UPSC CSE Prelims 1999
O. Schmidt proposed the Interstellar Dust Hypothesis in 1943. According to this theory, the Sun, in its journey through the galaxy, captured a cloud of interstellar gas and dust. This captured material subsequently began to rotate and condense, leading to the formation of planets, including Earth. The hypothesis specifically emphasizes the role of the accumulation of solid dust particles, along with gases, in planetary formation.
James Jeans is associated with the Tidal Hypothesis, which suggests that a passing star approached the Sun, causing a cigar-shaped extension of material to be drawn out due to tidal forces. This material then broke into pieces to form planets, a process not based on interstellar gas and dust.
H. Alfven proposed the Plasma Hypothesis, which explains planetary formation through the interaction of plasma clouds and magnetic fields in space, differing from the gas and dust accretion model.
F. Hoyle is primarily known for his contributions to the Steady-State theory of the universe, which posits that the universe has always existed and will always exist in roughly the same state, with new matter continuously being created. His work does not focus on the Earth's origin from gas and dust particles.