The field of quantum communication - the science of transmitting quantum states from one place to another - has received
significant attention in the last few years owing to the discovery of quantum cryptography.
Quantum cryptography exploits a unique property of single particles, such as photons: they can exist in two separate states
- such as vertically polarized or horizontally polarized - or something in-between, known as a quantum superposition.
Upon measuring the state of a particle you instantly change this state, meaning an encryption key made of photons can be
passed between two parties safe in the knowledge that if an eavesdropper intercepts it, this would be noticed.
Quantum cryptography has been described as a way of creating "unbreakable" messages and has attracted the attention of
major technology companies, governments, banks and other security-focused clients.
The transmission of encryption keys over long distances still remains a significant challenge for scientists, however,
as the intensity of signals tends to weaken as they travel further because photons get absorbed or scattered off molecules.
Up until now, the furthest that quantum-communication signals have been sent is a few hundred kilometres, which would
realistically enable communication between just one or two cities.
There is one place, however, where scattering doesn't appear to happen - empty space. Jennewein and Higgins lead just
one of several teams around the world looking to take advantage of this by pursuing the concept of a quantum satellite.
A signal travelling from a ground station on Earth to a satellite would spend most of its time in the empty vacuum of
space - rather than in Earth's atmosphere, which is crowded with gas molecules - so the signal would travel a lot
further without weakening.
A satellite orbiting at around 32000 km above Earth would act as a kind of relay between two ground stations in a
way that allows them to establish a secure link by sharing an encryption key made of photons.
"With the prospect of global-scale quantum communications and fundamental quantum science within new, unexplored
regimes, the next few years are sure to be exciting," Jennewein and Higgins write.
In addition to the basic mass and power of the satellite itself, the team led by Jennewein and Higgins has been
studying the overall design features of the satellite and ground stations and has emphasized the need for them both
to be precisely aligned so they can be certain that what they are measuring correctly corresponds to the photons
that are prepared.
Dangerous Fast and Furious - Birth Of Africa's New Ocean
The only places where mid-ocean ridges appear above sea level are Ethiopia and Iceland.
Two new studies into the so-called “plumbing systems” that lie under volcanoes could bring scientists closer to
predicting large eruptions and reveal new information about where magma is stored and how it moves through the geological plumbing network.
6 Surprising Things Falling From The Sky
Stories of strange things falling from the sky date back a long time ago.
Over the years, there have been many bizarre instances recorded when things have fallen from the skies that simply do not belong there.
We have put together a list of some surprising things that fell from the heavens.
These are things you certainly don't expect to fall down on you...
Exploding Lakes - Horrifying Natural Phenomena
Exploding lakes are a terrible natural phenomena and very serious environmental problem.
These lakes are capable of killing thousands, even millions of people and animals living in the region...
Lake Nyos is an active crater lake that formed by an eruption about 5 centuries ago...
Antarctica's Mysterious Lake Untersee And Its Otherworldly Ecosystem
A research team has now returned to Lake Untersee to begin the first real studies of this incredible environment.
This new high-quality image details the conical stromatolites that have formed on top of a boulder at a depth of about 20 meters, other
cones can be seen populating the sloping bottom...
Solar Tornadoes As Wide As Five Earths Discovered
Solar tornadoes several times as wide as the Earth can be generated in the solar atmosphere, say researchers in the UK.
"This is perhaps the first time that such a huge solar tornado is filmed by an imager. Previously much smaller solar
tornadoes were found my SOHO satellite. But they were not filmed," says Dr. Xing Li, of Aberystwyth University.
Living Earth Simulator - Supercomputer Predicting The Future
In Douglas Adams book the Hitchhikers Guide to the Galaxy we encounter a machine called Deep Thought. It is the most powerful computer ever built. Deep Thought is capable of answering questions
concerning life, the Universe, and simply everything. Now scientists are planning to create a similar machine. It is called the Living Earth Simulator (LES).