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Anil Ananthaswamy 談如何進行天體物理學的極致研究

Anil Ananthaswamy: What it takes to do extreme astrophysics

 

Photo of three lions hunting on the Serengeti.

講者:Anil Ananthaswamy

2010年12月演講,2011年4月在TED上線

 

翻譯:洪曉慧

編輯:朱學恆

簡繁轉換:洪曉慧

後製:洪曉慧

字幕影片後制:謝旻均

 

影片請按此下載

MAC及手持裝置版本請按此下載

閱讀中文字幕純文字版本

 

關於這場演講

遍佈地球的巨大望遠鏡和探測器正尋找(及聆聽)宇宙運行的線索。在INK Conference中,科學作家Anil Ananthaswamy帶領我們觀賞這些驚人的裝置,將我們帶到地球上一些最偏遠和寂靜的地方。

 

關於Anil Ananthaswamy

Anil Ananthaswamy是《物理的邊疆》(The Edge of Physics)一書作者。之前擔任軟體工程師的他,在對這個世界狂熱的好奇心驅使下,成為一位科學作家。

 

為什麼要聽他演講

Anil Ananthaswamy是倫敦《新科學人》雜誌顧問。自2000年以來,他在該雜誌擔任過多種職位,最近擔任新聞副編輯。他也是國家地理新聞的撰搞者。

 

Ananthaswamy曾於矽谷擔任軟體工程師,之後在加州大學聖塔克魯茲分校受訓成為一名記者。他是《物理的邊疆》(The Edge of Physics)一書作者,(在印度由企鵝出版社以《理性之邊疆》(The Edge of Reason)為名出版)。

 

觀賞Ananthaswamy於INK Conference短片

 

Anil Ananthaswamy的英語網上資料

 

[TED科技‧娛樂‧設計]

已有中譯字幕的TED影片目錄(繁體)(簡體)。請注意繁簡目錄是不一樣的。

 

Anil Ananthaswamy 談如何進行天體物理學的極致研究

我今天想談的是,關於我認為人類已著手進行的最大冒險之一,就是尋求對宇宙的瞭解,以及我們在其中的位置。在這個主題上,我自己的興趣和熱情開始的相當意外。我買了這本書,《宇宙與愛因斯坦博士》,在西雅圖一間二手書店買的平裝二手書。幾年之後,在班加羅爾在一個很難入睡的夜晚,我拿起這本書,以為它會讓我在十分鐘內睡著,而發生的情況是,我從午夜到清晨五點一口氣看完。我心中對於宇宙以及我們盡可能瞭解一切的能力,留下敬畏和興奮的強烈感覺,那份感覺還沒消失。

 

那份感覺促使我真正改變我的職業生涯,從一位軟體工程師成為一位科學作家,這樣我就可以浸淫在科學的喜悅,還有與他人交流的喜悅中。這種感覺也使我勉強稱得上成為一個朝聖者,可說是遊遍天涯海角,見識到望遠鏡、探測器,人們為更廣泛、更詳細探索宇宙,而正在建設、或已建成的裝置。所以,這將我從一些地方,如智利,智利的阿塔卡馬沙漠,帶到西伯利亞、地下礦區,還有日本的阿爾卑斯山、北美洲、一直到南極洲,甚至到了南極。

 

今天我想與大家分享一些圖片,一些旅行故事點滴。基本上,我花了過去幾年時間,將一些非常勇敢的男性及女性的努力紀錄下來。事實上,他們有時將生命置於險境,在一些非常偏遠、環境惡劣的地方工作,期許能收集到來自宇宙的微弱信號,為了讓我們瞭解這個宇宙。

 

我先以一張餅狀圖開始,我保證這是整場演講中唯一一張餅狀圖,但它顯示出我們對宇宙的知識狀態。以我們今天所有物理理論能適當解釋的所謂普通物質,也就是組成我們的東西,佔整個宇宙的百分之四。天文學家、宇宙學家和物理學家認為,宇宙中有一種叫做暗物質的東西,佔了宇宙組成的百分之二十三,某種叫做暗能量的東西,它貫穿時空結構,佔了另外的百分之七十三。所以,如果你看這張餅狀圖,宇宙的百分之九十六,以目前來說,我們對它的探索是未知或不甚理解。大多數實驗,及我所看過的天文望遠鏡,都試圖以某種方式解決這個問題,解決這孿生的暗物質和暗能量之謎。

 

首先,我將帶你們到明尼蘇達州北部的地下礦區。人們在那裡尋找所謂暗物質的東西,這裡的想法是,他們尋找著暗物質粒子擊中他們探測器的訊號,他們之所以要深入地底,是因為如果在地球表面進行這個實驗,這樣的實驗可能被一些其他物質引起的信號淹沒,如宇宙射線、周圍無線電的活動、甚至是我們自己的身體。你可能不相信,但即使是我們身體的放射線,就足以干擾這個實驗。所以他們深入礦區,尋找一個寂靜的環境,讓他們能夠聽到暗物質粒子擊中探測器的聲音。

 

我去看了其中一個實驗,這事實上是-你幾乎看不到它,原因是,那裡是全然的黑暗。這是一個礦工們留下的洞穴,他們在1960年棄置這個礦坑,物理學家前來並開始使用它,在80年代某個時候。這些礦工在上世紀初,事實上是在燭光下工作。今天,你會在礦區內看到這個景像,在地底半英里處,這是世界上最大的地底實驗室之一。除此之外,他們正尋找著暗物質。

 

還有另一種搜尋暗物質的方法,是間接的方式,如果暗物質存在於我們的宇宙、星系,那麼這些粒子應該會一起粉碎,產生其他我們所知的粒子,其中之一是微中子。你可以偵測微中子,藉由它們擊中水分子時留下的痕跡。當一個微中子擊中一個水分子時,會放射出一種藍光,一道藍色的閃光,藉由尋找這種藍光,基本上可以瞭解一些關於微中子的事。然後,間接的,瞭解一些可能製造出這個微中子的暗物質的事。但這需要非常大量的水才能做到這一點,你需要大約千萬噸的水,幾乎是十億噸的水,才有機會捕捉到這個微中子。世界上什麼地方能找到這麼多水?俄國人的後院有個湖,就是貝加爾湖。

 

它是世界上最大的湖,有800公里長,約40至50公里寬,大部份地方有一到兩公里深。俄國人正在做的是建造這些探測器,將它浸在湖面下方約一公里處,這樣他們就能觀察這些藍光的閃爍情形。這是我到達那裡時所看到的景像,這是貝加爾湖,在西伯利亞冬天最冷的時候,這座湖完全凍結,你們在背景中所看到成線性排列的黑點,是物理學家進行工作的冰營。他們之所以要在冬季工作,是因為他們沒錢在春季和夏季工作。如果他們要這麼做,將需要船和潛艇來進行工作,因此,他們等到冬天,當湖完全凍結時,他們利用這幾公尺厚的冰層作為一個平台,在其上建造營地來進行工作。

 

因此,這是俄國人在冰上工作,在西伯利亞冬天最冷的時候。他們必須在冰上鑽洞,潛進水裡-極度寒冷的水,抓住儀器,將它取出,做任何所需的維修和保養,在冰融化之前將它放回並離開,因為堅冰時期持續兩個月,且滿是裂縫,你得想像一下,下方是一整片正移動著、如大海般的湖。我還是不懂這個俄國人為何裸露著胸膛工作,但這顯示出他是如何努力工作。而這些人,這寥寥幾個人,已工作了20年,尋找可能並不存在的粒子,他們將畢生貢獻於此,只是讓你們知道一下,他們在二十年中花了兩千萬,這是非常嚴苛的處境,他們在極少的預算下工作,廁所事實上是地面上挖出的洞,用木製小屋遮著,如此簡陋,但他們每年都是如此。

 

從西伯利亞到智利的阿塔卡馬沙漠,可以看到一些所謂的超大望遠鏡,超大望遠鏡是天文學家進行的工程之一,他們為望遠鏡命名很沒想像力,我可以告訴你們一個事實,他們計劃將下一台命名為特大望遠鏡。(笑聲)你也不會相信,但之後的一台將被稱為巨無霸望遠鏡(一般取其英文縮寫,稱為貓頭鷹望遠鏡)。但無論如何,這是一項傑出的工程,這是四台8.2米望遠鏡,而這些望遠鏡除了其他功能之外,它們被用來研究宇宙膨脹如何隨時間變化。越瞭解這一點,就越能明白構成宇宙的暗能量是怎麼回事。

 

我還要告訴你們跟這台望遠鏡有關的一項工程,就是它的鏡面。每一個鏡面,共有四個,是由一整塊玻璃製成,單片的高科技陶瓷材料,被打磨和拋光成如此精確的程度,要瞭解那是怎麼回事的唯一方法,就是想像一個城市,如巴黎,還有其中所有建築和艾菲爾鐵塔。如果你將巴黎打磨到那樣的精確度,只會留下一個一毫米高的隆起,這也是這些鏡面得承受的拋光程度,一套非凡的望遠鏡裝置。這是望遠鏡的另一個角度,你之所以要建造這些望遠鏡,在如阿塔卡馬沙漠的地方,是因為它是高海拔的沙漠,乾燥的空氣對望遠鏡來說相當好,同時,雲覆蓋在低於山頂之處,使望遠鏡一年能擁有約300多天的晴朗天空。

 

最後,我要帶你們到南極洲,我想用最多時間來談世界這個部分,這是宇宙的最終邊界,一些最驚人、最極限的實驗目前正在南極洲進行。我到這裡觀看某種叫做長時飛行氣球的東西,基本上,它攜帶望遠鏡和儀器,一路飛到大氣層上方,平流層上方,高度40公里處,這正是他們做實驗的地方,然後放下這個氣球的負載物。這是我們降落在南極洲的羅斯冰架,這是一架美國 C - 17運輸機,將我們從紐西蘭載往南極洲的麥克默多,這是我們即將登上巴士,我不知道你們是否能看到上面的字,但它寫著,「恐怖大巴士伊凡」,它載著我們到麥克默多。

 

這是初到麥克默多所見景像。你也許能勉強辨認出這間小屋,這小屋是由Robert Falcon Scott和他的夥伴第一次來到南極洲時所建,在他們第一次遠征南極時,因為天氣如此寒冷,小屋中所有物品仍跟他們離開時一樣,他們最後一餐吃剩的食物仍在那裡。這是一個非比尋常的地方,這是麥克默多的景像,夏天大約有一千人在這裡工作,冬季約有200人,這半年時間完全是一片黑暗。

 

在這裡,我看到這個特殊裝置的發射,這是一個宇宙射線實驗,一路發射到高平流層,高度達40公里。想像一下,它有兩噸重,所以你用氣球攜帶兩噸重的東西,一路到達40公里高處,工程師、技術員、物理學家都得集合在羅斯冰架上,因為南極洲-我不打算講述原因,但它是發射這些氣球最適合的地方,除了天氣因素以外。這裡的天氣,如你能想像的,這是夏天,你正站在200英尺的冰上,後方有座火山,山頂有條冰川,他們必需做的是組裝整個氣球,氣球布、降落傘和所有一切-在冰上,然後將它充滿氦氣,這個過程大約需要兩小時。

 

在他們組裝整個裝置時天氣可能改變,舉例來說,他們放下最後得充滿氦氣的氣球布,你們可以看到最遠端那兩輛卡車,每輛運載了12瓶壓縮氦。現在,萬一天氣在發射前發生變化,他們必須將所有東西裝回箱中,將它帶回麥克默多研究站,而這個特殊的氣球,因為得發射兩噸的重量,是極其巨大的氣球,單是布條就重達兩噸,為了盡量減少重量,它非常薄,薄如三明治的包裝紙,如果他們要將它放回,將它放入箱中,得將它踩壓,才能同樣妥當地放回去。此外,他們第一次這麼做是在德州,但在這裡,穿著腳上那種鞋,他們無法做到這一點,所以他們不得不脫下鞋子,赤腳在這些箱中踩踏,在如此寒冷的天氣中進行這項工作,這就是這些人所做的奉獻。

 

這是氣球正充著氦氣,你可以看到,這是一個迷人的景像,這是氣球與負載物端點連接的景像,因此,在左側,氣球正充著氦氣,布條一路跑到中間,上面有連著一個降落傘的電子零件和炸藥,然後降落傘連接到負載物。請記住,這所有配線都是人們在極度寒冷、零下的溫度中進行的,他們穿著約15公斤重的衣物和裝備,但他們必須將手套脫掉才能做到這些。而我想與大家分享發射的情景。

 

(影片)無線電:好,鬆開氣球、鬆開氣球、鬆開氣球。

 

Anil Ananthaswamy:最後我想讓你們看兩張圖片,這是在喜馬拉雅山的天文台,在印度的拉達克,我要讓你們看的東西是右側的望遠鏡,最左邊的是有400年歷史的佛教寺院,這是佛教寺院近照。我對這兩種人類所擁有的偉大學科的並列性感到震驚,一個是探索地球之外的宇宙,另一個是探索我們內在的心靈,兩者都需要某種形式的寂靜。

 

讓我震驚的是,每一個我去看這些望遠鏡的地方,天文學家和宇宙學家都在搜尋著某種寂靜,無論是存在於無線訊號污染或光污染中的寂靜。這非常明顯,如果我們破壞了地球上這些寂靜的地方,我們將被困在一個星球上,沒有向外觀看的能力,因為我們將無法理解來自外太空的信號。

 

謝謝。

 

(掌聲)

 

以下為系統擷取之英文原文

About this talk

All over the planet, giant telescopes and detectors are looking (and listening) for clues to the workings of the universe. At the INK Conference, science writer Anil Ananthaswamy tours us around these amazing installations, taking us to some of the most remote and silent places on Earth.

About Anil Ananthaswamy

Anil Ananthaswamy is the author of "The Edge of Physics." A former software engineer, he was inspired to become a science writer by his passionate curiosity about the world. Full bio and more links

Transcript

I would like to talk today about what I think is one of the greatest adventures human beings have embarked upon, which is the quest to understand the universe and our place in it. My own interest in this subject, and my passion for it, began rather accidentally. I had bought a copy of this book, "The Universe and Dr. Einstein" -- a used paperback from a secondhand bookstore in Seattle. A few years after that, in Bangalore, I was finding it hard to fall asleep one night, and I picked up this book, thinking it would put me to sleep in 10 minutes. And as it happened, I read it from midnight to five in the morning in one shot. And I was left with this intense feeling of awe and exhilaration at the universe and our own ability to understand as much as we do. And that feeling hasn't left me yet.

That feeling was the trigger for me to actually change my career -- from being a software engineer to become a science writer -- so that I could partake in the joy of science, and also the joy of communicating it to others. And that feeling also led me to a pilgrimage of sorts, to go literally to the ends of the earth to see telescopes, detectors, instruments that people are building, or have built, in order to probe the cosmos in greater and greater detail. So it took me from places like Chile -- the Atacama Desert in Chile -- to Siberia, to underground mines, in the Japanese Alps, in Northern America, all the way to Antarctica and even to the South Pole.

And today I would like to share with you some images, some stories of these trips. I have been basically spending the last few years documenting the efforts of some extremely intrepid men and women who are putting, literally at times, their lives at stake working in some very remote and very hostile places so that they may gather the faintest signals from the cosmos in order for us to understand this universe.

And I first begin with a pie chart. And I promise this is the only pie chart in the whole presentation. But it sets up the state of our knowledge of the cosmos. All the theories in physics that we have today properly explain what is called normal matter -- the stuff that we're all made of -- and that's four percent of the universe. Astronomers and cosmologists and physicists think that there is something called dark matter in the universe, which makes up 23 percent of the universe, and something called dark energy, which permeates the fabric of space-time, that makes up another 73 percent. So if you look at this pie chart, 96 percent of the universe, at this point in our exploration of it, is unknown or not well understood. And most of the experiments, telescopes that I went to see are in some way addressing this question, these two twin mysteries of dark matter and dark energy.

I will take you first to an underground mine in Northern Minnesota where people are looking for something called dark matter. And the idea here is that they are looking for a sign of a dark matter particle hitting one of their detectors. And the reason why they have to go underground is that, if you did this experiment on the surface of the Earth, the same experiment would be swamped by signals that could be caused by things like cosmic rays, ambient radio activity, even our own bodies. You might not believe it, but even our own bodies are radioactive enough to disturb this experiment. So they go deep inside mines to find a kind of environmental silence that will allow them to hear the ping of a dark matter particle hitting their detector.

And I went to see one of these experiments, and this is actually -- you can barely see it, and the reason for that is it's entirely dark in there. This is a cavern that was left behind by the miners who left this mine in 1960. And physicists came and started using it sometime in the 1980s. And the miners in the early part of the last century worked, literally, in candle light. And today, you would see this inside the mine, half a mile underground. This is one of the largest underground labs in the world. And, among other things, they're looking for dark matter.

There is another way to search for dark matter, which is indirectly. If dark matter exists in our universe, in our galaxy, then these particles should be smashing together and producing other particles that we know about -- one of them being neutrinos. And neutrinos you can detect by the signature they leave when they hit water molecules. When a neutrino hits a water molecule it emits a kind of blue light, a flash of blue light, and by looking for this blue light, you can essentially understand something about the neutrino and then, indirectly, something about the dark matter that might have created this neutrino. But you need very, very large volumes of water in order to do this. You need something like tens of megatons of water -- almost a gigaton of water -- in order to have any chance of catching this neutrino. And where in the world would you find such water? Well the Russians have a tank in their own backyard.

This is Lake Baikal. It is the largest lake in the world. It's 800 km long. It's about 40 to 50 km wide in most places, and one to two kilometers deep. And what the Russians are doing is they're building these detectors and immersing them about a kilometer beneath the surface of the lake so that they can watch for these flashes of blue light. And this is the scene that greeted me when I landed there. This is Lake Baikal in the peak of the Siberian winter. The lake is entirely frozen. And the line of black dots that you see in the background, that's the ice camp where the physicists are working. The reason why they have to work in winter is because they don't have the money to work in summer and spring, which, if they did that, they would need ships and submersibles to do their work. So they wait until winter -- the lake is completely frozen over -- and they use this meter-thick ice as a platform on which to establish their ice camp and do their work.

So this is the Russians working on the ice in the peak of the Siberian winter. They have to drill holes in the ice, dive down into the water -- cold, cold water -- to get hold of the instrument, bring it up, do any repairs and maintenance that they need to do, put it back and get out before the ice melts. Because that phase of solid ice lasts for two months and it's full of cracks. And you have to imagine, there's an entire sea-like lake underneath, moving. I still don't understand this one Russian man working in his bare chest, but that tells you how hard he was working. And these people, a handful of people, have been working for 20 years, looking for particles that may or may not exist. And they have dedicated their lives to it. And just to give you an idea, they have spent 20 million over 20 years. It's very harsh conditions. They work on a shoestring budget. The toilets there are literally holes in the ground covered with a wooden shack. And it's that basic, but they do this every year.

From Siberia to the Atacama Desert in Chile, to see something called the The Very Large Telescope. The Very Large Telescope is one of these things that astronomers do -- they name their telescopes rather unimaginatively. I can tell you for a fact, that the next one that they're planning is called The Extremely Large Telescope. (Laughter) And you wouldn't believe it, but the one after that is going to be called The Overwhelmingly Large Telescope. But nonetheless, it's an extraordinary piece of engineering. These are four 8.2 meter telescopes. And these telescopes, among other things, they're being used to study how the expansion of the universe is changing with time. And the more you understand that, the better you would understand what this dark energy -- that the universe is made of -- is all about.

And one piece of engineering that I want to leave you with as regards this telescope is the mirror. Each mirror, there are four of them, is made of a single piece of glass, a monolithic piece of high-tech ceramic, that has been ground down and polished to such accuracy that the only way to understand what that is is imagine a city like Paris, with all its buildings and the Eiffel Tower, if you grind down Paris to that kind of accuracy, you would be left with bumps that that are one millimeter high. And that's the kind of polishing that these mirrors have endured. An extraordinary set of telescopes. Here's another view of the same. The reason why you have to build these telescopes in places like the Atacama Desert is because of the high altitude desert. The dry air is really good for telescopes, and also, the cloud cover is below the summit of this mountain so that the telescopes have about 300 days of clear skies.

Finally, I want to take you to Antarctica. I want to spend most of my time on this part of the world. This is cosmology's final frontier. Some of the most amazing experiments, some of the most extreme experiments, are being done in Antarctica. I was there to view something called a long-duration balloon flight, which basically takes telescopes and instruments all the way to the upper atmosphere, the upper stratosphere, 40 km up. And that's where they do their experiments, and then the balloon, the payload, is brought down. So this is us landing on the Ross Ice Shelf in Antarctica. That's an American C-17 cargo plane that flew us from New Zealand to McMurdo in Antarctica. And here we are about to board our bus. And I don't know if you can read the lettering, but it says, "Ivan the Terribus." And that's taking us to McMurdo.

And this is the scene that greets you in McMurdo. And you barely might be able to make out this hut here. This hut was built by Robert Falcon Scott and his men when they first came to Antarctica on their first expedition to go to the South Pole. Because it's so cold, the entire contents of that hut is still as they left it, with the remnants of the last meal they cooked still there. It's an extraordinary place. This is McMurdo itself. About a thousand people work here in summer, and about 200 in winter when it's completely dark for six months.

I was here to see the launch of this particular type of instrument. This is a cosmic ray experiment that has been launched all the way to the upper-stratosphere to an altitude of 40 km. What I want you to imagine is this is two tons in weight. So you're using a balloon to carry something that is two tons all the way to an altitude of 40 km. And the engineers, the technicians, the physicists have all got to assemble on the Ross Ice Shelf, because Antarctica -- I won't go into the reasons why -- but it's one of the most favorable places for doing these balloon launches, except for the weather. The weather, as you can imagine, this is summer, and you're standing on 200 ft of ice. And there's a volcano behind, which has glaciers at the very top. And what they have to do is they have to assemble the entire balloon -- the fabric, parachute and everything -- on the ice and then fill it up with helium. And that process takes about two hours.

And the weather can change as they're putting together this whole assembly. For instance, here they are laying down the balloon fabric behind, which is eventually going to be filled up with helium. Those two trucks you see at the very end carry 12 tanks each of compressed helium. Now, in case the weather changes before the launch, they have to actually pack everything back up into their boxes and take it out back to McMurdo Station. And this particular balloon, because it has to launch two tons of weight, is an extremely huge balloon. The fabric alone weighs two tons. In order to minimize the weight, it's very thin, it's as thin as a sandwich wrapper. And if they have to pack it back, they have to put it into boxes and stamp on it so that it fits into the box again -- except, when they did it first, it would have been done in Texas. Here, they can't do it with the kind shoes they're wearing, so they have to take their shoes off, get barefoot into the boxes in this cold and do that kind of work. That's the kind of dedication these people have.

Here's the balloon being filled up with helium, and you can see it's a gorgeous sight. Here's a scene that shows you the balloon and the payload end-to-end. So the balloon is being filled up with helium on the left-hand side, and the fabric actually runs all the way to the middle where there's a piece of electronics and explosives being connected to a parachute, and then the parachute is then connected to the payload. And remember, all this wiring is being done by people in extreme cold, in sub-zero temperatures. They're wearing about 15 kg of clothing and stuff, but they have to take their gloves off in order to do that. And I would like to share with you a launch.

(Video) Radio: Okay, release the balloon, release the balloon, release the balloon.

Anil Ananthaswamy: And I'll finally like to leave you with two images. This is an observatory in the Himalayas, in Ladakh in India. And the thing I want you to look at here is the telescope up on the right-hand side. And on the far left there is a 400 year-old Buddhist monastery. This is a close-up of the Buddhist monastery. And I was struck by the juxtaposition of these two enormous disciplines that humanity has. One is exploring the cosmos on the outside, and the other one is exploring our interior being. And both require silence of some sort.

And what struck me was every place that I went to to see these telescopes, the astronomers and cosmologists are in search of a certain kind of silence, whether it's silence from radio pollution or light pollution or whatever. And it was very obvious that, if we destroy these silent places on Earth, we will be stuck on a planet without the ability to look outwards, because we will not be able to understand the signals that come from outer space.

Thank you.

(Applause)
 


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Anonymous, 2011-05-21 14:33:49

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