The Blue Marble | How much has Earth changed 50 years after the iconic photo?

The Blue Marble |  How much has Earth changed 50 years after the iconic photo?

In 1972, Apollo 17 astronauts took the iconic photo called The Blue Marble (or “blue marble”), showing the Earth seen from space and becoming one of the most reproduced photos in history. The image also became a symbol for environmental activism in the 1970s and, half a century later, NASA made a portrait of our planet similar to the original, revealing how much our world has changed since then.

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In addition to being a historical record, Blue Marble has some peculiarities. This was the first time that Antarctica appeared in any space photography of our planet. Furthermore, the image departed from the traditional prioritization of Europe and North America on the globe, emphasizing Africa and the Middle East.

Photo history of Earth seen from space

Since the 1940s we have photos of the Earth taken from space, the first of which were clicked on suborbital flights and still in black and white. Color images began to emerge in the early 1960s, but none captured the entire globe—until the ATS-3 satellite image did so in 1967.

Other famous captures include those of the Apollo 8 mission, the first to take astronauts to lunar orbit, in 1968. Among them is the legendary Earthrise (“Earth Rise”, in analogy to sunrise, which is “sunrise” in English ).

With the great popularity of these records, NASA decided to end the Apollo Program in style, asking the members of Apollo 17 to produce the image that would later become known as Blue Marble.

The Blue Marble, 50 years later

Five decades later, the Deep Space Climate Observatory (a space observatory located about 1.5 million kilometers from Earth) reproduced the image under the same angle, allowing our planet to be compared back and forth.

The new photograph already shows the impacts of climate change, intensified over the last few decades. It can be difficult to differentiate between ice and clouds in the image, but it is remarkable that Antarctica has lost a large amount of material in these 50 years. Snow in the mountains of the Persian Gulf is also no longer seen, although this can also be attributed to seasonal variations.

The most striking change, however, is the large reduction in green cover between the tropics on the African continent. The region’s forests now begin hundreds of kilometers to the south, which is consistent with the desertification of the region, already pointed out in several studies.

The island of Madagascar has undergone similar changes: what was predominantly green is now seen in brown, as a result of changes in land use in the area. The island is a great biodiversity hotspot, home to many species of plants and animals that only exist there.

The result of the comparison would frustrate the environmental movements that adopted the Blue Marble as a symbol of the cause in the 1970s, when it was taken down. What remains for current times is the mission to end the degradation of the planet — so, when the iconic image completes 100 years, who knows the “blue marble” will be more colorful again.

Source: The Conversation