There are working fission bombs. Fusion reactions power the sun. The universe is thought to be expanding. A black hole was once a star with mass equal to that of the sun. When angular momentum is conserved, stationary objects begin spinning.
Continents contain granitic rocks.
The Jovian planets are rocky in composition. are larger than the terrestrial planets. are closer to the sun than the terrestrial planets. are denser than the terrestrial planets. If a sedimentary rock layer lies on top of a lava flow dated radiometrically at 44 million years, but is itself cut by an igneous body dated at 27 million years, is less than 27 million years. is more than 44 million years. To be useful as geologic clocks, radioactive isotopes must be extremely rare and have long half-lives. From center to surface, the chemically distinct layers of the earth are inner core, outer core, mantle, crust. The asthenosphere consists of completely molten peridotite.