Origin of Earth

Origin of the solar system Origin of earth -Origin of the moon -... 

What are the origins of Earth and other planets in the solar system Questions such as these have challenged philosophers and scientists for centuries. One of the earliest theories for the formation and evolution of the solar system was proposed by the French philosopher and mathematician Rene Descartes (1596-1650). Descartes suggested that the Sun and planets originally formed out of a swirling mass of matter that slowly condensed into one very large body (the Sun) and other smaller bodies (the planets) at various distances from the Sun. With some important refinements, that theory is one most astronomers subscribe to today. 

Meteorites have great scientific value because most of them are fragments of asteroids which are themselves remnants of larger bodies that formed in the solar system at the time the planets accreted from planetesimals in the protoplanetary disk that formed around the Sun at the time of its formation about 4.6 x 10 years ago. Therefore, meteorites are our principal source of information about the origin of Earth and of the other planets of the solar system. 

Jupiter s big family of moons holds tantalizing liquid flows. Europa and Ganymede both have liquid oceans hidden in darkness under miles of ice. Likewise for Saturn s moon Enceladus, which is warmed by underwater vents like those suspected in the origins of Earth-life. Jupiter itself has supercritical helium and hydrogen deep inside. After the disappointingly dry rocky planets near Earth, the gas-giant moons seem like veritable oceans of possibility. 

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