Awaiting Comet ISON

Astronomer David Levy once said "Comets are like cats: they have tails, and they do precisely what they want." This means that it's notoriously difficult to predict how bright any incoming comet will appear from Earth -  and seemingly promising comets  have disappointed before, failing to perform as expected. Having noted this, according to the most optimistic predictions for comet ISON, which arrives in the inner solar system next autumn/winter, it could become as bright as the full moon, the brightest comet since the Great Comet of 1680.

 

Source SPACE.com: All about our solar system, outer space and exploration