In order to take the best group photo of all time, you'll need technology that's a little more advanced than a selfie stick. Fortunately, NASA has that covered. Since the 1960s, astronauts and satellites have been sending us beautiful portraits of our home planet.
Photographing Earth as a whole is a bit daunting. For one, you need to be far enough away to get a full view of the planet's disc (so, for example, the low-earth orbit at the level of the International Space Station won't do). You also have to be at the right position between the Earth and the sun to avoid shadows — a tenuous operation as you're zooming away in a spacecraft or hurtling around the planet. Still, it can be done. And magnificently so.
The first "Blue Marble" shot isn't quite as well remembered as the second one, but still rates a mention.
This first color photograph of the entire Earth was taken in November 1967, by the experimental NASA communications and weather satellite ATS-3. While the satellite isn't a household name, it kept on trucking in its geosynchronous orbit for more than three decades before receiving its retirement papers in 2001.
Most likely ATS-3 remains circling the planet it photographed, another silent piece of space debris.
The Blue Marble photo that changed the world
But it was this 1972 photograph of Earth taken by the Apollo 17 astronauts that garnered the most notice and is forever enshrined as the best-loved "Blue Marble" photo. (Note: We're showing the true original photograph, with the South Pole on top. For publishing, NASA reversed the image to conform to certain cultural norms.) What might be less well known is that the picture almost never was.
"They weren't supposed to be taking pictures," film director Al Reinert — who also co-wrote the screenplay for the film Apollo 13 — wrote in The Atlantic in 2011. "Photo sessions were scheduled events in a rigorous flight plan that detailed every step essential to success. The film itself was strictly rationed like everything else on those perilous flights; there were 23 magazines onboard for the 70mm Hasselblad cameras, 12 color and 11 black-and-white, all intended for serious documentation purposes. They weren't supposed to be looking out the window, either."
But someone did — there's still controversy over which Apollo 17 crew member actually snapped the iconic shot, though NASA credits all three astronauts. The 1972 Blue Marble is all the more poignant for the fact that since Apollo 17, no human being has been far enough into space to capture a similar picture of Earth. And because this image was the first time people had the opportunity to see our planet in such a light, it was transformative. As Roger Launius put it in the Smithsonian's Air Space blog:
"This image, and the other stunning photographs of the Earth taken from space, inspired a reconsideration of our place in the universe. It became the rallying cry of environmental activists, politicians, and scientists during the annual Earth Day celebrations. They used it as an object lesson of the Earth as a small, vulnerable, lonely, and fragile body teeming with life in a dull, black, lifeless void. While self-regulating and ancient, humanity proved a threat to this place."
The Blue Marbles from 2002 and 2012
As imaging software improved, NASA found ways to create new Blue Marbles from photographs taken closer to the planet. In 2002, the agency released the above photograph, the most detailed "Blue Marble" at the time — albeit a composite marble made from months of satellite observations, mostly from the MODIS instrument aboard the Terra satellite.
In 2012, NASA released another composite image, made by stitching together observations from the satellite Suomi NPP.
Also in 2012, NASA used Suomi's observations of Earth's night side to take a breathtaking companion photo to the Blue Marble, the "Black Marble." The above photo was made from images taken over 22 days and 312 trips around Earth.
This year, the Deep Space Climate Observatory (DSCOVR) satellite aimed its camera, appropriately named EPIC (but really standing for Earth Polychromatic Imaging Camera), back at Earth to capture the most recent true "Blue Marble" shot. And there's more to come, too. DSCOVR is hanging out at the L1 Lagrangian Point to monitor the solar wind, but will continue to take daily images of Earth that will show daily variations of our planet. Soon, we'll have a veritable bagful of Blue Marbles to admire.