Mysterious Noctilucent Clouds as Seen from the International Space Station

Mysterious “night shining” or noctilucent clouds are beautiful to behold, and this stunning image offers an unusual view of these clouds as seen by astronauts on board the International Space Station. Also called polar mesospheric clouds, these clouds are puzzling scientists with their recent dramatic changes. They used to be considered rare, but now the clouds are growing brighter, are seen more frequently, are visible at lower and lower latitudes than ever before, and sometimes they are even appearing during the day.

The astronauts were also able to take a time-lapse sequence of these clouds on June 5, 2012, as seen below. According to NASA, it is first such sequence of images of the phenomena taken from orbit.

The sequence in this video was taken while the ISS was passing over western Asia. By focusing on the limb of the Earth at night with the Sun illuminating it, the crew was able to capture some movement to these mysterious clouds.

There is quite a bit of debate for the cause of noctilucent clouds. Dust from meteors, global warming, and rocket exhaust have all been tagged as contributors, but the latest research suggests that changes in atmospheric gas composition or temperature has caused the clouds to become brighter over time.

Noctilucent clouds are usually seen during the summertime, appearing at sunset. They are thin, wavy ice clouds that form at very high altitudes (between 76 to 85 kilometers (47 to 53 miles) above Earth’s surface and reflect sunlight long after the Sun has dropped below the horizon. They appear in both the Northern and Southern Hemisphere and appear as delicate, shining wispy clouds against the dark sky.

The top image from the ISS was taken on June 13, 2012, as the space station passed over the Tibetan Plateau. At the same time, polar mesospheric clouds were also visible to aircraft flying over Canada. In addition to the noctilucent/polar mesospheric clouds trending across the center of the image, lower layers of the atmosphere are also illuminated. The lowest layer of the atmosphere visible in this image—the stratosphere—is indicated by dim orange and red tones near the horizon.

Lead image caption: Noctilucent or Polar Mesospheric clouds captured by the crew of the ISS on June 13, 2012. Credit: NASA

Source: NASA Earth Observatory

4 Replies to “Mysterious Noctilucent Clouds as Seen from the International Space Station”

  1. After watching bbc secrets of our living planet, episode 2, the clouds resemble nitrogen sublimation. Perhaps its being stored in the polar ice caps. Maybe they wouldn’t be cold enough, but if the fresh water ice caps were formed by a great heating maybe large sums of nitrogen were locked from escaping. I imagine this high up in the atmosphere would be cold enough to support nitrogen clouds? Also it ties in that they might be seen around the Tibetan region with the highest cool mountains nearest the Earths emerald band, which supports an upper atmosphere general flow from pole to equator. I’m no scientist, but that is what my brain thinks.

    1. There is nowhere on Earth where it is cold enough to form liquid nitrogen – not even in the atmosphere. Nitrogen boils at ~ 80 K @ NTP. The atmosphere is ~ 150 K at the mesopause, which is just below (~ 80 km) space (~ 100 km) so not easy to condensate anyway.

      So no nitrogen ice or clouds. Life has a hard time to fixate nitrogen for metabolism (used in so called heterocyclic rings with carbon) in part because it thermodynamically prefers to be a gas.

  2. It should be easy enough to identify what elements the clouds are composed of. Why is this matter trying to escape this wonderful planet, if it hasn’t already!

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