NASA orbiter detects ultraviolet auroras on Mars
Just a day after聽skywatchers at mid- to upper-latitudes around the world were treated to a particularly energetic display of auroras on the night of March 17 as a result of an intense geomagnetic storm,聽researchers announced findings from NASA鈥檚听聽mission of auroral action observed on Mars 鈥� although in energetic ultraviolet wavelengths rather than visible light.
Detected by MAVEN鈥檚听Imaging Ultraviolet Spectrograph (IUVS) instrument over聽five days before聽Dec. 25, 2014, the ultraviolet auroras have been nicknamed Mars鈥� 鈥淐hristmas lights.鈥� They were observed across the planet鈥檚 mid-northern latitudes and are the result of Mars鈥� atmosphere interacting directly with the solar wind.
While auroras on Earth typically occur at altitudes of 80 to 300 kilometers (50 to 200 miles) and occasionally even higher, Mars鈥� atmospheric displays were found to be聽much lower, indicating higher levels of energy.
鈥淲hat鈥檚 especially surprising about the aurora we saw is how deep in the atmosphere it occurs 鈥� much deeper than at Earth or elsewhere on Mars,鈥� said Arnaud Stiepen, IUVS team member at the University of Colorado. 鈥淭he electrons producing it must be really energetic.鈥�
To a human observer on Mars the light show probably wouldn鈥檛 be very dramatic, though. Without abundant amounts of聽oxygen and nitrogen in its thin atmosphere a Martian聽aurora would be a dim聽blue glow at best, if not out of the visible spectrum entirely.
This isn鈥檛 the first time auroras have been spotted聽on Mars; observations with ESA鈥檚 Mars Express in 2004 were actually the聽聽of the phenomenon on the Red Planet. Made with the spacecraft鈥檚 SPICAM ultraviolet spectrometer, the observations showed that Mars鈥� auroras are unlike those聽found anywhere else in the Solar System in that they are generated by particle interactions with very localized magnetic field emissions, rather than a globally-generated one (like Earth鈥檚).
(So no, it鈥檚 not a total surprise鈥� but it鈥檚 still very cool!)
In addition to auroras MAVEN also detected diffuse but widespread dust clouds located surprisingly high in the Martian atmosphere. It鈥檚 not yet understood what process is delivering dust so high 鈥� 150-300 kilometers up (93-186 miles) 鈥� or if it聽is a permanent or temporary feature.
Source: NASA and聽
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A graphic designer in Rhode Island, writes about space exploration on his blog聽, Discovery News, and on Universe Today. Ad astra!
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