time-scale factor
81Dark energy — Not to be confused with dark matter, dark fluid, or dark flow. Physical cosmology …
82dating — I In geology and archaeology, the process of determining an object s or event s place within a chronological scheme. Scientists may use either relative dating, in which items are sequenced on the basis of stratigraphic clues (see stratigraphy) or …
83Euclidean vector — This article is about the vectors mainly used in physics and engineering to represent directed quantities. For mathematical vectors in general, see Vector (mathematics and physics). For other uses, see vector. Illustration of a vector …
84Molecular dynamics — (MD) is a computer simulation of physical movements of atoms and molecules. The atoms and molecules are allowed to interact for a period of time, giving a view of the motion of the atoms. In the most common version, the trajectories of molecules… …
85Gravitational microlensing — Gravitational Lensing Formalism Strong lensing …
86Metric expansion of space — Physical cosmology Universe · Big Bang …
87Physical cosmology — This article is about the physics subject. For other uses, see Cosmology. Physical cosmology …
88Renormalization — Quantum field theory (Feynman diagram) …
89Age of the universe — The age of the universe is the time elapsed between the theory of the Big Bang and the present day. Current observations suggest that this is about 13.73 billion years, with an uncertainty of about +/ 120 million years. The lowering of the… …
90Newton's theorem of revolving orbits — Figure 1: An attractive force F(r) causes the blue planet to move on the cyan circle. The green planet moves three times faster and thus requires a stronger centripetal force, which is supplied by adding an attractive inverse cube force. The …
