Sunday, December 20, 2009

The Creation And Evolution Of The Solar System

by : John Battelle

The creation and evolution of the Solar System is estimated to have begun 4.55 to 4.56 billion years ago with the gravitational collapse of a tiny part of a giant molecular cloud. Most of the collapsing mass collected in the centre, forming the Sun, though the rest flattened into a protoplanetary disc out of which the planets, moons, asteroids, and other small Solar System bodies shaped.

Effect of giant collision

This broadly accepted model, known as the nebular hypothesis, was first developed in the 18th century by Emanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace. Its succeeding development has interwoven a variety of scientific disciplines as well as astronomy, physics, geology, and planetary science. Since the dawn of the space era in the 1950s and the discovery of extrasolar planets in the 1990s, the models have been both challenged and refined to account for latest observations.

The Solar System has evolved considerably since its earlier formation. Many moons have formed from circling discs of gas and dust around their parent planets, while other moons are believed to have formed separately and later been captured by their planets. Still others, as the Earth's Moon, may be the effect of giant collisions.

Planetary migration of Solar System

Collisions between bodies have occurred continually up to the present day and have been middle to the evolution of the solar system. The positions of the planets often shifted, as well as planets have switched places. This planetary migration now is supposed to have been responsible for much of the Solar System's early evolution.

Approximately 5 billion years, the Sun will cool and expand outward to many times its current diameter (becoming a red giant), previous to casting off its outer layers as a planetary nebula, and leaving behind a planetary corpse known as a white dwarf. In the far-away future, the gravity of passing stars step by step will whittle away at the Sun's retinue of planets. Some of the planets will be destroyed, others ejected into interstellar space. Eventually, more than the course of trillions of years, it is probable that the Sun will be left alone with no bodies in orbit around it.

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