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Earth from Space is the title of a recent book published by the Smithsonian Institution's National Air and Space Museum that presents images of the planet collected by satellites orbiting thousands of kilometers above us. |
This may look like a delicate watercolor, but it's actually a satellite image of Afghanistan's Folded Mountains. It's one of several hundred images in Earth from Space, showing everything from snowy Siberian tundra to surplus airplanes parked in Arizona.
Geographer Andrew Johnston wrote the book for the National Museum of Air and Space, and says it wouldn't have been possible until recently. "Over the last five years or so, a whole new generation of commercial remote sensing satellites have been launched, and they've shown the surface of the earth in unprecedented detail,” says Mr. Johnston.
Remote-sensing satellites were first developed for military purposes, and those remain the largest applications. But civilian uses, including weather forecasting, planning, and large-scale environmental study, are growing. The pictures in Earth From Space are based on the data collected by these satellites.
"Most of the images in the book are digital. They were recorded by digital sensors, and then that information was radioed down to receiving stations on Earth, and then that was used, those data were used in computers to reconstruct images."
Some of the pictures, like one of skyscrapers in Kuala Lumpur, are so sharp they look as if they were taken from an airplane. Others resemble old-fashioned topographical maps, such as this one of the Himalayas.
"What's interesting about the image is that it shows how the earth's crust is dynamic,” says Mr. Johnston. “The Indian subcontinent is slowly moving north, pushing underneath the rest of Asia, which forces the Himalayan mountains up."
Earth from Space includes a few photographs taken by astronauts in orbit, such as the one of Mount Everest. A spooky-looking view of Antarctica was made from radar, which penetrates clouds and darkness.
The majority of the book's images, though, such as those of the Saudi Peninsula and northwestern China, were made using either visible or infrared light. Infrared also created the views of the Lena River delta in Russia, and an open-pit copper mine in Chile.
"Ah, the Escondida mine," says Mr Johnston appreciatively. “One view shows the area as the colors would appear to our eyes. But the other image shows the area as it would look in infrared wavelengths, and that's useful for looking at differences in vegetation cover, or in this instance, looking at differences in mineralogy."
Remote-sensing satellites can also show the effects of ancient storms from space; impact-craters created by large asteroids hitting the Earth.
But the starkest views from outer space today show the results of human activity, like center-pivot agriculture in Kansas, or the tip of lower Manhattan, or Europe lit up by street lamps at night. Brazil's deforestation is also seen most clearly from outer space, as is the slow death of the Aral Sea in central Asia.
Andrew Johnston says that all these views offer strong clues about how to live on the Earth.
"It really brings home how we have to be careful with how we use the land. Images like this can show us how humans use the Earth and how we can better design uses of that land in the future, so that we can all live together and have access to these resources as the Earth's population gets close to ten billion over the next century or so."
Andrew Johnston is a geographer on the staff of the National Air and Space Museum, in Washington, D.C., which published Earth From Space.