A beautiful blue-green comet with a golden tail, which has not passed Earth for 50,000 years, has reappeared in the skies and is about to reach the closest point to the planet, expected for next week. But it is already possible to glimpse it.
It’s not just a once-in-a-lifetime event, it’s a practically unique spectacle. The last time he passed through here he was still seen by the extinct Neanderthals.
Discovered last March by astronomers at the Zwicky Transient Facility (ZTF) At the Palomar Observatory in California, comet C/2022 E3 (ZTF) circles the Sun once every 50,000 years, meaning it last passed our planet in the Stone Age.
Comet C/2022 E3 (ZTF) is approaching the northern skies and is expected to reach its brightest magnitude in early February, when it will be at a distance of 2.5 light-minutes from Earth – just 44,000 km.
What are comets and why is this one green?
Comets are primordial balls of dust and ice that revolve around the Sun in giant elliptical orbits. As they approach the Sun, these celestial bodies heat up, turning surface ice into gas and expelling dust. In this way a cloud is created (or coma or wig – cloudiness surrounding the nucleus of comets) that surrounds the hard core of the comet and the accompanying dust tail.
The green glow of C/2022 E3 (ZTF) is due to the presence of biatomic carbon – pairs of carbon atoms that are joined together – in the comet’s head. The molecule emits green light when hit by the sun’s ultraviolet rays.
How to see the comet
To see the comet, choose a dark place, free of artificial lights and wait about 30 minutes for your eyes to adapt. Look north just after sunset and look for a slight greenish glow. The comet may be visible to the naked eye, but binoculars will certainly make the job easier.
The Sky live website helps find the comet. An illustration of the night sky on January 25th showing the position of comet C/2022 E3 (ZTF) near the constellation of Draco.
On your way you will pass by the Polar Star, the brightest star in Ursa Minor. It will be the best time to spot it at that time – around February 1st and 2nd. From the middle of the month, the comet will have “darkened” as it continues its journey through the solar system, on its journey back to the Oort cloud.