Martian sky pulses and glare when seen at night in UV light

Ultraviolet 'Nightglow' from Mars' atmosphere.

Ultraviolet ‘Nightglow’ from Mars’ atmosphere.
Image: NASA / MAVEN / Goddard Space Flight Center / CU / LASP

New ultra-violet observations of the Red Planet mark complex circulation patterns in the Martian atmosphere, including extremely regular night-glass pulses that are invisible to the unsupported eye.

The Martian atmosphere is, when viewed through ultraviolet light, very busy, but only at night, and only in certain seasons, when new research shows. These pulsating and glowing atmospheric effects are not fully understood, but their presence reminds us that Mars has a really intricate atmosphere.

The new study, published in the Journal of Geophysical Research, Space Physics, was made possible by the Imaging Ultraviolet Spectrograph (IUVS) instrument on NASA’s MAVEN spacecraft, which has been orbiting Mars since 2014. . UVS provides a completely new lens with which to observe the Red Planet, revealing unusual circulation patterns in the Martian atmosphere.

The new paper, led by Nick Schneider of the Laboratory of Atmospheric and Space Physics (LASP) at the University of Colorado, analyzed data collected by the UVS instrument over two consecutive Martian years (a year on Mars equals 687 days on earth). By studying Mars in ultraviolet light, the researchers were able to visualize the effects of wind conditions and waves worldwide high in the Martian sphere.

“The images from MAVEN provide our first global insight into atmospheric motions in the central atmosphere of Mars, a critical region where air currents carry gases between the lowest and highest layers,” Schneider explained in a NASA press release.

The night glass as seen at the Arctic.  The cause of the spiral shape remains a mystery.

The night glass as seen at the Arctic. The cause of the spiral shape remains a mystery.
Image: NASA / MAVEN / Goddard Space Flight Center / CU / LASP

This psychedelic actions, known as atmospheric tides, result from a recombination of nitrogen and oxygen atoms in the night side of Mars – the middle layer between the stratosphere and thermosphere. By observing Mars in UV light, the scientists were able to visualize changes in wind patterns over the different seasons, affecting the atmospheric night glass. These planet-surrounding waves are also affected by solar heat and topographic disturbances caused by Mars’ massive volcanoes, according to the study.

Indeed, the mountainous volcanic regions on Mars are known to produce some truly fascinating and freaky phenomena, including a massive elongated cloud which appears like clockwork above Arsia Mons, a 12.4-mile (20-kilometer) volcano near the Martian equator.

“MAVEN’s major discoveries of atmospheric loss and climate change demonstrate the importance of these large circulation patterns that carry atmospheric gases around the world and from the surface to the edge of space,” explained LASP scientist and study co-author Sonal Jain in the press release.

Interestingly, the atmospheric pulses occur exactly three times each night, but only in the spring and fall. The scientists also documented unexplained waves and spirals above the winter pole regions, along with some unusual bright spots seen over the winter poles.

Infographic that explains the night glass phenomenon.

Infographic that explains the night glass phenomenon.
Image: NASA / MAVEN / Goddard Space Flight Center / CU / LASP

In these bright areas, gases are pushed down by vertical winds, causing them to enter regions of higher atmospheric density. This serves to accelerate the chemical reactions responsible for nitric oxide, which “makes the ultraviolet glow”, according to a NASA press release. The UV emission mainly occurs at altitudes that reach 40 miles kilometers) above the surface, with some patches resembling 600 miles (965) kilometers) in diameter.

Tthis emission is not to be confused with Mars’s eerie green sheen– a visible tint caused by the rays of the sun exciting oxygen molecules in the upper atmosphere. To a human observer on Martian soil, these night glasses would be invisible. In the future, a possible fun activity for colonists would be to view this night glass with UV glasses, in a time-lapse of the sky roughly analogous to viewing the Northern Lights on Earth. This would apparently be quite the spectacle, as these bright patches zip across the Martian night sky at speeds of 180 mph (290 kph).