Jiggaboo Jim

General review questions for Test 1

What is the nebular hypothesis?

The nebular hypothesis states that diffuse, slowly rotating clouds of gas (hydrogen and helium) and other particles, contract under the force of gravity. Contraction accelerates the rotation of the particles and gas. Matter drifts to the center of the cloud heat up and a proto-Sun forms. Compressed under its own weight, the proto-Sun becomes hotter and hotter until a temperature is reached where nuclear reactions occur and hydrogen fuses to form helium and energy is released.

Describe how our solar system formed.

Our solar system formed from an immense rotating cloud of gas and dust called the solar nebula, in one of the arms of the milky way galaxy (It is estimated that our solar nebula started contracting about 5 Billion Years Ago). What happened was that a cloud started to contract under the influence of gravity. The force of gravity ultimately increase the rotation speed and the cloud flattens. The matter in the center of the cloud accumulates to form the Proto sun. The disk around the sun, cools and condenses, which causes planetisimals to form and start to collide and grow in size. Discrete planets and some moons form. Lighter elements are essentially blown away by the solar wind from the hot regions close to the sun, which ultimately form the light gaseous and icy outer planets. The heaviest material is concentrated closest to the sun, forming the “rocky” terrestrial planets. This whole planetary assembly process approximately took about 100-150 million years. This was followed by a half of a billion year period during which the planets were experiencing heavy bombardment by the remaining rocky and icy pieces leftover from planet formation.

What are the differences between the inner and outer planets? Why?

There are distinct differences between the inner and the outer planets. The inner planets are known as terrestrial planets, which are similar to that of...