Archives for category: NASA


While big game animals such as lions, leopards, elephants, rhinos, and water buffaloes draw most visitors to Pilanesberg National Park, the land these animals live on is just as compelling. Pilanesberg is located in one of the world’s largest and best preserved alkaline ring dike complexes—a rare circular feature that emerged from the subterranean plumbing of an ancient volcano.

The Operational Land Imager (OLI) on Landsat 8 acquired this image of the park in South Africa on June 19, 2015. Seen from above, the concentric rings of hills and valleys make a near perfect circle, with different rings composed of different types of igneous rock. The entire structure sits about 100 to 500 meters (300 to 1,600 feet) above the surrounding landscape.

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NASA Earth Observatory, July 2015


Ten thousand River Commissions, with the mines of the world at their back, can not tame that lawless stream, can not curb it or confine it, can not say to it, Go here or Go there, and make it obey. —Mark Twain, Life on the Mississippi

Twain’s pessimism has done little to deter the Mississippi River Commission. Since it was created in 1879, this division of the U.S. Army Corps of Engineers has waged a prolonged campaign to control the river. Their weapons in the battle are levees, dams, spillways, dikes, weirs and other pieces of infrastructure. Their mission is to prevent the river from abandoning its current course.

Left alone, nature would probably send the Lower Mississippi River whipping back and forth across a 200-mile arc every few thousand years. Like “a pianist playing with one hand,” is how John McPhee described the river’s restlessness in a story for The New Yorker. With the main channel flowing unusually far to the east in its current configuration, the Mississippi is primed to snap back toward the west. Such a change would send most of the Mississippi’s flow into the Atchafalaya River, a distributory (the opposite of a tributary) of the Mississippi and Red Rivers. Such a change would pose an existential crisis for port cities like New Orleans and Baton Rouge, starving them of the water that has come to define them.

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The NASA Earth Observatory, March 2015


Few images are as beautiful and as terrifying as a satellite view of a hurricane about to make landfall. On October 29, 2012, the Suomi NPP satellite captured an ominous nighttime view of Sandy—an enormous hybrid storm that was part hurricane, part Nor‘easter—churning off the coast of New Jersey.

The string of city lights that stretches from Washington to Boston was mostly gone, blanketed by thick, ghostly storm clouds. One of the most brightly lit cities in the world, New York, was little more than a faint smudge through Sandy’s clouds.

In a matter of hours, that smudge of light would go dark. Large swaths of Manhattan were under water. The Rockaways were on fire. Rooftops along the New Jersey shore became temporary islands for people escaping a wall of seawater that surged inland.

Was Superstorm Sandy an expression of a “new normal” for our weather? Was it a storm pumped up by global warming?

“If you look at the unique set of circumstances in which Sandy emerged and you know something about meteorology and climate,” says Marshall Shepherd, director of the atmospheric sciences program at the University of Georgia, “it’s hard not to ask yourself these kinds of questions.”

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NASA Earth Observatory, March  2013

Eight thousand is a perfectly arbitrary number. Yet, no other number looms larger for mountain climbers.

Fourteen mountain peaks stand taller than 8,000 meters (26,247 feet). There could have been many more of these “eight-thousanders” if the French commission that established the length of the meter (in 1793) had made it just a bit shorter; there would be hardly any if they had made the meter longer. The decision to make a meter equivalent to one ten-millionth of the distance between the equator and the North Pole left the world with fourteen 8K peaks. All of them are found in either the Karakoram or Himalayan mountain ranges of central Asia.

Fourteen is a number that pushes climbers to the point of obsession. It’s big enough that only the most ambitious consider climbing all of them, but small enough that doing so over a lifetime still seems possible. Even in the United States, a country where most people shun metric measurements, climbers dream of ascending the eight-thousanders. The “twenty-six-thousand, two-hundred-and-forty-seven-footers” hardly has the same ring.

The atmosphere was electric at Providence Landing Park in Lompoc, California as the first stage of an Atlas 5 rocket ignited in the distance on February 11, 2013.

Cheers erupted at 10:02 a.m. from the hundreds of people gathered there as the rocket rose, gathered itself, then surged into a perfect blue sky over Vandenberg Air Force Base. As the cheers subsided, it was surprisingly quiet for a moment as awe sank in, save for the patter of scores of cameras clicking in unison.

A full 30-or-so seconds later, the sound arrived. You could feel the roar in the ground. The Landsat Data Continuity Mission (LDCM), the latest satellite in the world’s longest-running series of Earth-observing satellites, was on its way to space.

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Earth Observatory, Earth Matters blog, February 2013

Today is a big day. I just arrived in Los Angeles from DC this afternoon, and I’m heading to Vandenberg Air Force Base in Lompoc, California, to see an Atlas 5 rocket blast Landsat 8 into space. Officially, the satellite is called the Landsat Data Continuity Mission (LDCM) until it reaches orbit safely, but I’m going to call it Landsat 8 anyway in the spirit of keeping jargon to a minimum.

This is the second time I’ve been fortunate to have a front-row seat to the launch of one of NASA’s Earth-observing satellites. The mission that brought me to Vandenberg the first time was called Glory; it was a climate-centered mission, designed to measure aerosols and fluctuations in the amount of sunlight that reaches the top of Earth’s atmosphere.

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Earth Observatory, Earth Matters blog, February 2013