Introduction

This is one version of the Greek creation myth. It considers that we started with ‘nothing’ and evolved fairly rapidly towards the environment which we experience today. In fact, this is a feature of nearly all creation myths - the Sun, the Earth, its inhabitants, and by inference, the planetary system around us, all formed soon after a divine event had acted to add purpose to the pre-existing nothingness, or chaos.

The details of the traditional scientific view are somewhat different. The Universe was created about 14 Ga ago, in the Big Bang (the exact age is unclear although somewhere between 13.7 and 13.9 Ga is the current consensus). Clumps of material then formed into galaxies, and galaxies spawned stars. From that time until the present day, the cycle of stellar birth and death has continued remorselessly. Our own Solar System formed around 4.56 Ga ago from materials that had been cycled in and out of stars several times (see Box 8.1).

There have been many different theories of how our Solar System formed. These can be split into theories suggesting that the processes that formed the Sun and the planets took place simultaneously in a single integrated event, versus theories suggesting that the planetary system was added to a pre-existing Sun, some time after the Sun's formation. These two approaches are referred to as monistic (single event) and dualistic (two separate events). An example of a dualistic theory of Solar System formation, would be the theory that another star passed close to the Sun, causing matter to be pulled from the Sun into a single filament, which then broke up along its length to form individual planets.