ÓÑÇéÌáʾ£ºÈç¹û±¾ÍøÒ³´ò¿ªÌ«Âý»òÏÔʾ²»ÍêÕû£¬Çë³¢ÊÔÊó±êÓÒ¼ü¡°Ë¢Ð¡±±¾ÍøÒ³£¡
¸»Ê¿¿µÐ¡ËµÍø ·µ»Ø±¾ÊéĿ¼ ¼ÓÈëÊéÇ© ÎÒµÄÊé¼Ü ÎÒµÄÊéÇ© TXTÈ«±¾ÏÂÔØ ¡ºÊղص½ÎÒµÄä¯ÀÀÆ÷¡»

pale blue dot -carl sagan-µÚ31²¿·Ö

¿ì½Ý²Ù×÷: °´¼üÅÌÉÏ·½Ïò¼ü ¡û »ò ¡ú ¿É¿ìËÙÉÏÏ·­Ò³ °´¼üÅÌÉ쵀 Enter ¼ü¿É»Øµ½±¾ÊéĿ¼ҳ °´¼üÅÌÉÏ·½Ïò¼ü ¡ü ¿É»Øµ½±¾Ò³¶¥²¿! Èç¹û±¾ÊéûÓÐÔĶÁÍ꣬ÏëÏ´μÌÐø½Ó×ÅÔĶÁ£¬¿ÉʹÓÃÉÏ·½ "Êղص½ÎÒµÄä¯ÀÀÆ÷" ¹¦ÄÜ ºÍ "¼ÓÈëÊéÇ©" ¹¦ÄÜ£¡


¡¡numbers¡¡of¡¡inoffensive¡¡asteroids¡¡whose¡¡orbits¡¡could¡¡be¡¡altered¡¡with¡¡nuclear¡¡warheads¡¡so¡¡they¡¡quickly¡¡collide¡¡with¡¡the¡¡Earth¡£

Suppose¡¡we¡¡restrict¡¡our¡¡attention¡¡to¡¡the¡¡2£»000¡¡or¡¡so¡¡near¡­Earth¡¡asteroids¡¡that¡¡are¡¡a¡¡kilometer¡¡across¡¡or¡¡bigger¡ªthat¡¡is£»¡¡the¡¡ones¡¡most¡¡likely¡¡to¡¡cause¡¡a¡¡global¡¡catastrophe¡£¡¡Today£»¡¡with¡¡only¡¡about¡¡100¡¡of¡¡these¡¡objects¡¡catalogued£»¡¡it¡¡would¡¡take¡¡about¡¡a¡¡century¡¡to¡¡catch¡¡one¡¡when¡¡it's¡¡easily¡¡deflectable¡¡to¡¡Earth¡¡and¡¡alter¡¡its¡¡orbit¡£¡¡We¡¡think¡¡we've¡¡found¡¡one£»¡¡an¡¡as¡­yet¡­unnamed*¡¡asteroid¡¡so¡¡far¡¡denoted¡¡only¡¡as¡¡1991OA¡£¡¡In¡¡2070£»¡¡this¡¡world£»¡¡about¡¡1¡¡kilometer¡¡in¡¡diameter£»¡¡will¡¡e¡¡within¡¡4¡£5¡¡million¡¡kilometers¡¡of¡¡the¡¡Earth's¡¡orbit¡ªonly¡¡fifteen¡¡times¡¡the¡¡distance¡¡to¡¡the¡¡Moon¡£¡¡To¡¡deflect¡¡1991OA¡¡so¡¡it¡¡hits¡¡the¡¡Earth£»¡¡only¡¡about¡¡60¡¡megatons¡¡of¡¡TNT¡¡equivalent¡¡needs¡¡to¡¡be¡¡exploded¡¡in¡¡the¡¡right¡¡way¡ªthe¡¡equivalent¡¡of¡¡a¡¡small¡¡number¡¡of¡¡currently¡¡available¡¡nuclear¡¡warheads¡£

*¡¡What¡¡should¡¡we¡¡call¡¡this¡¡world£¿¡¡Naming¡¡it¡¡after¡¡the¡¡Greek¡¡Fates¡¡or¡¡Furies¡¡or¡¡Nemesis¡¡seems¡¡inappropriate£»¡¡because¡¡whether¡¡it¡¡misses¡¡or¡¡hits¡¡the¡¡Earth¡¡is¡¡entirely¡¡in¡¡our¡¡hands¡£¡¡If¡¡we¡¡leave¡¡it¡¡alone£»¡¡it¡¡misses¡£¡¡If¡¡we¡¡push¡¡it¡¡cleverly¡¡and¡¡precisely£»¡¡it¡¡hits¡£¡¡Maybe¡¡we¡¡should¡¡call¡¡it¡¡¡¨Eight¡¡Ball¡£¡¨

Now¡¡imagine¡¡a¡¡time£»¡¡a¡¡few¡¡decades¡¡hence£»¡¡when¡¡all¡¡such¡¡near¡­Earth¡¡asteroids¡¡are¡¡inventoried¡¡and¡¡their¡¡orbits¡¡piled¡£¡¡Then£»¡¡as¡¡Alan¡¡Harris¡¡of¡¡JPL£»¡¡Greg¡¡Canavan¡¡of¡¡the¡¡Los¡¡Alamos¡¡National¡¡Laboratory£»¡¡Ostro£»¡¡and¡¡I¡¡have¡¡shown£»¡¡it¡¡might¡¡take¡¡only¡¡a¡¡year¡¡to¡¡select¡¡a¡¡suitable¡¡object£»¡¡alter¡¡its¡¡orbit£»¡¡and¡¡send¡¡it¡¡crashing¡¡into¡¡the¡¡Earth¡¡with¡¡cataclysmic¡¡effect¡£

The¡¡technology¡¡required¡ªlarge¡¡optical¡¡telescopes£»¡¡sensitive¡¡detectors£»¡¡rocket¡¡propulsion¡¡systems¡¡able¡¡to¡¡lift¡¡a¡¡few¡¡tons¡¡of¡¡payload¡¡and¡¡make¡¡precise¡¡rendezvous¡¡in¡¡nearby¡¡space£»¡¡and¡¡thermonuclear¡¡weapons¡ªall¡¡exist¡¡today¡£¡¡Improvements¡¡in¡¡all¡¡but¡¡perhaps¡¡the¡¡last¡¡can¡¡be¡¡confidently¡¡expected¡£¡¡If¡¡we're¡¡not¡¡careful£»¡¡many¡¡nations¡¡may¡¡have¡¡these¡¡capabilities¡¡in¡¡the¡¡next¡¡few¡¡decades¡£¡¡What¡¡kind¡¡of¡¡world¡¡will¡¡we¡¡then¡¡have¡¡made£¿

We¡¡have¡¡a¡¡tendency¡¡to¡¡minimize¡¡the¡¡dangers¡¡of¡¡new¡¡technologies¡£¡¡A¡¡year¡¡before¡¡the¡¡Chernobyl¡¡disaster£»¡¡a¡¡Soviet¡¡nuclear¡¡power¡¡industry¡¡deputy¡¡minister¡¡was¡¡asked¡¡about¡¡the¡¡safety¡¡of¡¡Soviet¡¡reactors£»¡¡and¡¡chose¡¡Chernobyl¡¡as¡¡a¡¡particularly¡¡safe¡¡site¡£¡¡The¡¡average¡¡waiting¡¡time¡¡to¡¡disaster£»¡¡he¡¡confidently¡¡estimated£»¡¡was¡¡a¡¡hundred¡¡thousand¡¡years¡£¡¡Less¡¡than¡¡a¡¡year¡¡later¡¡¡£¡¡¡£¡¡¡£¡¡devastation¡£¡¡Similar¡¡reassurances¡¡were¡¡provided¡¡by¡¡NASA¡¡contractors¡¡the¡¡year¡¡before¡¡the¡¡Challenger¡¡disaster£º¡¡You¡¡would¡¡have¡¡to¡¡wait¡¡ten¡¡thousand¡¡years£»¡¡they¡¡estimated£»¡¡for¡¡a¡¡catastrophic¡¡failure¡¡of¡¡the¡¡shuttle¡£¡¡One¡¡year¡¡later¡¡¡£¡¡¡£¡¡¡£¡¡heartbreak¡£

Chlorofluorocarbons¡¡£¨CFCs£©¡¡were¡¡developed¡¡specifically¡¡as¡¡a¡¡pletely¡¡safe¡¡refrigerant¡ªto¡¡replace¡¡ammonia¡¡and¡¡other¡¡refrigerants¡¡that£»¡¡on¡¡leaking¡¡out£»¡¡had¡¡caused¡¡illness¡¡and¡¡some¡¡deaths¡£¡¡Chemically¡¡inert£»¡¡nontoxic¡¡£¨in¡¡ordinary¡¡concentrations£©£»¡¡odorless£»¡¡tasteless£»¡¡non¡­allergenic£»¡¡nonflammable£»¡¡CFCs¡¡represent¡¡a¡¡brilliant¡¡technical¡¡solution¡¡to¡¡a¡¡well¡­defined¡¡practical¡¡problem¡£¡¡They¡¡found¡¡uses¡¡in¡¡many¡¡other¡¡industries¡¡besides¡¡refrigeration¡¡and¡¡air¡¡conditioning¡£¡¡But£»¡¡as¡¡I¡¡described¡¡above£»¡¡the¡¡chemists¡¡who¡¡developed¡¡CFCs¡¡overlooked¡¡one¡¡essential¡¡fact¡ªthat¡¡the¡¡molecules'¡¡very¡¡inertness¡¡guarantees¡¡that¡¡they¡¡are¡¡circulated¡¡to¡¡stratospheric¡¡altitudes¡¡and¡¡there¡¡cracked¡¡open¡¡by¡¡sunlight£»¡¡releasing¡¡chlorine¡¡atoms¡¡which¡¡then¡¡attack¡¡the¡¡protective¡¡ozone¡¡layer¡£¡¡Due¡¡to¡¡the¡¡work¡¡of¡¡a¡¡few¡¡scientists£»¡¡the¡¡dangers¡¡may¡¡have¡¡been¡¡recognized¡¡and¡¡averted¡¡in¡¡time¡£¡¡We¡¡humans¡¡have¡¡now¡¡almost¡¡stopped¡¡producing¡¡CFCs¡£¡¡We¡¡won't¡¡actually¡¡know¡¡if¡¡we've¡¡avoided¡¡real¡¡harm¡¡for¡¡about¡¡a¡¡century£»¡¡that's¡¡how¡¡long¡¡it¡¡takes¡¡for¡¡all¡¡the¡¡CFC¡¡damage¡¡to¡¡be¡¡pleted¡£¡¡Like¡¡the¡¡ancient¡¡Camarinans£»¡¡we¡¡make¡¡mistakes¡£*¡¡Not¡¡only¡¡do¡¡we¡¡often¡¡ignore¡¡the¡¡warnings¡¡of¡¡the¡¡Oracles£»¡¡characteristically¡¡we¡¡do¡¡not¡¡even¡¡consult¡¡them¡£

*¡¡There¡¡is¡¡of¡¡course¡¡a¡¡wide¡¡range¡¡of¡¡other¡¡problems¡¡brought¡¡on¡¡by¡¡the¡¡devastatingly¡¡powerful¡¡technology¡¡we've¡¡recently¡¡invented¡£¡¡But¡¡in¡¡most¡¡cases¡¡they're¡¡not¡¡Camarinan¡¡disasters¡­damned¡¡if¡¡you¡¡do¡¡and¡¡damned¡¡if¡¡you¡¡don't¡£¡¡Instead¡¡they're¡¡dilemmas¡¡of¡¡wisdom¡¡or¡¡timing¡­for¡¡example£»¡¡the¡¡wrong¡¡refrigerant¡¡or¡¡refrigeration¡¡physics¡¡out¡¡of¡¡many¡¡possible¡¡alternatives¡£

The¡¡notion¡¡of¡¡moving¡¡asteroids¡¡into¡¡Earth¡¡orbit¡¡has¡¡proved¡¡attractive¡¡to¡¡some¡¡space¡¡scientists¡¡and¡¡long¡­range¡¡planners¡£¡¡They¡¡foresee¡¡mining¡¡the¡¡minerals¡¡and¡¡precious¡¡metals¡¡of¡¡these¡¡worlds¡¡or¡¡providing¡¡resources¡¡for¡¡the¡¡construction¡¡of¡¡space¡¡infrastructure¡¡without¡¡having¡¡to¡¡fight¡¡the¡¡Earth's¡¡gravity¡¡to¡¡get¡¡them¡¡up¡¡there¡£¡¡Articles¡¡have¡¡been¡¡published¡¡on¡¡how¡¡to¡¡acplish¡¡this¡¡end¡¡and¡¡what¡¡the¡¡benefits¡¡will¡¡be¡£¡¡In¡¡modern¡¡discussions£»¡¡the¡¡asteroid¡¡is¡¡inserted¡¡into¡¡orbit¡¡around¡¡the¡¡Earth¡¡by¡¡first¡¡making¡¡it¡¡pass¡¡through¡¡and¡¡be¡¡braked¡¡by¡¡the¡¡Earth's¡¡atmosphere£»¡¡a¡¡maneuver¡¡with¡¡very¡¡little¡¡margin¡¡for¡¡error¡£¡¡For¡¡the¡¡near¡¡future¡¡we¡¡can£»¡¡I¡¡think£»¡¡recognize¡¡this¡¡whole¡¡endeavor¡¡as¡¡unusually¡¡dangerous¡¡and¡¡foolhardy£»¡¡especially¡¡for¡¡metal¡¡worldlets¡¡larger¡¡than¡¡tens¡¡of¡¡meters¡¡across¡£¡¡This¡¡is¡¡the¡¡one¡¡activity¡¡where¡¡errors¡¡in¡¡navigation¡¡or¡¡propulsion¡¡or¡¡mission¡¡design¡¡can¡¡have¡¡the¡¡most¡¡sweeping¡¡and¡¡catastrophic¡¡consequences¡£

The¡¡foregoing¡¡are¡¡examples¡¡of¡¡inadvertence¡£¡¡But¡¡there's¡¡another¡¡kind¡¡of¡¡peril£º¡¡We¡¡are¡¡sometimes¡¡told¡¡that¡¡this¡¡or¡¡that¡¡invention¡¡would¡¡of¡¡course¡¡not¡¡be¡¡misused¡£¡¡No¡¡sane¡¡person¡¡would¡¡be¡¡so¡¡reckless¡£¡¡This¡¡is¡¡the¡¡¡¨only¡¡a¡¡madman¡¨¡¡argument¡£¡¡Whenever¡¡I¡¡hear¡¡it¡¡£¨and¡¡it's¡¡often¡¡trotted¡¡out¡¡in¡¡such¡¡debates£©£»¡¡I¡¡remind¡¡myself¡¡that¡¡madmen¡¡really¡¡exist¡£¡¡Sometimes¡¡they¡¡achieve¡¡the¡¡highest¡¡levels¡¡of¡¡political¡¡power¡¡in¡¡modern¡¡industrial¡¡nations¡£¡¡This¡¡is¡¡the¡¡century¡¡of¡¡Hitler¡¡and¡¡Stalin£»¡¡tyrants¡¡who¡¡posed¡¡the¡¡gravest¡¡dangers¡¡not¡¡just¡¡to¡¡the¡¡rest¡¡of¡¡the¡¡human¡¡family£»¡¡but¡¡to¡¡their¡¡own¡¡people¡¡as¡¡well¡£¡¡In¡¡the¡¡winter¡¡and¡¡spring¡¡of¡¡1945£»¡¡Hitler¡¡ordered¡¡Germany¡¡to¡¡be¡¡destroyed¡ªeven¡¡¡¨what¡¡the¡¡people¡¡need¡¡for¡¡elementary¡¡survival¡¨¡ªbecause¡¡the¡¡surviving¡¡Germans¡¡had¡¡¡¨betrayed¡¨¡¡him£»¡¡and¡¡at¡¡any¡¡rate¡¡were¡¡¡¨inferior¡¨¡¡to¡¡those¡¡who¡¡had¡¡already¡¡died¡£¡¡If¡¡Hitler¡¡had¡¡had¡¡nuclear¡¡weapons£»¡¡the¡¡threat¡¡of¡¡a¡¡counterstrike¡¡by¡¡Allied¡¡nuclear¡¡weapons£»¡¡had¡¡there¡¡been¡¡any£»¡¡is¡¡unlikely¡¡to¡¡have¡¡dissuaded¡¡him¡£¡¡It¡¡might¡¡have¡¡encouraged¡¡him¡£

Can¡¡we¡¡humans¡¡be¡¡trusted¡¡with¡¡civilization¡­threatening¡¡technologies£¿¡¡If¡¡the¡¡chance¡¡is¡¡almost¡¡one¡¡in¡¡a¡¡thousand¡¡that¡¡much¡¡of¡¡the¡¡human¡¡population¡¡will¡¡be¡¡killed¡¡by¡¡an¡¡impact¡¡in¡¡the¡¡next¡¡century£»¡¡isn't¡¡it¡¡more¡¡likely¡¡that¡¡asteroid¡¡deflection¡¡technology¡¡will¡¡get¡¡into¡¡the¡¡wrong¡¡hands¡¡in¡¡another¡¡century¡ªsome¡¡misanthropic¡¡sociopath¡¡like¡¡a¡¡Hitler¡¡or¡¡a¡¡Stalin¡¡eager¡¡to¡¡kill¡¡everybody£»¡¡a¡¡megalomaniac¡¡lusting¡¡after¡¡¡¨greatness¡¨¡¡and¡¡¡¨glory£»¡¨¡¡a¡¡victim¡¡of¡¡ethnic¡¡violence¡¡bent¡¡on¡¡revenge£»¡¡someone¡¡in¡¡the¡¡grip¡¡of¡¡unusually¡¡severe¡¡testosterone¡¡poisoning£»¡¡some¡¡religious¡¡fanatic¡¡hastening¡¡the¡¡Day¡¡of¡¡judgment£»¡¡or¡¡just¡¡technicians¡¡inpetent¡¡or¡¡insufficiently¡¡vigilant¡¡in¡¡handling¡¡the¡¡controls¡¡and¡¡safeguards£¿¡¡Such¡¡people¡¡exist¡£¡¡The¡¡risks¡¡seem¡¡far¡¡worse¡¡than¡¡the¡¡benefits£»¡¡the¡¡cure¡¡worse¡¡than¡¡the¡¡disease¡£¡¡The¡¡cloud¡¡of¡¡near¡­Earth¡¡asteroids¡¡through¡¡which¡¡the¡¡Earth¡¡plows¡¡may¡¡constitute¡¡a¡¡modern¡¡Camarine¡¡marsh¡£

It's¡¡easy¡¡to¡¡think¡¡that¡¡all¡¡of¡¡this¡¡must¡¡be¡¡very¡¡unlikely£»¡¡mere¡¡anxious¡¡fantasy¡£¡¡Surely¡¡sober¡¡heads¡¡would¡¡prevail¡£¡¡Think¡¡of¡¡how¡¡many¡¡people¡¡would¡¡be¡¡involved¡¡in¡¡preparing¡¡and¡¡launching¡¡warheads£»¡¡in¡¡space¡¡navigation£»¡¡in¡¡detonating¡¡warheads£»¡¡in¡¡checking¡¡what¡¡orbital¡¡perturbation¡¡each¡¡nuclear¡¡explosion¡¡has¡¡made£»¡¡in¡¡herding¡¡the¡¡asteroid¡¡so¡¡it¡¡is¡¡on¡¡an¡¡impact¡¡trajectory¡¡with¡¡Earth£»¡¡and¡¡so¡¡on¡£¡¡Isn't¡¡it¡¡noteworthy¡¡that¡¡although¡¡Hitler¡¡gave¡¡orders¡¡for¡¡the¡¡retreating¡¡Nazi¡¡troops¡¡to¡¡burn¡¡Paris¡¡and¡¡to¡¡lay¡¡waste¡¡to¡¡Germany¡¡itself£»¡¡his¡¡orders¡¡were¡¡not¡¡carried¡¡out£¿¡¡Surely¡¡someone¡¡essential¡¡to¡¡the¡¡success¡¡of¡¡the¡¡deflection¡¡mission¡¡will¡¡recognize¡¡the¡¡danger¡£¡¡Even¡¡assurances¡¡that¡¡the¡¡project¡¡is¡¡designed¡¡to¡¡destroy¡¡some¡¡vile¡¡enemy¡¡nation¡¡would¡¡probably¡¡be¡¡disbelieved£»¡¡because¡¡the¡¡effects¡¡of¡¡collision¡¡are¡¡planet¡­wide¡¡£¨and¡¡anyway¡¡it's¡¡very¡¡hard¡¡to¡¡make¡¡sure¡¡your¡¡asteroid¡¡excavates¡¡its¡¡monster¡¡crater¡¡in¡¡a¡¡particularly¡¡deserving¡¡nation£©¡£

But¡¡now¡¡imagine¡¡a¡¡totalitarian¡¡state£»¡¡not¡¡overrun¡¡by¡¡enemy¡¡troops£»¡¡but¡¡one¡¡thriving¡¡and¡¡self¡­confident¡£¡¡Imagine¡¡a¡¡tradition¡¡in¡¡which¡¡orders¡¡are¡¡obeyed¡¡without¡¡question¡£¡¡Imagine¡¡that¡¡those¡¡involved¡¡in¡¡the¡¡operation¡¡are¡¡supplied¡¡a¡¡cover¡¡story£º¡¡The¡¡asteroid¡¡is¡¡about¡¡to¡¡impact¡¡the¡¡Earth£»¡¡and¡¡it¡¡is¡¡their¡¡job¡¡to¡¡deflect¡¡it¡ªbut¡¡in¡¡order¡¡not¡¡to¡¡worry¡¡people¡¡needlessly£»¡¡the¡¡operation¡¡must¡¡be¡¡performed¡¡in¡¡secret¡£¡¡In¡¡a¡¡military¡¡setting¡¡with¡¡a¡¡mand¡¡hierarchy¡¡firmly¡¡in¡¡place£»¡¡partmentalization¡¡of¡¡knowledge£»¡¡general¡¡secrecy£»¡¡and¡¡a¡¡cover¡¡story£»¡¡can¡¡we¡¡be¡¡confident¡¡that¡¡even¡¡apocalyptic¡¡orders¡¡would¡¡be¡¡disobeyed£¿¡¡Are¡¡we¡¡really¡¡sure¡¡that¡¡in¡¡the¡¡next¡¡decades¡¡and¡¡centuries¡¡and¡¡millennia£»¡¡nothing¡¡like¡¡this¡¡might¡¡happen£¿¡¡How¡¡sure¡¡are¡¡we£¿

It's¡¡no¡¡use¡¡saying¡¡that¡¡all¡¡technologies¡¡can¡¡be¡¡used¡¡for¡¡good¡¡or¡¡for¡¡ill¡£¡¡That¡¡is¡¡certainly¡¡true£»¡¡but¡¡when¡¡the¡¡¡¨ill¡¨¡¡achieves¡¡a¡¡sufficiently¡¡apocalyptic¡¡scale£»¡¡we¡¡may¡¡have¡¡to¡¡set¡¡limits¡¡on¡¡which¡¡technologies¡¡may¡¡be¡¡developed¡£¡¡£¨In¡¡a¡¡way¡¡we¡¡do¡¡this¡¡all¡¡the¡¡time£»¡¡because¡¡we¡¡can't¡¡afford¡¡to¡¡develop¡¡all¡¡technologies¡£¡¡Some¡¡are¡¡favored¡¡and¡¡some¡¡are¡¡not¡££©¡¡Or¡¡constraints¡¡may¡¡have¡¡to¡¡be¡¡levied¡¡by¡¡the¡¡munity¡¡of¡¡nations¡¡on¡¡madmen¡¡and¡¡autarchs¡¡and¡¡fanaticism¡£

Tracking¡¡asteroids¡¡and¡¡ets¡¡is¡¡prudent£»¡¡it's¡¡good¡¡science£»¡¡and¡¡it¡¡doesn't¡¡cost¡¡much¡£¡¡But£»¡¡knowing¡¡our¡¡weaknesses£»¡¡why¡¡would¡¡we¡¡even¡¡consider¡¡now¡¡developing¡¡the¡¡technology¡¡to¡¡deflect¡¡small¡¡worlds£¿¡¡For¡¡safety£»¡¡shall¡¡we¡¡imagine¡¡this¡¡technology¡¡in¡¡the¡¡hands¡¡of¡¡many¡¡nations£»¡¡each¡¡providing¡¡checks¡¡and¡¡balances¡¡against¡¡misuse¡¡by¡¡another£¿¡¡This¡¡is¡¡nothing¡¡like¡¡the¡¡old¡¡nuclear¡¡balance¡¡of¡¡terror¡£¡¡It¡¡hardly¡¡inhibits¡¡some¡¡madman¡¡intent¡¡on¡¡global¡¡catastrophe¡¡to¡¡know¡¡that¡¡if¡¡he¡¡does¡¡not¡¡hurry£»¡¡a¡¡rival¡¡may¡¡beat¡¡him¡¡to¡¡it¡£¡¡How¡¡confident¡¡can¡¡we¡¡be¡¡that¡¡the¡¡munity¡¡of¡¡nations¡¡will¡¡be¡¡able¡¡to¡¡detect¡¡a¡¡cleverly¡¡designed£»¡¡clandestine¡¡asteroid¡¡deflection¡¡in¡¡time¡¡to¡¡do¡¡something¡¡about¡¡it£¿¡¡If¡¡such¡¡a¡¡technology¡¡were¡¡developed£»¡¡can¡¡any¡¡international¡¡safeguards¡¡be¡¡envisioned¡¡that¡¡have¡¡a¡¡reliability¡¡mensurate¡¡with¡¡the¡¡risk£¿

Even¡¡if¡¡we¡¡restrict¡¡ourselves¡¡merely¡¡to¡¡surveillance£»¡¡there's¡¡a¡¡risk¡£¡¡Imagine¡¡that¡¡in¡¡a¡¡generation¡¡we¡¡characterize¡¡the¡¡orbits¡¡of¡¡30£»000¡¡objects¡¡of¡¡100¡­meter¡¡diameter¡¡or¡¡more£»¡¡and¡¡that¡¡this¡¡information¡¡is¡¡publicized£»¡¡as¡¡of¡¡course¡¡it¡¡should¡¡be¡£¡¡Maps¡¡will¡¡be¡¡published¡¡showing¡¡near¡­Earth¡¡space¡¡black¡¡with¡¡the¡¡orbits¡¡of¡¡asteroids¡¡and¡¡ets£»¡¡30£»000¡¡swords¡¡of¡¡Damocles¡¡hanging¡¡over¡¡our¡¡heads¡­ten¡¡times¡¡more¡¡than¡¡the¡¡number¡¡of¡¡stars¡¡visible¡¡to¡¡the¡¡naked¡¡eye¡¡under¡¡conditions¡¡of¡¡optimum¡¡atmospheric¡¡clarity¡£¡¡Public¡¡anxiety¡¡might¡¡be¡¡much¡¡greater¡¡in¡¡such¡¡a¡¡time¡¡of¡¡knowledge¡¡than¡¡in¡¡our¡¡current¡¡age¡¡of¡¡ignorance¡£¡¡There¡¡might¡¡be¡¡irresistible¡¡public¡¡pressure¡¡to¡¡develop¡¡means¡¡to¡¡mitigate¡¡even¡¡nonexistent¡¡threats£»¡¡which¡¡would¡¡then¡¡feed¡¡the¡¡danger¡¡that¡¡deflection¡¡technology¡¡would¡¡be¡¡misused¡£¡¡For¡¡this¡¡reason£»¡¡asteroid¡¡discovery¡¡and¡¡surveillance¡¡may¡¡not¡¡be¡¡a¡¡mere¡¡neutral¡¡tool¡¡of¡¡future¡¡policy£»¡¡but¡¡rather¡¡a¡¡kind¡¡of¡¡booby¡¡trap¡£¡¡To¡¡me£»¡¡the¡¡only¡¡foreseeable¡¡solution¡¡is¡¡a¡¡bination¡¡of¡¡accurate¡¡orbit¡¡estimation£»¡¡realistic¡¡threat¡¡assessment£»¡¡and¡¡effective¡¡public¡¡education¡ªso¡¡that¡¡in¡¡democracies¡¡at¡¡least£»¡¡the¡¡citizens¡¡can¡¡make¡¡their¡¡own£»¡¡informed¡¡decisions¡£¡¡This¡¡is¡¡a¡¡job¡¡for¡¡NASA¡£

Near¡­Earth¡¡asteroids£»¡¡and¡¡means¡¡of¡¡altering¡¡their¡¡orbits£»¡¡are¡¡being¡¡looked¡¡at¡¡seriously¡£¡¡There¡¡is¡¡some¡¡sign¡¡that¡¡officials¡¡in¡¡the¡¡Department¡¡of¡¡Defense¡¡and¡¡the¡¡weapons¡¡laboratories¡¡are¡¡beginning¡¡to¡¡understand¡¡that¡¡there¡¡may¡¡be¡¡real¡¡dangers¡¡in¡¡planning¡¡to¡¡push¡¡asteroids¡¡around¡£¡¡Civilian¡¡and¡¡military¡¡scientists¡¡have¡¡met¡¡to¡¡discuss¡¡the¡¡subject¡£¡¡On¡¡first¡¡hearing¡¡about¡¡the¡¡asteroid¡¡hazard£»¡¡many¡¡people¡¡think¡¡of¡¡it¡¡as¡¡a¡¡kind¡¡of¡¡Chicken¡¡Little¡¡fable£»¡¡Goosey¡­Lucy£»¡¡newly¡¡arrived¡¡and¡¡in¡¡great¡¡excitement£»¡¡is¡¡municating¡¡the¡¡urgent¡¡news¡¡that¡¡the¡¡sky¡¡is¡¡falling¡£¡¡The¡¡tendency¡¡to¡¡dismiss¡¡the¡¡prospect¡¡of¡¡any¡¡catastrophe¡¡that¡¡we¡¡have¡¡not¡¡personally¡¡witnessed¡¡is¡¡in¡¡the¡¡long¡¡run¡¡very¡¡foolish¡£¡¡But¡¡in¡¡this¡¡case¡¡it¡¡may¡¡be¡¡an¡¡ally¡¡of¡¡prudence¡£



MEANWHILE¡¡WE¡¡MUST¡¡STILL¡¡FACE¡¡the¡¡deflection¡¡dilemma¡£¡¡If¡¡we¡¡develop¡¡and¡¡deploy¡¡this¡¡technology£»¡¡it¡¡may¡¡do¡¡us¡¡in¡£¡¡If¡¡we¡¡don't£»¡¡some¡¡asteroid¡¡or¡¡et¡¡may¡¡do¡¡us¡¡in¡£¡¡The¡¡resolution¡¡of¡¡the¡¡dilemma¡¡hinges£»¡¡I¡¡think£»¡¡on¡¡the¡¡fact¡¡that¡¡the¡¡likely¡¡timescales¡¡of¡¡the¡¡two¡¡dangers¡¡are¡¡very¡¡different¡ªshort¡¡for¡¡the¡¡former£»¡¡long¡¡for¡¡the¡¡latter¡£

I¡¡like¡¡to¡¡think¡¡that¡¡our¡¡future¡¡involvement¡¡with¡¡near¡­Earth¡¡asteroids¡¡will¡¡go¡¡something¡¡like¡¡this£º¡¡From¡¡ground¡­based¡¡observatories£»¡¡we¡¡discover¡¡all¡¡the¡¡big¡¡ones£»¡¡plot¡¡and¡¡monitor¡¡their¡¡orbits£»¡¡determine¡¡rotation¡¡rates¡¡and¡¡positions¡£¡¡Scientists¡¡are¡¡diligent¡¡in¡¡explaining¡¡the¡¡dangers¡ªneither¡¡exaggerating¡¡nor¡¡muting¡¡the¡¡prospects¡£¡¡We¡¡send¡¡robotic¡¡spacecraft¡¡to¡¡fly¡¡by¡¡a¡¡few¡¡selected¡¡bodies£»¡¡orbit¡¡them£»¡¡land¡¡on¡¡them£»¡¡and¡¡return¡¡surface¡¡samples¡¡to¡¡laboratories¡¡on¡¡Earth¡£¡¡Eventually¡¡we¡¡send¡¡humans¡£¡¡£¨Because¡¡of¡¡the¡¡low¡¡gravities£»¡¡they¡¡will¡¡be¡¡able¡¡to¡¡make¡¡standing¡¡broad¡¡jumps¡¡of¡¡ten¡¡kilometers¡¡or¡¡more¡¡into¡¡the¡¡sky£»¡¡and¡¡lob¡¡a¡¡baseball¡¡into¡¡orbit¡¡around¡¡the¡¡asteroid¡££©¡¡Fully¡¡aware¡¡of¡¡the¡¡dangers£»¡¡we¡¡make¡¡no¡¡attempts¡¡to¡¡alter¡¡trajectories¡¡until¡¡the¡¡potential¡¡for¡¡misuse¡¡of¡¡world¡­altering¡¡technologies¡¡is¡¡much¡¡less¡£¡¡That¡¡might¡¡take¡¡a¡¡while¡£

If¡¡we're¡¡too¡¡quick¡¡in¡¡developing¡¡the¡¡technology¡¡to¡¡move¡¡worlds¡¡around£»¡¡we¡¡may¡¡destroy¡¡ourselves£»¡¡if¡¡we're¡¡too¡¡slow£»¡¡we¡¡will¡¡surely¡¡destroy¡¡ourselves¡£¡¡The¡¡reliability¡¡of¡¡world¡¡political¡¡organizations¡¡and¡¡the¡¡confidence¡¡they¡¡inspire¡¡will¡¡have¡¡to¡¡make¡¡significant¡¡strides¡¡before¡¡they¡¡can¡¡be¡¡trusted¡¡to¡¡deal¡¡with¡¡a¡¡problem¡¡of¡¡this¡¡seriousness¡£¡¡At¡¡the¡¡same¡¡time£»¡¡there¡¡seems¡¡to¡¡be¡¡no¡¡acceptable¡¡national¡¡solution¡£¡¡Who¡¡would¡¡feel¡¡fortable¡¡with¡¡the¡¡means¡¡of¡¡world¡¡destruction¡¡in¡¡the¡¡hands¡¡of¡¡some¡¡dedicated¡¡£¨or¡¡even¡¡potential£©¡¡enemy¡¡nation£»¡¡whether¡¡or¡¡not¡¡our¡¡nation¡¡had¡¡parable¡¡powers£¿¡¡The¡¡existence¡¡of¡¡interplanetary¡¡collision¡¡hazards£»¡¡when¡¡widely¡¡understood£»¡¡works¡¡to¡¡bring¡¡our¡¡species¡¡together¡£¡¡When¡¡facing¡¡a¡¡mon¡¡danger£»¡¡we¡¡humans¡¡have¡¡sometimes¡¡reached¡¡heights¡¡widely¡¡thought¡¡impossible£»¡¡we¡¡have¡¡set¡¡aside¡¡our¡¡differences¡ªat¡¡least¡¡until¡¡the¡¡danger¡¡passed¡£

But¡¡this¡¡danger¡¡never¡¡passes¡£¡¡The¡¡asteroids£»¡¡gravitationally¡¡churning£»¡¡are¡¡slowly¡¡altering¡¡their¡¡orbits£»¡¡without¡¡warning£»¡¡new¡¡ets¡¡e¡¡careening¡¡toward¡¡us¡¡from¡¡the¡¡transplutonian¡¡darkness¡£¡¡There¡¡will¡¡always¡¡be¡¡a¡¡need¡¡to¡¡deal¡¡with¡¡them¡¡in¡¡a¡¡way¡¡that¡¡does¡¡not¡¡endanger¡¡us¡£¡¡By¡¡posing¡¡two¡¡different¡¡classes¡¡of¡¡peril¡ªone¡¡natural£»¡¡the¡¡other¡¡human¡­made¡ªthe¡¡small¡¡near¡­Earth¡¡worlds¡¡provide¡¡a¡¡new¡¡and¡¡potent¡¡motivation¡¡to¡¡create¡¡effective¡¡transnational¡¡institutions¡¡and¡¡to¡¡unify¡¡the¡¡human¡¡species¡£¡¡It's¡¡hard¡¡to¡¡see¡¡any¡¡satisfactory¡¡alternative¡£

In¡¡our¡¡usual¡¡jittery£»¡¡two¡­steps¡­forward¡­one¡­step¡­back¡¡mode£»¡¡We¡¡are¡¡moving¡¡toward¡¡unification¡¡anyway¡£¡¡There¡¡are¡¡powerful¡¡influences¡¡deriving¡¡from¡¡transportation¡¡and¡¡munications¡¡technologies£»¡¡the¡¡interdependent¡¡world¡¡economy£»¡¡and¡¡the¡¡global¡¡environmental¡¡crisis¡£¡¡The¡¡impact¡¡hazard¡¡merely¡¡hastens¡¡the¡¡pace¡£

Eventually£»¡¡cautiously£»¡¡scrupulously¡¡careful¡¡to¡¡attempt¡¡nothing¡¡with¡¡asteroids¡¡that¡¡could¡¡inadvertently¡¡cause¡¡a¡¡catastrophe¡¡on¡¡Earth£»¡¡I¡¡imagine¡¡we¡¡will¡¡begin¡¡to¡¡learn¡¡how¡¡to¡¡change¡¡the¡¡orbits¡¡of¡¡little¡¡nonmetallic¡¡worlds£»¡¡smaller¡¡than¡¡100¡¡meters¡¡across¡£¡¡We¡¡begin¡¡with¡¡smaller¡¡explosions¡¡and¡¡slowly¡¡work¡¡our¡¡way¡¡up¡£¡¡We¡¡gain¡¡experience¡¡in¡¡changing¡¡the¡¡orbits¡¡of¡¡various¡¡asteroids¡¡and¡¡ets¡¡of¡¡different¡¡positions¡¡and¡¡strengths¡£¡¡We¡¡try¡¡to¡¡determine¡¡which¡¡ones¡¡can¡¡be¡¡pushed¡¡around¡¡and¡¡which¡¡cannot¡£¡¡By¡¡the¡¡twenty¡­second¡¡century£»¡¡perhaps£»¡¡we¡¡move¡¡small¡¡worlds¡¡around¡¡the¡¡Solar¡¡System£»¡¡using¡¡£¨see¡¡next¡¡chapter£©¡¡not¡¡nuclear¡¡explosions¡¡but¡¡nuclear¡¡fusion¡¡engines¡¡or¡¡their¡¡equivalents¡£¡¡We¡¡insert¡¡small¡¡asteroids¡¡made¡¡of¡¡precious¡¡and¡¡industrial¡¡metals¡¡into¡¡Earth¡¡orbit¡£¡¡Gradually¡¡develop
·µ»ØĿ¼ ÉÏÒ»Ò³ ÏÂÒ»Ò³ »Øµ½¶¥²¿ ÔÞ£¨0£© ²È£¨0£©
¿ì½Ý²Ù×÷: °´¼üÅÌÉÏ·½Ïò¼ü ¡û »ò ¡ú ¿É¿ìËÙÉÏÏ·­Ò³ °´¼üÅÌÉ쵀 Enter ¼ü¿É»Øµ½±¾ÊéĿ¼ҳ °´¼üÅÌÉÏ·½Ïò¼ü ¡ü ¿É»Øµ½±¾Ò³¶¥²¿!
ÎÂÜ°Ìáʾ£º ο´Ð¡ËµµÄͬʱ·¢±íÆÀÂÛ£¬Ëµ³ö×Ô¼ºµÄ¿´·¨ºÍÆäËüС»ï°éÃÇ·ÖÏíÒ²²»´íŶ£¡·¢±íÊéÆÀ»¹¿ÉÒÔ»ñµÃ»ý·ÖºÍ¾­Ñé½±Àø£¬ÈÏÕæдԭ´´ÊéÆÀ ±»²ÉÄÉΪ¾«ÆÀ¿ÉÒÔ»ñµÃ´óÁ¿½ð±Ò¡¢»ý·ÖºÍ¾­Ñé½±ÀøŶ£¡