Finding the stars
When observing the night sky, is a restless spirit, the first question is: What is a star? A star is a big ball of hot gas and light, lest his own power held by the known nuclear reactions in the core center of the star produces reach to enormous temperatures, and appear as a luminous phenomenon that accompanies us on our observations of the night sky in a clear night.
Stars have a life like any living creature to be born, to develop and grow and grow and eventually die and disappear more or less violent as a supernova explosion, the process of the birth of new stars can cause the other.
The universe is a nearly infinite space with room for millions of stars, star clusters and galaxies. The distance from the Sun, the nearest star to Earth is the astronomical unit, AU – and is 149.59787 million km. The nearest star, the Sun is Proxima Centauri, and the emitted light takes 4 years to reach Earth.
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, the stars can be born. One could say that this cloud has to provide the raw material for star formation.
The embryos of the future stars are hidden in molecular clouds, and only the emitted radio and infrared waves of the electromagnetic spectrum from embryos of the stars, through the dark regions – not visible light.
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 large that they can collect enough mass to produce thousands, even millions of stars like the sun
The formation process is triggered when one or other reason, there is a “fragmentation” of the cloud, it breaks into pieces with sufficient density ratio between the amount of mass and volume occupied to begin to shrink slowly. This event is the core of the star: The protostar, still fall on the rest of the field of the fragment cloud.
As material continues to decline in the protostar, it begins to turn, press jets of matter (such as water heaters), large distances and high speeds, which runs the protostar is not too fast, which can lead to decay.
This first phase of star formation takes about 100,000 years, and if it obscured by the dust cloud. We must, as already mentioned, radio telescopes (recording the emitted radio waves) or to detect infrared telescopes at that stage. Then, if the material falls onto the protostar and fragment shell of gas and dust cloud disappears, the embryo is visible. In a sun-like star, this is one million years after the beginning of the process from collapse.
A new star
Terminate after 10 million years, until the first contraction process of collapse due to gravity. During this time the temperature has increased the protostar and the temperature so high that when the collapse ends to take the thermonuclear reactions start with hydrogen as fuel in the core of the star, making it a heavier element called helium.
The star is stable because it is known as hydrostatic equilibrium: the force that pushes outward (the pressure of the energy produced by nuclear reactions) is compensated by the inward force of gravity pushes.
