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Signals from aliens
來自外星人的信號
The Search for Extra-Terrestrial Intelligence Institute （SETI）, listening to the cosmos for signs of signals from alien civilizations, may be monitoring the wrong “channels,” a U.S. astrophysicist says.
一位美國天體物理學家表示，地外智能生命搜尋研究所（SETI）一直以來探索宇宙外星文明信號的方法可能是“走了彎路”。
Gregory Benford of the University of California, Irvine,
美國加州大學歐文分校的科學家格雷戈里·本福德近日稱，
says such a civilization wanting to announce its presence would transmit “cost-optimized” narrowly focused signals,
試圖跟人類建立聯系的外星人很可能從“成本最優”方面考慮只發送較短的定向信息，
not the continuous omni-directional signals the SETI program has been scanning for, a university release said recently.
而不是漫無方向地持續發送信息。而SETI 一直以來搜索的信息正是后者。
“This approach is more like Twitter and less like War and Peace, ”James Benford, Gregory Benford`s twin and fellow physicist, says.
“這種發送消息的方法更像是推特（Twitter），而不是場面宏大的《戰爭與和平》，”格雷戈里·本福德的孿生兄弟，物理學家詹姆斯·本福德說。
“Whatever the life form, evolution selects for economy of resources. Transmitting signals across light years would require considerable resources.”
“不論是何種生命形式，進化的方向都是節約資源。穿越光年發送信息，要花費相當巨大的資源。”
They says alien signals would not be blasted out in all directions
他們還說，外星人不會向外漫無目的地全方位傳送信號，
but narrowly directed in the one-to-ten gigahertz broadband signal range and SETI’s broad sweeping search could leave many days when brief Twitter-like flashes of “ here we are” from alien civilizations go undetected.
而只會在1-10千兆赫的波段內定向發送。但SETI 采取的是大范圍的信號掃描方式，這樣一來，在外星文明發出“我們在這兒！”的信號時，可能就已經錯過SETI 的掃描了。
Such short, targeted blips, dubbed Benford beacons, should be the targets of SETI efforts, a growing number of scientists say.
越來越多的科學家支持他們的觀點，認為這種簡短、定向的信息（被稱為本福德信號）才應該是SETI 搜索的目標。
And the Benfords also suggest concentrating the search on our own Milky Way galaxy, especially its center where 90 percent of its stars are located.“
本福德兄弟還建議將搜索地點鎖定在我們自身所處的銀河系，特別是90％恒星所在的中心地區。
The stars there are a billion years older than our sun,” Gregory Benford says,
“那里的恒星壽命比太陽還早10 億年，”格雷戈里·本福德說，
“which suggests a greater possibility of contact with an advanced civilization than does pointing SETI receivers outward to the newer and less crowded edge of our galaxy. ”
“這意味著那里更有可能存在高等智慧生命。這比將SETI 的天線對準銀河系邊緣更年輕恒星、也更稀疏的區域要好得多了?！?/p>
