angular length
121Newton'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 …
122Spin (physics) — This article is about spin in quantum mechanics. For rotation in classical mechanics, see angular momentum. In quantum mechanics and particle physics, spin is a fundamental characteristic property of elementary particles, composite particles… …
123microscope — /muy kreuh skohp /, n. 1. an optical instrument having a magnifying lens or a combination of lenses for inspecting objects too small to be seen or too small to be seen distinctly and in detail by the unaided eye. 2. (cap.) Astron. the… …
124Nonimaging optics — (also called anidolic optics)[1][2] is the branch of optics concerned with the optimal transfer of light radiation between a source and a target. Unlike traditional imaging optics, the techniques involved do not attempt to form an image of the… …
125Cosmic microwave background radiation — CMB and Cosmic background radiation redirect here. For other uses see CMB (disambiguation) and Cosmic background (disambiguation). Physical cosmology …
126ΔT — This article is about the time difference. For the temperature difference, see psychrometrics. ΔT vs. time from 1657 to 1984[1] ΔT, Delta T, delta T, deltaT, or DT is the time difference obtained by subtracting Universal Time (UT) from… …
127Natural units — In physics, natural units are physical units of measurement based only on universal physical constants. For example the elementary charge e is a natural unit of electric charge, or the speed of light c is a natural unit of speed. A purely natural …
128Quantum mechanics — For a generally accessible and less technical introduction to the topic, see Introduction to quantum mechanics. Quantum mechanics …
