Crust (geology) formed almost immediately after formation of the Moon. Magmatism continued after the period of intense meteorite impacts ended about 3.9 billion years ago, but igneous rocks younger than 3.9 billion years make up only a minor part of the crust. Crust (geology) In geology, the crust is the outermost solid shell of a rocky planet, dwarf planet, or natural satellite. It is usually distinguished from the underlying mantle by its chemical makeup; however, in the case of icy satellites, it may be distinguished based on its phase (solid crust vs. liquid mantle). The crusts of Earth, Moon, Mercury, Venus, Mars,
What Shall We Do Now? the form of a fist that becomes a hammer (a hammer that would reappear in the animated sequence of "Waiting for the Worms"). "What Shall We Do Now?" would be performed at all concerts for "The Wall", and so appears on "Is There Anybody Out There? The Wall Live 1980–81". It was also included in Waters' 1990 "The Wall" Concert in Berlin, therefore appears on the album "The Wall – Live in Berlin". Waters also performed it on his 2010-2013 tour. What Shall We Do Now? "What Shall We Do Now?" (working title "Backs to the Wall") is a song