TED演讲.这是我们最后的世纪吗doc.doc

1、 国际海员服务中心网 http:/ 国际海员服务中心网 http:/ TED 演讲：这是我们最后的世纪吗？Martin Rees asks: Is this our final century?Speaking as both an astronomer and “a concerned member ofthe human race,“ Sir Martin Rees examines our planet and itsfuture from a cosmic perspective. He urges action to preventdark consequences from our

2、 scientific and technological development.Martin Rees, one of the worlds most eminent astronomers, is a professor of cosmology andastrophysics at the University of Cambridge and the UKs Astronomer Royal. He is one of our keythinkers on the future of humanity in the cosmos.Speakers Martin Rees: Astro

3、physicistWhy you should listen to him:国际海员服务中心网 http:/ 国际海员服务中心网 http:/ Sir Martin Rees has issued a clarion call for humanity. His 2004 book, ominously titled Our FinalHour, catalogues the threats facing the human race in a 21st century dominated byunprecedented and accelerating scientific change.

4、He calls on scientists and nonscientists alike totake steps that will ensure our survival as a species.One of the worlds leading astronomers, Rees is a professor of cosmology and astrophysics atCambridge, and UK Astronomer Royal. Author of more than 500 research papers on cosmologicaltopics ranging

5、from black holes to quantum physics to the Big Bang, Rees has received countlessawards for his scientific contributions. But equally significant has been his devotion to explaining thecomplexities of science for a general audience, in books like Before the Beginning and Our CosmicHabitat.“It is Sir

6、Martins eminent position as a leading cosmologist, studying the Universe, its birth andultimate fate, which makes his new pronouncements both important and thought-provoking.“BBCIf you take 10,000 people at random, 9,999 have something in common: their interests inbusiness lie on or near the Earths

7、surface. The odd one out is an astronomer, and I am one of thatstrange breed. (Laughter) My talk will be in two parts. Ill talk first as an astronomer, and then as aworried member of the human race. But lets start off by remembering that Darwin showed howwere the outcome of four billion years of evo

8、lution. And what we try to do in astronomy 国际海员服务中心网 http:/ 国际海员服务中心网 http:/ andcosmology is to go back before Darwins simple beginning, to set our Earth in a cosmic context.And let me just run through a few slides. This was the impact that happened last week on a comet. If theyd sent a nuke, it wou

9、ld have been rather more spectacular than what actually happenedlast Monday. So thats another project for NASA. Thats Mars from the European Mars Express, and at NewYear. This artists impression turned into reality when a parachute landed on Titan, Saturns giantmoon. It landed on the surface. This i

10、s pictures taken on the way down. That looks like a coastline. It is indeed, but the ocean is liquid methane - the temperature minus 170 degrees centigrade. Ifwe go beyond our solar system, weve learned that the stars arent twinkly points of light. Eachone is like a sun with a retinue of planets orb

11、iting around it. And we can see places where stars areforming, like the Eagle Nebula. We see stars dying. In six billion years, the sun will look like that. Andsome stars die spectacularly in a supernova explosion, leaving remnants like that.On a still bigger scale, we see entire galaxies of stars.

12、We see entire ecosystems where gas is beingrecycled. And to the cosmologist, these galaxies are just the atoms, as it were, of the large-scaleuniverse. This picture shows a patch of sky so small that it would take about 100 patches like it tocover the full moon in the sky. Through a small telescope,

13、 this would look quite blank, but you seehere hundreds of little, faint smudges.国际海员服务中心网 http:/ 国际海员服务中心网 http:/ Each is a galaxy, fully like ours or Andromeda, which looks so small and faint because its light hastaken 10 billion light-years to get to us. The stars in those galaxies probably dont h

14、ave planetsaround them. Theres scant chance of life there - thats because theres been no time for thenuclear fusion in stars to make silicon and carbon and iron, the building blocks of planets and of life. We believe that all of this emerged from a BigBang - a hot, dense state. So how did that amorp

15、hous Big Bang turn into our complex cosmos?Im going to show you a movie simulation 16 powers of 10 faster than real time, which shows apatch of the universe where the expansions have subtracted out. But you see, as time goes on ingigayears at the bottom, you will see structures evolve as gravity fee

16、ds on small, denseirregularities, and structures develop. And well end up after 13 billion years with something lookingrather like our own universe. And we compare simulated universes like that - Ill show you a bettersimulation at the end of my talk - with what we actually see in the sky. Well, we c

17、an trace thingsback to the earlier stages of the Big Bang, but we still dont know what banged and why it banged.Thats a challenge for 21st-century science. If my research group had a logo, it would be thispicture here: an ouroboros, where you see the micro-world on the left - the world of the quantu

18、m - and on the right the large-scale universe of planets, stars and galaxies. We know our universesare united though - links 国际海员服务中心网 http:/ 国际海员服务中心网 http:/ between left and right. The everyday world is determined by atoms, howthey stick together to make molecules. Stars are fueled by how the nucl

19、ei in those atoms reacttogether. And, as weve learned in the last few years, galaxies are held together by the gravitationalpull of so-called dark matter: particles in huge swarms, far smaller even than atomic nuclei. Butwed like to know the synthesis symbolized at the very top. The micro-world of t

20、he quantum isunderstood. On the right hand side, gravity holds sway.Einstein explained that. But the unfinished business for 21st-century science is to link togethercosmos and micro-world with a unified theory - symbolized, as it were, gastronomically at the topof that picture.(Laughter) And until w

21、e have that synthesis, we wont be able to understand the very beginning ofour universe because when our universe was itself the size of an atom, quantum effects couldshake everything.And so we need a theory that unifies the very large and the very small, which we dont yet have. One idea, incidentall

22、y - and I had this hazard sign to say Im going to speculate from now on - isthat our Big Bang was not the only one. One idea is that our three-dimensional universe may beembedded in a high-dimensional space, just as you can imagine on these sheets of paper.You can imagine ants on one of them thinkin

23、g its a two-dimensional universe, not being aware ofanother population of ants on the other. So there could be another universe just a millimeter awayfrom ours, but were not aware of it 国际海员服务中心网 http:/ 国际海员服务中心网 http:/ because that millimeter is measured in some fourth spatialdimension, and were im

24、prisoned in our three. And so we believe that there may be a lot more tophysical reality than what weve normally called our universe - the aftermath of our Big Bang. Andheres another picture. Bottom right depicts our universe, which on the horizon is not beyondthat, but even that is just one bubble,

25、 as it were, in some vaster reality. Many people suspect thatjust as weve gone from believing in one solar system to zillions of solar systems, one galaxy tomany galaxies, we have to go to many Big Bangs from one Big Bang, perhaps these many BigBangs displaying an immense variety of properties.Well,

26、 lets go back to this picture. Theres one challenge symbolized at the top, but theres anotherchallenge to science symbolized at the bottom. You want to not only synthesize the very large andthe very small, but we want to understand the very complex. And the most complex things areourselves, midway b

27、etween atoms and stars. We depend on stars to make the atoms were madeof. We depend on chemistry to determine our complex structure. We clearly have to be large, compared to atoms, to have layer upon layer of complex structure. We clearly have to be small, compared to stars and planets - otherwise w

28、ed be crushed by gravity. And in fact, we aremidway. It would take as many human bodies to make up the sun as there are atoms in each ofus. The geometric mean of the mass of a proton and the mass of the sun is 50 kilograms, within afactor of two of the mass of each person here. Well, most of you any

29、way. The science ofcomplexity is probably the greatest challenge of all, greater than that of the very 国际海员服务中心网 http:/ 国际海员服务中心网 http:/ small on the leftand the very large on the right. And its this science, which is not only enlightening ourunderstanding of the biological world, but also transform

30、ing our world faster than ever. And morethan that, its engendering new kinds of change.And I now move on to the second part of my talk, and the book “Our Final Century“ wasmentioned. If I was not a self-effacing Brit, I would mention the book myself, and I would add thatits available in paperback.(L

31、aughter)And in America it was called “Our Final Hour“ because Americans like instant gratification.(Laughter)But my theme is that in this century, not only has science changed the world faster than ever, butin new and different ways. Targeted drugs, genetic modification, artificial intelligence, per

32、haps evenimplants into our brains, may change human beings themselves. And human beings, theirphysique and character, has not changed for thousands of years. It may change this century. Itsnew in our history. And the human impact on the global environment - greenhouse warming, mass extinctions and s

33、o forth - is unprecedented, too. And so, this makes this coming century achallenge. Bio- and cybertechnologies are environmentally benign in that they offer marvelousprospects, while, nonetheless, reducing pressure on energy and resources. But they will have adark side. In our 国际海员服务中心网 http:/ 国际海员服

34、务中心网 http:/ interconnected world, novel technology could empower just one fanatic, or someweirdo with a mindset of those who now design computer viruses, to trigger some kind ondisaster. Indeed, catastrophe could arise simply from technical misadventure - error rather thanterror. And even a tiny pro

35、bability of catastrophe is unacceptable when the downside could be ofglobal consequence.In fact, some years ago, Bill Joy wrote an article expressing tremendous concern about robotstaking us over, etc. I dont go along with all that, but its interesting that he had a simple solution. Itwas what he ca

36、lled “fine-grained relinquishment.“ He wanted to give up the dangerous kind ofscience and keep the good bits. Now, thats absurdly naive for two reasons. First, any scientificdiscovery has benign consequences as well as dangerous ones.And also, when a scientist makes a discovery, he or she normally h

37、as no clue what the applicationsare going to be. And so what this means is that we have to accept the risks if we are going toenjoy the benefits of science. We have to accept that there will be hazards. And I think we have togo back to what happened in the post-War era, post-World War II, when the n

38、uclear scientistswhod been involved in making the atomic bomb, in many cases were concerned that they shoulddo all they could to alert the world to the dangers.And they were inspired not by the young Einstein, who did the great work in relativity, but by theold Einstein, the icon of poster and t-shi

39、rt, who failed in his scientific efforts to unify the physicallaws. He was premature. But he was a moral 国际海员服务中心网 http:/ 国际海员服务中心网 http:/ compass - an inspiration to scientists who wereconcerned with arms control. And perhaps the greatest living person is someone Im privileged toknow, Joe Rothblatt

40、. Equally untidy office there, as you can see. Hes 96 years old, and hefounded the Pugwash movement. He persuaded Einstein, as his last act, to sign the famousmemorandum ofBertrand Russell. And he sets an example of the concerned scientist. And I think to harness scienceoptimally, to choose which do

41、ors to open and which to leave closed, we need latter-daycounterparts of people like Joseph Rothblatt.We need not just campaigning physicists, but we need biologists, computer experts andenvironmentalists as well. And I think academics and independent entrepreneurs have a specialobligation because t

42、hey have more freedom than those in government service, or companyemployees subject to commercial pressure. I wrote my book, “Our Final Century,“ as a scientist, just a general scientist. But theres one respect, I think, in which being a cosmologist offered aspecial perspective, and thats that it of

43、fers an awareness of the immense future. The stupendoustime spans of the evolutionary past are now part of common culture - outside the AmericanBible Belt, anyway - (Laughter) but most people, even those who are familiar with evolution, arentmindful that even more time lies ahead.The sun has been sh

44、ining for four and a half billion years, but itll be another six billion years beforeits fuel runs out. On that schematic picture, a sort of time-国际海员服务中心网 http:/ 国际海员服务中心网 http:/ lapse picture, were halfway. And itll beanother six billion before that happens, and any remaining life on Earth is vapo

45、rized. Theres anunthinking tendency to imagine that humans will be there, experiencing the suns demise, but anylife and intelligence that exists then will be as different from us as we are from bacteria. Theunfolding of intelligence and complexity still has immensely far to go, here on Earth and pro

46、bablyfar beyond. So we are still at the beginning of the emergence of complexity in our Earth andbeyond. If you represent the Earths lifetime by a single year, say from January when it was madeto December, the21st-century would be a quarter of a second in June - a tiny fraction of the year. But even

47、 in thisconcertinaed cosmic perspective, our century is very, very special, the first when humans canchange themselves and their home planet.As I should have shown this earlier, it will not be humans who witness the end point of the sun; itwill be creatures as different from us as we are from bacter

48、ia. When Einstein died in 1955, onestriking tribute to his global status was this cartoon by Herblock in the Washington Post. Theplaque reads,“Albert Einstein lived here.“ And Id like to end with a vignette, as it were, inspired by this image. Weve been familiar for 40 years with this image: the fragile beauty of land, ocean and clouds, contrasted with the sterile moonscap