The Cassini spacecraft detected an unusual bright spot on Saturn's moon Titan with its Visual and Infrared Mapping Spectrometer (VIMS). The spot is about the size of Ireland and is located south-east of the bright region called Xanadu. This new brightest spot on Titan mystifies scientists because they aren't sure what's causing it.
The 483-kilometre-wide region may be a 'hot' spot, an area possibly warmed by a recent asteroid impact or by a mixture of water ice and ammonia from a warm interior, oozing out of an ice volcano on to colder surrounding terrain. Other possibilities for the unusual bright spot include landscape features holding clouds in place or unusual materials on the surface. This bright patch may also be due to an impact event, landslide, cryovolcanism or atmospheric processes.
Other bright spots have been seen on Titan, but all have been transient features that move or disappear within hours, and have different spectral (colour) properties than this feature. This spot is persistent in both its color and location.
Scientists have also considered that the spot might be mountains. If so, they would have to be much higher than the 100-metre-high hills Cassini's radar altimeter has seen so far. Scientists doubt that Titan's crust could support such high mountains.
Next year on July 2 the Cassini space craft will fly-by to take night-time images of the area. If the spot glows at night, then researchers will know it is hot. More info about this spot at ESA