Green comet last visible during the Ice Age to pass Earth

A comet that last appeared in the night sky when Neanderthals still roamed the Earth is set to make a reappearance.

The C/2022 E3 (ZTF) comet orbits the sun every 50,000 years and will pass within 26 million miles of Earth on 1 February 2023, making it visible to the naked eye.

It is already visible using binoculars and low-level telescopes when the skies are clear, and should become visible without specialist equipment from mid to late January.

Astronomers have already been tracking the E3 comet, revealing a blue-green coma and a golden tail.

E3 will be the first comet to light up the sky since the Neowise comet in summer 2020.

The E3 comet captured by astronomers at Nasa in December 2022 (Nasa)
The E3 comet captured by astronomers at Nasa in December 2022 (Nasa)

First discovered by the Zwicky Transient Facility (ZTF) in California, the E3 comet has since been photographed by astronomers at Nasa.

The E3 comet got its name for being the third comet discovered in the fifth fortnight of the year.

Astronomers advise anyone hoping to see the E3 comet to pick a dark place free of ambient light and allow 30 minutes for eyes to adjust.

Specialist smartphone apps and websites can also be used to determine the comet’s position in the sky, such as Star Chart, Sky Safari and SkyView.

“Comets are intrinsically highly unpredictable objects, since their brightness depends on the scattering of sunlight from dust particles in the comet’s coma and tail,” comet-tracking website In-The-Sky noted.

“This dust is continually streaming away from the comet’s nucleus, and its density at any particular time is governed by the rate of sublimation of the ice in the comet’s nucleus, as it is heated by the sun’s rays. It also depends on the amount of dust that is mixed in with that ice. This is very difficult to predict in advance, and can be highly variable even between successive apparitions of the same comet.”