Finding Star
When observing the night sky, is a restless spirit, the first question is: What is a star? A star is a giant ball of hot gas and light, which produces its own energy enormously by the so-called nuclear reactions, which can be reached in the city center of the star temperatures, and appear like a luminous phenomenon that accompanies us on our observations of night sky on a clear night.

The stars have given birth to a life cycle like any living being, to develop and grow and grow and eventually die and disappear more or less violently, as can trigger a supernova explosion the process of the birth of other stars. But it happens so slowly that they can be seen in the human time scale.

The universe is a nearly infinite space with room for millions of stars, galaxies and star clusters. And amounts to 149.59787 million kilometers – the distance between the Sun, the nearest star to Earth is the astronomical unit, called AE. Since the observed speed of light 300,000 km per second, visible light from the sun takes about 8 minutes to reach Earth. The nearest star to the Sun is Proxima Centauri, and the emitted light has to reach over 4 years on the earth. This means that if you thing about this star look “see” how it was more than four years now and do not know how. And in fact if you observe the sun with the proper eye protection, it “sees” what he was about 8 minutes.

Molecular clouds
On clear nights, especially when viewed in the field with a small telescope, far from towns or villages, which light up the night sky, you can also use the gray areas, where stars are born, like the Orion or M42 in the constellation with the same name. They are called molecular clouds.

Molecular clouds are huge and deep, dark clouds, formed by a gas called hydrogen (99%) and interstellar dust in a very small percentage (1%), but enough that under certain conditions, stars can be born. One could say that these clouds provide the raw material for star formation.

The embryos of the future stars are hidden in molecular clouds, and emits only radio waves and infrared of the electromagnetic spectrum by these stars of embryos, through these dark regions – not visible light. With the proper equipment such as telescopes in space or radio antennas on ground-based observatories, we can interpret the results of the data and the development of a theory of star formation.

The birth of a star
Although the proportion of dust in the cloud material is small compared to the amount of gas, these clouds are so important they accumulate enough mass to produce thousands or even millions of stars like the sun.

The training process is triggered, if for some reason there is a “fragmentation” of the cloud, they break into fragments with sufficient density relationship between the amount of mass and volume occupied to begin to shrink slowly. The reason for this is the cause of fragmentation, the arrival of a shock wave from a supernova explosion near the top – the final stage of stars with large mass

This process is irreversible, is the fragment to contract cloud and dense twenty to a value of magnitude larger than the original cloud fragment – of which there is enough mass to start acting force of gravity, so that the cloud collapses so that it under his own weight breaks. This event is the core of the star: the protostar, which falls on the rest of the field of cloud fragment further.

As a further material falling into the protostar, it begins to turn, press jets of material (eg, geysers) for large distances and high speeds, so that the protostar is not running too fast, what his resolution.

Because of this first rotation is the case, preferably of the cloud in the equator of the protostar is deposited, forming what is known as a disk of material orbiting the protostar, and this can the seeds be a future system of planets around it, even the solar system .

This first phase of star formation takes about 100,000 years and how it obscured by the dust cloud. We must, as already mentioned by radio telescopes (capture the emission of radio waves) or infrared telescopes to see at this point. Then, when the material is evaporated onto the hull and the protostar fragment cloud gas and dust of the embryo is visible. In a sun-like star, takes this a million years after the beginning of the process from collapse.

A new star
After 10 million years, the process of collapse at the end of the first contraction of gravity. Meanwhile, the temperature of the protostar has grown strongly and the temperature so high that when the collapse ends to use thermonuclear reactions of hydrogen fuel, begin in the heart of the star that is actually a heavier element called helium. At this point we can say that a new star is born and is named in a main-sequence phase of life.

The star is stable, because they are in a state known as hydrostatic equilibrium: the force that pushes outward (pressure of the energy produced by nuclear reactions) is the force that pushes the inside of the gravity compensated.