With all the amazing Science coming from Mars in the last decade, its seems easy to conclude that humans have a good understanding of our rusty neighbour. And then something new and unexpected happens. To someone who thought we knew all there was to know, this may be a disappointment. But to a scientist who has a passion for discovery, new and unexpected results are where the biggest breakthroughs happen!
Massive plumes have been spotted high in the atmosphere of Mars, at an altitude of over 250 Km, where the thin Martian atmosphere is nearly indistinguishable from the emptiness of space.
In March and April of 2012, the plumes were spotted by astronomers, developing in just 10 hours, and sticking around for up to 10 days, while changing their structure daily. It’s estimated that the plumes covered an area of 500,000 square Kilometres.
None of the Martian orbital spacecraft saw the plumes, and so a team of astronomers led by Agustin Sanchez-Lavega of the Universidad del País Vasco in Spain decided to look back through Hubble images of Mars spanning the past two decades. They found that occasionally plumes would reach as high as 100 Km above Mars, but rarely as high as the observations in 2012.
There is one case, from May 1997, where the plumes were comparable to those seen in 2012. These seem to be a rare occurrence, but unexpected nonetheless. Now that we have an idea how often these occur, we can start to look at what caused them. “One idea we’ve discussed is that the features are caused by a reflective cloud of water-ice, carbon dioxide-ice or dust particles, but this would require exceptional deviations from standard atmospheric circulation models to explain cloud formations at such high altitudes,” says Agustin.
But there are other ideas as well. “…they are related to an auroral emission, and indeed auroras have been previously observed at these locations, linked to a known region on the surface where there is a large anomaly in the crustal magnetic field,” adds Antonio Garcia Munoz, a research fellow at ESA’s ESTEC and co-author of the study.
Being a Science Communicator, it’s exciting to see stories unfold over time. Right now we are seeing the first observations and the big questions about these plumes, but over the coming months and years, we will see what their origin is as well learn more about the ever-enigmatic Mars.