In October 2014, comet C/2013 A1 (Siding Spring) swept past Mars at a very close distance and was also considered as the only known comet to come so near to Mars. At its closest approach, it was just 90,000 miles away from Mars that is one-third of the distance between the Earth and its Moon. It was observed that the tail of the comet dumped debris into the thin atmosphere. Through the coordination of multiple spacecraft of different space agencies, a spectacular meteor shower was witnessed which was also the largest in the history.
But now, scientists have discovered that the Sun, played a crucial part during this astonishing event. Trying to get on in the act, the Sun had launched a very powerful and vigorous coronal mass ejection (CME) towards Mars that entered Mars’ atmosphere just 44 hours before the comet.
At a special session of the European Planetary Science Congress (EPSC) 2017 in Riga, Latvia, scientists informed that the coronal mass ejection from the Sun created significant disturbances at the upper atmosphere of Mars and hence complicated the data analysis process. Beatriz Sanchez-Cano of the University of Leicester said that the event of Comet Siding Springing coming very close to Mars was very spectacular and exciting and the coma (comet’s outer atmosphere) almost engulfed the Mars. But when the event was deeply analyzed then it was observed that the comet’s close interaction of with Mars came out to be much more complicated than expected due to the interference of the Sun’s powerful CME.
The presence of the CME made the scientists disappointed because they were not able to study the comet event. Also at that time, the martian dust season was at its peak. But whatever may be the issue, the event of Siding Spring’s close encounter with Mars was very interesting and rare, and scientists informed that such spectacular events occur only once in every 100,000 years. Hence, the analysis of such type of event was very important.
Sanchez-Cano investigated the interaction of the comet with energy particles from the Sun as well as the effects of CME and the cometary encounter with the Martian atmosphere, with the help of the data collected from ESA’s Mars Express mission, NASA’s MAVEN and Mars Odyssey orbiters and the Curiosity rover present on the surface of Mars.
