A comet that orbits the sun just once every 50,000 years should be visible to the naked eye from Earth.
The previous time the comet arrived, the Sahara was moist and fertile, Neanderthals and woolly mammoths still roamed the planet, and humans had not yet reached North America, as far as we know.
C/2022 E3 (ZTF) was discovered for the first time by the Zwicky Transient Facility (ZTF) on March 2, 2022, and is expected to reach perihelion on January 12, 2023. ZTF is an astronomical survey undertaken in California by the Palomar Observatory.
Comets are “cosmic snowballs” composed of icy gases, dust, and rock that orbit the sun. As these delicate structures approach our star, they are bombarded with increasing levels of radiation, a process that can generate two enormous tails of gas and dust.
Comet C/2022 E3 (ZTF) is around 117 million miles from Earth at this time. It is expected to make a near encounter to Earth on February 1, 2023, coming within around 26 million miles on that date. This exceeds 109 times the normal distance between the Earth and the moon.
Predicting the brightness of comets with precision is quite difficult. However, current data suggests that C/2022 E3 (ZTF) will achieve a minimum magnitude of +6 around the time of its closest approach to Earth.
When measuring the brightness of astronomical objects, the magnitude of an object decreases as its brightness increases. As an illustration, an item with magnitude +2 is brighter than one with magnitude +8.
“It’s notoriously hard to predict the brightness of comets, however, sky watchers everywhere have been keeping track of Comet C/2022 E3 (ZTF) since it was discovered in March 2022, and the current prediction is that it might reach magnitude +6—the limit of what the naked eye can see—or even slightly brighter when it’s at its closest approach to the Earth on the 1st of February,” Tania de Sales Marques, an astronomer at the Royal Observatory Greenwich in the United Kingdom, told Newsweek.
Robert Massey, the deputy executive director of the U.K. Royal Astronomical Society, told Newsweek that the comet, which is projected to complete one circuit around the sun every 50,000 years, might become visible to the naked eye as early as the second part of January, assuming optimal conditions. The expected peak luminosity of the object is magnitude 4.75 on February 1.
If current projections of brightness are accurate, C/2022 E3 (ZTF) will be the first comet visible to the naked eye since NEOWISE’s magnificent display in 2020. Massey stated that expectations for C/2022 E3 (ZTF) should be lowered.
“I’ve seen rising interest in this comet, though it won’t be anything like NEOWISE,” he said.
C/2022 E3 (ZTF) is currently visible with binoculars or a telescope in the early morning hours before dawn as it passes through the northern constellation Corona Borealis. In the coming weeks, the comet will become easier to observe as it steadily brightens.
“It’s traveling in the general direction of Polaris, the North Star, where we’ll be able to find it in early February,” Marques said. “By then, it should be visible throughout the night.”
Massey stated that the comet will not be simple to locate. He suggests seeing on a clear night from a dark location, away from light pollution, when the moon is not visible in the sky; hence, it is preferable to avoid the days surrounding the full moon on February 6.
“I would recommend the use of a finder chart like this one to help find it with binoculars,” Massey said. “Binoculars are ideal for beginners trying to find a comet as they’re easy to use, whereas a telescope has a much smaller field of view. If you can see it with binoculars then try with your naked eye.”
At the time of the comet’s closest approach, it will still be rather weak, so folks in locations with dark skies may be able to see it with their naked eyes, but a pair of binoculars will boost your chances, according to Marques.
“Although it’s unlikely that it will be as impressive as comet NEOWISE, it’s still worth trying to catch a glimpse of C/2022 E3 (ZTF) since it won’t return for another 50,000 years,” Marques said.
The comet will likely lose visible to the human eye by the second week of February of next year. And by April, it will be so close to the sun in the sky and so much fainter that it will be extremely difficult to locate, even with a telescope.