Non catastrophic theories

Non - Catastrophic theories

Gaseous Hypothesis :  Immanuel kant, the German philosopher, presented this hypothesis in 1755.  His theory is based on the Newton’s laws of gravitation and rotatory motion.  According to Kant, there was a primeval, slowly rotating cloud of gas, (now called nebula) and matter comprised of very cold, solid and motionless particles.  He further assumed that these particles began to collide against each other under their mutual gravitational attraction.  This collision generated random motion in the primordial matter along with the frictional force which generated heat energy as a result the primordial matter got heated up and started up rotating.  The rise in temperature also changed the state of matter from solid to gaseous, thereby the rotating matter started to move as a nebula.  With continuous rise in temperature and rate of rotatory motion the nebula started expanding in size. 

     According to Immanuel kant as the heat increased, the size of nebula increased and as the size of nebula increased, the angular velocity or rotatory speed further increased.  Due to continues increase in the size of nebula the speed of rotation become so fast that the centrifugal force exceeded the centripetal force.  The nebula started spinning so rapidly that an irregular ring was separated from the middle part of the nebula and was ultimately thrown off due to centrifugal force, by repetition of the same process eight concentric ring were separated from the nebula.  The residual central mass remained as the sun.  The irregularity of the rings caused the development of the cores for the formation of the corresponding planets. In other words, all the matters of the each ring were aggregated at a point to form and ultimately grew as planets in due course of time.

 Nebular Hypothesis : This was propounded by the French mathematician Laplace in 1796.  This hypothesis is just the modification of the kant’s hypothesis.  According to Laplace, there was a huge and hot gaseous nebula in the space and from the very beginning this huge and hot nebula was rotating on its axis, therefore because of the rotation the nebula continuously cooling due to loss of heat from its outer surface through the process of radiation and thus it was continuously reducing in size due to the contraction on cooling.  As the size of the nebula continued to reduce in size, the velocity of the rotatory motion continued to increase.  Thus nebula started spinning at very fast and consequently the centrifugal force became so great that it exceeded the centripetal force, when this stage was reached the material at the periphery  that is the outer layer cooled and contracted so it couldn’t rotate with the same velocity of that of nuclei and was separated from the remaining part of the nebula.  This separated ring of material started moving around the nebula.  This original ring further divided into eight rings and each ring moved away from each other.  All the materials of each ring condensed at a point in the form of hot gaseous agglomeration.  Each such agglomeration was later cooled and condensed to form planet.