The atmosphere of our neighboring planet, Mars, glows at night!
The phenomenon known as nightglow is caused when the atmosphere of a planet illuminates in the absence of external light. It was first spotted in mid 2016 by the Mars Atmosphere and Volatile Evolution Mission (MAVEN).
Nightglow: The phenomenon that causes atmosphere of Mars to glow at night.
The Martian atmosphere has thinned as much as 100 to 150 times than that of Earth’s because of the energy released from sun’s nuclear reactions. As found by scientists, nightglow is being caused by the stripping of the Martian atmosphere.
Nightglow occurs through a process called photodissociation. When the ultraviolet rays from the sun strike the leading edge of the planet, the energy in the particles breaks down carbon dioxide, nitrogen and oxygen. These particles are then carried all over the planet by winds. Upon reaching the nightside of the planet, the free nitrogen and oxygen atoms interact 37 to 62 miles above the surface of Mars to form nitric oxide. This process is accompanied by release of energy, causing the atmosphere to illuminate.
Nightglow occurs on Earth too!
By studying the Martian atmosphere, scientists are hoping to better understand the planet’s cloud formation, how the air moves in different seasons and presence of water molecules in the atmosphere.
Nightglow also occurs on our own planet through chemical reactions that take place in the upper atmosphere. According to NASA’s Earth Observatory, the nightglow observed on Earth is a billionth as bright as sunlight. Therefore, it is extremely faint to see. A study in Astropartical physics done in 2005 found out the presence of 564 photons per meter squared per second over the Mediterranean Sea.