Refraction (sound) a downward bending of the sound rays towards the ground. The same holds if the temperature is decreasing with height. If the temperature is increasing with height (inversion) and the wind speed is low, sound rays are bend upwards. 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
James A. Abrahamson retrieval and repair mission. Abrahamson was appointed by President Ronald Reagan to be the first director of the Strategic Defense Initiative ("SDI") in April 1984. The "Star Wars" program, as SDI's detractors dubbed it, was initiated to develop a sophisticated anti-ballistic missile system that would prevent missile attacks from other countries, particularly the Soviet Union. Some countries opposed to U.S. missile defense efforts raised concerns about the program "contravening" the anti-ballistic missile (ABM) of the Strategic Arms Limitation Talks in years before the program was enacted. Ultimately, concerns about the objectives of SDI and fiscal budgetary constraints forced the Reagan