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  • 技术签字

    Given the fascination with aliens in Hollywood science fiction movies, one would think that the public and the government would consider  SETI (the Search for ExtraTerrestrial I ntelligence)   to be an exciting and worthwhile area of research . This is a research field that costs little but has faced active opposition. The federally funded SETI program was started in 1992, and just a year later,  Senator Richard Bryan of Nevada argued that funding should be shut down: "...As of today, millions have been spent and we have yet to bag a single little green fellow. Not a single Martian has said 'take me to your leader,' and not a single flying saucer has applied for FAA approval." 
    ::鉴于好莱坞科幻小说电影中外星人的魅力,人们会认为公众和政府会认为SETI(搜索地外情报)是一个令人振奋和有价值的研究领域。 这是一个研究领域,花费很少,但却面临积极的反对。 联邦资助的SETI方案始于1992年,仅仅一年后,内华达州参议员理查德·布赖恩(Richard Bryan)认为资金应该关闭:“......今天,数百万人已经花光了,我们还没有把一个小绿人包起来。没有一个火星人说“带我见你们的领袖 ” , 没有一个飞碟申请过FAA批准。 ”

    Cleverly argued, but is the issue really fiscal conservatism?  Scientists  have been  funded to search for elusive dark matter particles for more than 40 years, but not a single one has yet been found.  Searches for black holes went on for decades before the first candidates were found.  The hunt  for exoplanets  dates back a few centuries, but the first exoplanet was not detected around a Sun-like star until 1995. Transformational science requires that we push the boundaries. 
    ::聪明的争论,但问题是真正的财政保守主义问题吗?40多年来,科学家一直被资助寻找难以捉摸的暗物质粒子,但至今还没有找到任何一颗。 寻找黑洞的工作在第一批候选人被找到之前已经持续了几十年。 寻找外行星的搜索可追溯到几个世纪,但第一个外行星的搜索直到1995年才在类似太阳的恒星周围被发现。 变革科学要求我们推开界限。

    The issue  can not simply be that little green men (LGM) have not yet been found. It seems likely that there are other reasons motivating  Richard Bryan and others who  have  wanted to stop SETI. It is possible that religious or cultural beliefs  lead some people to a privileged (if incorrect) view   on this issue. Perhaps they believe that humans are the pinnacle of existence and the reason for the universe; therefore, they cannot imagine that anything else exists. Or perhaps  people are afraid - if LGM really exist, some people might  just prefer to be oblivious to this issue .  However, individuals  who are curious about the universe want to know. The range of possibilities is staggering. On the one hand, we  may be alone. On the other... if  life turns out to  exist on even one-in-a-million  Earth-like planets, then our galaxy could be  teeming with life. Either case has profound implications.  SETI   is a scientific exploration and a  search for knowledge. Ultimately, being informed and knowledgeable is an advantage, no matter what the truth.  SETI is no longer funded by the federal government. Instead, private donors now fund this enterprise. 
    ::问题不可能仅仅是小绿人(LGM)尚未被发现。似乎似乎还有其他原因促使理查德·布莱恩和其他想阻止SETI的人阻止SETI。 宗教或文化信仰有可能使一些人在这个问题上获得特权(如果不正确的话)观点。 也许他们认为人类是生存的顶峰,是宇宙的原因; 因此,他们无法想象还有其它东西存在。 或者人们害怕 — — 如果LGM真的存在, 一些人可能宁愿忽略这个问题。 但是,那些对宇宙好奇的人想要知道。 可能性的范围是惊人的。 一方面,我们可能是孤单的。 另一方面,如果生命在一百万个像地球的星球上出现, 那么我们的银河系就会充满生命。 任何一种情况都具有深远的影响。 SETI是一种科学探索和知识的探索。 最后, 知情和知识是优势, 不论真相是什么。 SETI不再由联邦政府资助。 相反, 私人捐赠者现在为这个企业提供资金。

    In 2007, wrote: 
    ::2007年写道:

    If we can find technosignatures - evidence of some technology that modifies its environment in ways that are detectable - then we will be permitted to infer the existence, at least at some time, of intelligent technologists. 
    ::如果我们能找到技术签名, 证明某些技术 改变了环境, 其方式是可以检测到的, 那么我们就被允许推断,至少在某些时候, 智能技术人员的存在。

     

    lesson content

    Jill Tarter served as project scientist for NASA's SETI program before funding was terminated in 1994. She is now Chair Emeritus for SETI research.
    ::Jill Tarter在1994年资金终止之前曾担任美国航天局SETI项目项目科学家,现在担任SETI研究名誉主席。

    In the late 1950s radio astronomers  were able to send or receive radio signals over large distances in our galaxy and realized that they could use this technology to search for technological, communicating civilizations that might either be leaking or transmitting signals. SETI began in 1960, when Frank Drake  used the Green Bank radio telescope  to observe  the nearby stars Tau Ceti and Epsilon Eridani in a project that he  dubbed " ."   T o minimize confusion from background sources, t he radio search concentrated on a very narrow wavelength band near 1420 Megahertz. Drake  observed  the stars for four months, always with a negative result until he found a surprising signal on April 8,1960.  An extraordinarily careful scientist, Drake followed up and ultimately discovered that this was a  false signal from a high-flying aircraft.  But, the realization of what it would feel like to detect another civilization started him on a lifelong search for  technological signatures (coined "technosignatures" by Jill Tarter). 
    ::1950年代后期,无线电天文学家得以在银河系的很远的地方发送或接收无线电信号,并意识到他们可以利用这一技术寻找技术,交流可能泄漏或传播信号的文明。 SETI始于1960年,当时Frank Drake利用绿色银行的射电望远镜观察附近的Tau Ceti和Epsilon Eridani星群。为了尽量减少背景来源的混乱,无线电搜索集中在距离1420Megahertz附近的一个非常狭窄的波长波段上。 Drake观察了四个月的恒星,直到他于1960年4月8日发现了一个令人惊讶的信号,结果总是消极的。 Drake是一位极为谨慎的科学家,随后发现这是一架高空飞机发出的虚假信号。但是,为了发现另一个文明,他开始了对技术签名的终身搜索(吉尔·塔特的“技术签名 ” ) 。

    Narrow-band radio searches were the first way that astronomers searched for technological signals.  The low-energy radio waves pass uninterrupted through the dust in our galaxy. Hydrogen, which is the most common element in the universe, forms H 2 molecules in cold interstellar space  and  radiates  at the 1420 MHz wavelength that Frank Drake was observing. Alien astronomers would likewise  understand the importance of this wavelength - they would know that astute astronomers elsewhere would be studying the galaxy at the 1420 MHz wavelength. If the alien astronomers  wanted their signals to be found, what better way than to  broadcast   their message at  a wavelength where others would be looking?    
    ::窄波段无线电搜索是天文学家寻找技术信号的第一种方式。低能无线电波通过银河系中的尘埃不间断地传递。氢是宇宙中最常见的元素,在冷星际空间中形成H2分子,在弗兰克·德雷克观察的1420兆赫波长下辐射。外星人天文学家同样会理解这种波长的重要性 — — 他们知道其他地方的天文学家将会在1420兆赫波长上研究星系。如果外星人希望找到他们的信号,还有什么比用波长在其他人的视线上传播他们的信息更好呢?

    In addition to searches for radio signals, there is an optical SETI program that scans the sky to search for brief flashes of laser light from known planetary systems. If humans set up a research station on Mars, one efficient way of communicating with Earth would be to send pulsed laser signals  - a sort of Morse code. The high frequency of optical light makes it possible to send vast amounts of information. Lasers are highly coherent beams, but there would still be some scattered spill-over light that might be detectable in directions that are approximately aligned at that moment with Earth and Mars. 
    ::除了搜索无线电信号外,还有一个光学SETI程序,对天空进行扫描,以寻找已知行星系统的激光光短闪光。如果人类在火星上设立一个研究站,与地球通信的一个有效方式就是发送脉冲激光信号,这是一种摩斯代码。光学光能的高频率使得能够发送大量信息。激光是高度连贯的梁,但是仍然有一些分散的溢出光线,在当时可以探测到的方向与地球和火星大致一致。

    Another possible technosignature would be the observation of a structure built by aliens, perhaps to efficiently  harvest energy from their host star. This idea was popularized by Freeman Dyson in his 1960 paper "Search for Artificial Sources of Infrared Radiation." Dyson thought that advanced civilizations  might build build artificial megastructures in response to increasing energy demands. He envisioned the megastructure as a swarm of  satellites orbiting the star and beaming energy back to their home planet.  Starlight would be dimmed and perhaps reddened  if the swarm  was dense enough, and  this effect might be observable in the stellar spectrum. 
    ::另一种可能的技术标志是观察由外星人建造的结构,或许是为了有效地从主星中获取能量。Freeman Dyson在其1960年的论文“红外辐射人为源的搜索”中推广了这一想法。 Dyson认为先进的文明可以建设人造巨型结构,以应对日益增长的能源需求。他设想巨型结构是卫星群,将恒星环绕轨道,将能量传回自己的星球。 如果星光足够稠密,星光会缩小,甚至红化,而这种效应可能在星光中可见。

    KIC 8462852: Tabby's star
    ::KIC 8462852: 塔比的星

    In 2016, a postdoctoral fellow at Yale University, Tabby Boyajian, published a paper on a strange light curve measured by Kepler. The signal was strong but irregular and unlike anything that had been seen before. The paper sat on her desk for two years as the Planet Hunter team tried to reason out an explanation - the best idea was that this was a disintegrating asteroid or irregular dust cloud. Failing any  certain ideas for the source of the  signal, the paper was published in the hopes that someone else would have a better explanation.  Almost immediately, Jason Wright at Penn State University suggested an idea: perhaps this was an alien megastructure, like the one suggested by Freeman Dyson. Of course, this idea was picked up in the popular press. While the answer is still unknown, there is still an  ongoing research program to better understand this star. 
    ::2016年,耶鲁大学的一位博士后研究员Tabby Boyajian发表了一篇关于开普勒测量的奇特光曲线的论文。这个信号是强烈的,但不正常的,与以前看到的任何情况不同。当行星猎人团队试图解释一个解释时,该论文在她桌上坐了两年,最佳的想法是这是小行星的分解或不规则的尘云。由于对信号的来源没有任何特定的想法,因此,该论文的发表希望是让别人有更好的解释。几乎很快,宾恩州立大学的Jason Wright提出了一个想法:也许这是一个外来巨型结构,就像Freeman Dyson所建议的那样。当然,这个想法在大众媒体中被采纳了。虽然答案还不清楚,但仍有一个正在进行的研究方案来更好地了解这个恒星。

     

    While there is no evidence for life elsewhere today, in an interview with , Jill Tarter  posits that we will figure out in this century whether life exists beyond Earth .  Even though SETI searches have been carried out since 1960, Tarter compares the vastness of the search of space to the oceans and the  relative size of space that has been searched to a bathtub. If we find even a single example of life elsewhere, we will know that life is statistically ubiquitous. 
    ::虽然今天其他地方没有生命的证据,但吉尔·塔尔特在接受采访时认为,我们将在本世纪中弄清楚地球以外的生命是否存在。 尽管自1960年以来,SETI就进行了搜索,但塔尔特将空间探索的广度与海洋和被搜索空间的相对大小相比较,如果我们在其他地方找到一个生命的例子,我们就会知道,在统计学上,生命无处不在。