K2 Comet Photos and Reaction After Reaching Closest Point to Earth

The comet C/2017 K2 passed its closest point to Earth on Wednesday and Thursday, prompting casual astronomers to set up their backyard telescopes and take a look.

The comet has attracted interest in recent weeks as it nears the end of its roughly 3 million-year journey towards the sun from the outer region of the solar system known as the Oort Cloud.

In December, it will reach its closest point to the sun before heading back towards the icy outer reaches of the solar system once again.

Scientists have known about K2 for years. NASA captured an image of it with the Hubble Space Telescope back in 2017 when it was 1.5 billion miles away from the sun, beyond the orbit of Saturn. It became the farthest active inbound comet ever seen.

A stock illustration depicts a comet—not C/2017 K2—moving through space. Comets are icy objects left over from the solar system's early days. ClaudioVentrella/Getty

Active comets are comets that are heated up by the sun so that they begin to expel gas and dust. This is what gives comets their characteristic tails and brightness. Indeed, when Hubble saw K2 back in 2017, the comet had already developed a cloud—also known as a coma—80,000 miles wide.

On Thursday K2 reached its closest point to Earth at a distance of roughly 1.8 astronomical units according to space news outlet Space.com—nearly twice the distance from the sun to the Earth.

While this was not close enough for the comet to be noticeable to the naked eye, it was close enough for backyard astronomers to take a look.

Astrophotographer Stephen Peters managed to get the below image from the U.K. using ten two-minute exposures stacked together.

Comet C/2017 K2
A composite image of the comet C/2017 K2 taken by astrophotographer Stephen Peters in July, 2022. Stephen Peters

Dave Eagle, also in the U.K., tweeted a photo of the comet seen to the upper right of the star cluster Messier 10.

Some observers said they had a tough time pinpointing the comet's exact location or getting a decent view of it. Twitter user HyenaDae noted that high humidity led to a foggy lens, while moonlight made clear shots extra difficult.

Twitter user @yolkregion managed to capture the below shot, though there was glare from the moon and city lights. "Pointing south over the Toronto glare with a full moon rising was not ideal, but had to try!", they wrote.

In short, C/2017 K2 has not proved to be as spectacular a sight as other icy visitors to our part of the solar system, including Comet NEOWISE in 2020 or Comet Hale-Bopp in 1997, both of which were visible to the naked eye.

Still, comets in general are interesting to scientists as they represent pristine remnants from the early days of the solar system.

Update 07/15/22, 11:47 a.m. ET: This article was updated with a new tweet.