Buzz
A conceptual illustration depicting Mars' potentially lush past contrasted with its current barren and frigid landscape.
Since its arrival in Mars' orbit over 13 months ago on September 21, 2014, MAVEN (Mars Atmosphere and Volatile EvolutioN) has been investigating the upper atmosphere, ionosphere, and magnetosphere of Mars. Its goal is to uncover the history of the Martian climate and determine how the planet gradually lost its atmospheric gases. Billions of years ago, Mars was a warmer and wetter world. The question remains: what happened to the water and carbon dioxide that once dominated its early climate?
During the initial phase of the mission, MAVEN charted the presence of carbon, oxygen, and hydrogen forming a cloud around Mars. While carbon and oxygen remain closely bound to the planet, hydrogen extends far beyond its surface. Studying how hydrogen escapes the atmosphere is crucial, as it is a key component of water. MAVEN's orbit takes it near Mars' polar regions, and the planet's rotation allows the spacecraft to examine its atmosphere from all angles, providing a comprehensive view of atmospheric behavior.
Today, MAVEN’s researchers unveiled several discoveries derived from the extensive data collected during its mission:
Mars' atmosphere is influenced by solar activity. This conclusion was drawn from MAVEN's observations during a solar gas and magnetic burst in March 2015. The interplanetary coronal mass ejection (ICME) triggered intense magnetic fluctuations, creating rope-like structures extending over 3100 miles into space. The increased ion escape rate during such solar events suggests a possible mechanism for significant atmospheric loss in Mars' early history.
The thermosphere and ionosphere exhibit significant vertical variations in temperature and density. These variations result from the continuous mixing of carbon dioxide, argon, nitrogen dioxide, and unexpectedly high levels of oxygen. These findings will enhance scientists' understanding of how solar wind interacts with the Martian atmosphere.
Mars features auroras resembling Earth's Northern Lights, occurring as close as 37 miles above the surface—the lowest ever observed. First detected last year in the planet's northern hemisphere using a UV light instrument, these auroras are created by particle acceleration along electromagnetic fields, similar to Earth's auroras. However, while Earth's auroras are driven by polar magnetism, Mars' auroras may stem from its crust's remnant magnetic field, producing a more widespread and diffuse glow. A breathtaking sight, if one could witness it from the Martian surface.
Additionally, the atmospheric dust is unlike anything on Earth. Researchers found dust particles evenly distributed at altitudes ranging from 124 to 621 miles above the surface. If this dust originates from Mars, its presence at such heights is unexplained, as no known processes can lift significant amounts of surface particles to these altitudes. The team hypothesizes that the dust may have an interplanetary source.
What do these findings collectively mean? At 2 pm ET, the researchers started delving into this very topic on NASA TV. If you miss the live discussion, be sure to check back with mental_floss tomorrow for a comprehensive analysis of these breakthroughs by space journalist and frequent contributor David Brown.
