دانلود کتاب نجوم رادیویی – مشاهده جهان نامرئی

Over thousands of years, the field of astronomy has progressed from watching the skies with our eyes to building telescopes to magnify the light and capture it on photographic film or with electronic detectors. But traditionally, astronomy always meant looking at light. We now know that visible light is just one of the channels that carries information about the universe. The accidental discovery of celestial radio waves gave us our first look into hitherto unexplored parts of the electromagnetic spectrum and inaugurated the discipline of radio astronomy. Radio astronomy is the study of the universe through measurement of natural radio signals. Objects that emit radio waves have enormous diversity, and many of them don’t emit any light. In some sense, radio astronomy is the exploration of an invisible universe—a universe that sometimes can only be detected through its radio emission.