Earth’s night sky receives a surprise visitor this month.
Comet C/2022 E3 ZTF will make its closest approach to both Earth and the Sun in the coming weeks. The comet was first spotted in March 2022 by astronomers at the Zwicky Transient Facility, part of the California Institute of Technology’s Palomar Observatory, when it was 399 million miles (643 million kilometers) from the Sun, just inside Jupiter’s orbit. Since then, comet C/2022 E3 ZTF has moved much closer to the Sun and Earth.
Actual, at 11:00 PM EST on January 12 (04:00 GMT on January 13), the comet will make its closest approach to the Sun, known as perihelion. During this time, skywatchers may be able to observe the comet with the naked eye, if the conditions are right, you should be able to find it with binoculars or a telescope. Even if you don’t have the right conditions or optics to see C/2022 E3 ZTF, you can watch a free live webcast courtesy of the Virtual Telescope Project via its website (opens in a new tab) or its YouTube channel (opens in a new tab).
Related: Watch a comet’s closest approach in 50,000 years online next week
Comet C/2022 E3 ZTF has an orbital period of 50,000 years, which means it has not come close to Earth since the very early Upper Palaeolithic period Homo sapiens and the Neanderthals.
Not only has the comet not visited for a long time, but this may also be the last time it comes our way. The path is not closed, meaning it does not return to the same angular position as it began. Because of its highly parabolic orbit, C/2022 E3 ZTF will zoom out into deep space after its closest approach to Earth—perhaps never to return. Jessica Lee, an astronomer at the Royal Observatory Greenwich, told Newsweek (opens in a new tab) that “predictions suggest that the orbit of this comet is so eccentric that it’s no longer in an orbit—so it’s not going to return at all and will just keep going.”
Several astrophotographers around the world have already taken great pictures of the comet as it glides through the solar system. Its coma, the cloud of gases and debris surrounding the comet’s nucleus, has a characteristic green color in photographs due to its chemical composition. The green color suggests the presence of diatomic carbon, or dicarbons, molecules with two carbon atoms bonded together.
Comet C/2022 E3 ZTF should be visible throughout the month, not just at perihelion on January 12. After this close approach to the Sun, the comet will pass within 26 million miles of Earth on February 2.
Comet C/2022 E3 ZTF presents an excellent skywatching opportunity for skywatchers of all levels. If you don’t have the equipment you need (or want!), be sure to read our guides to the best binoculars and the best telescopes for viewing comets or other objects of interest in the sky. To capture the best comet images you can, we have recommendations for the best cameras for astrophotography and the best lenses for astrophotography.