Sunday Special - Aurora on Mars

Aurora are commonplace on Earth. When charged particles from the solar wind interact with the planet's magnetosphere, a grand light display is visible in varying colours and complexities near the poles. However, aurora are not just restricted to Earth.

Around mid-September, 2017, the sun released a coronal mass ejection that sent charged solar particles hurtling towards Mars. This resulted in a global aurora more than 25 times brighter than any previously seen by NASA's MAVEN orbiter. Other Mars missions also detected the event, including the European Space Agency's Mars Express orbiter, and NASA's Curiosity rover on the surface of Mars.

Unlike Earth, Mars does not have a global magnetic field that envelops the entire planet. Instead, Mars has umbrella-shaped magnetic fields that sprout out of the ground like mushrooms here and there, but mostly found in the southern hemisphere. These umbrellas are remnants of an ancient global field that decayed billions of years ago.
"The canopies of the patchwork umbrellas are where we expect to find Martian auroras," said Nick Schneider, head of MAVEN's IUVS instrument team. "But MAVEN is seeing them outside these umbrellas, so this is something new."