astronomical theories the naval observatory says the belief Is commonly held among astronomers mers that mars Is an older planet than the earth the old theory of the origin of the solar system called the nebular hypothesis was vaa first proposed by laplace it a hundred bundred or more years yeara ici according to ills his view the sun was once so large that it extended as far as the orbit of neptune in the process of shrinking to its present size it if soft left bits of itself behind each of which became a planet so that the further out a planet Is Is the older it la Is however there are arc ninny many astronomers who 10 lo do not accept this theory several different the theories orlen are now given to explain e the origin of the solar olar system mateio vat eio