“穿越”回过去真的有可能吗？

 “穿越”回过去真的有可能吗？

Are you weirded out by wormholes? Flummoxed by your flux¹ capacitor? Strap² yourself in for this time-travel primer.

你是不是觉得虫洞很神奇呢？对你不稳定的电容器感到疑惑？那么就来学些关于时空之旅的基本知识吧。

You will need: a basic knowledge of the theory of relativity and an open mind.

你需要：相对论的基本知识和开阔的思维。

Optional: a PhD in Physics.

可选项：拥有物理系博士学位。

Time-travel theories are riddled³ with paradoxes⁵ that may make your brain explode.

时空之旅的理论充满着矛盾，这将会让你的思维爆炸！

Step 1:

Brush up on your Einstein: His special theory of relativity revolutionized physics by suggesting that traveling into the future is possible. The idea is that time slows down when you're traveling at high speeds relative to stationary⁶ objects. So if you're in a spaceship going very close to the speed of light for five years, you could return home to find that it's 50 years later on Earth.

重温一下你有关爱因斯坦的知识：他的相对论是物理学的一个革命性理论——穿越到未来是有可能的。这个理论是这样的，如果你的移动速度相对于静止的物体非常快，那么时间就会减缓。因此，如果你坐在一艘接近光速的宇宙飞船上行驶5年，当你回到家发现这已经是50年后的地球了。

Even on a normal transatlantic flight, time slows down with speed. In one experiment using two atomic clocks, the clock sent into space fell 40 nanoseconds behind the one left on the ground.

即使在普通的飞行器上，时间也会随着速度的增加而减缓。用两个原子表做实验，送入太空的原子表比在地球上的这个原子表时间要落后400亿分之一秒。

Step 2:

Going back in time is a far trickier⁷ proposition – but might be possible if you could travel faster than the speed of light. Theoretically, if you were moving faster than light speed, you could receive a signal from Earth before it was even sent. Upon returning home, you’d find yourself back in time. The only problem is that traveling that fast is scientifically impossible – at least for now.

穿越回过去是一个很棘手的课题，但是如果你行驶的速度能超过光速这就有可能。理论上讲，如果你的移动速度大于光速，即使地球还没有发出信号，你都能接收到。当你回到家，你就会发现你回到了过去。唯一的问题就是移动速度超过光速在科学理论中是不可能的——至少现在不可能。

Step 3:

Make the quantum leap. Some quantum physicists⁹ believe that traveling back in time could be possible on a subatomic level. But unless you’re a subatomic particle, you’re out of luck.

让量子论飞越吧。一些量子物理学家相信在亚原子水平上穿越回过去是有可能的。但是除非你是一个亚原子颗粒，但很不幸你并不是。

Step 4:

Currently, the most popular time-travel theory involves wormholes, or tunnels through the fabric¹⁰ of space and time. If you were to tow one end of a wormhole into space close to the speed of light, then return that end to Earth, you would theoretically be able to enter the wormhole today and come out of the other end in yesterday.

当今最流行的时间旅行理论要属虫洞了，也就是构造空间和时间物质的小缝隙。如果你以接近光速被拖入虫洞的一端，然后从另一端回到地球，理论上你可以是今天进入虫洞但在昨天从虫洞里出来。

Be skeptical¹¹. Wormholes are so tiny and close so rapidly that it would take a great leap of science to be able to harness them for time travel.

值得怀疑的是虫洞如此小而且关闭的如此迅速，要驾驭虫洞去进行时间之旅，当今科学还需要很大的飞跃啊！

Step 5:

Get to know your granddad. The so-called Grandfather Paradox⁴ – going back in time and killing¹² your grandfather, thus preventing your own birth and making it impossible for you to travel back in the first place – has been used to help illustrate¹³ why backward time travel is impossible.

想去了解下你的祖父？所谓的祖父悖论——回到过去杀掉你的祖父，因此阻止了你的出生，因此让你不可能穿越回过去——这个悖论帮助我们阐明为什么穿越回到过去是不可能的。

Step 6:

Understand what's done is done. Most ideas about backward time travel include the “chronology protection conjecture,” meaning that nature would prevent you from changing the past. For example, you could try to go back in time to shoot your grandfather, but the gun wouldn't fire. It also means that all the embarrassing moments you'd love to erase¹⁴ are going to happen all over again.

要了解做过的事就是做过了。大部分有关于回到过去的理论，包括“时序保护假说”，意思就是大自然会组织你去改变过去。例如，你可能终于回到了过去，想杀了你的祖父，但是枪却没有开火。也就是说所有你想抹去的窘迫的瞬间依然会重新上演。

Step 7:

Open your mind to the “many-worlds” interpretation¹⁵. Some theorists have gotten around the rigid¹⁶ “whatever happened, happened” idea by claiming that every different action you take in the past splits off into a parallel universe. So there might be hope yet for preventing those embarrassing moments, at least in one universe.

开阔你的思维，试着想像“多重世界”的解释。有些理论在“无论发生了什么，已经发生了”的思想上非常严格，它们主张你在过去所有的动作会分裂进一个平行宇宙中。因此至少在我们的宇宙中，阻止这些窘迫的时刻发生可能是大家所希望的。

Did you know? Theoretical physicist⁸ Stephen Hawking¹⁷ once said, “Time travel might be possible, but if that is the case why haven’t we been overrun by tourists from the future?”

你知道吗？理论物理学家史蒂芬·霍金曾经说过：“时间旅行是有可能的，但是如果真能如此为什么还没有从未来来的游客来拜访我们呢？”

1 flux   

n.流动；不断的改变

参考例句：

• The market is in a constant state of flux.市场行情在不断变化。
• In most reactors,there is a significant flux of fast neutrons.在大部分反应堆中都有一定强度的快中子流。

2 strap   

n.皮带，带子；v.用带扣住，束牢；用绷带包扎

参考例句：

• She held onto a strap to steady herself.她抓住拉手吊带以便站稳。
• The nurse will strap up your wound.护士会绑扎你的伤口。

3 riddled   

adj.布满的；充斥的；泛滥的v.解谜，出谜题(riddle的过去分词形式)

参考例句：

• The beams are riddled with woodworm. 这些木梁被蛀虫蛀得都是洞。
• The bodies of the hostages were found riddled with bullets. 在人质的尸体上发现了很多弹孔。 来自《简明英汉词典》

4 paradox   

n.似乎矛盾却正确的说法；自相矛盾的人(物)

参考例句：

• The story contains many levels of paradox.这个故事存在多重悖论。
• The paradox is that Japan does need serious education reform.矛盾的地方是日本确实需要教育改革。

5 paradoxes   

n.似非而是的隽语，看似矛盾而实际却可能正确的说法( paradox的名词复数 )；用于语言文学中的上述隽语；有矛盾特点的人[事物，情况]

参考例句：

• Contradictions and paradoxes arose in increasing numbers. 矛盾和悖论越来越多。 来自辞典例句
• As far as these paradoxes are concerned, the garden definitely a heterotopia. 就这些吊诡性而言，花园无疑地是个异质空间。 来自互联网

6 stationary   

adj.固定的，静止不动的

参考例句：

• A stationary object is easy to be aimed at.一个静止不动的物体是容易瞄准的。
• Wait until the bus is stationary before you get off.你要等公共汽车停稳了再下车。

7 trickier   

adj.狡猾的( tricky的比较级 )；（形势、工作等）复杂的；机警的；微妙的

参考例句：

• This is the general rule, but some cases are trickier than others. 以上是一般规则，但某些案例会比别的案例更为棘手。 来自互联网
• The lower the numbers go, the trickier the problems get. 武器的数量越低，问题就越复杂。 来自互联网

8 physicist   

n.物理学家，研究物理学的人

参考例句：

• He is a physicist of the first rank.他是一流的物理学家。
• The successful physicist never puts on airs.这位卓有成就的物理学家从不摆架子。

9 physicists   

物理学家( physicist的名词复数 )

参考例句：

• For many particle physicists, however, it was a year of frustration. 对于许多粒子物理学家来说，这是受挫折的一年。 来自英汉非文学 - 科技
• Physicists seek rules or patterns to provide a framework. 物理学家寻求用法则或图式来构成一个框架。

10 fabric   

n.织物，织品，布；构造，结构，组织

参考例句：

• The fabric will spot easily.这种织品很容易玷污。
• I don't like the pattern on the fabric.我不喜欢那块布料上的图案。

11 skeptical   

adj.怀疑的，多疑的

参考例句：

• Others here are more skeptical about the chances for justice being done.这里的其他人更为怀疑正义能否得到伸张。
• Her look was skeptical and resigned.她的表情是将信将疑而又无可奈何。

12 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

13 illustrate   

v.举例说明，阐明；图解，加插图

参考例句：

• The company's bank statements illustrate its success.这家公司的银行报表说明了它的成功。
• This diagram will illustrate what I mean.这个图表可说明我的意思。

14 erase   

v.擦掉；消除某事物的痕迹

参考例句：

• He tried to erase the idea from his mind.他试图从头脑中抹掉这个想法。
• Please erase my name from the list.请把我的名字从名单上擦去。

15 interpretation   

n.解释，说明，描述；艺术处理

参考例句：

• His statement admits of one interpretation only.他的话只有一种解释。
• Analysis and interpretation is a very personal thing.分析与说明是个很主观的事情。

16 rigid   

adj.严格的，死板的；刚硬的，僵硬的

参考例句：

• She became as rigid as adamant.她变得如顽石般的固执。
• The examination was so rigid that nearly all aspirants were ruled out.考试很严，几乎所有的考生都被淘汰了。

17 hawking   

利用鹰行猎

参考例句：

• He is hawking his goods everywhere. 他在到处兜售他的货物。
• We obtain the event horizon and the Hawking spectrumformula. 得到了黑洞的局部事件视界位置和Hawking温度以及Klein—Gordon粒子的Hawking辐射谱。