All about this comet’s “moving” visit, after 50,000 years of absence

It is an ice and dust star bearing the sweet name “C/2022 E3 (ZTF)”. This comet, which originates at the edge of the solar system, does not point its tail near the Sun for about 50,000 years. With a diameter of one kilometer – half that of the Principality of Monaco, this celestial body can be seen with the naked eye in late January. It will reach its perihelion, which is its closest point to the Sun, this Thursday, according to astronomers’ calculations.

It will be closest to Earth on February 1, just under 42 million kilometers. But what’s so special about this comet? What’s the best way to observe it in the coming weeks? 20 minutes see the stars that will adorn our night sky thanks to the lighting of Léa Griton, lecturer at the Sorbonne University and researcher at the Paris Observatory.

Why is this comet special?

“We don’t have the opportunity to observe comets with the naked eye every day”, notes Léa Griton early on, adding that this celestial body is “always a pleasure to look at, even for the amateur astronomer” . With its tail, comets have fascinated mankind for a long time. Their name comes from the ancient Greek “hairy star” and they are nicknamed “star broom” in Japan. The specialty of “C/2022 E3 (ZTF)” is that it comes from very far away. “In the solar system, all objects are subject to the immense attraction of the Sun. The orbits of the planets are almost spherical but comets have a very shattered ellipse”, explained researchers at the Paris Observatory. Farthest from the oval, the comet is at the edge of the solar system.

However, “often comets give us information about where they came from in the solar system”, underscores Léa Griton. Astronomers are observing these comets closely to learn more about their composition and universe. But the European Space Agency project is planned for 2029 “Comet Interceptor” (Comet interceptor) should allow for much more learning. “We will place the small spacecraft at one of the balance points around Earth, i.e. where objects can stay in place – and intercept incoming comets from the other end of the planet’s solar system for the first time”, explains the astronomer. Researchers want to catch “primitive comets,” which never pass close to the Sun. It is therefore a rare pearl, because even “C/2022 E3 (ZTF)” does not meet this criterion. “The idea is to analyze a comet before heating it with microwaves, near the Sun, as this can change its composition”, Léa Griton simplifies.

What do we see when observing comets from Earth?

Planets, milky way, shooting stars, etc. The space is beautiful. And, with their light trails, comets don’t miss a beat. In particular, it is this tail of light that can be observed from Earth. “A comet has two tails: one of them emits gas, while the other consists of plasma”, underlines Léa Griton. As it approaches the sun, comets experience furnaces but also solar winds. Part of its body sublimes, meaning it goes from a solid state to a gaseous state, causing these beautiful lines. “As we approach the sun, where the temperature is higher and the solar wind is stronger, the two tails become stronger, which allows us to see them with the naked eye,” explains the lecturer at the Sorbonne.

“It is very moving to observe a comet, it is a celestial body that you will never see again in your life. We have the opportunity to see millions of objects, even billions of kilometers from us and which would continue to exist without us”, underlines Léa Griton. It will take 50,000 years for the next “C/2022 E3 (ZTF)” visit. But comets that are more extroverted rarely pass by more than once in a human’s lifetime. The most famous of them, Halley, only returns every 76 years and his next visit is scheduled for 2061.

How to take advantage of this opportunity?

For “C/2022 E3 (ZTF)”, the odds start tonight. “Considering the distance between Earth and the comet, the ideal time to observe it is around February 3. But the Moon will be full on the 5th, so it’s better to try your luck around January 24th or mid-February,” explains Léa Griton. Because the Moon’s luminosity can be seriously handicapped when one tries to observe a celestial body that is less bright than it – meaning most of it. However, the comet should be “relatively easy to spot”, especially as it would be visible from the constellation Ursa Major.

To best contemplate this celestial body, it is better to stay away from big cities where light pollution washes out all the details of the sky. “At the Paris Observatory, we only observe the sun because everything else is degraded by light pollution,” says Léa Griton. The specialist encourages those who are most motivated to invest in binoculars: “For objects of this kind it is better to have very good binoculars than a ‘cheap’ telescope. They are much more practical for reuse during the day, much easier to carry and allow you to easily search for objects with your hands when the telescope has to be positioned and installed. “With good binoculars it will be possible to observe some of the satellites of Jupiter and even “almost observe the rings of Saturn”, assures the expert. For “C/2022 E3 (ZTF)”, it is first necessary to pray for clear weather because if the sky is full of clouds, the comet will make its visit silently, out of sight…