5. Formation of the Solar System

Joshua Barnes -- Fall 1999

The Solar System formed when a cold, slowly-rotating cloud of gas and dust collapsed because of its own gravity about 4.5 billion years ago. As the Sun grew hot enough to ignite the nuclear reactions which sustain it today, it vaporized the cold ices and frozen gasses in the inner solar system, leaving behind the rocky dust and metals which form the inner planets. The outer Solar System remained cold, and the ices and gas there collected into the giant outer planets.

The problem with this scenario is that we now have observations of about a half-dozen planetary systems around other stars -- and none of them resemble the Solar System.

Topics:

• Cloud collapse
• Angular momentum
• Protoplanets
• Differentiation
• Gas accretion
• Impacts
• Dead worlds

Web Resources:

• The Nine Planets

  Extensive pages on the Solar System, by Bill Arnett.

• Views of the Solar System

  Multimedia web pages on the Solar System, by Calvin J. Hamilton.

• Overview Of The Solar System

  A summary of the Solar System, describing the properties of the major planets as well as the contents of assorted belts of rubble.

• Origin of the Solar System (3.4 Mbyte avi animation).

  Clip of the NASA movie I Will See Such Things, from web site http://spaceart.com .

• Cloud collapse: face-on and edge-on (1.7 Mbyte mpegs)

  Computer simulations of a cloud of gas collapsing to a thin rotating disk. Seperate views face-on and edge-on to the disk are shown. Color indicates gas density, with blue for the lowest densities and red for the highest densities.

• Collision (1.1 Mbyte mpeg)

  Collision and merger of two gas giants, shown here to illustrate the rotation of the end-product.

Homework 5: Using Kepler's Laws, due 9/27. Answer.

Quiz 5: Properties Of The Solar System