article_snippet: they also made the unexpected discovery of dust about 93 miles (150 km) to 190 miles (300 km) above the red planet's surface.
article_snippet: Although the source and composition of the dust are unknown, Nasa said there is no hazard to Maven probe and other spacecraft orbiting Mars.
article_snippet: 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.
article_snippet: So far, no indication of it presence has been seen in observations from any of the other Maven instruments.
article_snippet: 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.
article_snippet: However, no known process on Mars can explain the appearance of dust in the observed locations from any of Possible sources for the observed dust.
article_snippet: The findings are being presented this week at the 46th Lunar and Planetary Science Conference in The Woodlands, Texas.
highlights_snippet: Dust was also found up to 190 miles (300 km) above planet's surface .
  
highlights_snippet: No known process on Mars can explain the appearance of dust clouds .