A newly discovered comet will make its closest approach to our planet on Wednesday.
Astronomers say the object's journey to us took about 50,000 years.
Photographs captured by astronomers show a distinctive green hue around the comet's body.
But those hoping for a bright emerald ray in the sky will be disappointed.Its brightness is just on the threshold of what is visible to the naked eye.
"You may have seen these reports that this bright green object will light up the sky," says Dr Robert Massey, deputy chief executive of the Royal Astronomical Society.
"Unfortunately, that will not be the case"
However, away from light pollution and under dark skies, you may be able to see a smudge in the sky, if you know what you're looking for.
Would-be stargazers have a better chance of spotting it with binoculars, where it will appear as a faint white spot.
