First Martian aurora

In June 2006 ESA announced that its Mars Express orbiter had detected localised aurorae on Mars. On Earth the northern/southern lights are caused by charged particles from the Sun interacting with our magnetic field and making parts of the upper atmosphere glow like a neon tube. Mars has no magnetic field and, instead, its aurorae are caused by the solar particles interacting with regions of locally magnetised rock – remnants from when Mars once had a magnetic field of its own.