If you are a passionate skywatcher you have surely watched the extraordinary show Mars has put on in our sky during the night over the past month. On July 27, Earth will pass between Mars and the Sun and on September 16, Mars will appear extra bright to us because it will have its closest point to the Sun. The same event has created the conditions for a huge dust storm that has enveloped the entire planet. These global storms only appear every six to eight years (that’s three to four Mars years).
The Mars Reconnaissance Orbiter, Mars Odyssey, and Mars Atmosphere and Volatile EvolutioN (MAVEN) orbiters are all observing this enormous dust storm from outside the planet, hoping to learn more about Mars’ weather patterns. The NASA Curiosity rover is studying the dust storm from the Martian surface. The Opportunity rover, however, was less fortunate. For it, this dust storm was not good news and it has been inoperable since July 18, because it runs on solar batteries and scientists had to suspend its activity to preserve its energy.
The Mars Reconnaissance Orbiter has two instruments, the Mars Color Imager and the Mars Climate Sounder that help it study the dust storm. With the Mars Color Imager the satellite maps the entire planet in mid-afternoon and tracks the evolution of the storm. The Mars Climate Sounder measures changes in the atmosphere’s temperature at different altitudes.
The other NASA orbiter, MAVEN, isn’t studying the dust storm itself, although that’s what it has been waiting for since it started orbiting Mars in 2014. According to NASA, the MAVEN wants to study how the dust storm affects Mars’ upper atmosphere, where the dust doesn’t even reach. MAVEN’s mission is to figure out what happened to Mars’ early atmosphere. At some point, billions of years ago, there was liquid water on Mars and that means it must have had a thicker and more insulating atmosphere, much like the Earth.
In its investigations MAVEN found it is possible that this atmosphere may have been stripped away by a torrent of solar wind.
Unlike Opportunity, the Curiosity rover doesn’t run on solar energy. It is fueled by nuclear power and therefore is not affected by the dust storm on Mars. It is still able to collect data, in spite of all the martian dust flying around it. Curiosity has received another mission, besides that of collecting a fresh rock sample. It has a chance now to study the development of the dust storm. With its numerous sophisticated instruments, Curiosity can determine the abundance and size of dust particles and can study atmospheric tides, that is shifts in pressure that are similar to waves moving across the entire planet’s thin air.
With this dust storm expected to last several more months, there is a great opportunity for scientists to get new results in studying this strange and troubled world.