Posted on behalf of Elizabeth Gibney
For centuries, the only way to ‘see’ Earth whole was through globes and maps; its grandeur was merely glimpsed in mountain vistas or across a stretch of ocean. That changed in the 1940s, when the first images of the planet were snapped from rockets probing the border of space, 100 kilometres up. The imaginable became the visible.
Since then, satellites and spacecraft have beamed down shots from ever greater distances and in growing detail. Now Nature Video has captured the most iconic of these in the film Portraits of a Planet: Earth from Space.
These images have massively boosted science and technology – from weather forecasting to monitoring natural disasters, forest cover and climate change. And they have had a subtler psychological impact. Revealing this majestic, finite, vulnerable entity framed in blackness has elicited deep responses feeding into policy and culture.
The first images of Earth from space — from 1946 and 1947 — were black-and-white, grainy and remarkable partly for the fact that they happened at all. Both were taken by cameras retrofitted into the empty nosecone of V-2 rockets, long-range ballistic missiles the United States captured from Germany at the end of the Second World War.
In 1946, all that protected the film during the rocket’s crash landing was a steel cassette. When the photos were first projected onto a screen, “the scientists just went nuts”, recalled Fred Rulli, a member of the rocket’s recovery team, in an interview with Air and Space magazine. The following year’s project nudged the rocket further into space to 160 kilometres, bringing more detailed images clearly revealing Earth’s curvature.
The cold-war space race soon pushed cameras to greater heights. In 1957, the Soviet Union launched its first satellite, Sputnik; the US quickly followed suit. Three years later, the newly formed NASA put TIROS 1, its first weather satellite, into orbit, which sent video back to Earth using dual television cameras. TIROS 1 proved that such images could provide be used to monitor cloud formation, one of the first indications of the potential scientific power of satellites.
Human-crewed efforts began with the orbital missions of Yuri Gagarin in 1961 and John Glenn in 1962. But it was not until 24 December 1968 that Apollo 8 astronaut Bill Anders captured arguably the most iconic image of Earth. Later dubbed ‘Earthrise’, it was the first to show the planet from the perspective of another celestial body, as a luminous blue hemisphere rising above the Moon’s horizon. Anders had had to fight to get the long-lens camera on board, and deviated from the craft’s flight plan to get the snap (as he wrote in his obituary of Glenn earlier this year).
That awe-inspiring image was a shot across the bows of the cold war. It was also transformational for earthbound observers: the moniker ‘Spaceship Earth’ gained traction as people fully grasped the planet’s limits. Ultimately, ‘Earthrise’ supercharged the nascent environmental movement in the United States particularly, pioneered by environmentalists, scientists and thinkers such as Buckminster Fuller; and it proved a trigger for the US Earth Day, which launched in 1970.
That grassroots clamour, bolstered by works such as biologist Rachel Carson’s 1962 Silent Spring, had an influence on policy shifts at the federal level. The period from 1970 to 1973 saw the Environmental Protection Agency established and the US Clean Air Act, Clean Water Act and Endangered Species Act passed. Anders notes, “I wouldn’t say [Earthrise] was the only reason, but it certainly was an important reason motivating folks to take better care of our planet.”
The spectacular ’Blue Marble’ (see opening image), shot by the crew of Apollo 17 in 1972, fuelled further activism; it has been recreated by NASA many times over. The photograph captured Earth with the Sun behind the camera illuminating most of the globe, and from a distance (45,000 kilometres from the planet) no one has managed since.
Inspired by the potential of such astounding images, the US Geological Survey and NASA launched the first satellite in the Landsat programme in 1972, to chart Earth’s terrain in detail. Landsat satellites have documented burning oil wells in the first Gulf War, the impact of Hurricane Katrina and deforestation in the Amazon. Landsat’s false-colour rendering of Alaska’s Malaspina glacier, taken with a thermal imaging camera, is mesmerizingly beautiful.
In recent years, a parade of Earth monitoring and robotic exploration craft have added countless images to the file. In 2012, over 312 orbits, the Suomi National Polar-orbiting Partnership satellite built up a night-side image of Earth and its lit-up cities in ‘The Black Marble’. In 2013, NASA’s Cassini craft turned around in the outer Solar System to capture Earth — a pinprick of light — through the rings and moons of backlit Saturn.
Called ‘The Day the Earth Smiled’, that shot was taken from more than 1.2 billion kilometres away, making it a far cry from the images of our planet revealed some 70 years ago. But while the photographs have become ever more impressive, rarely are they as powerful as those first images of the ‘ground beneath our feet’ in its sublime entirety.
Elizabeth Gibney is a reporter on physics for Nature based in London. She tweets at @LizzieGibney.
For Nature’s full coverage of science in culture, visit www.nature.com/news/booksandarts.