Mysterious Noctilucent Clouds as Seen from the International Space Station

By Nancy Atkinson - June 25, 2012 at 4:23 PM UTC | Planetary Science
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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

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com