The Universe is in a continuous evolution. Heavy elements are formed by dead stars which have ended their lives as Supernovas.
In the image you can see the Crab Nebula which was seen in 1054 by the arabs and chinese astronomers. The Crab Nebula is 6500 light years away from us which represents 1/20 of the diameter of the Milky Way, our own galaxy.
Explanation:
In the Early Universe it has formed only one type of atom : the Hydrogen which is the most simple atom and it has a single proton and a single electron. They begun to form clusters of gas and slowly they begin to condensate. Is now when they begun to have a little rotation movement . In a few million of years they formed big clusters of hydrogen with irregular shapes : the galaxies. There are known lots of galaxies with irregular shapes or there are also galaxies in a formation process. But they are very difficult to see because of the distance where they can be found: billions of light years away. Only the most powerful telescopes can penetrate at that distance.
The accretion process which followed lasted hundreds of millions of years and consisted in the continuous process of modeling this irregular shape with a rotating movement in something which can be seen today as a galaxy: Elliptical, Lenticular or Spiral Galaxies. But the material was only the atom of hydrogen.
By this time, has begun also the separation of other small bubbles of hydrogen gas inside the galaxies, which later has formed the stars that we see today. This is another process that lasts a billion years or more depending on how big is the small amount of hydrogen gas which separated inside the galaxy.
In the center of the galaxy, where the density of the hydrogen is much greater than to the edge of the galaxy, the stars which resulted were considerably bigger than the stars away from the center. Also the process of accretion (condensation in a spherical balloon) was much much faster. The mass of these stars was considerably much greater and all the process of condensation is much faster.
In short time the gravity of these newly big balloons has begin the fusion reactions in the center of these huge stars giving birth to first star generation. From the fusion reaction of the Hydrogen (H) results Helium (He). Two atoms of hydrogen combines and form one atom of Helium. In the process much Energy is released which is originally a gamma ray and x-ray photon shower. But because the process is in the core of the star, much part of the energy of the photons is absorbed until the surface and the star is seen to emit in the most area of the electromagnetic spectrum: radio, infrared, visible, ultraviolet, x-ray, gamma ray. In fact, this is why we can see the stars, because much of their energy of the photons is lost when they reach the surface of the star.
But this process of fusion of hydrogen into helium is much much shorter for the massive stars. To give a comparison, our Sun will end his hydrogen after 10 billions years of life. There are so massive stars in the galaxies that burn their combustible in about 1 billion years or even less. Their time was gone billions of years before our Sun be born. The explanation is that the gravitation inside these massive stars is superior, the pressure bigger and the process of fusion takes place with a larger number of atoms. So the process of burning the hydrogen is much shorter.
After 1 billion years, by the time when the star has ended his hydrogen, the process takes place in the superior layers of the star (because in the center is only helium already), almost to his surface. By this time is when the superior layers of the star can’t resist the superior pressure made by the fusion process which is closer to the surface. And also the middle helium of the star is compressed by this force. There is a critical time when the equilibrium is break and the superior layers are rejected in an explosion while the core is compressed in an implosion. This is the phenomenon of Supernova. The forces are tremendous and much of the mass of the star is rejected into the space while the core continue the process of compression until it forms a black hole. Massive stars with a mass bigger than 2 solar masses always form black holes. We are talking here about the first massive stars generation with a mass 10- 100 times bigger than the Sun.
But this is the most important moment in the life of the massive star. After 1 billion of years (it could be also only 100 millions years) that the star had only two elements, hydrogen and helium, this process of Supernova, gives birth to heavier elements as oxygen, nitrogen, phosphor, iron, gold, uranium and so on. All the atoms from the Mendeleev chemical table of elements are formed by this moment. In fact the process is so chaotic that these elements are formed mainly in the superior layer. Heavy elements always takes energy in a fusion process. From the fusion process is given energy until the iron element. From the iron up in the atomic A scale, (for example uranium) energy is taken energy in the process. In a fusion process which form heavy elements, uranium, plutonium and so on, much energy is absorbed. This is the only place in the Universe where these elements are formed because here is the place were it’s a totally waste of energy which can be used to produce such heavy elements: in the moments of the death of a Supernova. In a normal star the loss of energy is almost constant. In a Supernova the mass and the energy are lost instantaneous.The process is so violent that a Supernova can emit so much energy as an entire galaxy : the equivalent of 100 billions stars.
After the explosion the exterior layers expand undefinitively in thousands and millions of years. But small balloons of hydrogen gases, which are not forming yet stars, are still rotating. They are situated a little far from the center of the galaxy. The forces here are less that in the center of the galaxy. Maybe they haven’t sufficient gravity, the gas balloon is not sufficiently big to be ready to form a new star, it’s in a sort of equilibrium. The process of star formation takes much longer, and a star hasn’t been born yet. If the remnants of a supernova reach a balloon in formation they give it a very important energy supply. This is a crucial moment for the balloon and the process is accelerated, and soon we will have a new star, of course a medium star, like our Sun. (because if the balloon of gas was bigger it would have sufficient gravitation energy to form alone a star, it would not have need to be helped from the exterior).
But remember that the supernova rejected also heavy elements, so the newly balloon will not form a simple star. Because of the complexity of the gas, which contains a large amount and diverse atom elements the new star will have also companions. Planets will be born in the proximity of the star, in his solar gravitational field. These planets will contain diverse elements and also heavy elements, iron, gold, zinc, magnesium and so on.
After the consolidation of the young solar system, the planets will begin to have a spherical shape. And in a period of billion of years molecules will be formed to the surface or in the atmosphere of these planets. They will be followed by macromolecules and organic molecules. And then complex organic molecules. Is now when the signs of biological life are seen.
But this is happening only because the planet has heavy elements. Heavy elements are crucial for the formation of life.
The scope of this presentation is not to describe all the complex processes that take place from a stellar formation to the explosion in a Supernova. The things are of course a little more complicated and there are also unsolved mysteries. But mystery is the most intriguing feeling that makes us go further. But as principle is good to know from whom we have hemoglobin (based on Iron) in our blood.
The conclusion will be that : life isn’t possible without Supernovas. One of the most violent process in the Universe gives birth to life by stimulating the smaller stars to form with planetary systems which can support biological life. Which is a proof that the Universe is the most fascinating and most stimulating for our imagination. We couldn’t exist today without a Universe with a long long history, without violent phenomenons which are taking place near us. But to understand all these we must look, we must think and we must search. Without the supernovas, our solar system if it would exist it would be formed only from hydrogen an probably helium which are only gases. Not sufficient to make a biological life.
Thanks to the Supernova we exist today.
Article made by Trif Bogdan
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