Saturday, March 28, 2015

Supernova Hypothesis of Origin of Earth

This hypothesis was put forth by Fred Hoyle in 1946. The sun had once a companion star as its former twin, which exploded due to nuclear reactions resulting in transformation of lighter elements into heavier ones.
This explosion in the companion star produced a cloud of incandescent gases and this stage is named by him as the "Supernova stage". This gaseous cloud was retained by the sun's gravitational force and the remainder of the star as the nucleus receded away far off. In the supernova stage, the gaseous cloud contained particles of iron and other terrestrial elements.
These particles aggregated to form the earth and other planets and satellites. As they were within the sun's gravitational field, they revolved round the sun and gradually cooled down to the solid form in which the planets and the satellites exist at present. This hypothesis explains:-
 (i) the great distance between the sun and its planets 
(ii) problem of angular momentum of the planets 
(iii) compositional differences in elements of the sun and the planets. 
However, it fails to account for the cigar shaped arrangements of the planets.
Origin not yet fully known: Of the many hypotheses so far postulated, some had gained acceptance for a time and then were discarded on the advent of new ones which earned followers to meet the same fate.
Notwithstanding the fact that there has been astounding development in the fields of astronomy and astrophysics, the origin of the solar system in general and of the earth, in particular is not as yet definitely known. There seems to be a great deal to know and theorise.
The general consensus among the astronomers is that the earth like other planets and satellites had its birth as a gaseous and hot ball of fire. It cooled down from a primary gaseous state to its present solid form.

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