By Jeffrey Kluger
(TIME) – Spacecraft and telescopes are not built by people interested in what’s going on at home. Rockets fly in one direction: up. Telescopes point in one direction: out. Of all the cosmic bodies studied in the long history of astronomy and space travel, the one that got the least attention was the one that ought to matter most to us—Earth.
That changed when NASA created the Landsat program, a series of satellites that would perpetually orbit our planet, looking not out but down. Surveillance spacecraft had done that before, of course, but they paid attention only to military or tactical sites. Landsat was a notable exception, built not for spycraft but for public monitoring of how the human species was altering the surface of the planet. Two generations, eight satellites and millions of pictures later, the space agency, along with the U.S. Geological Survey (USGS), has accumulated a stunning catalog of images that, when riffled through and stitched together, create a high-definition slide show of our rapidly changing Earth. TIME is proud to host the public unveiling of these images from orbit, which for the first time date all the way back to 1984.
Over here is Dubai, growing from sparse desert metropolis to modern, sprawling megalopolis. Over there are the central-pivot irrigation systems turning the sands of Saudi Arabia into an agricultural breadbasket — a surreal green-on-brown polka-dot pattern in the desert. Elsewhere is the bad news: the high-speed retreat of Mendenhall Glacier in Alaska; the West Virginia Mountains decapitated by the mining industry; the denuded forests of the Amazon, cut to stubble by loggers.
It took the folks at Google to upgrade these choppy visual sequences from crude flip-book quality to true video footage. With the help of massive amounts of computer muscle, they have scrubbed away cloud cover, filled in missing pixels, digitally stitched puzzle-piece pictures together, until the growing, thriving, sometimes dying planet is revealed in all its dynamic churn. The images are striking not just because of their vast sweep of geography and time but also because of their staggering detail. Consider: a standard TV image uses about one-third of a million pixels per frame, while a high-definition image uses 2 million. The Landsat images, by contrast, weigh in at 1.8 trillion pixels per frame, the equivalent of 900,000 high-def TVs assembled into a single mosaic.
These Timelapse pictures tell the pretty and not-so-pretty story of a finite planet and how its residents are treating it — razing even as we build, destroying even as we preserve. It takes a certain amount of courage to look at the videos, but once you start, it’s impossible to look away. [more]