Rare green comet approaching

A rare green comet, a unique traveller, is revisiting our solar system next month after 50,000 earth years when people still lived in caves.

Astrophysicist Dr Stelios Tsangarides told CNA that comet C/2022 E3 (ZTF) would reach its closest distance to Earth on February 1, when it will be at a distance of 42 million km from our planet.

The comet was discovered on March 3, 2022, by astronomers Bryce Bolin and Frank Masci (Zwicky Transient Facility, USA) when it was still on its way to the inner solar system.

A year later, the comet orbited the Sun and will soon pass close to the Earth.

He said what makes C/2022 E3 interesting is its greenish colour caused by the presence of molecular carbon (C2) on its surface.

The comet, Tsangarides noted, is also interesting because, as a long-period comet, its orbit around the Sun may take about 50,000 Earth years.

“This means that the last time it was in our neighbourhood – if there was a previous time – people were still living in caves, and not even oral historical records have survived – the oldest of which, the songs of the Australian aborigines, are estimated to be around 40,000 years old”.

Tsangarides added: “On February 1, it will be 42 million km from our planet.

“It will become visible to the naked eye, but at the limits of human vision, as a faint, nebulous object near the north celestial pole in the constellation Camelopardalis.”

For those who would like to see it with the naked eye, he noted that its dim appearance and the fact that there will be more than a half moon would make it invisible from the cities, with their intense light pollution.

“It may only be visible from the areas of our island with the darkest skies”, Tsangarides concluded.