Unusually bright comet Neowise can be seen with the unaided eye.
Comet Neowise streaks over Clear Lake. The recently discovered comet will be visible to the naked eye for several weeks.
An enchanting comet is gracing night skies across the Northern Hemisphere for the next several weeks — and it won’t return for nearly 7,000 years.
Comet Neowise made an extraordinary trip past the sun, which caused dust and gas to burn off its icy surface and create an even bigger debris tail.
Now, the 3milewide comet is headed toward Earth, with the closest approach expected in two weeks.
“This comet is notable because it is easily visible to the unaided eye,” said Elinor Gates, an astronomer for the Lick Observatory on Mount Hamilton. “That’s a relatively rare occurrence. The last time we had a comet this easily
visible in the Northern Hemisphere was back in 1997 with comet HaleBopp.”
The comet Neowise is poised to shift this week. It initially sailed across the sky just before dawn each day — much to the satisfaction of the world’s early risers and science buffs — but will appear in the evenings starting this week as it speeds away from the sun.
It will be most visible between Tuesday and Sunday evening, astronomers said.
“Most comets are very far away, but every once in a while one will get directed inward and come in very close to the sun and sometimes close to the Earth,” said Andrew Fraknoi, an astronomy professor at the University of San Francisco’s Fromm Institute. “That rare event, when a chunk of ice actually makes an orbit where we can see it, where it’s both illuminated by the sun and relatively close to us, that’s pretty rare. That’s what everybody is excited about.”
Astronomers discovered Comet C2020 F3 NEOWISE at the end of March. Its nickname is short for NASA’s NearEarth Object Widefield Infrared Survey Explorer, which first spotted the comet.
Neowise will be visible around the world until midAugust, when it heads back toward the outer solar system. While it’s visible with the naked eye in dark skies with little or no light pollution, binoculars are needed to see the long, streaky tail, according to NASA.
It’ll reach its closest approach to Earth on July 22. But it may fade and become less visible over time, Gates said.
“Comets are inherently unpredictable — sometimes they get brighter because they have a big outburst of gas and dust, making them more visible for a time,” she said. “Sometimes they break apart and become fainter.
So I do recommend people look at the comet sooner rather than later while we know it’s still bright and easily visible.”
Scientists involved in the NASA mission said the comet is covered with sooty material dating to the origin of our solar system 4.6 billion years ago.
The Associated Press contributed to this report.
Tatiana Sanchez is a San Francisco Chronicle staff writer. Email: tatiana. sanchez@sfchronicle.com Twitter: @TatianaY Sanchez