按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
irlpool Nebula； or Centaurus A； or the Virgo cluster of galaxies； or the nearest Seyfert galaxies； none among any of the hundred trillion stars in thousands of nearby galaxies。 Stake through its heart or not； the geocentric conceit stirs again。
Of course； it might be a token not of intelligence but of stupidity to pour so much energy into interstellar （and intergalactic） munication。 Perhaps they have good reasons not to hail all ers。 Or perhaps they don't care about civilizations as backward as we are。 But still—not one civilization in a hundred trillion stars broadcasting with such power on such a frequency？ If the META results are negative； we have set an instructive limit—but whether on the abundance of very advanced civilizations or their munications strategy we have no way of knowing。 Even if META has found nothing； a broad middle range remains open—of abundant civilizations； more advanced than we and broadcasting omnidirectionally at magic frequencies。 We would not have heard from them yet。
ON OCTOBER 12； 1992—auspiciously or otherwise the 500th anniversary of the 〃discovery〃 of America by Christopher Columbus—NASA turned on its new SETI program。 At a radio telescope in the Mojave Desert； a search was initiated intended to cover the entire sky systematically—like META； making no guesses about which stars are more likely； but greatly expanding the frequency coverage。 At the Arecibo Observatory； an even more sensitive NASA study began that concentrated on promising nearby star systems。 When fully operational； the NASA searches would have been able to detect much fainter signals than META； and look for kinds of signals that META could not。
The META experience reveals a thicket of background static and radio interference。 Quick reobservation and confirmation of the signal—specially at other； independent radio telescopes—is the key to being sure。 Horowitz and I gave NASA scientists the coordinates of our fleeting and enigmatic events。 Perhaps they would be able to confirm and clarify our results。 The NASA program was also developing new technology； stimulating ideas； and exciting schoolchildren。 In the eyes of many it was well worth the 10 million a year being spent on it。 But almost exactly a year after authorizing it； Congress pulled the plug on NASA's SETI program。 It cost too much； they said。 The post…Cold War U。S。 defense budget is some 30；000 times larger。
The chief argument of the principal opponent of the NASA SETI program—Senator Richard Bryan of Nevada—was this ＇from the Congressional Record for September 22； 1993＇：
So far； the NASA SETI Program has found nothing。 In fact； all the decades of SETI research have found no confirmable signs of extraterrestrial life。
Even with the current NASA version of SETI； I do not think many of its scientists would be willing to guarantee that we are likely to see any tangible results in the ＇foreseeable＇ future 。 。 。
Scientific research rarely； if ever； offers guarantees of success—and I understand that—and the full benefits of such research are often unknown until very late in the process。 And I accept that； as well。
In the case of SETI； however； the chances of success are so remote； and the likely benefits of the program are so limited； that there is little justification for 12 million taxpayer dollars to be expended for this program。
But how； before we have found extraterrestrial intelligence； can we 〃guarantee〃 that we will find it？ How； on the other hand； can we know that the chances of success are 〃remote〃？ And if we find extraterrestrial intelligence； are the benefits really likely to be 〃so limited〃？ As in all great exploratory ventures； we do not know what we will find and we don't know the probability of finding it。 If we did； we would not have to look。
SETI is one of those search programs irritating to those who want well…defined cost/benefit ratios。 Whether ETI can be found； how long it would take to find it； and what it would cost to do so are all unknown。 The benefits might be enormous； but we can't really be sure of that either。 It would of course be foolish to spend a major fraction of the national treasure on such ventures； but I wonder if civilizations cannot be calibrated by whether they pay some attention to trying to solve the great problems。
Despite these setbacks； a dedicated band of scientists and engineers； centered at the SETI Institute in Palo Alto； California； has decided to go ahead； government or no government。 NASA has given them permission to use the equipment already paid for； captains of the electronics industry have donated a few million dollars； at least one appropriate radio telescope is available； and the initial stages of this grandest of all SETI programs is on track。 If it can demonstrate that a useful sky survey is possible without being swamped by background noise—and especially if； as is very likely from the META experience； there are unexplained candidate signals…perhaps Congress will change its mind once more and fund the project。
Meanwhile； Paul Horowitz has e up with a new program—different from META； different from what NASA was doing—called BETA。 BETA stands for 〃Billion…channel ExtraTerrestrial Assay。〃 It bines narrow…band sensitivity； wide frequency coverage； and a clever way to verify signals as they're detected。 If The Planetary Society can find the additional support； this system—much cheaper than the former NASA program—should be on the air soon。
WOULD I LIKE TO BELIEVE that with META we've detected transmissions from other civilizations out there in the dark； sprinkled through the vast Milky Way Galaxy？ You bet。 After decades of wondering and studying this problem； of course I would。 To me； such a discovery would be thrilling。 It would change everything。 We would be hearing from other beings； independently evolved over billions of years； viewing the Universe perhaps very differently； probably much smarter； certainly not human。 How much do they know that we don't？
For me； no signals； no one calling out to us is a depressing prospect。 〃plete silence；〃 said Jean…Jacques Rousseau in a different context； 〃induces melancholy； it is an image of death。〃 But I'm with Henry David Thoreau： 〃Why should I feel lonely？ Is not our planet in the Milky Way？〃
The realization that such beings exist and that； as the evolutionary process requires； they must be very different from us； would have a striking implication： Whatever differences divide us down here on Earth are trivial pared to the differences between any of us and any of them。 Maybe it's a long shot； but the discovery of extraterrestrial intelligence might play a role in unifying our squabbling and divided planet。 It would be the last of the Great Demotions； a rite of passage for our species and a transforming event in the ancient quest to discover our place in the Universe。
In our fascination with SETI； we might be tempted； even without good evidence； to succumb to belief but this would be self…indulgent and foolish。 We must surrender our skepticism only in the face of rock…solid evidence。 Science demands a tolerance for ambiguity。 Where we are ignorant； we withhold belief。 Whatever annoyance the uncertainty engenders serves a higher purpose： It drives us to accumulate better data。 This attitude is the difference between science and so much else。 Science offers little in the way of cheap thrills。 The standards of evidence are strict。 But when followed they allow us to see far； illuminating even a great darkness。
CHAPTER 21 TO THE SKY！
The stairs of the sky are let down for him that he may ascend thereon to heaven。 O gods； put your arms under the king： raise him； lift him to the sky。 To the sky！ To the sky！
—HYMN FOR A DEAD PHARAOH （EGYPT； CA。 2600 B。C。）
When my grandparents were children； the electric light； the automobile； the airplane； and the radio were Stupefying technological advances； the wonders of the age。 You might hear wild stories about them； but you could not find a single exemplar in that little village in Austria…Hungary； near the banks of the river Bug。 But in that same time； around the turn of the last century； there were two men who foresaw other； far more ambitious； inventions—Konstantin Tsiolkovsky； the theoretician； a nearly deaf schoolteacher in the obscure Russian town of Kaluga； and Robert Goddard； the engineer； a professor at an equally obscure American college in Massachusetts。 They dreamt of using rockets to journey to the planets and the stars。 Step by step； they worked out the fundamental physics and many of the details。 Gradually； their machines took shape。 Ultimately； their dream proved infectious。
In their time； the very idea was considered disreputable； or even a symptom of some obscure derangement。 Goddard found that merely mentioning a voyage to other worlds subjected him to ridicule； and he dared not publish or even discuss in public his long…term vision of flights to the stars。 As teenagers； both had epiphanal visions of spaceflight that never left them。 〃I still have dreams in which I fly up to the stars in my machine；〃 Tsiolkovsky wrote in middle age。 〃It is difficult to work all on your own for many years； in adverse conditions without a gleam of ho