Comet ISON is visiting the inner solar system and is set to put on spectacular views for the Northern Hemisphere across November and December as it heads towards the sun.
It may prove to be brighter than any comet of the last century - visible even in broad daylight - and this may end up being its one and only trip to the solar system, as its trajectory may see it plunge into the sun in a fiery death.
It is currently moving inwards from beyond Jupiter, and as it approaches the Earth, the 'dirty snowball' could produce a dazzling display, burning brighter than the moon and potentially being visible in broad daylight.
The comet, discovered by astronomers using the International Scientific Optical Network telescope in Russia, will pass within two million miles of the sun's surface - making it s 'sun-grazing' comet.
It is on a 'parabolic' orbit, which means it probably originated from the outer skirts of the solar system, perhaps from the Oort cloud - a mass of icy debris which lies 50,000 times further from the sun than the Earth does.
If comet ISON survives the encounter, it could take thousands - potentially millions - of years before the comet passes back through the inner solar system.