The newly discovered Comet Leonard is set to light up the sky this month, as it passes by Earth for the first time in 70,000 years.
It will be visible in the Northern Hemisphere's pre-dawn sky with a telescope, or binoculars in dark-sky locations, as it increases in brightness during December.
Later in the month it may even be possible to spot the bright green iceball briefly in the evening shortly after sunset, astronomers say.
The comet has a green tail because its icy rock interior heats up the closer it gets to the sun, first emitting a blue dust, then yellow or white and finally green.
When it turns this teal colour, it means the comet is warm, contains lots of cyanide and diatomic carbon and the potential for it to break up is at its highest.
Unfortunately for skywatchers in the UK, it may be more difficult to see Leonard around the time of its closest approach because of its low position on the south-eastern horizon before twilight.
Britons are better off looking early in the morning at around 04:00 GMT up to December 10.
People in North America and the Southern Hemisphere should get their best view on December 14, with the comet possibly visible above the horizon after sunset.
There may even be a chance to spot Leonard on Christmas day, on the southwest horizon after sunset, depending on where you are in the world.
The comet, which is expected to be the brightest of 2021, even has its own Twitter account so stargazers can stay up to date about where it is.
It was discovered by astronomer Gregory J Leonard on January 3 at the Mount Lemmon Infrared Observatory in Arizona and catalogued as C/2021 AI.
The newly discovered Comet Leonard (pictured) is set to light up the sky this month, as it passes by Earth for the first time in 70,000 years
The object, catalogued as C/2021 AI, was discovered by astronomer Gregory J Leonard on January 3 at the Mount Lemmon Infrared Observatory in Arizona
Since its discovery, the comet has been approaching both the sun and Earth but has been a very dim object.
Most comets remain too faint for amateur telescopes to catch, but for a short while in December, Comet Leonard is set to light up the night sky.
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