Professional and amateur astronomers alike are turning their eyes — and telescopes — to a rare visitor: Comet C/2022 E3 (ZTF), which it hasn’t passed close to Earth for 50,000 years.
It is technically visible from the southern hemisphere, including Brazil, but it is a difficult task to find it in the sky (below we give some tips for those who want to try).
In the northern hemisphere, however, the comet has put on a show in recent weeks, appearing very bright and greenish.
It should be seen by the 15th of February — each day it gets less bright as it moves away from the Sun.
Check out some of the best photos:
How to see?
Over here it appears close the horizon and in a small window of time. Observers from the North and Northeast regions have a certain advantage.
It is imperative to use an astronomy app (such as Star Walk, Stellarium, Star Chart, SkySafari or Night Sky) to find the exact location of the comet at that time and place. But we have some tips:
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Look for a high place with an unobstructed northern horizon and no light pollution.
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Look north between sunset and midnight; the best time is around 20:00
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The comet appears in the region of the Charioteer (Auriga) constellation, close to the star Capela
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It is moving upwards towards the constellation of Taurus and the planet Mars, which it approaches on the 10th.
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Look for a blurry star, a speck in the sky (you can’t see the tail with the naked eye)
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We recommend using binoculars
Its brightness is already at the limit of what the human eye can see, so it is very difficult to see it with the naked eye, even more so in the full moon phase, whose brightness overshadows other objects.
Anyone with a professional camera, or even a cell phone with settings, can point it in the estimated direction, zoom in, and program a long exposure (20 or 30 seconds should be enough), to try to record the comet’s greenish glow.
“When viewing the images, you will possibly notice a diffuse object with a tail. Using this technique, many are managing to photograph the comet even if they do not see it in the sky”, explains astronomer Filipe Monteiro, from the National Observatory.
Why is it green?
In the images recorded by telescopes, it draws attention to its green glow and long, bluish tail.
A comet only “lights up” like this when it approaches the Sun (far from it, it’s just a ball of dirty ice, with pieces of rocks), and substances from its nucleus pass directly from the solid to the gaseous state, releasing gases and dust, which they create a cloud around them — called a coma or ‘hair’.
That of C/2022 E3 (ZTF) is quite greenish, due to its different composition from the whitish comets. The color is due to the presence of diatomic carbon.
The closer to the Sun, these particles are spread over thousands of kilometers, “blown” by the solar wind. There the tail forms – which disappears when the comet moves away from our star. That of C/2022 E3 (ZTF) is bluish and has a triple appearance.
But these details are only seen with the aid of professional telescopes and cameras (astrophotographs).
🇵🇪 The #cometaverde It’s already happening over the skies of Peru right now. Make your wish.
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ᶜᵒᵐᵉᵗᵃ ᵛᵉʳᵈᵉ • #ᵍʳᵉᵉⁿᶜᵒᵐᵉᵗ • ˡᵘⁿᵃ • ˡⁱᵐᵃ pic.twitter.com/vsoEQ6k6qZ
— Omar 👁️🗨️ (@iamOmarPE) February 2, 2023
the comet
C/2022 E3 (ZTF) is a small, icy, rocky body, just 1 km in diameter, hailing from the depths of the Solar System. It last passed close to Earth at the end of the Ice Age; the witnesses were our Neanderthal ancestors and the first A wise man.
The errant object was discovered in March 2022 by a telescope at the Zwicky Transient Facility (ZTF — hence its name) in California, United States. Initially, it was believed to be an asteroid. But the increase in brightness as it passed Jupiter’s orbit revealed that C/2022 E3 (ZTF) was cometary in origin.
On Wednesday (1st), it passed “only” 42 million kilometers from Earth – the closest point to our planet, called perigee -, which is equivalent to 28% of the distance between our planet and the Sun.
Now, it is returning to the depths of the Solar System. Astronomers don’t know if it will ever return to Earth – but if it does, it should take another 50,000 years.
Learn about comets, meteors and asteroids.
