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Nebular hypothesis

Short answer

Kant and LaPlace proposed the solar system originated from a rotating nebular cloud that contracted, flattened into a disk, and shed rings which condensed into planets. The central mass formed the Sun. The hypothesis fails to account for the Sun's low angular momentum and retrograde satellite orbits.

Discuss the nebular hypothesis for the origin of the earth.

The nebular hypothesis was proposed by Immanuel Kant (1755) and developed by Laplace (1796).

  • The solar system began as a huge, hot, rotating cloud of gas and dust called a nebula.
  • As it cooled, it contracted and, to conserve angular momentum, rotated faster and flattened into a disc.
  • When the centrifugal force at the edge equalled gravity, a ring of gas was thrown off. This repeated several times, forming rings.
  • Each ring condensed into a planet; the central mass became the Sun. Rings around planets formed satellites.
  • The Earth cooled from a hot gaseous ball into a liquid and then formed a solid crust.

Limitation: it cannot explain why the Sun has only 2% of the angular momentum of the solar system, or why some satellites move backwards.

✓ Answer checked by Claude Opus 5.5 (high effort)

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