The Fate of the Sun and Planetary System

Abstract

Approximately 4.6 billion years ago, a lump possessing higher than average gravitational energy attracted more and more interstellar gas and dust enriched with heavy elements spewed out by supernova explosion, and the process of gravitational collapse was initiated. The core, unable to support the weight of trillions of tons of infalling gas, contracted and the temperature increased from 3K to approximately 180,000K, as gravitational and kinetic energy was being converted to heat. At this moment, the internal gas pressure was sufficiently high to support the outer layers and a hydrostatic equilibrium was achieved. This signaled the birth of the protosun (Figure 23.1).