They may not even be observable directly

Nov 24, 2008 12:40 GMT  ·  By

The memorable event that takes place on the Earth's poles, called aurora, is not only restricted to our planet. The Sun and the magnetic fields of other planets allow for it to occur in the different atmospheres of the latter as well, although it may look nothing like what we're accustomed to. In fact, they may not be visible at all for human direct observers, outside their ultraviolet or infrared spectrum.

Among the other planets in our solar system known to possess such a wondrous phenomenon are Venus, Jupiter, Saturn and, more oddly, Mars. The event is generated by the charged particles carried by solar winds, which enter a planet's atmosphere along and accelerated by the lines of its magnetic field. The Earth's aurora is emitted in visible light, Saturn's is in infrared, Jupiter's complex one is in UV, but Mars' is still more intriguing.

 

As already explained, Mars has a very weird kind of a magnetic field. It is believed to have been killed off a long time ago by a massive asteroid impact, leaving only bits of magnetic rock every here and there, on the red planet's surface. Martian auroras, as they've been depicted nine times since 2004 by Mars Express' SPICAM device, were discovered to be tightly linked to the spreading of these rocks on the planetary surface. But it's still uncertain whether an absolute influence is involved.

 

“It may be that magnetic fields on Mars connect with the solar wind, providing a road for the electrons to travel along,” said Francois Leblanc from the Service d’Aeronomie in France, quoted by Universe Today. Further doubt is fueled by SPICAM's UV-only sight, as well as by the fact that Mars' atmosphere is scarce in molecular and atomic oxygen and molecular nitrogen, which give the beautiful colors of the Earth's aurora. So, it's not clear what Martian colonists would see when gazing upon the event. “We’re not sure whether the aurorae will be bright enough to be observed at visible wavelengths,” shared Leblanc.