An astronaut has captured a breathtaking image from the International Space Station (ISS), showcasing Earth's golden airglow adorning the planet's horizon.
Golden Airglow Above Earth
The recently shared photo by NASA on January 21 captures the mesmerizing airglow, a radiant effect resulting from the interaction of sunlight with atoms and molecules in Earth's atmosphere.
This luminous display manifests as a brilliant golden glow arching above the planet, complemented by an auburn-colored band contrasting against the backdrop of a starry sky. The image was taken at an altitude of 258 miles (415 kilometers) as the International Space Station (ISS) traversed the Pacific Ocean northeast of Papua New Guinea.
Traveling at a rapid pace of 5 miles (8 kilometers) per second, the ISS completes an orbit around Earth approximately every 90 minutes, experiencing 16 sunrises and sunsets in a single 24-hour period.
This orbital pattern leads to alternating periods of 45 minutes of daylight and 45 minutes of darkness during each revolution. The dynamic nature of the ISS's trajectory allows it to offer a unique perspective, capturing various atmospheric phenomena and celestial elements.
In addition to the captivating golden airglow, the photograph showcases delicate white clouds hovering above the deep blue expanses of the Pacific Ocean. Intriguingly, elements of the space station itself are visible, including the Prichal docking module and the Nauka multipurpose laboratory module, both integral components of Russia's space agency Roscosmos.
Positioned on the left side of the image, the Prichal module is connected to the Nauka module, featuring five docking ports and fuel transfer capabilities. The Nauka module, serving as the primary laboratory for the Russian segment of the ISS, was introduced to the space station in July 2021, followed closely by the Prichal module in November 2021.
What Is an Airglow?
Airglow, a phenomenon in Earth's upper atmosphere, results from the interaction of molecules like nitrogen, oxygen, sodium, and ozone being stimulated by ultraviolet radiation from sunlight. In response, these molecules emit light upon colliding with each other, creating a mesmerizing display best observed during the night.
The recent photograph was taken with a high exposure setting, allowing sufficient light to enter the camera and capture both Earth and the star-filled sky.
Astronaut Andreas Mogensen's image reveals a dual airglow in the atmosphere, where the yellow glow originates from sodium particles, while the red glow is attributed to oxygen and, to a lesser extent, hydroxyl. The weak luminescence is a consequence of the interaction between light and molecules or atoms.
Sunlight energizes molecules during the day, causing them to split apart or excite electrons, and the subsequent energy release, through collisions with other molecules, produces a specific color, defining the characteristics of airglow.
It is categorized into dayglow, twilightglow, and nightglow, each displaying unique characteristics based on the illumination of the atmosphere by sunlight and the observer's position in relation to it. Despite being predominantly observed in a narrow region between 50 and 300 kilometers (31 to 180 miles), airglow can extend over twice that distance.
Beyond its aesthetic appeal, airglow serves as a valuable tool, providing insights into the motion and distribution of the rarefied layers in the uppermost portions of the atmosphere.
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