ISS shares stunning airglow photo from space revealing vibrant green, orange and red layers in Earth’s upper atmosphere

The International Space Station recently shared a beautiful image that displays the vibrant colours of Earth's atmosphere as seen from space. The photograph appears to depict our globe covered in an iridescent yellow glow.

The photo, which was captured by NASA astronaut Don Pettit, looks stunning with stars twinkling in the background. “The colors of our atmosphere seen from space! Multiple vibrant layers of green atomic oxygen, orange hydroxyl radicals, and red airglow excited from solar activity,” the caption read on Instagram.

The vibrant colours are caused by a phenomenon called airglow, a natural process where the Earth's atmosphere emits light.

What is airglow?

When sunlight excites atoms and molecules in the upper atmosphere, they release light as a means to dissipate excess energy, a phenomenon known as airglow, according to NASA.

It can also happen when atoms and molecules that have been ionised by sunlight collide with and capture a free electron. In both circumstances, they eject a photon to relax again. The phenomenon is comparable to auroras, but where auroras are driven by high-energy particles originating from the solar wind, airglow is energised by ordinary, day-to-day solar radiation.

Unlike auroras, which are episodic and transient, airglow consistently glows throughout Earth’s atmosphere, and the result is a tenuous bubble of light that snugly encases our entire planet. Airglow is far more modest than auroras, only a tenth as brilliant as all the stars in the night sky. It is too dim to be easily seen outside of orbit or on the ground with clear, dark skies and a sensitive camera. Nevertheless, it serves as a landmark for the dynamic area where space and Earth collide.

About the International Space Station

Astronauts live and work aboard the International Space Station (ISS), a habitable artificial satellite in low Earth orbit. It is a cooperation initiative amongst space agencies, including NASA, Roscosmos, JAXA, ESA, and CSA. Together, they conduct aerial observations of Earth and produce stunning photographs that highlight the planet's oceans, forests, and other features.

ISS acts as a research laboratory, observatory and testbed for spaceflight technology. It also tracks climate change, monitors sea level rise, deforestation, and ocean currents.

Scientists have conducted numerous research experiments related to health, including microgravity experiments aimed at improving our understanding of osteoporosis and cancer.

FAQs

Are airglows and auroras the same?

No, airglows and auroras are not the same.

When do airglows occur?

Airglows occur when atoms and molecules in the upper atmosphere emit light to shed their excess energy.