¶¶¶¶(Correct Option:- D) (Otto Schmidt suggests the earth's origin is from gases and dust particles. O. Schmidt in 1943 gave Inter-Slellar Dust Hypothesis for the origin of the earth and solar system).¶¶¶¶
A large number of hypotheses were put forth
by different philosophers and scientists
regarding the origin of the earth. One of the
earlier and popular arguments was by German
philosopher Immanuel Kant. Mathematician
Laplace revised it in 1796. It is known as
Nebular Hypothesis. The hypothesis considered
that the planets were formed out of a cloud of
material associated with a youthful sun, which
was slowly rotating. Later in 1900, Chamberlain and Moulton considered that a wandering star approached the sun. As a result, a cigar-shaped extension of material was separated from the solar surface. As the passing star moved away, the material separated from the solar surface continued to revolve around the sun and it slowly condensed into planets. Sir James Jeans
and later Sir Harold Jeffrey supported this argument. At a later date, the arguments considered of a companion to the sun to have been coexisting. These arguments are called binary theories. In 1950, Otto Schmidt in Russia and Carl Weizascar in Germany
somewhat revised the ‘nebular hypothesis’, though differing in details. They considered that the sun was surrounded by solar nebula containing mostly the hydrogen and helium along with what may be termed as dust. The friction and collision of particles led to formation of a disk-shaped cloud and the planets were formed through the process of accretion.
However, scientists in later period took up the problems of origin of universe rather than that of just the earth or the planets.