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ces that you would be on or near a planet would be less than one in a billiontrillion trillion。鈥潯。╰hat鈥檚 1033； or a one followed by thirty…three zeroes。） 鈥渨orlds are precious。鈥�
which is why perhaps it is good news that in february 1999 the international astronomicalunion ruled officially that pluto is a planet。 the universe is a big and lonely place。 we can dowith all the neighbors we can get。
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3 THE REVEREND EVANS鈥橲 UNIVERSE
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when the skies are clear and the moon is not too bright； the reverend robert evans； aquiet and cheerful man； lugs a bulky telescope onto the back deck of his home in the bluemountains of australia； about fifty miles west of sydney； and does an extraordinary thing。 helooks deep into the past and finds dying stars。
looking into the past is of course the easy part。 glance at the night sky and what you see ishistory and lots of it鈥攖he stars not as they are now but as they were when their light leftthem。 for all we know； the north star； our faithful panion； might actually have burnedout last january or in 1854 or at any time since the early fourteenth century and news of it justhasn鈥檛 reached us yet。 the best we can say鈥攃an ever say鈥攊s that it was still burning on thisdate 680 years ago。 stars die all the time。 what bob evans does better than anyone else whohas ever tried is spot these moments of celestial farewell。
by day； evans is a kindly and now semiretired minister in the uniting church in australia；who does a bit of freelance work and researches the history of nineteenth…century religiousmovements。 but by night he is； in his unassuming way； a titan of the skies。 he huntssupernovae。
supernovae occur when a giant star； one much bigger than our own sun； collapses and thenspectacularly explodes； releasing in an instant the energy of a hundred billion suns； burningfor a time brighter than all the stars in its galaxy。 鈥渋t鈥檚 like a trillion hydrogen bombs going offat once；鈥潯ays evans。 if a supernova explosion happened within five hundred light…years of us；we would be goners； according to evans鈥斺�渋t would wreck the show；鈥潯s he cheerfully puts it。
but the universe is vast； and supernovae are normally much too far away to harm us。 in fact；most are so unimaginably distant that their light reaches us as no more than the faintesttwinkle。 for the month or so that they are visible； all that distinguishes them from the otherstars in the sky is that they occupy a point of space that wasn鈥檛 filled before。 it is theseanomalous； very occasional pricks in the crowded dome of the night sky that the reverendevans finds。
to understand what a feat this is； imagine a standard dining room table covered in a blacktablecloth and someone throwing a handful of salt across it。 the scattered grains can bethought of as a galaxy。 now imagine fifteen hundred more tables like the first one鈥攅nough tofill a wal…mart parking lot； say； or to make a single line two miles long鈥攅ach with a randomarray of salt across it。 now add one grain of salt to any table and let bob evans walk amongthem。 at a glance he will spot it。 that grain of salt is the supernova。
evans鈥檚 is a talent so exceptional that oliver sacks； in an anthropologist on mars； devotesa passage to him in a chapter on autistic savants鈥攓uickly adding that 鈥渢here is no suggestionthat he is autistic。鈥潯vans； who has not met sacks； laughs at the suggestion that he might beeither autistic or a savant； but he is powerless to explain quite where his talent es from。
鈥渋 just seem to have a knack for memorizing star fields；鈥潯e told me； with a franklyapologetic look； when i visited him and his wife； elaine； in their picture…book bungalow on atranquil edge of the village of hazelbrook； out where sydney finally ends and the boundlessaustralian bush begins。 鈥渋鈥檓 not particularly good at other things；鈥潯e added。 鈥渋 don鈥檛remember names well。鈥�
鈥渙r where he鈥檚 put things；鈥潯alled elaine from the kitchen。
he nodded frankly again and grinned； then asked me if i鈥檇 like to see his telescope。 i hadimagined that evans would have a proper observatory in his backyard鈥攁 scaled…downversion of a mount wilson or palomar； with a sliding domed roof and a mechanized chair thatwould be a pleasure to maneuver。 in fact； he led me not outside but to a crowded storeroomoff the kitchen where he keeps his books and papers and where his telescope鈥攁 whitecylinder that is about the size and shape of a household hot…water tank鈥攔ests in a homemade；swiveling plywood mount。 when he wishes to observe； he carries them in two trips to a smalldeck off the kitchen。 between the overhang of the roof and the feathery tops of eucalyptustrees growing up from the slope below； he has only a letter…box view of the sky； but he says itis more than good enough for his purposes。 and there； when the skies are clear and the moonnot too bright； he finds his supernovae。
the term supernova was coined in the 1930s by a memorably odd astrophysicist namedfritz zwicky。 born in bulgaria and raised in switzerland； zwicky came to the californiainstitute of technology in the 1920s and there at once distinguished himself by his abrasivepersonality and erratic talents。 he didn鈥檛 seem to be outstandingly bright； and many of hiscolleagues considered him little more than 鈥渁n irritating buffoon。鈥潯 fitness buff； he wouldoften drop to the floor of the caltech dining hall or other public areas and do one…armedpushups to demonstrate his virility to anyone who seemed inclined to doubt it。 he wasnotoriously aggressive； his manner eventually being so intimidating that his closestcollaborator； a gentle man named walter baade； refused to be left alone with him。 amongother things； zwicky accused baade； who was german； of being a nazi； which he was not。 onat least one occasion zwicky threatened to kill baade； who worked up the hill at the mountwilson observatory； if he saw him on the caltech campus。
but zwicky was also capable of insights of the most startling brilliance。 in the early 1930s；he turned his attention to a question that had long troubled astronomers： the appearance in thesky of occasional une