How do we understand the composition and early evolution of the Earth?

To understand the composition and early evolution of the Earth it is necessary to consider as far back as the formation of our solar system. Solar system formation was a complex process that is not well understood because of the lack of data and the vast physical and chemical complexities of the process.

What do we know about Solar System formation?

Solar system formation was a complex process that is not well understood because of the lack of data and the vast physical and chemical complexities of the process. However, there are certain key parameters that we do know. As discussed in a later lecture, we know from the study of meteorites the age of the solar system and its initial composition.

How do Solar System evolution models work?

Solar system evolution models must show how the protosun’s angular momentum gets transported outward. Most models invoke magnetic and gravitational torques that spin down the sun and spin up the planets. Magnetizations of meteorites are consistent with this idea.

Why is there no gas between planets in the Solar System?

The conspicuous absence of gas between the planets in the solar system must be explained in any model of solar system formation. Before a new star reaches the main sequence it goes through a pre-main sequence evolution of gravitational collapse from a protostellar nebula.

Do all planets have satellites?

All the planets except Mercury and Venus have satellites. More than 130 satellites are known. Jupiter has more than 60. Seven large satellites are almost as big as the terrestrial planets. Comparable in size to the planet Mercury Ganymede and Titan are the largest; Titan has an atmosphere.