Mars Plumes

Speculation is rampant, but offers no solid conclusion regarding the plumes of supposed clouds that amateur astronomers documented rising from a large area on Mars in 2012. Although the event took place more than two years ago, experts have been trying to understand the phenomena and published a paper recently in Nature. The cause and the source remain a mystery.

In the paper, astronomers offered two distinct theories. Plumes like those seen in 2012 have been observed by different instruments (observatories and satellites) since the mid 1990's but they were always confined to a height of roughly 60 miles. The previous plumes were determined to be clouds of either CO2/H2O ice crystals or dust particles, or they were auroras caused by "magnetic field anomalies." But even the auroras were only approximately 80 miles high. The 2012 plumes were from 120 miles to 150 miles high.

This means that these plumes are something new. According to the present gathered knowledge of Earth's astronomers, these plumes are impossible. It would be easiest to say that they are caused by magnetic flux within the planet and thus auroras, but that does not seem to be the case. An aurora bright enough to be seen at that distance would have to be 1000X more intense than those seen at Earth's poles. It is also unlikely to be either dust or ice crystals due to the height of the plume. At those elevations, the clouds should have dissipated before they could be seen.

So, astronomers, both amateur and professional, continue to observe the Martian limb hoping it happens again. A ray of light is the satellite MAVEN that has circled Mars since September of last year. Its purpose is to examine the Martian atmosphere closely. Maybe next time scientists will get a close up look at the plumes.

References

Nature - An extremely high-altitude plume seen at Mars' morning terminator

Nature - Bizarre Martian plumes discovered by amateur astronomers