PREFACE Circling silently in space a few hundred miles above our heads is one of the most amazing scientific instruments ever made -- the Hubble Space Telescope (HST). Day after day it is returning images of the universe with incredible beauty, as it peers deep into space to spy on the stars, the vast stellar nurseries where they are born, and distant galaxies. It was not always so. The HST made a disastrous debut. When first launched in April 1990, it had faulty vision because its primary light-gathering mirror had been inadvertently ground to the wrong shape. The mirror was only two-fiftieths of the width of a human hair out of true, but this was enough to blur the images the HST produced. But the very perfection of the imperfection of the primary mirror made it relatively easy, optically speaking, to correct. And in December 1993, spacewalking astronauts recovered the HST in orbit and corrected its flawed vision. The telescope then at last began to fulfil its promise of opening up a new window on the universe. On subsequent servicing missions, new instruments have broadened and deepened the view through that window. The HST is a monster of a satellite, as big as a bus and twice as heavy as a bull elephant. Yet it can manipulated remotely with microsurgical precision to view a particular region of space. And it can stay locked onto that region for hours at a time, even though it is hurling in orbit around Earth at more than ten times the speed of a rifle bullet. Compared with leading ground-based telescopes, the HST has quite a small light-gathering mirror -- the Keck telescopes in Hawaii have mirrors more than four times the size. But the HST is a much more effective light-gatherer than ordinary telescopes: they look at the heavens through the "dirty window" that is the Earth's atmosphere, whereas the HST looks at the universe through the pristine clarity of airless space. So it can detect the faintest smudges of light coming from even the remotest depths of the universe. It also has the advantage over ordinary telescopes that it can detect invisible radiation from the heavens that the atmosphere absorbs. This book reveals the wonderful, mysterious and awesome universe of ours through the eyes of the Hubble Space Telescope. You don't have to be an astronomer to appreciate the often breathtakingly, hauntingly beautiful images, which chronicle frozen moments in the life of the cosmos -- from Martian dust storms to extrasolar planetary systems; from the birth pangs of young stars to the death throes of ancient ones; from starbursts in neighboring galaxies to catastrophic collisions in remote galactic clusters. So travel with me on an incredible journey into space. The ultimate incredible journey. To the ends of the universe. To the beginning of time. Robin Kerrod Salisbury, England. Excerpted from Hubble: The Mirror on the Universe by Robin Kerrod All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.
