Green Comet C/2022 E3 (ZTF) will approach Earth on February 1st and, although pale in the northern sky, will be seen near the carts/bears before sailing into deep space for millions of years if ever to return
On February 1, a bright green comet named C/2022 E3 (ZTF) will approach Earth for the first time since the Stone Age. Researchers have calculated that the frozen ball of gas, dust and rocks has been orbiting the Sun for about 50,000 years, which means Neanderthals were still walking the Earth and modern humans were just migrating out of Africa for the first time when the comet passed them by.
But you don’t have to wait until February to catch a glimpse of the comet, you can already see it in the sky late at night and early in the morning. Stargazers have been tracking the comet’s path for weeks and got a particularly good view of it on January 12, when the comet reached its closest point to the Sun.
The path of the green comet
When astronomers first discovered C/2022 E3 in March 2022, the comet was hurtling around the Solar System about 400 million miles from the Sun. Although the object was faint—about 25,000 times fainter than the faintest stars visible to the unaided eye—researchers quickly spotted a clear tail that proved the object was indeed a comet. And not an asteroid.
By January 12, 2023, it had come 482 million km to Earth, and was visible in the night sky near the northern constellation of the Northern Crown. From there, it continued to move westward across the sky. The experts calculated that the comet would be visible to the unaided eye in the third week of January.
On the nights of January 26 and 27, the comet will be visible slightly east of the wheels of the little cart (the bear). On February 1, when the comet will be at its closest point to Earth, it will appear near the constellation Giraffe, not far from the Big Dipper.
A few days later, on February 5th and 6th, the comet will pass in the night sky to the west of the star Capella and then appear to enter the Rachave group. From there it will descend towards the Taurus group, and will dim even more as it moves away from Earth, back to the edge of the solar system.
Before the comet’s last trip near our sun it traveled very far at the edge of the solar system for about 50,000 years. Astronomers aren’t sure how far from Earth C/2022 E3 will now travel, but there seems to be consensus that its orbit has changed and become eccentric and is therefore on its way to leaving the solar system entirely. After that the humans may never see him again.
Viewing the Haruk bat
When the comet speeds past Earth on February 1, it will be about as bright as the faintest stars in the night sky. But the comet will not look like a sharp, pointed star, but like a diffuse glowing spot that may spread its light over an area the size of the moon.
Stargazers who live in cities or other areas with light pollution will have difficulty seeing the comet. It is recommended that they get to the darkest place possible, allow their eyes to adjust to the darkness for 20-30 minutes, and then look towards the North Star, which is at the far end of the big cart. With unaided eyes, look for the comet’s bright halo around this area of the sky. It may be easier to locate the comet this way rather than trying to find it with binoculars or a telescope, according to Space.com.
why C/2022 E3 green?
The comet itself is not green, but its head appears to glow green due to a rare chemical reaction. The glow probably comes from diatomic carbon (C2) – a simple molecule consisting of two carbon atoms. When UV light from the sun breaks down this molecule, it emits a greenish glow that can last for days.
C2 is common in comets, but not usually found in their tails. This is why the halo – the haze surrounding the ball of frozen gas, dust and rock at the center of the comet – glows green, while the tail remains white.