Meaning of X-RAY ASTRONOMY in English

Study of astronomical objects and phenomena that emit radiation at

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 star s. 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 star s 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 {{link=galaxy">galaxies , and the composition and activity of supernova remnants.

Britannica English dictionary.      Английский словарь Британика.