Comet McNaught pays a visit
Although poor weather hampered most chances of seeing it from the UK, some people were able to spot the comet just above the western horizon shortly after sunset. The following image was taken in Leeds (West Yorkshire) and clearly shows the bright core of the comet with a faint tail stretching away from it.
You can think of comets as great dirty snowballs that hurtle around the solar system in stretched-out oval orbits around the Sun. Those that get too close find material on their surfaces being evaporated (turned into gas) by the immense heat of the Sun. The water vapour and dust released is then blown away by Sun's rays to form an enormous tail that stretches out behind the comet.