ESA's Mars Express spacecraft has detected an aurora above the planet for the first time. This type of aurora has never previously been observed in the solar system.

Images taken earlier on the vehicle's SPICAM instrument (SPectroscopy for the Investigations and the Characteristics of the Atmosphere on Mars) show light emissions that have now been interpreted as being an aurora.

Aurorae are spectacular light displays, often seen at high latitudes on Earth (Northern/Southern Lights) and caused by charged particles from the Sun being channelled towards the planet's poles.

They have also been observed on Jupiter, Saturn, Uranus and Neptune. On Venus, which has no intrinsic magnetic field, aurorae are produced by the impact of electrons originating from the solar wind and hitting the night-side atmosphere.

Like Venus, Mars has no intrinsic magnetic field, but SPICAM has detected light emissions in the planet's southern hemisphere indicating the excitation of the upper atmosphere by charged particles - probably electrons.

The theory is that magnetic anomalies in the Martian crust are moving electrons along the field lines.

Source: Flight Daily News