"Universe's expansion" . "universe was expanding" . "cosmic expansion" . "Expansion of the universe" . "Expansion of the universe" . . "local expansion of the universe" . . "expanding space" . "cosmological origin" . "the universe is expanding" . "space has been expanding" . . "expansion" . "expands space" . "expanded" . "expansion of the universe" . "expanding" . "rate of expansion" . . . "expansion [of the universe]" . . "expansion history of the universe" . . "universe's expansion" . "metric expansion of space" . "expand" . "universe expanded" . . . "expansion of space" . . "universe is expanding" . . . "expanding universe" . "Expansion" . "expansion of space itself" . . "Expanding Rubber Sheet Universe" .