我國首顆“量子衛(wèi)星”升空

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China launched the world's first quantum experiment satellite on Tuesday, taking a big step in building a space-based quantum communication network that would be virtually uncrackable.

8月16日，中國發(fā)射了世界首顆量子實驗衛(wèi)星，朝著建立一個防破解的空間量子通信網絡邁進了一大步。

The satellite has been named "Micius" after a 5th century B.C. Chinese philosopher and scientist who is credited as being the first person in history to conduct optical experiments.

這顆衛(wèi)星以公元前5世紀我國著名的哲學家和科學家墨子的名字命名，墨子被譽為歷史上進行光學試驗的第一人。

開個小差，古代各位賢達的英文名你們都記得嗎?孔子(Confucius)、孟子(Mencius)、老子(Lao Tzu)、墨子(Micius)、莊子(Chuang Tzu)。

量子衛(wèi)星(quantum satellite)的真正身份仍然是通信衛(wèi)星(communications satellite)，唯一不同的是，它是一顆靠量子來傳遞信息的通信衛(wèi)星，可以向外發(fā)射量子。從500公里開外的太空向地面的實驗站發(fā)射光量子，這是史無前例、世界首次。

量子衛(wèi)星是中國科學院空間科學先導專項首批科學實驗衛(wèi)星之一，

其主要科學目標是進行四大實驗任務：

星地高速量子密鑰分發(fā)實驗(experiment on high-speed quantum key distribution from space to earth)

廣域量子通信網絡實驗(wide-area quantum communications network experiment)

星地量子糾纏分發(fā)實驗(experiment on distribution of quantum entanglement from space to earth)

地星量子隱形傳態(tài)實驗(experiment on quantum teleportation from earth to space)

量子通信是迄今唯一被嚴格證明為無條件安全的通信方式。因為量子通信的密碼不是預先設定好的，而是在傳輸過程中隨機形成的。

The satellite will create pairs of so-called entangled photons, beaming one half of each pair down to base stations in China and Austria.

衛(wèi)星會將一對對糾纏光子拆分后發(fā)射到位于中國和奧地利的基站。

This special kind of laser has several curious properties, one of which is known as "the observer effect" - its quantum state cannot be observed without changing it.

這種特殊光束有很多特質，其中一個就是所謂的“觀測者效應”，其量子狀態(tài)一旦發(fā)生變化就會被觀測到。

So, if the satellite were to encode an encryption key in that quantum state, any interception would be obvious. It would also change the key, making it useless.

因此，如果衛(wèi)星在量子狀態(tài)下編寫了加密密鑰，任何截取行為都會被發(fā)現。密鑰就會隨之發(fā)生變化，從而失效。