EARTH IS GETTING A RARE GIFT FROM THE COSMOS. A new comet has appeared in the night skies. It’s getting brighter and will peak at the end of the month and early February, which should make it easy to spot with a pair of binoculars—or, on a dark, clear moonless night, without them—as it passes between the Big and Little Dippers.
If you’re considering braving the chill winter air to catch a glimpse, don’t expect a visual extravaganza. The new comet won’t stay visible nearly as long as Hale-Bopp in 1997, which lasted 15 months, a record. To the unaided eye, it will be a small blob—nothing like Halley’s Comet of 1910, whose tail stretched two-thirds of the way across the sky. It also has a name only an astronomer could love: C/2022 E3 ZTF, after the Zwicky Transient Facility in California, whose astronomers discovered it in March.
But the ZTF comet has other things going for it. For one thing, it glows green, from molecules of carbon and nitrogen being ionized as it approaches the sun, which a pair of binoculars should reveal. It is also a rare visitor from deep space.
Astronomers are cock-a-hoop over its appearance because it gives them a chance to observe, close up, an object from the early days of the solar system, about 4 billion years ago, when a cloud of gas and dust collapsed upon itself to form the sun and the planets. Comets like this one are pieces
