An earth like planet has to be formed if a cloud of gas of the size that formed the solar system condensed under the pull of gravity. Astronomers have proved this beginning with a cloud of dust and gas of the same mass and density that is thought to have served as the origin of the solar system and setting up experiments for random motion and collision under gravitational forces. In every case a planetary system very much like ours resulted and an earth like planet formed more or less at the same distance as the earth is now from the sun. Scientists believe that there must be many earth like planets in the universe as a concomitant of the formation of a sun like star anywhere in the universe.
It has been proved too that on an earth like planet placed in the vicinity of a sun like star
life has to be evolved. After years of careful study of the primordial earth atmosphere, it is suggested that life originated in this planet through chemical changes in the primordial conditions with the sun as the energy source.
Even in scanty interstellar gas (it is so rarified that they exist as atoms) researchers have observed that molecules that form always tend to progress towards amino acids and fatty acids –the basis of living tissues. Ever since living cells formed they were subjected to the laws of evolution proceeding form simple to complex forms. In the course of millions of years life has evolved from simple cells to the complexity we see in humans. No power could have stopped this relentless march. It is through the multiplication of the living cells that nature has managed to carry out this process. Each organism takes birth, reproduces and disappears. Similarities between various species have been observed since the time of Aristotle. But it was Charles Darwin who presented the comprehensive thesis. Whatever Darwin could not explain then has been taken up and cleared up subsequently. Now the evolution of man form the lower species is universally accepted.
Today we know there is no life in any other planet of the Solar System. But it could have sprouted out in the thousands of earth like planets placed in the ecosphere of their sun like stars. In the young ones life may be just germinating, in the older ones more complex forms could be roaming about. In others evolution may have reached our levels or more. But no form is permanent here; everything will ‘unform’. The death of our planet and the sun that powers it now are certain events. The earth will remain in its present orbit, shape and surface texture until the sun leaves its main sequence. Once the sun starts to expand signalling its demise, death of earth and all the life it supports will be imminent.
Many suns are now probably forming up while many others are in their death throes. The formation of suns, planets and galaxies, their eventual death, the reorganization of the scattered cloud gases forming new stars and planets will go on with the unwinding of the universal clock. In these eternal cycles of the universe we got birth now and here. Our lives are infinitesimal energy bubbles forming and bursting almost simultaneously.