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.
Photos taken by astronomers show a distinct green hue around the comet’s body.
But those expecting a brilliant streak of emerald in the sky will be disappointed. The brightness is right on the threshold of what is visible to the naked eye.
“You may have seen these reports saying we’re going to have this bright green object light up the sky,” said Dr Robert Massey, deputy executive director of the Royal Astronomical Society.
“Unfortunately, that won’t be the case.”
However, away from light pollution and under a dark sky, you may be able to see a spot in the sky – if you know what you’re looking for.
Potential stargazers are more likely to see it with binoculars, in which it will appear as a faint white blur.
“Even a small pair of binoculars will help you find it,” says Massey.
Comets are largely made up of ice and dust. As they approach the sun, the ice evaporates and the dust is shaken off to create the signature long tail.
“If you’re lucky, you’ll see a hint of the tail coming off it, so it will look more like a classic comet,” says Massey.
Astronomers discovered comet C/2022 E3 (ZTF) at the Palomar Observatory in California last March.
It has been visible to people in the Northern Hemisphere through binoculars for the past few weeks.
But it will make its closest approach to Earth this Wednesday at a distance of about 41 million km (26 million miles).
The object originates in the Oort cloud, a collection of icy bodies at the edge of the solar system.
To find it, Massey suggests looking first for the North Star, which is always in the same spot in the sky.
You can identify the North Star by looking straight north and locating a star clearly hanging on itself.
You can then use free online planetarium software to determine where the comet will move relative to the pole star the night you watch it.
The best time to view it is in the early hours of Thursday morning when the moon has set.
At that point, the comet should appear just to the right of the pole star.
A green appearance for comets is not uncommon and usually results from the breakdown of a reactive molecule called dicarbon — two carbon atoms linked by a double bond.
Such colors are picked up better by digital cameras, which are more sensitive to color.
The comet will not match the spectacle of 2020’s comet NEOWISE – the brightest comet visible from the northern hemisphere since 1997.
But the Planetary Society said “an opportunity to see it only comes once in a lifetime”.