Abundance of the chemical elements in the Sun and outer planets is similar to that in the universe. Due to solar heating, the elements of Earth and the inner rocky planets of the Solar System have undergone an additional depletion of volatile hydrogen, helium, neon, nitrogen, and carbon (which volatilizes as methane). The crust, mantle, and core of the Earth show evidence of chemical segregation plus some sequestration by density. Lighter silicates of aluminum are found in the crust, with more magnesium silicate in the mantle, while metallic iron and nickel compose the core. The abundance of elements in specialized environments, such as atmospheres, or
Journey to the Centre of the Earth (album) flee the forest for the Lidenbrook Sea and enter a dark tunnel that plunged deep into rock which they blast through with dynamite. The explosion causes an earthquake, and they become trapped in an active volcano shaft which projects them to the surface of the Earth by Mount Etna in Sicily. The concerts and album were first announced in October 1973, and organised during a break when Yes were touring "Tales from Topographic Oceans". Two sell-out performances were held at 6 and 8 p.m. on Friday 18 January 1974 at the Royal Festival Hall in London, attended by 3,000 people