x-ray astronomy

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Definition of x-ray astronomy in English English dictionary

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X-ray astronomy

An observational branch of astronomy, which deals with the study of X-ray emission from celestial objects

x-ray astronomy

The branch of astronomy that deals with the origin and nature of emissions from extraterrestrial sources in the x-ray range of electromagnetic radiation rather than in the visible range. Study of astronomical objects and phenomena that emit radiation at X-ray wavelengths. Because Earth's atmosphere absorbs most X rays, X-ray telescopes and detectors are taken to high altitudes or into space by balloons and spacecraft. In 1949 detectors aboard sounding rockets showed that the Sun gives off X rays, but it is a weak source; it took 30 more years to clearly detect X rays from other ordinary stars. Beginning with the Uhuru X-ray satellite (launched 1970), a succession of space observatories carried increasingly sophisticated instruments into Earth orbit. Astronomers discovered that most types of stars emit X rays but usually as a tiny fraction of their energy output. Supernova remnants are more powerful X-ray sources; the strongest sources known in the Milky Way Galaxy are certain binary stars in which one star is probably a black hole. In addition to myriad point sources, astronomers have found a diffuse background of X-ray radiation emanating from all directions; unlike cosmic background radiation, it appears to have many distant individual sources. The Chandra X-Ray Observatory and XMM-Newton X-ray satellite (both launched 1999) have made numerous discoveries relating to the nature and quantity of black holes in the universe, the evolution of stars and galaxies, and the composition and activity of supernova remnants

gamma-ray astronomy

Study of astronomical objects and phenomena that emit gamma rays. Gamma-ray telescopes are designed to observe high-energy astrophysical systems, including stellar coronas, white dwarf stars, neutron stars, black holes, supernova remnants, clusters of galaxies, and diffuse gamma-ray background radiation found along the plane of the Milky Way Galaxy. Because Earth's atmosphere blocks most gamma rays, observations are generally conducted by high-altitude balloons or spacecraft. In the 1960s defense satellites designed to detect X rays and gamma rays from clandestine nuclear testing serendipitously discovered enigmatic gamma-ray bursts coming from deep space. In the 1970s Earth-orbiting observatories found a number of gamma-ray point sources, including an exceptionally strong one, dubbed Geminga, that was later identified as a pulsar, the nearest yet detected. The Compton Gamma Ray Observatory, launched in 1991, mapped thousands of celestial gamma-ray sources; it also showed that the mysterious bursts are distributed across the sky, implying that their sources are at the distant reaches of the universe rather than in the Milky Way

Hyphenation

x-ray as-tron-o-my

Turkish pronunciation

eksrey ıstränımi

Pronunciation

/ˈekˌsrā əˈstränəmē/ /ˈɛkˌsreɪ əˈstrɑːnəmiː/