ThesearchforET寻找外星人Clusteranalysis星团解析Agoodplacetolookforlittlegreenmen找寻小绿人的绝佳之地Jan9th2016|KISSIMMEE，FLORIDA|Fromtheprintedition· ·Ripe for colonization是时候向外星殖民了ONE of astronomy’s biggest changes of perspective in recent years has been the realisation that planets are abundant in the cosmos. But not everywhere. Collections of stars called globular clusters seem bereft of them.天文学界近年最大的突破之一就是发现宇宙中的行星数不胜数，但是分布不均。而由大片恒星聚集而成的球状星团中却似乎很难找到它们的踪迹。Globular clusters are roughly spherical collections of hundreds of thousands of stars. These， in turn， are among the oldest stellar inhabitants of galaxies. But though the Milky Way， the Earth’s home galaxy， has more than 150 globular clusters， so far only a single planet has been spotted in one: Messier 4 (see picture).球状星团由几十万恒星聚集而成，外貌呈球形。这些星团如今都是宇宙星系最长寿的居民。尽管地球所在的银河系拥有超过150个星团，但到目前为止，在这么多星团中仅发现过一颗行星——天体4号（见图）。Nothing daunted， Rosanne Di Stefano of the Harvard-Smithsonian Centre for Astrophysics and Alak Ray of the Tata Institute of Fundamental Research， in India， told the 2016 meeting of the American Astronomical Society why they think globular clusters are a good place to go hunting for advanced civilisations. 我们无需气馁，哈佛史密森天文物理中心（Harvard-Smithsonian Centre for Astrophysics）的Rosanne Di Stefano和印度塔塔基础研究所（Tata Institute of Fundamental Research）的Alak Ray两位博士在美国天文协会（American Astronomical Society）2016大会上发表了讲话，阐述了他们认为未来要在球状星团寻找发达文明的原因所在。First， the clusters’ very age means that life will have had the best chance of coming into existence and then climbing the ladder of complexity to the point where it can travel from star to star. Second， that age also means clusters have stopped being disrupted by life-destroying stellar explosions like supernovae and gamma-ray bursts. Third， the proximity of a cluster’s stars to one another means interstellar travel is not nearly as onerous as it would be for humanity. A spacefaring cluster-inhabitant would have to travel， on average， only about 1，000 times the distance from Earth to the sun to get to its nearest stellar neighbour. For humans， that distance is 275，000 times the Earth-sun distance. Not only does this make travel easier， it also makes communication practical. Messages between a home planet and its outposts could be sent and received with the same sort of delay as those between European countries and their colonies before the invention of the electric telegraph.首先，这些星团寿命够长，为生命在其中生存、发展提供了足够的时间，最终帮助他们攻克了星际穿越的难题。其二，寿命长也意味着星团已经过了星球毁灭的危险期，不会出现类似超新星爆或是伽马暴之类的灾难。其三，星团中恒星距离相近，因此实现恒星间穿梭并不会比地球到星团更困难。在宇宙中，星团上的居住者要想到达距其最近的星球，所需飞行的平均距离只有地球与太阳间距的1000倍。而对地球人来说，到达星团的距离是这个间距的275000倍。相近的距离不仅让旅行变得轻松，也让信息互通成为可能。母星与其周边星球信息传递的效率可以达到电报发明前欧洲大陆与殖民地间通信的程度。This speculation does， of course， require the existence of many more globular-cluster planets than the lone example so far discovered. But Dr Di Stefano and Dr Ray are optimistic about that. Their models suggest that such planets will often be in stable orbits in the “Goldilocks” zones (not too hot and not too cold) of their host stars. It may be， then， that the galactic empires dreamed of by science-fiction writers were wrong only in scale， rather than concept. Colonising an entire galaxy was always going to be a big ask. Annexing a cluster， though， looks eminently doable.当然，这个推断成立的基础是宇宙中存在大量球状行星团，而不是目前这种孤独星球的状态。但是Di Stefano和Ray博士却对此持乐观态度。他们建立的模型显示这类行星通常稳定地围绕着主星的“宜居地带”（不冷不热）运行。也许科幻小说家笔下的银河王朝并非白日做梦，只是规模稍显夸张。殖民整个银河系难免有些痴心妄想，但兼并一片星团也许指日可待。From the print edition: Science and technology在金融圈混，你不得不知的五大微信火柴商业评论复制ID?：JJXREN【经济学人】翻译爱好者非官方组织，每天几分钟，学习财经英语，为考研英语雅思阅读提供复习材料，免费的双语杂志和经典剪报内容，在知识上和精神上给您学习生活双重享受，内容仅限个人学术研究或者个人翻译作品欣赏用途，请勿转载用于商业。公司报表分析复制ID?：CPACFA从事金融，创业，财务和会计的人士关注此微信号！提供财务报表分析知识与案例，帮助您看懂美国中国上市公司财务报表。CFA公共主页复制ID?：FORCFACFA金融分析师学习备考交流，每天推送CFA最值得关注的学习和考试信息，让不必上培训班，就可以了解到CFA的各种考试资料和新鲜事。CFA60秒复制ID?：CFA60SCFA60秒是为CFA学习者量身打造的CFA电台.每天为CFA学习者提供60秒语音学习CFA知识点.轻松学习金融分析师考试知识.火柴汇复制ID?：CFACLASS火柴财经汇，简称火柴汇，定期特邀名人稿件，关注精英人士聚集的生活方式和观点， 瀑布可以逆流; 蒲公英从远处飘回；我还在你身旁； 而我们更加接近真相！