Solar System largely of materials with lower melting points. The boundary in the Solar System beyond which those volatile substances could condense is known as the frost line, and it lies at roughly 5 AU from the Sun. The objects of the inner Solar System are composed mostly of rock, the collective name for compounds with high melting points, such as silicates, iron or nickel, that remained solid under almost all conditions in the protoplanetary nebula. Jupiter and Saturn are composed mainly of gases, the astronomical term for materials with extremely low melting points and high vapour pressure, such as hydrogen, helium,
Wheelers (novel) presence of gas giants may actually be a necessary factor in the formation of habitable terrestrial planets, as their mass deflects and breaks up potentially devastating threats. Earth-bound comets from outside the solar system tend to either slingshot past Jupiter and launch into hyperbolic orbits that take them far from the terrestrial planets, or may lose momentum and drift peaceably into the Sun. Without the incredible gravitational presence of Jupiter, it's possible that our planet would experience so many impacts and close calls as to prevent advanced evolution or even the formation of life. All the same, Jupiter also pulls