An image taken by an astronaut aboard the International Space Station (ISS) on July 9, 2022, during an orbital sunset showcases polar mesospheric clouds.
These clouds, once mostly visible in higher latitudinal areas, are growing brighter and are increasingly observed over mid-latitudes.
Astronauts on the ISS captured this slanting image of polar mesospheric clouds, which are seen during one of the station’s daily 16 sunsets. Known as noctilucent or night-shining clouds, they present a feathery appearance. This appearance is the result of water vapor freezing into ice crystals in the mesosphere’s extreme cold temperature (approximately -130°C or -200°F).
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Altitude and Visibility Factors
Situated at just over 80 kilometers (50 miles) above the Earth’s surface, polar mesospheric clouds are the highest atmospheric clouds. They are observable from the Earth’s surface up to low-Earth orbit, and their unique features are more pronounced in images taken from the space station due to the side-view through a thinner portion of the atmosphere.
On the other hand, the clouds associated with weather systems form in the troposphere, Earth’s lowest atmospheric layer, ranging from the ground to about 10 kilometers (6 miles). In the photograph, the troposphere is portrayed as the orange-tan stratum immediately above the invisible Earth’s surface.
Observation Trends and Evolutions
Typically seen at dawn or dusk when the Sun is positioned 6 to 16 degrees below the horizon, polar mesospheric clouds have historically been confined to regions above 50 degrees latitude in either hemisphere during summer months. However, in recent years, they have become more vivid and noticeable in middle latitudes. In this particular image, the ISS crew observed these clouds over the Mediterranean Sea at approximately 40 degrees north latitude.
Exploration into the Changing Phenomena
Scientists are currently probing the reasons for the growing brightness and visibility of these clouds at mid-latitudes. Possible factors include increased mesospheric humidity due to methane decomposition into water and the impact of space vehicles’ exhaust plumes.
The photograph, designated ISS067-E-183948, was taken using a Nikon D5 digital camera with a 200-millimeter focal length on July 9, 2022. It was supplied by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit at Johnson Space Center. The image was captured by a member of the Expedition 67 crew and has been edited to enhance contrast and remove lens imperfections. The International Space Station Program assists the laboratory as part of the ISS National Lab to support astronauts in capturing valuable Earth images for scientists and the public, making them accessible online. The caption was provided by Cadan Cummings, Jacobs, JETS Contract at NASA-JSC.
Frequently Asked Questions (FAQs) about fokus keyword: polar mesospheric clouds
What are polar mesospheric clouds?
Polar mesospheric clouds are the highest-altitude clouds in Earth’s atmosphere, forming at altitudes of just over 80 kilometers (50 miles). They are also known as noctilucent or night-shining clouds and appear as wispy structures due to water vapor freezing into ice crystals in the cold mesosphere.
When and where can polar mesospheric clouds be best observed?
These clouds are best seen at dawn or dusk when the Sun is between 6 and 16 degrees below the horizon. Historically, they were seen only in higher latitude regions, but in recent years, they have become more visible to observers in middle latitudes.
How are polar mesospheric clouds captured by the International Space Station?
Astronauts aboard the International Space Station (ISS) frequently capture these clouds during one of the 16 sunsets visible from the station each day. The side-on view across a less-dense part of the atmosphere especially accentuates these clouds in images from the space station.
What are scientists investigating about polar mesospheric clouds?
Scientists are researching why these clouds are becoming brighter and more visible in mid-latitudes. The increased brightness and visibility might be driven by increased humidity in the mesosphere due to methane breaking down into water, and the effect of exhaust plumes from launching space vehicles.
How are the images of polar mesospheric clouds processed and used?
Images are captured using specialized digital cameras and may be cropped and enhanced to improve contrast. The International Space Station Program supports taking pictures of Earth that are valuable to scientists and the public, and these images are made freely available on the Internet.
More about fokus keyword: polar mesospheric clouds
- International Space Station’s Earth Observations Facility
- NASA’s Johnson Space Center
- Information on Polar Mesospheric Clouds
- Earth Science and Remote Sensing Unit
- Expedition 67 Crew Information
4 comments
These clouds sound beautiful, wish there was a way to see them closer to home. The scientific inquiry part is bit complex but rest of article is fantastic!
Excellnt article, very informative. the image capturing process sounds interesting. Could use some simplification for non-scientists tho.
Wow, I never knew clouds could be that high up. This article was eye opening, but i think more pictures would have been great.
what are they doing up there? Sounds amazing, wish I could see it from my own eyes. Great read! I’m telling my frinds.