The Secrets behind Earth’s Multi-colored Glow

Airglow occurs when atoms and molecules in the upper atmosphere, excited by sunlight, emit light in order to shed their excess energy. The phenomenon is similar to auroras, but where auroras are driven by high-energy particles originating from the solar wind, airglow is sparked by day-to-day solar radiation. Airglow carries information on the upper atmosphere’s temperature, density, and composition, but it also helps us trace how particles move through the region itself. Vast, high-altitude winds sweep through the ionosphere, pushing its contents around the globe — and airglow’s subtle dance follows their lead, highlighting global patterns. PhotographHow many of these can you find in this photograph: an aurora, airglow, one of the oldest impact craters on the Earth, snow and ice, stars, city lights, and part of the International Space Station? Most of these can be identified by their distinctive colors. The aurora here appears green at the bottom, red at the top, and is visible across the left of image. Airglow appears orange and can be seen hovering over the curve of the Earth. The circular Manicouagan Crater in Canada, about 100 kilometers across and 200 million years old, is visible toward the lower right and is covered in white snow and ice. Stars, light in color, dot the dark background of space. City lights appear a bright yellow and dot the landscape. Finally, across the top, part of the International Space Station (ISS) appears mostly tan. This image was taken from the ISS in 2012.Credit: NASA PhotographIf you could circle the Earth aboard the International Space Station, what might you see? Some amazing vistas, one of which was captured in this breathtaking picture in mid-2015. First, visible at the top, are parts of the space station itself including solar panels. Just below the station is the band of our Milky Way Galaxy, glowing with the combined light of billions of stars, but dimmed in patches by filaments of dark dust. The band of red light just below the Milky Way is airglow -- Earth s central bulge appears with starfields cut by dark rifts of obscuring interstellar dust. The picture was taken by Astronaut Scott Kelly on August 9, 2015, the 135th day of his one-year mission in space.Credit: NASA/Scott Kelly PhotographA composite photograph of star trails captured from the International Space Station. Bands of red and green airglow are also visible. Credit: NASA/Don Pettit PhotographA composite photograph of star trails captured from the International Space Station. Bands of red and green airglow are also visible. Credit: NASA/Don Pettit PhotographA composite photograph of star trails captured from the International Space Station. Bands of red and green airglow are also visible. Credit: NASA/Don Pettit PhotographA composite photograph of star trails captured from the International Space Station. Bands of red and green airglow are also visible. Credit: NASA/Don Pettit VideoLovejoy Comet over Southern Hemisphere Credit: NASA VideoAfrica and Mideast at Night Credit: NASA VideoNorthern Africa and Mideast (Evening)Credit: NASA VideoBangkok to North PacificCredit: NASA VideoCity Lights over Middle EastCredit: NASA VideoWestern Quebec to Southern OceanCredit: NASA VideoAurora Borealis over Eastern North AmericaCredit: NASA VideoWestern Europe to IndiaCredit: NASA VideoEastern Europe to Southeastern AsiaCredit: NASA VideoHalfway across the WorldCredit: NASA VideoInternational Space Station Near Aurora BorealisCredit: NASA VideoAurora Borealis over Western EuropeCredit: NASA VideoLightning over AsiaCredit: NASA VideoOver the Mediterranean SeaCredit: NASA VideoThe Milky Way and Storms over AfricaCredit: NASA VideoMilky Way on the HorizonCredit: NASA VideoRed and green swaths in the atmosphere, known as airglow, are seen in this video of Earth’s limb shot from the International Space Station. Credit: NASA

Stretching from roughly 50 to 400 miles above Earth’s surface, the ionosphere is an electrified layer of the upper atmosphere, generated by extreme ultraviolet radiation from the Sun. It’s neither fully Earth nor space, and instead, reacts to both terrestrial weather below and solar energy streaming in from above, forming a complex space weather system of its own. The particles of the ionosphere carry electrical charge that can disrupt communications signals, cause satellites in low-Earth orbit to become electrically charged, and, in extreme cases, cause power outages on the ground. Positioned on the edge of space and intermingled with the neutral atmosphere, the ionosphere’s response to conditions on Earth and in space is difficult to pin down. Stretching from roughly 50 to 400 miles above the surface, this region, called the ionosphere, is an electrified layer of the upper atmosphere, generated by extreme ultraviolet radiation from the Sun. Understanding the ionosphere’s extreme variability is tricky because it requires detangling interactions between the different factors at play — interactions of which we don’t have a clear picture. That’s where airglow comes in. Airglow occurs when atoms and molecules in the upper atmosphere, excited by sunlight, emit light in order to shed their excess energy. The phenomenon is similar to auroras, but where auroras are driven by high-energy particles originating from the solar wind, airglow is sparked by day-to-day solar radiation. Airglow carries information on the upper atmosphere’s temperature, density, and composition, but it also helps us trace how particles move through the region itself. Vast, high-altitude winds sweep through the ionosphere, pushing its contents around the globe — and airglow’s subtle dance follows their lead, highlighting global patterns. Credit: NASA s Goddard Space Flight Center/Mary Pat Hrybyk-Keith

Learn about the features of the ionosphere! This little-explored region exists between space and Earth. It is home to the aurora, the international space station, a variety of satellites, and radio communication waves. We know it is sensitive to weather from Earth and conditions in space, called space weather. Join us as we venture to this interface to space! Music credit: Foxy Trot by Luis Enriquez Bacalov Complete transcript available.Watch this video on the NASA Goddard YouTube channel. Gif from Welcome to the Ionosphere intro animation Credit: NASA/GSFC/CIL/Krystofer Kim Airglow in the ionosphere. Credit: NASA/GSFC/CIL/Krystofer Kim Earth s weather impacts the ionosphere. Credit: NASA/GSFC/CIL/Krystofer Kim Ionosphere changes over a 24 hour period. Credit: NASA/GSFC/CIL/Krystofer Kim Ionosphere goes through fluctuations over the course of a year. Credit: NASA/GSFC/CIL/Krystofer Kim Space weather impacts the ionosphere. Credit: NASA/GSFC/CIL/Krystofer Kim The solar wind impacts the ionosphere. Credit: NASA/GSFC/CIL/Krystofer Kim