Green comet C/2022 E3 (ZTF) will be the closest its been to Earth since the last ice age on February 1, says NASA

A bright green comet, not seen in our solar system since the last ice age, is now hurtling towards Earth for the first time in 50,000 years.

Comet C/2022 E3 (ZTF), says NASA, was discovered by astronomers using a wide-field survey camera in early March 2022 at an observatory in California.

Since then, say experts, the comet has brightened substantially and is now passing through the inner solar system and will be closest to the Sun on January 12 with a chance that it may be visible to the naked eye just a few weeks later.

According to the website Space.com it is estimated that the comet, which has been photographed surrounded by a blue green hue, takes 50,000 years to fully orbit the Sun.

This means that prior to it coming within 100 million miles of the Sun on January 12 and 26 million miles away from Earth on February 2, the last time it most likely came this close to our planet was during the Upper Paleolithic period - also called the Old Stone Age because of the development of chipped stone tools - and means that the last humans likely to have spotted C/2022 E3 (ZTF) would have been early homo sapiens alive during the last ice age or glacial period.

While at the moment the comet - described as having a short broad dust trail and a long faint ion tail, is too dim to be seen without a telescope, stargazers are hopeful that as it comes closer to Earth in the coming weeks there may be a chance it could be seen by those without any telescopic lens during dark skies early next month.

While NASA admits that 'the brightness of comets is notoriously unpredictable', for those living in the northern hemisphere - including the UK - the best chance to catch sight of the comet without a telescope or binoculars is expected to be between February 1 and 2.

In a blog post NASA explained: "On a voyage through the inner Solar System comet 2022 E3 will be at perihelion, its closest to the Sun, in the new year on January 12 and at perigee, its closest to our fair planet, on February 1.

"The brightness of comets is notoriously unpredictable, but by then C/2022 E3 (ZTF) could become only just visible to the eye in dark night skies."