Flyby Comet Siding Spring Electrified Mars' Atmosphere

Just last month, the comet Siding Spring (C/2013 A1) whipped by Mars within 88,000 miles of the planet. And while that may not sound too close, debris from the comet still had a shocking effect on the Red Planet's thin atmosphere.

The flyby happened Oct. 19, and went off without a hitch, not damaging any of Mars' orbiting man-made satellites. That's because NASA's Mars Odyssey, the Mars Reconnaissance Orbiter (MRO), and the Mars Atmosphere and Volatile Evolution (MAVEN) orbiter, along with a host of international crafts, were all safely tucked away on the other side of the planet to avoid any flying debris.

Still, even while as far away from Siding Spring as possible (while staying in orbit), the crafts were able to catch brief glimpses of the comet and the direct effects this once-in-a-lifetime event had on the Red Plant.

"This historic event allowed us to observe the details of this fast-moving Oort Cloud comet in a way never before possible using our existing Mars missions," Jim Green, director of NASA's Planetary Science Division at the agency's Headquarters in Washington, said in a statement. "Observing the effects on Mars of the comet's dust slamming into the upper atmosphere makes me very happy that we decided to put our spacecraft on the other side of Mars at the peak of the dust tail passage and out of harm's way."

Most notably, data from MAVEN, the MRO, and the European Space Agency's (ESA) Mars Express spacecraft have revealed that debris from the comet added a temporary and very strong layer of ions to the ionosphere, temporarily boosting the electrically charged layer.

The Mars Express data in particular, collected by a joint US and Italian-made instrument, observed "a huge increase" in the density of electrons following the comet's flyby.

"This spike occurred at a substantially lower altitude than the normal density peak in the Martian ionosphere," NASA reported.

Just like our own ionosphere experiences heightened charges during an intense meteor storm, NASA experts suspect that this spike marked a particularly stunning meteor shower.

Unfortunately, no one was on the planet to see the show for themselves.

However, that may all change by 2030, when NASA plans to have a man or woman set foot on the Red Planet for the first time.