 What if I were to tell you that the way we do business over the Internet today is the technological equivalent of sending our information with postcards? The Internet has had a huge economic and social impact on the developed nations. We've overturned norms which have existed for centuries before it. Despite these technological advances, huge proportion of the globe still don't have the network resources to take advantage of these technologies. Industry is looking to solve these problems by launching thousands of satellites, Boeing, SpaceX, OneWeb, they're all looking at launching these mega constellations. Usually what I do involves developing telescopes to receive light from distant stars and galaxies. But I thought instead of doing this, we could turn this around and instead use the same telescopes to transmit information, not galactically but globally. Not only would we be able to transmit a vast amount of data, but I wondered, could we use the very quantum nature of light to encrypt the communication signal itself? A lot of work has been done on developing quantum encryption in fibre optics. But can we do this over free space, between points on the ground or from ground to space? The problem with launching thousands of satellites is that this creates tens of thousands of pieces of space debris. These satellites themselves rely on radio communications and this has a very limited bandwidth because there's only a limited number of radio frequency slots available. The encryption that we're used to transmit data around the world today relies on hard to solve mathematical problems. This encryption only works because we can't solve these problems fast enough for it to be any of use. Websites that use this technology today are safe for many years using these techniques. But with the rise of quantum computers, the idea of secure encryption can go away. These computers can solve these problems quite easily because they can solve many simple calculations simultaneously. Instead, what we can do is we can use quantum encryption. We can make a quantum encryption key by carefully measuring and controlling properties of a laser, such as its polarization. We can manipulate this property by randomising it with a truly random quantum number generator. This allows us to provide an unlimited number of quantum encryption keys. These keys can be generated at a very high rate. If we use them only once, we can have an unbreakable cipher. This allows us to have an opportunity to have a very high bandwidth global communication network secured by quantum encryption. A number of research institutes are working on this technology. Recently, a Chinese satellite demonstrated with a world record connecting Austria with China with a quantum link. While this is a very impressive technology demonstration, it's limited in the amount of data it can transmit because each bit of information is transmitted with a single photon once per second. Instead, if we use a continuous stream of photons, we can transmit a much higher data rate. And you have a lot of expertise in achieving this with quantum links over fiber optics. The problem with transmitting this information to satellites is the atmosphere. It's not the absorption, but it's the distortion that it causes. We use our adaptive optics technologies on the ground to correct for the atmospheric distortions to transmit and receive these quantum signals. This allows us to achieve a much higher data rate. We're developing a quantum satellite which will allow us to demonstrate our encryption. This satellite will be the first stepping stone towards making a global secure quantum network. The ANU also has other technology. We have the world record for the longest storage time for a quantum memory. This technology would allow us to relay data securely around the world with only a handful of satellites. We would also remove the need to rely on trusting the hardware in space. This means that any nation around the world can make this hardware and deploy it anywhere in the world. Having a secure global network will drive economic and social benefit to developing nations. This will allow a whole new area of the world to experience advanced technologies that we have today, rather than doing internet banking via postcards, the technological equivalent that most of the world uses. Thank you.