我国首颗“量子卫星”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，中国发射了世界首颗量子实验卫星，朝着建立一个防破解的空间量子通信网络迈进了一大步。

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.

这颗卫星以公元前5世纪我国著名的哲学家和科学家墨子的名字命名，墨子被誉为历史上进行光学试验的第一人。

开个小差，古代各位贤达的英文名你们都记得吗?孔子(Confucius)、孟子(Mencius)、老子(Lao Tzu)、墨子(Micius)、庄子(Chuang Tzu)。

量子卫星(quantum satellite)的真正身份仍然是通信卫星(communications satellite)，唯一不同的是，它是一颗靠量子来传递信息的通信卫星，可以向外发射量子。从500公里开外的太空向地面的实验站发射光量子，这是史无前例、世界首次。

量子卫星是中国科学院空间科学先导专项首批科学实验卫星之一，

其主要科学目标是进行四大实验任务：

星地高速量子密钥分发实验(experiment on high-speed quantum key distribution from space to earth)

广域量子通信网络实验(wide-area quantum communications network experiment)

星地量子纠缠分发实验(experiment on distribution of quantum entanglement from space to earth)

地星量子隐形传态实验(experiment on quantum teleportation from earth to space)

量子通信是迄今唯一被严格证明为无条件安全的通信方式。因为量子通信的密码不是预先设定好的，而是在传输过程中随机形成的。

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

卫星会将一对对纠缠光子拆分后发射到位于中国和奥地利的基站。

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.

这种特殊光束有很多特质，其中一个就是所谓的“观测者效应”，其量子状态一旦发生变化就会被观测到。

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，如果卫星在量子状态下编写了加密密钥，任何截取行为都会被发现。密钥就会随之发生变化，从而失效。