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What time will the huge comet K2 make its closest approach to Earth?

a comet
An image of comet C/2017 K2 PANSTARRS (K2) taken in June 2017 by the Hubble Space Telescope's Wide Field Camera 3. (Image credit: NASA, ESA, and D. Jewitt (UCLA))

A huge comet is going to make a safe flyby of Earth in just a few more days.

Comet C/2017 K2 (PANSTARRS), called K2 for short, is one of the farthest active comets ever spotted. This little world will whizz by our planet on July 13 at a relatively far distance.

The official time of closest approach will be 11:09 p.m. EDT (0309 GMT July 14), when the comet will be 1.8 astronomical units from the center of our planet, according to data from NASA's Jet Propulsion Laboratory. (An astronomical unit is the average distance between the sun and Earth: about 93 million miles or 150 million kilometers.)

While the comet will be a little far and faint, it's still an exciting time for astronomers. It was spotted way back in 2017 in the outer solar system and is finally drawing near enough to Earth for amateurs to contemplate seeing it in binoculars or telescopes, although how bright K2 will get is a big unknown.

Related: Giant comet was active way farther from the sun than expected, scientists confirm

Some outlets, like EarthSky (opens in new tab), have predicted the comet might eventually get as bright as magnitude 7, and that the comet may brighten even after close approach to our planet as K2 draws nearer to the sun. 

That's still too dim for naked eye observing, as the best most folks can do is to see stars of magnitude 6 in dark-sky conditions.

For people with binoculars or a telescope, however, magnitude 7 is well within reach. If visible, the comet will likely appear quite diffuse as it releases gases due to the heat and pressure of the sun affecting its surface.

Professional observatories will be interested in learning the size of the nucleus, which is under debate. Hubble Space Telescope observations suggested it might be only 11 miles (18 km) across at most, while work with the Canada–France–Hawaii Telescope (CFHT) suggests a range of between 18 and 100 miles (30 to 160 km), according to EarthSky.

If you're looking for binoculars or a telescope to see the comet in the night sky, check out our guide for the best binocular deals and the best telescope deals now. If you need equipment for photography, consider our guides for the best cameras for astrophotography and the best lenses for astrophotography to make sure you're ready for the next comet sighting.

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Elizabeth Howell
Elizabeth Howell

Elizabeth Howell, Ph.D., is a staff writer in the spaceflight channel since 2022. She was contributing writer for Space.com (opens in new tab) for 10 years before that, since 2012. As a proud Trekkie and Canadian, she also tackles topics like diversity, science fiction, astronomy and gaming to help others explore the universe. Elizabeth's on-site reporting includes two human spaceflight launches from Kazakhstan, three space shuttle missions in Florida, and embedded reporting from a simulated Mars mission in Utah. She holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, and a Bachelor of Journalism from Canada's Carleton University. Elizabeth is also a post-secondary instructor in communications and science since 2015. Her latest book, Leadership Moments from NASA, is co-written with astronaut Dave Williams. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday.