The pictures of Earth against the blackness of space are perhaps the greatest legacy of the Apollo Program.
As Apollo 8 astronaut Bill Anders said on returning from the first voyage beyond Earth’s orbit: "We came all this way to explore the Moon, and the most important thing is that we discovered the Earth."
'Earthrise', captured by Bill Anders during Apollo 8, and 'The Blue Marble', captured by the Apollo 17 crew, are not just famous pictures of Earth from space, they are among the most widely reproduced photos of all time.
Apollo pictures of Earth from space remain the most eye-catching.
The contrast of the delicate blue and white sphere with the inhospitable void and barren Moon became the iconic image for the growing environmentalist movement.
And the image of a world without borders helped people see a world more united than divided.
But why haven’t Apollo pictures of Earth from space, great as they are, been bettered by others since then?
A key reason is that since the Apollo Program, astronauts have got no higher than low-Earth orbit – less than 1% of the way to the Moon.
Taking a photo of Earth from there is like taking a portrait of a friend with the camera less than a centimetre from their face.
You might be able to capture the texture of their skin, but any attempt to render their entire face would be distorted.
And while some of the autonomous spacecraft destined for other worlds turned their sensors around for a parting shot, their cameras weren’t designed for the job, producing inferior images.
In contrast, as the Apollo astronauts travelled out towards the Moon, they reached the perfect distances for capturing pictures of Earth from space.
NASA had provided some of the world’s best equipment for photographing Earth: Hasselblad 500 EL cameras, Zeiss lenses and 70mm Kodak Ektachrome film.
They were thus able to faithfully record Earth’s true colours as they appeared to the human eye.
If we look at this image from Apollo 16 (above), what we see isn’t the bright green and blue circle that has come to represent our planet.
Instead, it is primarily a world of blue and white, with brown continents and just a suggestion of muted green in places of lush vegetation:
"I was able to look out the window to see this incredible sight of the whole circle of the Earth," said Apollo 16’s Charlie Duke.
"Oceans were crystal blue, the land was brown, and the clouds and the snow were pure white. And that jewel of Earth was just hung up in the blackness of space."
Restoring Apollo Earth photographs
Struck by the beauty of the most famous of these Apollo pictures of Earth from space, I wondered if there were more.
So began a journey that would occupy my evenings over the next three years.
I hunted through all 18,000 Hasselblad photos from the Apollo missions for the best images that time forgot, and digitally restored them to bring out their full glory.
It was these lost images of Apollo that were the real rivals to the most well-known ones.
One of my favourite hidden gems is the crescent earthrise from Apollo 12 (above).
It was captured by Richard Gordon as he circled the Moon alone in the Command Module, awaiting his companions’ return.
It was overlooked for years as the original negative was poorly exposed and washed out.
But as soon as I properly adjusted the levels, it took my breath away, revealing a haunting scene with an even more graceful and fragile view of the Earth and Moon than Apollo 8’s famous ‘Earthrise’ photo.
I chose it for the cover of my book The Precipice, which looks at humanity’s own fragility in these challenging times.
Another one of my favourite pictures of Earth from space is from Apollo 13.
Two days in, the craft suffered a dramatic explosion, venting the contents of the Service Module’s oxygen tanks into space, leaving the Command Module without enough breathable air to get home.
This ethereal photo (below), at first appears to show the Moon, but it is really the crescent Earth amidst the ghostly reflections of the Lunar Module.
They were 80,000km and seven hours away from safety – this photo captures this stolen moment, yearning for home.
It was an absolute treat to be able to play a role in reviving these images. There are so many more great photos that have never been restored.
But, since raw scans of all the images are publicly available, anyone can try their hand.
Since the Apollo era, pictures of Earth from space are captured by satellites and astronauts onboard the International Space Station.
These images are captured too close to Earth to encompass the entirety of our planet's globe, but instead they offer more detailed views of individual cities, countries, continents and natural phenomena.