People and robots have gone beyond Earth to send back images of our universe. Robin McKie takes a photographic voyage from the dark side of the Moon to Mars
For astronaut Frank Borman it was simply "the most beautiful, heart-catching sight of my life, one that sent a torrent of nostalgia, of sheer homesickness, surging through me." Borman was describing the sight of the Earth, rising over the lunar surface, from the Apollo 8 capsule that he was sharing with fellow astronauts Jim Lovell and Bill Anders in December 1968. Their craft was the first to carry humans into orbit round the Moon, and that image of Earthrise, captured by Anders on a Hasselblad camera, caused a sensation when it was published in magazines and newspapers after the astronauts' return.
For the first time, humans could see their planet as a world that was "whole and round and beautiful and small", as the poet Archibald MacLeish put it. Many credit the Apollo 8 photograph of the Earth – hanging like a fragile blue Christmas ornament – as being the most important environmental image ever taken. "I clearly remember my first sight [of the photograph], says Sir David Attenborough. "I suddenly realised how isolated and lonely we are on Earth."
Earthrise remains the greatest space photograph ever taken, most observers would argue, though it is certainly not the only jaw-dropping picture to be brought back by astronauts or transmitted to Earth by robot spacecraft. Indeed, the list of iconic images is almost endless: Buzz Aldrin standing on the Moon with Neil Armstrong's reflection on his space helmet; a photograph of a single boot-print left on the moon's surface by the Apollo 11 astronauts; images from the Voyager and Pioneer probes that revealed the planets and moons of the outer solar system in glorious, colourful detail; and views of distant stars and galaxies provided by the Hubble Space Telescope. And that is just the work of NASA.
The Russians have an equally impressive history in this field, having pioneered it in October 1959 when their Luna III probe returned the first images of the far side of the Moon. Other Soviet space photographs include the first views from the surface of Venus sent back by the Venera probes, and the sight of cosmonaut Alexei Leonov floating outside his Voskhod 2 capsule as he made the first space walk in history in 1965.
For the public, these early photographs – although sometimes scratchy and poorly detailed – were seen as proof that humanity was on the threshold of the conquest of space. Indeed, without those early pictures, it is unlikely that US citizens would have supported the extraordinary cost of the country's space programme – in particular the Apollo moon landings. This last point was certainly appreciated by NASA, which went to great pains to ensure its craft sent back images that were not just scientifically useful, but also had good PR appeal. This often involved an ingenuity that is perhaps hard
to appreciate in an era of easy-to-use digital photography.
Consider the example of the unmanned US Lunar Orbiters that mapped the Moon in the sixties. These robot spaceships automatically developed their own film, scanned the resulting images electronically, and beamed them back to Earth. Similarly the US Surveyor craft, which touched down on the Moon to survey the terrain ahead of the Apollo missions, were equipped with TV cameras that could resolve objects as small as one millimetre, and – using a special periscope – could survey a 360° horizon. Some of the Surveyor moon panoramas are to be offered by Bonhams New York in December, and make compulsive viewing.
It was only later that space photographs were seen in a less triumphant, more reflective, manner – particularly in the wake of that picture of Earthrise. As scientists later pointed out, the blue disc of Earth, half in shadow, is sharply defined in Anders' photograph. There is none of the blurring that might be expected from the blanket of oxygen and nitrogen that envelops our planet. Our atmosphere, which protects and sustains all life on Earth, is too thin to be seen from the Moon.
It was a point seized on by the environmental movement, then in its infancy, as a stark demonstration of the frailty of the biosphere that keeps us alive. Viewed from the Moon, our planet looks lonely, while human settlements are invisible. "It was a rebuke to the vanity of humankind," says the UK space historian Robert Poole.
Our vulnerability as a species was further exposed by missions like the Voyager 1 spacecraft, that was launched on its journey to the outer planets in 1977. Not long after it was sent aloft, its cameras were turned back to Earth to snap the first long-range photograph of our planet and the Moon together.
Thirteen years later, as Voyager reached the edge of the solar system, its instruments were again pointed back towards home, which was by now 3.7 billion miles away. Earth now appeared a single pixel, a minuscule blue dot, as the US scientist Carl Sagan later described it. "Consider that dot. That's here. That's home. That's us," Sagan pointed out. "On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world."
Since then, space photography has produced even greater riches, particularly with the launch of the Hubble Space Telescope in 1990. Its visions of gleaming nebulae, remote galaxies, stars being born and stars in their death throes have entranced both the scientific world and the public, and have probably done more to attract young people to careers in research than any other human venture.
Certainly, they have eclipsed recent manned space endeavours. As the Astronomer Royal, Lord Rees, has pointed out, the international space station only makes headlines today when its toilets get blocked. By contrast, panoramas of deep space provided by the Hubble continue to fill newspapers and dominate TV news programmes.
Curiosity, the car-sized robot rover that is now trundling across the Martian surface, looks set to maintain this tradition. It carries a total of 17 cameras, bolted to different parts of its structure, that provide images of Mars from every conceivable angle. Curiosity has already sent back pictures of a half-familiar world of washed-out river beds, crumbling hills and fragmented landscapes that look eerily like places on Earth. This was a world whose surface may once have been bathed by seas and lakes, but which has slowly been turned into a dead, dried-out desert some time over the past few billion years.
The contrast between Mars and Earth is intriguing, and demonstrates the real value of space photographs. It is not what they say about space or about other worlds, but what they say about Earth. That is what really touches us, a point best summed up by T.S. Eliot in the last of the Four Quartets:
"We shall not cease from exploration
And the end of all our exploring
Will be to arrive where we started
And know the place for the first time."
Robin McKie is Science Editor of The Observer.