He became a global star - sharing stunning images of earth - from space. And, today, Chris Hadfield was in the region, launching his new book.
The astronaut took photos from the International Space Station - and put them on Twitter last year.
We caught up with Chris Hadfield and asked him what it was like looking down to Earth from space!
A new way of measuring precise distances to galaxies tens of millions of light years away has been developed by scientists from the University of Southampton. Dr Sebastian Hoenig has created the method which is similar to what land surveyors use on earth, by measuring the physical and angular, or "apparent", size of a standard ruler in the galaxy, to calibrate the distance from this information. The research,which is published in the journal Nature, was used to identify the accurate distance of the nearby NGC 4151 galaxy, which wasn't previously available. The galaxy NGC 4151, which is dubbed the Eye of Sauron by astronomers for its similarity to the film depiction of the eye of the character in The Lord Of The Rings, is important for accurately measuring black hole masses. Recently reported distances range from 4 to 29 megaparsecs, but using this new method the researchers calculated the distance of 19 megaparsecs to the supermassive black hole.
One of the key findings is that the distance determined in this new fashion is quite precise - with only about 10% uncertainty. In fact, if the current result for NGC 4151 holds for other objects, it can potentially beat any other current methods to reach the same precision to determine distances for remote galaxies directly based on simple geometrical principles. Moreover, it can be readily used on many more sources than the current most precise method. Such distances are key in pinning down the cosmological parameters that characterise our universe or for accurately measuring black hole masses. Indeed, NGC 4151 is a crucial anchor to calibrate various techniques to estimate black hole masses. Our new distance implies that these masses may have been systematically underestimated by 40%.
A university spokesman explained that the method involves measuring the dust rings that form around supermassive black holes. The hot dust forms a ring around the supermassive black hole and emits infrared radiation, which the researchers used as the ruler. However, the apparent size of this ring is so small that the observations were carried out using infrared interferometry to combine WM Keck Observatory's twin 10m telescopes, to achieve the resolution power of an 85m telescope. To measure the physical size of the dusty ring, the researchers measured the time delay between the emission of light from very close to the black hole and the infrared emission. This delay is the distance the light has to travel (at the speed-of-light) from close to the black hole out to the hot dust. By combining this physical size of the dust ring with the apparent size measured with the data from the Keck interferometer, the researchers were able to determine a distance to the galaxy NGC 4151. Dr Hoenig, together with colleagues in Denmark and Japan, is currently setting up a new programme to extend their work to establish precise distances to a dozen galaxies in this new way and use them to constrain cosmological parameters to within a few per cent. In combination with other measurements, this will provide a better understanding of the history of expansion of our universe.
The skies above the UK have been brought to life like never before in a timelapse video capturing a day of air traffic in less than three minutes.
Created from actual radar data showing over 7,000 flights, the video graphically illustrates the daily task facing air traffic controllers and the airspace features that help make it all work.
Created by air traffic management company, NATS, the video takes viewers on a unique tour of some of the key features of UK airspace – from the four holding stacks over London and the military training zones above Wales, to the helicopters delivering people and vital supplies to the North Sea oil and gas rigs.
It finishes with an overview of the structure of UK airspace, highlighting the major air routes and showing how this ‘invisible infrastructure’ helps underpin the entire operation.
Matt Mills, NATS Head of Digital Communications, said:
We’ve made data visualisations in the past, but we wanted to now take people on a deeper journey into what makes UK airspace work and some of its important features.
Airspace might be the invisible infrastructure, but it is every bit as important as the airports and runways on the ground.
The British astronaut Major Tim Peake is to fly on a mission to the International Space Station in 2015. The European Space Agency (ESA) have launched a competition to find a name for the mission. The astronaut was born in Chichester in Sussex.
It's set to revolutionise the way we view the Earth from space. Two special cameras, designed and built by scientists in South Oxfordshire, have blasted off to the International Space Station, ready to reveal video and images of our planet, never seen before.
Cary Johnston took a trip to the final frontier.
The beach at West Wittering is a beautiful place to sunbathe and relax but it also provides the perfect training ground for prototype space rovers. A team from Surrey University have been testing the machines that could one day be sent to the moon or Mars. Charlotte Wilkins reports.
A science project organised by a school in Kent has reached new heights. Sevenoaks School holds a "science week" each year and this time they sent cameras up to the edge of space on a weather ballon - and despite a hiccup over Belgium, have brought back some amazing images.
David Johns explains, talking to physics teacher Elizabeth Harper-Clark, and Head of Science Graeme Lawrie.
A Dutch astronaut had to be rescued after his sailing boat got into difficulty off the Sussex coast. Physicist Wubbo Johannes Ockels - who flew into space in 1985 - was in his schooner when its engines failed seven miles from Newhaven last night. He was then towed to safety by Newhaven RNLI.