The solar storms that gave rise to the hugely impressive auroras seen around the world on May 10 also gave Mars a lashing, sparking auroras over the Red Planet and dousing the surface with harmful radiation.
The primary source of the solar storms was an active region, AR3664, which was an intense knot of magnetic flux on the sun populated by dozens of sunspots that unleashed a large number of powerful flares and coronal mass ejections (CMEs) first at us, and then later as it rotated around the sun, towards Mars.
