Astronaut on ISS Reveals What an Erupting Volcano Looks Like in Infrared

Astronaut Don Pettit has shared spectacular pictures of a violent volcanic eruption taken all the way from the International Space Station.

The image shows an alien pink and gray landscape, with the volcano smoldering in the center of the frame and spewing out smoke. It was taken during the ISS Expedition 30, in 2011 and 2012.

"Erupting volcano in near infrared ... south Patagonia region, #Argentina," Pettit tweeted. "The magenta regions show healthy forests, the gray areas show where the eruption has decimated the surroundings. Taken from @Space_Station on my previous mission."

Infrared light is light with a longer wavelength, or closer to the red end of the spectrum, than the light we can see. The heat emitted from our bodies can be seen in IR, as can heat from storm cells. IR light is also emitted from astronomical bodies in places where they don't emit visible light: In dark clouds of gas and dust, hidden stars can be seen in IR only. Using a camera capable of viewing IR light is therefore very useful in a number of fields, including meteorology, policing and astronomy.

Pettit also tweeted the visible-light version of the picture.

Comparing the visible-light and IR versions of the volcano shows the decimation caused by the volcanic eruption. Pettit does not identify the particular volcano in the picture, but Patagonia has several active volcanoes.

Depending on the type of eruption, a volcano can have a variety of effects on the surrounding landscape. Some volcanic eruptions are explosive and others are not, depending on the thickness of the magma. Thin magma leads to lava flows, which seep down the ridge of the volcano, while thick magma leads to pressure building up and the volcano exploding, which releases large amounts of steam, gas and ash. This can then turn into a deadly pyroclastic flow, which happened during the eruption of Vesuvius in A.D. 79, or ashy, muddy landslides known as lahars.

Additionally, ash released into the air can settle on plants in thick layers, preventing photosynthesis.

Pettit has also photographed some other rarely seen views from the ISS, including the Mississippi River Delta, the Florida Peninsula at night and other infrared scenes.

"My infrared/normal visible camera system during Expedition 30 to the ISS. The IR camera has the yellow-orange filter, the normal camera has none," Pettit said in a viral Reddit post, accompanied by a picture of him holding the camera. The post has received over 40,000 upvotes.

"Dan Burbank, one of my crew mates, figured out how to mount the cameras together so sequential IR/normal photos could be taken near simultaneously. I could snap one photo, then quickly spin the camera thanks to the zero-G, and take another. Both have 180mm f2.8 lenses," he said.

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