Origin of earth - big bang hypothesis, PL-SQL Programming

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ORIGIN OF EARTH -

BIG-BANG HYPOTHESIS -

Origin of life is linked to origin of earth.
Cosmos, the Universe originated 10-20 billion years ago by Big Bang (thermonuclear explosion).
Its part, a galaxy, (e.g., our Milky Way) comprises millions of stars, (our Sun is one of those).
Sun, its planets and satellite constitute the solar system.
Our earth is the 3rd planet with rocks, water & atmosphere.
It began as gaseous clouds of metals and non-metal atoms, later condensed to form surface rocks and boiling fluid core with gaseous atmosphere.

Chronology of events
Origin	Ago (Billion yrs)
Universe	10-20
Solar system	4.6
Earth	4.5
Oldest surviving rock	4.3
Life (Heterotrophs)	4.2-3.9
Old rock	3.9
Chemosynthetic procaryotes	3.8-3.5
Oldest microfossils (Cyanobacteria)	3.3-3.5
Photosynthetic procaryotes	3.5-3.3
Eukaryotes	1.6-1.5

NEBULAR HYPOTHESIS -

Earth is formed by gradual condensation of interstellar dust, from which our entire solar system is presumed to be formed.

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