JIUQUAN, CHINA — China this week launched the world’s first quantum communications satellite, which Beijing hopes could lead to a hack-proof communications system. <br /> <br />The Quantum Experiments at Space Scale (QUESS) satellite, launched on a Long March-2D rocket, is nicknamed Micius, in reference to a fifth century B.C. Chinese philosopher. <br /> <br />Quantum communication relies on a phenomenon known as quantum entanglement, in which particles influence each other, even when separated by great distances. <br /> <br />A photon can be split into pairs of entangled photons by a laser beam. The entangled photons influence one another, so that if one photon changes its state, the other reacts instantly by taking up a state relative to the photon. The photons remain entangled even when one is far away. <br /> <br />Quantum communication could greatly enhance security, as any interception of the information will necessarily alter the state of the photons, thus giving away the eavesdropper. <br /> <br />According to the Chinese government’s Xinhua news agency, scientists will test the technology during the two-year mission by conducting quantum communications between Beijing and Urumqi in China’s far west.
