Vast areas of the Martian night sky pulse in ultraviolet light, according to images from NASA’s MAVEN spacecraft. The results are being used to illuminate complex circulation patterns in the Martian atmosphere.

Mars ’nightside atmosphere glows and pulsates in this data animation from MAVEN spacecraft observations. Green-to-white false color shows the enhanced brightenings on Mars’ ultraviolet “nightglow” measured by MAVEN’s Imaging UltraViolet Spectrograph at about 70 kilometers (approximately 40 miles) altitude. A simulated view of the Mars globe is added digitally for context, with ice caps visible at the poles.

Three nightglow brightenings occur over one Mars rotation, the first much brighter than the other two.All three brightenings occur shortly after sunset, appearing on the left of this view of the night side of the planet.The pulsations are caused by downwards winds which enhance the chemical reaction creating nitric oxide which causes the glow.Months of data were averaged to identify these patterns, indicating they repeat nightly.
Credits: NASA / MAVEN / Goddard Space Flight Center / CU / LASP

The MAVEN team was surprised to find that the atmosphere pulsed exactly three times a night, and only during Mars ’spring and fall. The new data also revealed unexpected waves and spirals over the winter poles, while also confirming the Mars Express spacecraft results that this nightglow was brightest over the winter polar regions.

This is an image of the ultraviolet “nightglow” in the Martian atmosphere. Green and white false colors represent the intensity of ultraviolet light, with white being the brightest. The nightglow was measured at about 70 kilometers (approximately 40 miles) altitude by the Imaging UltraViolet Spectrograph instrument on NASA’s MAVEN spacecraft. A simulated view of the Mars globe is added digitally for context. The image shows an intense brightening in Mars ’nightside atmosphere. The brightenings occur regularly after sunset on Martian evenings during fall and winter seasons, and fade by midnight. The brightening is caused by increased downwards winds which enhance the chemical reaction creating nitric oxide which causes the glow.
Credits: NASA / MAVEN / Goddard Space Flight Center / CU / LASP

“MAVEN’s images offer our first global insights into atmospheric motions in Mars’ middle atmosphere, a critical region where air currents carry gases between the lowest and highest layers, ”said Nick Schneider of the University of Colorado Laboratory for Atmospheric and Space Physics (LASP). , Boulder, Colorado. The brightenings occur where vertical winds carry gases down to regions of higher density, accelerating up the chemical reactions that create nitric oxide and power the ultraviolet glow. Schneider is the instrument lead for the MAVEN Imaging Ultraviolet Spectrograph (IUVS) instrument that made these observations, and the lead author of a paper on this research appearing August 6 in the Journal of Geophysical Research, Space Physics. Ultraviolet light is invisible to the human eye but detectable by specialized instruments.

The diagram explains the cause of Mars ’glowing nightside atmosphere. On Mars ’dayside, molecules are torn apart by energetic solar photons. Global circulation patterns carry the atomic fragments to the nightside, where downward winds increase the reaction rate for the atoms to reform molecules. The downwards winds occur near the poles at some seasons and in the equatorial regions at others. The new molecules hold extra energy which they emit as ultraviolet light.
Credits: NASA / MAVEN / Goddard Space Flight Center / CU / LASP

“The ultraviolet glow comes mostly from an altitude of about 70 kilometers (approximately 40 miles), with the brightest spot about a thousand kilometers (approximately 600 miles) across, and is as bright in the ultraviolet as Earth’s northern lights,” said Zac Milby , also of LASP. “Unfortunately, the composition of Mars’ atmosphere means that these bright spots emit no light at visible wavelengths that would allow them to be seen by future Mars astronauts. Too bad: the bright patches would intensify overhead every night after sunset, and drift across the sky at 300 kilometers per hour (about 180 miles per hour). ”

The pulsations reveal the importance of planet-encircling waves in the Mars atmosphere. The number of waves and their speed indicates that Mars ’middle atmosphere is influenced by the daily pattern of solar heating and disturbances from the topography of Mars’ huge volcanic mountains. These pulsating spots are the clearest evidence that the middle atmosphere waves match those known to dominate the layers above and below.

“MAVEN’s main discoveries of atmospheric loss and climate change show the importance of these vast circulation patterns that transport atmospheric gases around the globe and from the surface to the edge of space.” said Sonal Jain, also of LASP.

This is an image of the ultraviolet “nightglow” in the Martian atmosphere over the south pole. Green and white false colors represent the intensity of ultraviolet light, with white being the brightest. The nightglow was measured at about 70 kilometers (approximately 40 miles) altitude by the Imaging UltraViolet Spectrograph instrument on NASA’s MAVEN spacecraft. A simulated view of the Mars globe is added digitally for context, and the faint white area in the center of the image is the polar ice cap. The image shows an unexpectedly bright glowing spiral in Mars ’nightside atmosphere. The cause of the spiral pattern is unknown.
Credits: NASA / MAVEN / Goddard Space Flight Center / CU / LASP

Next, the team plans to look at the nightglow “sideways,” instead of down from above, using data taken by IUVS looking just above the edge of the planet. This new perspective will be used to understand the vertical winds and seasonal changes even more accurately.

The Martian nightglow was first observed by the SPICAM instrument on the European Space Agency’s Mars Express spacecraft. However, IUVS is a next-generation instrument better able to repeatedly map out the nightside glow, finding patterns and periodic behaviors. Many planets including Earth have nightglow, but MAVEN is the first mission to collect so many images of another planet’s nightglow.

The research was funded by the MAVEN mission. MAVEN’s principal investigator is based at the University of Colorado’s Laboratory for Atmospheric and Space Physics, Boulder, and NASA Goddard manages the MAVEN project. NASA is exploring our Solar System and beyond, uncovering worlds, stars, and cosmic mysteries near and far with our powerful fleet of space and ground-based missions.

Bill Steigerwald / Nancy Jones

NASA Goddard Space Flight Center, Greenbelt, Maryland

NASA’s MAVEN Maps Winds in the Martian Upper Atmosphere that Mirror the Terrain Below and Gives Clues to Martian Climate

Mars Wind Currents Reveal a Surprising Feature

MAVEN is the first spacecraft specifically designed to study the Mars upper atmosphere, in order to better understand the evolution of its climate. By measuring windspeed and direction near the top of the atmosphere, MAVEN has discovered that high-altitude wind currents are being disturbed by terrain features far below. This unexpected and surprising finding means that MAVEN can sense the presence of mountains and valleys on the surface of Mars while skimming the edge of space.

MAVEN Mars Electric Current Systems

Five years after NASA’s MAVEN spacecraft entered into orbit around Mars, data from the mission has led to the creation of a map of electric current systems in the Martian atmosphere. Unlike Earth, Mars lacks a protective global magnetic field to shield its upper atmosphere from the solar wind. Instead, the solar wind crashes into the upper atmosphere and its magnetic field lines drape around the planet. This creates an induced magnetosphere that tugs on charged particles in the Mars upper atmosphere, generating electric currents. Now, MAVEN’s detailed measurements of the magnetic environment surrounding Mars have revealed the shape of these electric currents for the first time.

Here we show a visualization of the idealized current systems that form as a result of a solar wind driven convective electric field around the planet as the solar wind passes Mars.

Unlike the Earth, Mars lacks a global magnetic dipole. Because its upper atmosphere is ionized by solar X-rays and extreme ultraviolet (EUV) radiations, the ionosphere of Mars presents a highly conductive obstacle to the flow of the magnetized solar wind plasma. The resulting interaction induces electric currents in the ionosphere which, in turn, create sufficient magnetic pressure to slow and deflect the solar wind around the bulk of the ionosphere, forming an induced magnetosphere.

NASA scientists used magnetic field measurements from the Mars Atmosphere and Volatiles EvolutioN (MAVEN) orbiter to make the first quantitative global map of the induced currents that shape the Martian induced magnetosphere. In doing so they found strong asymmetries between the north-south electric-polar hemispheres, especially in the concentration of sunward currents, an electric connection between the planet’s ionosphere and its bow shock, as well as a twist in the global near-Mars current system . Mapping the currents reveals how the solar wind’s energy transfers into the induced magnetosphere where it powers escape of the Martian atmosphere.

Visualizers: Cindy Starr (lead), Horace Mitchell, Tom Bridgman

This visualization shows the actual detailed electric current around Mars as measured by the MAVEN orbiter.

An image of the sun-facing view of the Mars current system with transparency

An image of a side-facing view of the Mars current system with transparency

An image of a side-facing view of the Mars current system with the bow shock and IMB with transparency