[meteorite-list] MAVEN Spacecraft Detects Aurora and Mysterious Dust Cloud around Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 18 Mar 2015 17:19:39 -0700 (PDT)
Message-ID: <201503190019.t2J0Jd6P001964_at_zagami.jpl.nasa.gov>

     
March 18, 2015
     
NASA Spacecraft Detects Aurora and Mysterious Dust Cloud around Mars

NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has observed
two unexpected phenomena in the Martian atmosphere: an unexplained
high-altitude dust cloud and aurora that reaches deep into the Martian
atmosphere.

The presence of the dust at orbital altitudes from about 93 miles (150
kilometers) to 190 miles (300 kilometers) above the surface was not
predicted. Although the source and composition of the dust are unknown, there
is no hazard to MAVEN and other spacecraft orbiting Mars.

"If the dust originates from the atmosphere, this suggests we are missing
some fundamental process in the Martian atmosphere," said Laila Andersson of
the University of Colorado's Laboratory for Atmospherics and Space Physics
(CU LASP), Boulder, Colorado.

The cloud was detected by the spacecraft's Langmuir Probe and Waves (LPW)
instrument, and has been present the whole time MAVEN has been in operation.
It is unknown if the cloud is a temporary phenomenon or something long
lasting. The cloud density is greatest at lower altitudes. However, even in
the densest areas it is still very thin. So far, no indication of its
presence has been seen in observations from any of the other MAVEN
instruments.

Possible sources for the observed dust include dust wafted up from the
atmosphere; dust coming from Phobos and Deimos, the two moons of Mars; dust
moving in the solar wind away from the sun; or debris orbiting the sun from
comets. However, no known process on Mars can explain the appearance of dust
in the observed locations from any of these sources.

[Image]
A map of IUVS' auroral detections in December 2014 overlaid on Mars'
surface. The map shows that the aurora was widespread in the northern
hemisphere, not tied to any geographic location. The aurora was detected in
all observations during a 5-day period.
Image Credit: University of Colorado

MAVEN's Imaging Ultraviolet Spectrograph (IUVS) observed what scientists have
named "Christmas lights." For five days just before Dec. 25, MAVEN saw a
bright ultraviolet auroral glow spanning Mars' northern hemisphere. Aurora,
known on Earth as northern or southern lights, are caused by energetic
particles like electrons crashing down into the atmosphere and causing the
gas to glow.

"What's especially surprising about the aurora we saw is how deep in the
atmosphere it occurs - much deeper than at Earth or elsewhere on Mars,"
said Arnaud Stiepen, IUVS team member at the University of Colorado. "The
electrons producing it must be really energetic."

The source of the energetic particles appears to be the sun. MAVEN's Solar
Energetic Particle instrument detected a huge surge in energetic electrons
at the onset of the aurora. Billions of years ago, Mars lost a global
protective magnetic field like Earth has, so solar particles can directly
strike the atmosphere. The electrons producing the aurora have about 100
times more energy than you get from a spark of house current, so they can
penetrate deeply in the atmosphere.

The findings are being presented at the 46th Lunar and Planetary Science
Conference in The Woodlands, Texas.

MAVEN was launched to Mars on Nov. 18, 2013, to help solve the mystery of how
the Red Planet lost most of its atmosphere and much of its water. The
spacecraft arrived at Mars on Sept. 21, and is four months into its
one-Earth-year primary mission.

"The MAVEN science instruments all are performing nominally, and the data
coming out of the mission are excellent," said Bruce Jakosky of CU LASP,
Principal Investigator for the mission.

MAVEN is part of the agency's Mars Exploration Program, which includes the
Opportunity and Curiosity rovers, the Mars Odyssey and Mars Reconnaissance
Orbiter spacecraft currently orbiting the planet.

NASA's Mars Exploration Program seeks to characterize and understand Mars as
a dynamic system, including its present and past environment, climate cycles,
geology and biological potential. In parallel, NASA is developing the human
spaceflight capabilities needed for its journey to Mars or a future
round-trip mission to the Red Planet in the 2030's.

MAVEN's principal investigator is based at the University of Colorado's
Laboratory for Atmospheric and Space Physics, and NASA's Goddard Space Flight
Center in Greenbelt, Maryland, manages the MAVEN project. Partner
institutions include Lockheed Martin, the University of California at
Berkeley, and NASA's Jet Propulsion Laboratory.

For images related to the findings, visit:

http://www.nasa.gov/maven

-end-

Dwayne Brown
Headquarters, Washington
dwayne.c.brown at nasa.gov
202-358-1726

Nancy Neal-Jones / Bill Steigerwald
Goddard Space Flight Center, Greenbelt, Md.
nancy.n.jones at nasa.gov / william.a.steigerwald at nasa.gov
301-286-0039 / 301-286-5017

Jim Scott
University of Colorado, Boulder, Colorado
jim.scott at colorado.edu
303-492-3114
Received on Wed 18 Mar 2015 08:19:39 PM PDT