China launched the world』s first quantum communications satellite (量子通信衛星) from Jiuquan Satellite Launch Center (酒泉衛星發射中心) on August 16。 It was a major step in the country』s attempt to be in a leading position in quantum research, which could lead to new, completely secure methods of transmitting information。
The 600-kilogram satellite is nicknamed Micius (墨子), a Chinese philosopher and scientist in the fifth century B.C。 It is expected to circle the earth every 90 minutes after entering orbit (軌道) at an altitude of about 500 kilometers。 Researchers hope to use the satellite to send communications from space to earth and establish secure transmissions between two ground sites。 China has previously announced the construction of a quantum link between Beijing and Shanghai to be used by government agencies and banks。
Traditional communications satellites send signals using radio waves while a quantum communications satellite uses a crystal (結晶體)。 The crystal produces a pair of entangled photons (互相糾纏的光子)。 They remain entangled even if one is transmitted over a large distance。 It is hence impossible to wiretap (竊聽) or crack the information transmitted through it。
Cybersecurity (網路安全) has been a major focus in recent years around the world in the wake of Edward Snowden』s (愛德華•斯諾登) revelations of widespread surveillance (監視) by the U.S。 Quantum messaging could become a major defense against hackers and have applications ranging from military and government communications to online shopping。
Scientists and security experts in many countries are studying the quantum technology。 The biggest challenge is being able to accurately orient the satellite to a location on Earth where it can send and receive data without being affected by any disturbances in Earth』s atmosphere。
China has spent years researching into quantum technology and developing the satellite and other uses for it。 The launch is a major triumph for the country。 Pan Jianwei (潘建偉), chief scientist on the satellite project, said the launch proved China was no longer a follower in information technology, but 「one of the leaders guiding future IT achievements。 」