Orbital View: NASA's Guessing Game

Editor’s Note: This article previously appeared in a different format as part of The Atlantic’s Notes section, retired in 2021.

NASA’s Earth Observatory released its “newest puzzler” last week and asked its Instagram followers the following questions:

What do you think is the cause of the grid pattern? How would you explain why there are different shades of green (and brown) present? What part of the world do you think this image shows? Your challenge is to use the comments section to tell us what part of the world we are looking at, when the image was acquired, what the image shows, and why the scene is interesting. Good luck!

A few days later, they revealed the answer with a zoomed-out image. Both are revealed after the jump, if you’d like to guess first:

The location: Argentina’s Chaco Forest, in the northern province of Salta. Further details from the caption:

Shrubs and hardwood forests thrive in the semi-arid region. For many years, puestos—small settlements centered around water sources—dotted the landscape. But in the past decade, large-scale farm and ranch operators have cleared broad swaths of the chaco to make way for livestock and crops raised on an industrial scale.

In fact, an analysis of data collected by several Landsat satellites suggests that Argentina’s chaco faces one of the fastest tropical deforestation rates in the world. On October 15, 2015, the Operational Land Imager (#OLI) on #Landsat 8 captured this false-color image of fields, forests, and puestos in the #Salta province of northern Argentina. The fields, most of which appear to be fenced, are arranged in a grid pattern. Fires are actively burning in a few sectors of the grid, likely lit by land managers trying to clear shrubs and trees to make room for livestock, timber, or crops. Fresh burn scars are dark brown; older burn scars are lighter brown.

Over time, burned areas become light green and eventually dark green. In the lower right of the image, several traditional puestos are visible as light green patches. These settlements usually consist of a few dwellings, farmhouses, and small-scale crops located near a well. Tree cover declines significantly at the center of a #puesto because of heavy grazing by cattle, goats, and other free-ranging livestock near the water source. Ecologists call the distinctive grazing patterns piospheres.

(See all Orbital Views here)