Textbook in PDF format In The Echoing Universe, Emma Chapman tunes us in to the universe and what it is trying to say, through the science of radio astronomy. Everything is sending out signals: the surface of the Moon, distant stars—maybe even extraterrestrials. With radio waves, we can uncover what visible light cannot show us and peer into realms that are otherwise unreachable. Even the hostile surface of Venus, where high temperatures, lethal acid rain, and crushing pressure rapidly annihilate even the hardiest robotic probes, yields its secrets through radio observations