This paragraph is going to explain the collapse of Solar Nebula. Nebula essentially means cloud. Orion Nebula is good to begin with for the understanding of formation of our solar systems. Clouds of gas and dust are originally dark blocking light from the stars behind. This dust is warm. The studies show that Orion nebula has complex molecules that include hydrocarbons. When cloud is so dense that its own gravity triggers its collapse and that is what has happened with our own nebula causing collapse and forming current solar system. It is important to note here that our own nebula before formation of the solar systems was a million times larger than the size of our current solar system. With the contraction of clouds and to conserve angular momentum, it rotates at a faster and faster rate. The contraction and spinning causes to form a disk creating a large dense blob in the center called protosun. When angular momentum of nebula is high, it collapses forming more than one protosun. Scientists believe that most of the systems have multiple stars. This paragraph will explain how fusion reaction starts at the center of the new star. Contraction of the nebula has taken place which is full of enormous amount of hydrocarbons. Gradually, pressure and density of the hydrogen at the center of the collapsed nebula starts building up when it crosses its threshold limit, nuclear fusion reaction starts. In this process, hydrogen converts into helium liberating huge amount of energy.
will explain about the formation of planets. Sun has already formed but remaining gas and dust is still there in the form of disk. Sun will start heating the dust and gas cluster. The source of heat is at center and disk will be hottest nearer to the center. As distance from the center increases the temperature also falls. The temperature within distance of 1AU is in the range of 1000sK and then going down as the radial distance increases. Over time, the gas temperature drops below the condensation temperatures of metals and silicates. More refractory material is found closer to the sun and more volatile material is found away from the sun. Having high melting and condensation temperatures, refractory materials remain in the solid forms. Due to low melting and condensation temperatures, all volatile materials remain in gaseous or liquid forms. That is how rock kind material in the earth and going farther toward Jupiter volatile material like ammonia, carbon dioxide, methane, nitrogen are found in abundance. With the process of nebula cooling down and materials condensing and forming clumps, a beginning of formation of planetary system takes place. Inner solar system would have more of a rocky/metal substance and outer solar system would have ice and gaseous formation. These materials eventually coalesced and formed planets. These planets continue to revolve around its center now called Sun. The paragraph will explain why the Saturn has rings. The particles that do not have regular and equatorial orbits will eventually collide and break up and forced to form a regular orbit. This process confines material to a thin disk making them in the orbits of regular circles so that no further collisions take place. That is how the formation of rings took place around Saturn. Our solar system is more than 4.5 billion years old. Radioactivity is the technique used to measure the age of solar system. Radio isotopes that are used to measure the age of rocks are potassium-40, argon-40. These isotopes have half-life of 1.3 billion years. The oldest rocks found on the