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Science and technology
科學技術
Table-top astrophysics
桌面上的天體物理學
How to build a multiverse
怎樣建立一個多元宇宙
Small models of cosmic phenomena are shedding light on the real thing
宇宙現象的一些小模型反映了真相
THE heavens do not lend themselves to poking and prodding.
天空不會幫助任何企圖研究它的行為。
Astronomers therefore have no choice but to rely on whatever data the cosmos deigns to throw at them.
因此，天文學家們只能聽天由命，任何宇宙透露出的一些數據，他們都當做寶貝一樣。
And they have learnt a lot this way.
不過他們通過這種方式也學到了很多。
Thus you can even study chemistry in space that would be impossible in a laboratory.
因此，人們甚至能在太空中研究化學，而這在實驗室是無法做到的。
Some astronomers, though, are dissatisfied with being passive observers. Real scientists, they think, do experiments.
雖然，一些天文學家們對成為被動的觀察者很是不滿，他們認為真正的科學家應該是有所行動的。
It is impossible—not to mention inadvisable—to get close enough to a star or a black hole to manipulate it experimentally.
要想接近一顆星或者一個黑洞，進行實驗性地操作是不可能的，其實也是不可取的。
But some think it might be possible to make meaningful analogues of such things, and even of the universe itself, and experiment on those instead.
但是，一些人認為，如果進行類似方面，甚至宇宙方面的有意義的研究，而不是試驗，是有可能的。
Ben Murdin of the University of Surrey, for example, has been making white dwarfs.
比如說，薩里大學的本-穆迪一直在制作白矮星。
A white dwarf is the stellar equivalent of a shrunken but feisty old-age pensioner.
從某種程度上說，白矮星是一顆雖然已經萎縮，但仍舊不服老的高齡恒星。
It has run out of fuel and is contracting and cooling as it heads towards oblivion—but taking its time about it.
當它正慢慢淡出宇宙這個大家庭時，它的動力已漸漸耗盡，而且正在縮小，漸漸變冷，但是還是值得花些時間的。
As they shrink white dwarfs pack a mass up to eight times the sun's into a volume the size of Earth.
當它們縮小時，這些白矮星把自己相當于八個太陽那么大的個頭壓縮到了地球這么大的個頭。
A consequence of stuffing so much matter into so little space is that white dwarfs have powerful magnetic fields.
把如此之大的東西壓縮到了這么小空間的結果是，白矮星擁有強大的磁場。
Many aspects of a white dwarf's mechanics, including how long it will last, are thought to depend on its magnetism.
天文學家認為，白矮星形成過程的許多問題，包括它會存在多久，都基于它的磁場。
But it is hard to measure.
但是這是無法衡量的。
To make estimates, scientists examine the light a white dwarf emits for telltale patterns left by stellar ingredients like hydrogen.
為了做出這方面的估計，科學家們檢測了白矮星發出的光，這種光正說明了這種問題的某種方式，是由組成恒星的元素，比如氫產生的。
They then compare this spectrum with a theory, based on calculations from first principles, of how magnetic fields effect light emitted by hydrogen.
然后，他們把測得的光譜與理論計算得到的結果進行了比較，這種理論是基于氫怎樣產生磁場效應區域的第一原則得到的。
The predictions agree with experiments up to the strongest fields mankind can muster—about 1,000 tesla, generated in a thermonuclear detonator.
結果，預測與試驗完全一致—即達到人類在這個領域最高水準，能夠在熱核雷管中產生1000特斯拉的磁感應。
The problem is that the theory puts white dwarfs' magnetic fields at 100,000 tesla or more, well beyond humanity's reach.
問題是，這個第一原則認為白矮星的磁場強度可以達到100,000特斯拉或者更多，遠遠超過了人類的極限。
Dr Murdin built his own little white dwarf to see if the theory looked good.
穆迪博士建造了他自己的小白矮星，想弄明白這種理論是否真的正確。
It consists of a silicon crystal sprinkled with phosphorus atoms.
這個小白矮星由布滿磷原子的硅晶體組成。
A silicon atom has four electrons in its outer shell.
一個硅原子外有四個電子。
In a crystal, all four are used to bind it to neighbouring atoms.
在晶體中，所有的四個電子都是與其相鄰的原子緊緊捆綁在一起。
Phosphorus has five outer electrons.
磷原子外有5個電子。
Insert a phosphorus atom into the silicon lattice and you are left with an unused electron.
把一個磷原子嵌入到硅晶格中，那還剩下一個電子。
Since phosphorus also has one more proton in its nucleus than silicon does, taken together the extra particles resemble a hydrogen atom: a single electron tethered to a single proton.
因為磷的細胞核中比硅還多一個質子，把多余的質子、電子收集起來，這和氫原子的結構很相似：一個獨立的電子捆綁著一個獨立的質子。
However, the extra electron is much less tightly held by the extra proton in this pseudo-hydrogen than it would be in real hydrogen.
然而，在這個山寨版的氫中，這個額外的電子與額外質子的結合并不如真正氫原子中那么緊密。
This weaker grasp means that it takes much less magnetism to make a given change in the pseudo-hydrogen's spectrum than it would for real hydrogen.
這種越來越弱的結合意味著，如果要讓這個山寨版頻譜產生一個額定的變化，它所需要的磁場比真正的氫少得多。
So when Dr Murdin placed the crystal in a 30-tesla magnet at Radboud University in the Netherlands, he was mimicking the conditions in a 100,000-tesla white dwarf.
因此，當穆迪博士這個晶體放到一個30特斯拉的磁體中時，因為他在格爾福德的實驗室缺少必要的設備，他是在模仿一個100,000特斯拉磁場強度的白矮星所處環境。
And the spectrum came out looking just the way the theory predicted.
結果得到的頻譜與理論預測的看起來很像。
A black hole in a bath
浴缸中的黑洞
Creating a star in a laboratory is small beer compared with creating a black hole.
在實驗室中建立一顆星星，相比于建立一個黑洞簡直就是不值一提。
This is an object that is so massive and dense that not even light can flee its gravitational field.
黑洞是一個很龐大，密度很高的物體，甚至連光都無法逃脫它的引力場。
Looking inside one is therefore, by definition, impossible.
因此，向里面看—就是字面意思上的看—一眼都是不可能的。
All the more reason to try, says Silke Weinfurtner of the International School for Advanced Studies, in Trieste, Italy.
所有的，越來越的理由都讓人們想試試建立一個山寨版的黑洞—意大利里雅斯特國際高級學院的西爾克-威福特納這樣表示。
Dr Weinfurtner plans to make her black hole in the bath.
威福特納博士計劃在浴缸中建立一個她的黑洞。
The bath in question, properly called a flume, is a water-filled receptacle 3 metres by 1.5 metres and 50cm deep, across which carefully crafted trains of ripples can pass.
這里說到的浴缸，更應該稱之為水槽，因為它是一個3米乘1.5米，50厘米深的裝滿水的容器，橫跨其中的是精心制作的漣波車隊。
In the middle of the tank is a plug hole.
在這個水槽中有一個泄水孔。
If the water going down the hole rotates faster than the ripples can propagate, the ripples which stray beyond the aqueous event horizon will not make it out.
如果水旋轉至水孔的速度快于漣波擴散的速度，那么超過水的黑洞邊境—是黑洞的不歸路--的漣波就不會讓水漫出來的。
They are sucked down the drain.
水將會被吸到下水道里。
Then the researchers will check whether the simulacrum affects water waves in a way analogous to that which general relativity predicts for light—itself a wave—approaching an astrophysical black hole.
到時，研究者會檢查這個模擬物，是否會以一種與廣義相對論預測的光，接近天體物理學黑洞類似的方式影響水波。
According to Albert Einstein's theory, a region immediately outside the event horizon of a rotating black hole will be dragged round by the rotation.
根據愛因斯坦理論，一個靠近旋轉黑洞邊界的外部區域會在這個旋渦的影響下也轉動起來。
Any wave that enters this region but does not stray past the event horizon should be deflected and come out with more energy than it carried on the way in.
任何進入這個區域，沒能穿越過去的光波會發生偏離，并且將會帶著比它接近這里時更多的能量出現。
To detect this super-radiant scattering, as the effect is called, Dr Weinfurtner will add fluorescent dye to the water and illuminate the surface waves with lasers.
為了檢測這種越輻射的輻射—這種效應被這樣稱謂，威福特納博士會在水中加入熒光染料，資助用激光照亮表面的水波。
The waves, often no bigger than one millimetre, can then be detected using high-definition cameras.
這些往往不會超過1毫米的水波，屆時可以通過高清度攝像機拍下來。
Stefano Liberati, Dr Weinfurtner's colleague in Trieste, reserves the greatest enthusiasm for another aspect of the experiment.
威福特納博士在里雅斯特的同事，斯特凡諾-萊伯拉蒂對這個試驗的另一個方面表現出了極大的熱情。
It might, if the researchers are lucky enough, offer clues to the nature of space-time.
如果研究者們運氣好的話，這可能會是研究空間-時間本質的一個線索。
Could the cosmic fabric be made up of discrete chunks, atoms of space if you like, rather than being continuous, as is assumed by relativity?
宇宙的會是由一塊塊的獨立物質，空間微粒—如果你愿意相信的話--組成，而不是像相對論認為連接在一起的嗎？
This problem has perplexed physicists for decades.
這個問題已經困擾了物理學家們數十年了。
Many suspect black holes hold the answer, because they are sites where continuous relativity meets chunky quantum physics.
他們中的許多人猜測，黑洞就是答案，因為黑洞是連續性相對論與厚實量子物理學都無法研究出真相的地方。
Waterborne holes serve as a proxy.
水面上的洞就代表了這種現象。
Water is, after all, made up of just such discrete chunks: molecules of H2O.
畢竟，水是由類似上述的一個個分散的物質組成：水分子。
As wavelengths fall—equivalent to rising energy—waves reach a point where the size of molecules may begin to influence how they behave.
隨著波長的減小—相當于光波能量的增加，當波長達到一定的值時，水分子的大小可能會開始影響水波的行為。
If Dr Weinfurtner and Dr Liberati observe some strange behaviour around their event horizons, theorists will be thrilled.
如果威福特納博士和萊伯拉蒂博士能夠觀察到這些水波的黑洞邊界周圍的一些奇怪表現時，那么理論學家們會興奮不已。
and home-brewed universes
自家制作的宇宙
Even benchtop black holes, though, are nothing compared with the ambitions of Igor Smolyaninov of the University of Maryland.
即使是桌面上的黑洞，但是也無法與馬里蘭大學的伊戈爾-斯莫利亞尼諾夫的雄心相比。
For Dr Smolyaninov wants to create entire universes.
因為，斯莫利亞尼諾夫想創造一個完整的宇宙。
The way light travels through the four dimensions of space-time is mathematically akin to how it moves through metamaterial.
從數學的角度看，光穿越四維空間的方式與它穿透超材料的方式很接近。
These are substances with features measured in nanometres, or billionths of a metre, which let them bend light in unusual ways.
這些材料是以納米為單位，或者是以一米的十億分之一為單位的特別物質，所以可以以特別的方式改變光的方向。
For example they can force light to skirt along the outside of an object, hiding it from view as if behind an invisibility cloak.
比如說，它們可以讓光波繞開一個物體的外圍，就好像隱藏在一個隱形斗篷的后面，讓人無法看到它。
Space-time, too, bends light, in ways that depend on how mass is distributed within it.
時空也同樣可以改變光的方向，改變方式取決于這個空間質量的分配方式。
In principle, then, metamaterials ought to be able to mimic how light moves not just through the space-time scientists on Earth are familiar with, but also other possible space-times to which they do not, and never will, have access.
原則上講，超材料應該不僅能夠模擬地球科學家們熟悉的光波穿越時空，而且可以模擬光穿越其它可能存在的，地球科學家們無法觸及，也可能永遠無法打開的時空。
Two years ago Dr Smolyaninov suggested an experiment with various metamaterials, corresponding to universes with different properties lashed together into a home-brewed multiverse.
兩年前，斯莫利亞尼諾夫曾建議用不同的超材料進行試驗，相當于把擁有各種特性的宇宙集中到了自家創造的宇宙中。
In a paper to be published inOptics Express, he and his colleagues report that they have succeeded.
他和他的同事在光學快報上發表了一篇論文，稱他們的試驗取得了成功。
Rather than fine-tune metamaterial to exact specifications, which is finicky and expensive, the researchers used nanoparticles of cobalt, which are relatively easy to get hold of, and suspended them in kerosene.
研究者并沒有對超材料的具體規格進行微調，因為這樣既繁雜又增加成本，他們使用了鈷的納米粒子，這個相對而言容易得到，可以把它們暫時存放在煤油中。
They then applied a magnetic field which, thanks to cobalt's ferromagnetic nature, arranged the particles into thin columns.
然后，根據鈷的鐵磁性，他們應用一個磁場把這些粒子安置到了薄薄的柱子中。
In space-time terms the length of the columns is time and the two axes perpendicular to the length represent the three spatial dimensions in a real universe.
在時空的術語中，這種柱子的長度就表示，時間和兩個垂直于距離的軸代表著真實宇宙中的三維空間。
To build his multiverse, Dr Smolyaninov added slightly less cobalt to the kerosene, about 8% by volume, than was needed to maintain stable nanocolumns.
為了創建他的多元宇宙，斯莫利亞尼諾夫博士在煤油中加了些鈷，大概是總體積的8%，這比穩定納米柱的需要量略少。
Natural fluctuations in the density of the fluid then lead to the spontaneous erection of transient nanocolumns—equivalent to space-times popping up only to fizzle and re-emerge elsewhere in the multiverse.
在這個液體濃中的自然流動，會導致臨時納米柱的自發性的直立—相當于時空突然出現，卻只能以失敗結束，但是會在這個多元宇宙中的某個其它地方再次出現。
They could be detected by their effect on polarised light shone through the material.
要想探測到它們，可以通過它們在極化光通過物質時所施加的影響來檢測。
Whether all this ingenuity unravels any cosmic truth is uncertain.
所有這種獨出心裁是否能解開宇宙的真相，還不確定。
Cliff Burgess, a theorist at Perimeter Institute for Theoretical Physics in Ontario, has his doubts.
安大略省周邊物理理論研究所的克里夫-伯吉斯是一位理論學家，他還對此存有疑問。
But he thinks that such experiments are nevertheless worth pursuing.
但是，他認為，這些試驗還是值得一試的。
Like tap-dancing snakes, he says, the point is not that they do it well, it is that they do it at all.
他說，就像跳踢踏舞的蛇一樣，關鍵不是他們做得非常好，而是他們已經在做了。
