure constantly.^[4]

When a protostar reaches the hydrostatic equilibrium point and continues incorporate hydrogen to be helium, this stage called as star's main sequence stage. In this stage, most of the star composition still consists of hydrogen, but there was increasing of hydrogen for supplying helium to its core. The age of a star depends on its mass and the whole life of a star depends on its initial mass, the larger mass of stars the shorter of stars age and vice versa.

When the star starts run out of hydrogen fuel, then the star undergoes shrinkage because gravity force has no balance, but a amount of hydrogen fusion still occurs in upper layers, when the star core was contracting, the nucleus will warm and heat up top layer so that the layer expanding, when this happens the radius of a star will grow larger and the star turn to red giant.

After this phase a part of the core get thermal, it causes melting of helium to be a carbon, when helium has been converted to a carbon, the core will expand and cool. The top layer will expand and release the material over time will accumulate around a dead star to form a nebula, Finally, the core of a cold star and a white dwarf can turn to black dwarf star, but all of this process takes time about a billion years.^[5]

Black Hole

Image Source

Black hole is a large concentration of mass which produces the larger of gravity force, black holes can possess any size, from microscopic to universe size. Based on star evolution theory, the black hole is a kind of blue star that has surface temperature more than 25.000^oC and it has mass greater than 1.4 times of the sun mass, the hydrogen combustion of blue star takes times about 10 million years, it will contract and expand into gigantic blue star. Then it will undergoes cold to a massive red giant, in this phase, due of its own gravitational pull, red giant stars have gravitational collapse result in a powerful explosion known as Supernova, Supernova marked by increasing of brightness light up to billions times of ordinary starlight, then spawned two star classes, the neutron star and Black Hole^[6]. In physics science, the magnitude of gravity force inversely proportional to the squared distance or can be formulated F = G.μ1/r2. Based on this formula we can understand why the black hole has a very gravitational force and very powerful, because the smaller of r value or close to zero (0) then the gravitational force will be greater.^[7]

The black hole mass will increase by absorbing all material around it, all objects passing too close or thermonuclear explosion gases of other stars around it will be sucked to the black hole, the mass also can increase if it collides with another black hole so that it becomes one bigger Black Hole. The black hole doesn't emit light but it will be visible when the internal friction of the gas is sucked into very hot about 2.000.000^oC then emits a X-rays, With this ray the black whole can be traced by researchers.

Supermassive black hole is a Black Hole with a higher density than usual black hole and it is core of any galaxy in the universe, because it has an extraordinary density it will create larger gravity force and estimated has diameter more than 1000 times of sun and has gravity more than million times of solar gravity.^[8]

Conclusion

From above description start with hydrogen clouds, stars, and black holes and three images in the post, I conclude the beginning of the birth of a star and the death of a star and then it absorbed by black hole, if we describe every picture, the first image is a substance of star molecule (Hydrogen Cloud), the second image is the star's birth process Or the formation of the star (Stars), and third image is the death of a stars in Black Hole (Black hole). And overall picture we can conclude the Cycle of Star Life.