velocity doppler limit
121Outline of astronomy — Mauna Kea in Hawaii is one of the world s premier observatory sites. Pictured is the W. M. Keck Observatory, an optical interferometer. The following outline is provided as an overview of and topical guide to astronomy: Astronomy – studies the… …
122Acoustics — is the interdisciplinary science that deals with the study of sound, ultrasound and infrasound (all mechanical waves in gases, liquids, and solids). A scientist who works in the field of acoustics is an acoustician. The application of acoustics… …
123Sea level rise — is an increase in sea level. Multiple complex factors may influence this change. Sea level has risen about 130 meters (400 ft) since the peak of the last ice age about 18,000 years ago. Most of the rise occurred before 6,000 years ago. From 3,000 …
124Scattering — is a general physical process where some forms of radiation, such as light, sound, or moving particles, are forced to deviate from a straight trajectory by one or more localized non uniformities in the medium through which they pass. In… …
125Active galactic nucleus — An active galactic nucleus (AGN) is a compact region at the centre of a galaxy which has a much higher than normal luminosity over some or all of the electromagnetic spectrum (in the radio, infrared, optical, ultra violet, X ray and/or gamma ray… …
126ExoMars — Operator ESA, NASA Major contractors Thales Alenia Space and Astrium Mission type Orbiter, lander and rover Orbital insertion date 2017 and 2019 Launch date …
127Radar jamming and deception — is the intentional emission of radio frequency signals to interfere with the operation of a radar by saturating its receiver with noise or false information. There are two types of radar jamming: Mechanical and Electronic jamming . Mechanical… …
128Redshift quantization — is the hypothesis that the redshifts of cosmologically distant objects (in particular galaxies) tend to cluster around multiples of some particular value. Since there is a correlation of distance and redshift as expressed in Hubble s Law,… …
