THE WANDERING ASTRONOMER Reprinted 2010 by CRC Press CRC Press 6000 Broken Sound Parkway, NW Suite 300, Boca Raton, FL 33487 270 Madison Avenue New York, NY 10016 2 Park Square, Milton Park Abingdon, Oxon OX14 4RN, UK Copynghr ©Patrick Moore 1999 Copyright © David Bateman Ltd, 1999 First published tn 1999 by lOP Publishing Lrd Dirac House, Temple Back, Bnsrol BS I 6BE lnsorute of Physrcs Publishing rs whoUy owned by The I nstirure of Physrcs, London Produced tn assoe1aoon wrth Davrd Bateman Ltd 30 Tarndale Grove, AJbany, North Shore Crry, AuciJand, New Zealand Britzsb LibraYJ• Catalogumg-m-rub/zcarwn Data A catalogue record for this book rs available from the Briosh Library ISBN 0 7503 0693 9 This book is copyright. Except for the purpose of fair reVlew, no pan may be stored or transmitted in any form of by any means, electronic or mecharucal, including recording or storage tn an tnformanon remeval system Wlthout perm1ssion in writing from the publisher. No reproducnon may be made, whether by photocopytng or by any other means, unJess a licence has been obtamed from the publisher or ns agent. Cover destgn by Kevin Lowry Typeset tn 12pt Garamond Printed tn Hong Kong by Colorcrafr Lrd THE WANDERING ASTRONOMER PATRICK MOORE 0 2!~,~~~~,. Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business Author's Preface Most books have a set plan. This one has not; it has no plan at all, and like its two predecessors, Armchair Astronomy and Fireside Astronomy, it is simply a coUection of totally unconnected essays. Some are more tech nical than others bur whar I have tried to do is ro presenr material which you will probably nor flnd in conventionaJ textbooks. Certainly ir is nor a book to be read straight through in the usual way; but if you dip inro it at random, I hope you will flnd something thar will appeal ro you. I have done my best! Patrick Moore Selsey, June I 000 Contents I. The Atmosphere of the Mooo 7 2. The !\1an Who Discovered a Planet 13 3. Moon in Shadcm: 19 4. The Zodiacal intruder 23 5. Fishing Hipparcos Down 27 u/ . The Past and Future Moon 30 7. Visitor to the Ares Vallis 34 8. Harvest Moons, Wolf Moons and Blue Moons 38 9. The Cosmic Zebra 41 HL Flying Saucers in Selsey 47 II. Gene Shoemaker 52 12. The Blackness of Mathilde 59 13. Hitch-Hiker- and Others 62 4. Ice on the Moon) (J 15. Mira Stella 71 16. The Case of the Vanishing Planets 75 17. Poetic Moons 82 1 8. A l jghtning Decision! 84 1< ). The Strange Case of SS Lacertae 87 20. How the Lunar Craters fV'eren I Formed 90 21. The Lonely Brown Dwarf <)7 22. Sister Marie - and Others 100 23. To Catch a Comet 105 24. Curious Callisto 08 25. A Year on Icarus 1 1 1 26. The Lighter Side of Space 115 27. Alshain 122 28. Names in the Sky 127 29. Travel to the Stars? 133 30. Ghost Moons 137 31. Ripples of Creation 152 32. "Des. Res. " on Mars? 155 33. The Edge of the Moon 157 34. The Sad Case of Dr Elliott 163 35. Fast Lane to Pluto 169 36. Life Can Appear- but Will it? 173 37. Thatcher's Comet 175 38. Apocalypse Postponed 179 39. The Star in the East 181 40. It \\ias in the Papers! 185 41. Caribbean Eclipse 197 Glossary 202 Lndex 206 Picture Credits 208 1 The Atmosphere of the Moon "The Moon is an airless world." You will find this statement in countless books and, essentially, of course it is true enough. There is a very simple way to show that the Moon has at best a very thin atmosphere. \'Vhen a star is occulted, it shines steadily right up to the moment when it is covered by the advancing lunar limb; there is no pre-immersion ilickering or fading, as there is before occultation by Venus (and to a much lesser ex tent, Mars). But can we be confident that there is no atmosphere at all? Originally, it was of course assumed that the Moon must have an atmosphere dense enough to support life. This was the firm belief of observers such as Johann Schroter, the first really great lunar observer, wbo began his work in the late 1770s. William Herschel, discoverer of Uranus and arguably the most skilled of alJ observers, beUeved the habitability of the Moon to be "an absolute certainty'' (for good measure, he also beUeved in a cool, Sir William Herschel, discoverer of Uranus. 7 P.\TRJCk MooRF inhabited Sun), and in 1822 Franz von Paula Gruithuisen announced that he had identified a true dry with "dark gigantic ramparts", though, alas, there is nothing in this particular area other than low, haphazard ridges. This was in 1822; in the fol lowing decade many Americans were taken in by the celebrated Lunar Hoax, \vhen the New 'r'ork paper Sun announced that fan tastic life-forms had been detected there by Sir John Herschel, who was busily surveying the southern skies from the Cape. (One earnest group even wrote to inguire whether there were any immediate plans to convert the Moon-men to Christianity.) Low-type vegetation was still considered a possibility, even though a remote one, until less than a century ago, but so far as I know the last serious astronomer to believe in anything more advanced was WH. Pickering, who made very notable contribu tions to lunar and planetary astronomy. Pickering observed an occultation of Jupiter, in 1892, and recorded a dark band cross ing the planer's disk, tilted with respect to the usual surface belts. This he attributed to the absorbing effect of a lunar atmosphere. He repeated the observation at several later occultations, and found that the dark band was seen only when Jupiter was cut the Moon's bright limb. At the dark or night side of the Moon it was never seen and Pickering concluded that the lunar atmos phere responsible for it was frozen solid during the Moon's night. He worked out that the ground density of the lunar atmosphere was about 1/1800 of the density of our own air at sea level. But Pickering did not stop there. Between 1919 and 1924 he carried out a series of lunar observations from the clear skies of Jamaica, and in particular concentrated on the crater Eratosthenes, which has high, terraced walls and a central peak. Pickering claimed that dark patches inside it, which are easy telescopic objects, moved around during the lunar dav and, although he was sure that vegetation tracts did exist on the Moon, he held that the spreading patches were better explained by swarms of insects. Finally, in 1924, he published a paper in which he claimed that the parches were probably due to much more advanced life-forms, which would make them even more curi cms. "WhiJe this suggestion of a round of lunar life may seem a 8 THE Wo.." DERING AsTRONO~IER The Great Meteor or 7 October 1862 appears in this old painting. It was seen across England and apparently was much brighter than the full moon. tittle fanciful, and the evidence on which it is founded frail, yet it is based on the analogy of the migration of the fur bearing seals of the Pribiloff Islands ... The distance involved is about rwenry rniies, and is completed in rwelve days. This involves an average speed of six feet a minute, which, as we have seen, implies small animals." Pickering died in 1938, and the idea of lunar creatures died with him, but the question of a residual lunar atmosphere was still carefully considered. In 1949 Bernard Lyot and udouin Dollfus, both great French observers, used the fine 24-inch refractor at the high-altitude Pic du Midi Observatory, in the Pyrenees, ro search for lunar twilight effects. They found none and concluded that any atmosphere must have a density less than 1/10,000 of ours. Next, V. f'esenkov and Y. N. Lipski, in what was then the USSR, carried out a search for nvilight effects 9