The antenna in the valley
Monday, May 9, 2011 - 10:00
in Astronomy & Space
When Galileo Galilei turned his modest spy glass towards the stars in the summer of 1609, he opened up new skies. He observed things which no one had ever seen before: mountains and craters on the moon, the phases of Venus, individual stars of the Milky Way. Galileo Galilei had pushed the window into space wide open. He had no way of knowing that his telescope observed only a tiny octave in the cosmic keyboard of light, because the electromagnetic spectrum we receive from space stretches across twelve orders of magnitude: at one end are the high-energy gamma rays with wavelengths of 0.01 nanometres (one billionth of a meter); at the other, the radio region with wavelengths of several metres.