China made history by successfully shooting a hack-proof quantum signal from space that smashed previous records on the transmission of such entangled particles. Beijing used its new quantum communication satellite, Micus, which it launched last August to transmit the quantum signal to Earth over an unprecedented 1,200 Kms.

The experiment is considered a massive step forward in paving the way for highly secure and 'unhackable' communications in the near future. "We have demonstrated the distribution of two entangled photons from a satellite to two ground stations that are 1,203 kilometres apart," Juan Yin, lead author and physicist at the Science and Technology University of China in Shanghai said. "Long-distance entanglement distribution is essential for the testing of quantum physics and quantum networks."

The research paper was published in Science.

What is quantum entanglement and how does it work?

Until recently quantum entanglement was explored only in theory. The complex physics phenomenon was once even scoffed at by Albert Einstein, who dismissed it as "spooky action at a distance."However, new research now indicates that not only is quantum entanglement possible theoretically but it can also be demonstrated practically and could be the harbinger of a complete quantum satellite communication network.

Quantum entanglement is a phenomenon that allows particles in different locations to sync and affect each other, in such a way as to having a single particle simultaneously existing in multiple locations. Particle entanglement can be an ideal way by which to transmit data securely as it deters anyone from intercepting it. In other words, hackers wouldn't be able to extract data or even observe it, without altering the state of the particle, which in turn would alert the party receiving the data that it has been interfered with.

Chinese scientists split a laser beam shot out of from Micus into two polarised states. One of these beams was then used to transmit the entangled particles, while the other beam functioned as a photon receiver. The photons successfully maintained their entangled state, despite the vast distance they needed to travel and were successfully received by the research team's ground station on Earth.

China's scientists said that this method of transmitting entangled particles via satellite is "12 and 17 orders of magnitude higher" than previous methods of entanglement distribution via optical fibre and open air. Those methods risk the particles being degraded when journeying long distances. In other words, space's unique inhospitable nature is ideal for transmitting quantum signals.

Although scientists still need to figure out how to go about developing a quantum communication satellite network, as well as ascertain how actual data and not just single photons can be transmitted, China's successful experiment in transmitting entangled photons is the first and significant step toward developing highly secure, space-based quantum communication.