Archives for category: NASA

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For a chemical compound that shows up nearly everywhere on the planet, methane still surprises us. It is one of the most potent greenhouse gases, and yet the reasons for why and where it shows up are often a mystery. What we know for sure is that a lot more methane (CH4) has made its way into the atmosphere since the beginning of the Industrial Revolution. Less understood is why the ebb and flow of this gas has changed in recent decades.

You can find the odorless, transparent gas miles below Earth’s surface and miles above it. Methane bubbles up from swamps and rivers, belches from volcanoes, rises from wildfires, and seeps from the guts of cows and termites (where is it made by microbes). Human settlements are awash with the gas. Methane leaks silently from natural gas and oil wells and pipelines, as well as coal mines. It stews in landfills, sewage treatment plants, and rice paddies.

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NASA Earth Observatory, March 2016

Image mosaic by Daily Mail.

Image mosaic by Daily Mail.

A few years ago, while working on a story about wildfires, a V appeared to me in a satellite image of a smoke plume over Canada. That image made me wonder: could I track down all 26 letters of the English alphabet using only NASA satellite imagery and astronaut photography?

With the help of readers and colleagues, I started to collect images of ephemeral features like clouds, phytoplankton blooms, and dust clouds that formed shapes reminiscent of letters. Some letters, like O and C, were easy to find. Others—A, B, and R—were maddeningly difficult.

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NASA Earth Observatory, December 2015

 

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(Photo by Martin Wooster.)

In September and October 2015, tens of thousands of fires sent clouds of toxic gas and particulate matter into the air over Indonesia. Despite the moist climate of tropical Asia, fire is not unusual at this time of year. For the past few decades, people have used fire to clear land for farming and to burn away leftover crop debris. What was unusual in 2015 was how many fires burned and how many escaped their handlers and went uncontrolled for weeks and even months.

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NASA Earth Observatory, March 2015

IDL TIFF file

 

Though it has been quiet during recent decades, Mauna Loa has a long history of volcanic activity. Geologists estimate that the hotspot that feeds Mauna Loa first started to erupt about one million to 700,000 years ago. After underwater eruptions built up a seamount for hundreds of thousands of years, lava emerged above the Pacific surface about 400,000 years ago.

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NASA Earth Observatory, November 2015

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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

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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