Wonders of the Universe. Andrew Cohen

but these soon departed to reveal dusty, unmistakably African landscapes and breathtaking vistas.

      Our camp is idyllic by the strictest definition of the word. Khaki tents nestle beneath acacia trees in the shadow of a giant copper-striped rock populated by a tribe of itinerant baboons intent on stealing our tape stock. Fortunately, we are guarded by the Masai, who, all cliché aside, are as tough as hell and scare not only the baboons but also the Serengeti lions and the BBC in equal amount.

      So much for the visuals; the reason for the resonance of this place lies in the deep past of this dramatic landscape of life. The Great Rift Valley is not just an extraordinary geological feature that stretches 6,000 kilometres (3,700 miles) from Syria to Mozambique; there is more to this place because the echoes of the history of humanity ring louder across these plains than anywhere else on the planet. To walk this earth is to walk in the footsteps of the true ancients. Ancestors like Lucy, one of the most important fossils ever discovered, a skeleton uncovered in the Ethiopian section of the valley in 1974 by Donald Johanson. Lucy is 3.2 million years old; the remains of an Australopithecus, an extinct hominid species many anthropologists believe links directly to our own heritage. Further down the rift, in Tanzania, more closely related human ancestors have been discovered. In the early 1960s, Mary and Louis Leakey unearthed the remains of the earliest known species of our genus, Homo. Homo habilis is thought to have been a direct descendant of Australopithecus, and may be the first of our ancestors to have made tools. It’s all in the mind, I suppose, but sitting around a fire on a cool evening in the Serengeti I felt as if I had returned to the place where I had been born after many years away. There is something about geographic origins that resonates, over a lifetime or a hundred thousand lifetimes

FINDING ANDROMEDA

      The connection between the history of the Serengeti and the science of light is a dimly glowing jewel in the velvet Tanzanian sky. With no cities to pollute the darkness, the plains of the African night are bathed in the light of a billion suns. The glowing arc of the Milky Way Galaxy dominates the sky, a silver mist of stars so numerous, they are impossible to count. Every single point of light and every patch of magnificent mist visible to the unaided human eye have as their origin a star in our own galaxy, or the misty clouds known as the Magellanic clouds – two small dwarf galaxies in orbit around the Milky Way. All except for one…

      To find it, you first need to recognise the distinctive ‘W’ shape of the constellation of Cassiopeia. It sits on the opposite side of Polaris, the North Star, to the constellation Ursa Major, otherwise known as The Great Bear or The Plough. Cassiopeia, being so close to Polaris, is a constant feature in the northern skies – it simply rotates around the pole once every twenty-four hours and never sets below the horizon at high latitudes. If in your mind’s eye you put the ‘W’ of Cassiopeia upright, then just beneath the rightmost ‘V’ you will be able to see quite a large, faint, misty patch in the sky. It is comparable in brightness to most of the stars surrounding it, although dimmer than the bright stars of Cassiopeia. This unremarkable little patch is, in my view, the most intellectually stunning object you can see with the naked eye, because it is an entire galaxy beyond the Milky Way. It is called Andromeda, and is our nearest galactic neighbour. It is home to a trillion suns, over twice as many stars as our galaxy. It is roughly twenty-five million million million kilometres (fifteen million million million miles) away, and here is the connection.

      This Homo habilis skull was found in the Olduvai Gorge in Tanzania and is believed to be around 1.8 million years old.

       PASCAL GOETGHELUCK / SCIENCE PHOTO LIBRARY

      Two and a half million years ago, when our distant relative Homo habilis was foraging for food across the Tanzanian savannah, a beam of light left the Andromeda Galaxy and began its journey across the Universe. As that light beam raced across space at the speed of light, generations of pre-humans and humans lived and died; whole species evolved and became extinct, until one member of that unbroken lineage, me, happened to gaze up into the sky below the constellation we call Cassiopeia and focus that beam of light onto his retina. A two-and-a-half-billion-year journey ends by creating an electrical impulse in a nerve fibre, triggering a cascade of wonder in a complex organ called the human brain that didn’t exist anywhere in the Universe when the journey began

      AlltheSky.com

      On autumn and winter evenings, the spiral galaxy M31 (Andromeda) is visible to the naked eye in northern skies. To locate it, you first need to identify Cassiopeia, and its distinctive ‘W’ shape. Using the point of the ‘V’ on the right-hand side as an arrow, look beneath it for a large misty patch in the sky.

       NASA

      Observing the night skies with the naked eye can only take us so far on our journey to discover and understand the wonders of our universe. Advances in technology have brought us crafts that can take humans on expeditions beyond our planet, but also sophisticated equipment that has changed our view of the Universe entirely.

      The Hubble Space Telescope being repaired by an astronaut from Endeavour. This eleven-tonne telescope has allowed astronomers and scientists to see further into our universe than ever before.

       NASA

THE HUBBLE TELESCOPE

      The naked eye can only allow us to travel back in time to the beginnings of our species; a mere 2.5 million light years away. Until recently, Andromeda was the furthest we could look back unaided, but modern, more powerful telescopes now enable us to peer deeper and deeper into space, so that we can travel way beyond Andromeda, capturing a bounty of messengers laden with information from the far distant past.

      In the history of astronomy, no telescope since Galileo’s original has a greater impact than the eleven-tonne machine called Hubble. The Hubble Space Telescope was conceived in the 1970s and given the go-ahead by Congress during the tenure of President Jimmy Carter, with a launch date originally set for 1983. Named after Edwin Hubble, the man who discovered that the Universe is expanding, this complex project was plagued with problems from the start. By 1986, the telescope was ready for lift off, three years later than planned, and the new launch date was set for October of that year. But when the Challenger Space Shuttle broke apart seventy-three seconds into its launch in January 1986, the shutters came down not only on Hubble, but on the whole US space programme. Locked away in a clean room for the next four years, the storage costs alone for keeping Hubble in an envelope of pure nitrogen came to $6 million dollars a month.

      With the restart of the shuttle programme, the new launch date was set for 24 April 1990 and, seven years behind schedule, shuttle mission STS-31 launched Hubble into its planned orbit 600 kilometres (370 miles) above Earth. The promise of Hubble was simple: images from the depths of space unclouded by the distorting effects of Earth’s atmosphere. A new eye was about to open and gaze at the pristine heavens, but within weeks it was clear that Hubble’s vision was anything but 20:20. The returning images showed there was a significant optical flaw, and after preliminary investigations it slowly dawned on the Hubble team that after decades of planning and billions of dollars, the Hubble Space Telescope had been launched with a primary mirror that was minutely but disastrously misshapen. Designed to be the most perfect mirror ever constructed, Hubble’s shining retina was 2.2 thousandths of a millimetre out of shape, and as a result its vision of the Universe was ruined.

      Such was the value and promise of Hubble that an audacious mission was immediately conceived to fix it. This was possible because Hubble was designed to be the