Mars has surprised scientists with a captivating green glow illuminating its night sky. European Space Agency (ESA) researchers have witnessed this unique phenomenon for the first time using the ExoMars Trace Gas Orbiter (TGO), capturing Mars' atmosphere aglow in the visible light spectrum.
Known as nightglow, this phenomenon shares some similarities with Earth's northern lights but has different underlying causes. On Mars, nightglow occurs when two oxygen atoms combine to form an oxygen molecule, typically at an altitude of around 31 miles (50 km) above the planet's surface.
Scientists have speculated about the existence of nightglow on Mars for over four decades, but it was only a decade ago that ESA's Mars Express orbiter detected it in the infrared spectrum. Subsequently, in 2020, the phenomenon was observed in visible light during Martian daylight using TGO. Now, scientists have observed it at night through TGO, providing valuable insights into this captivating phenomenon.
Studying Mars' nightglow will enhance our understanding of processes occurring in the Martian atmosphere and facilitate the design of future spacecraft destined for the Red Planet.