Refraction (sound) Refraction (sound) Refraction, in acoustics, comparable to the refraction of electromagnetic radiation, is the bending of sound propagation trajectories (rays) in inhomogeneous elastic media (gases, liquids, and solids) in which the wave velocity is a function of spatial coordinates. Bending of acoustic rays in layered inhomogeneous media occurs towards a layer with a smaller sound velocity. This effect is responsible for guided propagation of sound waves over long distances in the ocean and in the atmosphere. In the atmosphere, vertical gradients of wind speed and temperature lead to refraction. The wind speed is usually increasing with height, which leads to
A-35 anti-ballistic missile system Vitalii Leonidovich Kataev states that the A-35M system was capable of intercepting "a single ballistic missile from some directions and up to 6 Pershing II-type missiles from the FRG". A-35 anti-ballistic missile system The A-35 anti-ballistic missile system was a Soviet military anti-ballistic missile (ABM) system deployed around Moscow to intercept enemy ballistic missiles targeting the city or its surrounding areas. The A-35 was the only Soviet ABM system allowed under the 1972 Anti-Ballistic Missile Treaty. In development since the 1960s and in operation from 1971 until the 1990s, it featured the nuclear-tipped A350 exoatmospheric interceptor missile. The A-35 was