ABSTRACT
The birth of the solar system is dated to just less than 5 billion years ago. Gravitational condensation of a massive cloud of dust and gas whose composition was thought to be like that of the sun formed around the solar core. As the solar nebula contracted and heated up, the volatile elements were driven to the outer portion of the planetary disc that was taking shape. Photographs of Earth’s atmosphere taken from the moon and filtered through wavelengths specific to hydrogen atoms unequivocally show the presence of the gas hydrogen. Earth’s early atmospheric chemicals were continuously resupplied by accretion from then-abundant comets and meteors. Besides atmospheric changes, there are alterations in the solid structures of the planet’s surface. Earth’s atmosphere has constrained temperatures to be moderately warm at a very roughly constant level, except for arguable periods in antiquity when extreme ice ages pertained.
