stellar evolution

Nebula Orion

The stars are the first generation born around 13 billion years ago, when our galaxy began to condense from the expansion of the universe. Most of them are still made of hydrogen and helium. Both these elements are the only elements that are formed in large quantities during the big bang of (big bang) is believed to mark the beginning of the creation of the universe.

Stars like the Sun was born in groups in the complexes termampatkan large cloud known as nebulae. One of the famous nebula is the birth place of many stars is a faint spot in the constellation Orion is known as the Orion Nebula. Viewed from the outside, a nebula look dark and gloomy, but inside they teriluminasi with brilliant stars newborn. After that, the young stars that will melanglang out from his birthplace in the parent galaxy to the star Deneb in the constellation Cygnus is a super bubble that is larger than the very hot gases that may be produced by a supernova explosion near the center of that bubble. At the edges, compressed interstellar material by a supernova and triggered a wave of cloud collapse and star formation. From this aspect, as human life, the star also has a parent. And as we sometimes experience, parents can also experience the death of her child during labor.

In the period of adolescence, a star is usually still covered by the beam of glowing gas nebulae, the remnants of the formation process of the gravitational still attached to it. Examples of this kind of stars we can see the stars in the constellation Pleiades.

Similar to those experienced by humans, the stars who grew up traveling far from home, and siblings rarely saw each other. It could be somewhere in the Milky Way there are the stars, perhaps dozens of them, which is the sibling of our sun. They are formed from the same nebula about 5 billion years ago. But we do not know which of the stars. They could be on the other side of our galaxy, or perhaps become one of the small stars do not mean that we see flickering in the night sky.

In the birth of a star, the collision of gas molecules in the interior of the cloud heating it until the end came to the point where the hydrogen atoms began to merge into helium: four hydrogen atoms together to form one helium nucleus. This process is followed by release of gamma ray photons. Experienced alternation photon emission and absorption by the material which lay, which gradually to reach the surface of the star.

In this way, the photons continue to experience loss of energy. It took up to a million years for photons to reach the surface of the star and are emitted into space. The star has now been lit. Gravitational collapse of pre-star clouds had stalled. Load the outer layers of the star is now supported by the high temperature and pressure generated in the interior of the core reaction. The sun is at such a stable condition during the last 5 billion years. Thermonuclear reactions like that in a hydrogen bomb to the sun provides energy in a continuous explosion and berwadah, change about 4 million tons of hydrogen every second. When we look up at the night sky and see the twinkling stars, all that we see glowing because of the merger of hydrogen nuclei in the distance.