Potentially 'Alien' Comet Survives a Close Encounter With the Sun

It's far bigger than the average "sun-grazing" comet.

Eric Mack Contributing Editor
Eric Mack has been a CNET contributor since 2011. Eric and his family live 100% energy and water independent on his off-grid compound in the New Mexico desert. Eric uses his passion for writing about energy, renewables, science and climate to bring educational content to life on topics around the solar panel and deregulated energy industries. Eric helps consumers by demystifying solar, battery, renewable energy, energy choice concepts, and also reviews solar installers. Previously, Eric covered space, science, climate change and all things futuristic. His encrypted email for tips is ericcmack@protonmail.com.
Expertise Solar, solar storage, space, science, climate change, deregulated energy, DIY solar panels, DIY off-grid life projects, and CNET's "Living off the Grid" series Credentials
  • Finalist for the Nesta Tipping Point prize and a degree in broadcast journalism from the University of Missouri-Columbia.
Eric Mack
2 min read
Comet 96P/Machholz soaring against a backdrop of stars

Comet 96P/Machholz as seen in 2007.


Right before the bright green Comet C/2022 E3 (ZTF) makes its closest pass by Earth in 50,000 years, a bigger and stranger comet buzzed by the sun Tuesday in an unusual encounter.   

Most so-called "sun grazer" comets are about the size of a house and end up getting vaporized by their daredevil dive around our star, but Comet 96P/Machholz is more like the size of a town at 6 kilometers (3.7 miles) across, and at least one astronomer suggests it might also be "alien."

Not necessarily alien as in created by extraterrestrial intelligence, but rather an interstellar comet alien to our own solar system. If that's the case, it could be very different from all other known comets, and all bets are off on how it will react to what looks to be a super-close encounter with the sun. 

"96P is one of the most compositionally and behaviorally weird comets in the solar system," Karl Battams, who directs the US Naval Research Laboratory's Sungrazer Project, said in a Jan. 29 tweet

Battams has tracked 96P's progress toward the sun using SOHO, NASA's solar observatory, providing some pretty striking visuals. On Tuesday, he retweeted a 96P fan's time-lapse video.

Most sun-grazing comets don't survive a close pass by the sun, but 96P was apparently big enough to make it. That said, Battams had tracked what might be fragments that broke off the nucleus in the days before the moment of closest approach, or perihelion, on Tuesday.

The comet's strange trajectory that takes it so close to the sun and its apparently low levels of carbon are just a few of the reasons researchers suggest it might be from beyond the solar system. Only in recent years have astronomers documented the presence of interstellar comets visiting our neighborhood, and at least one controversial astronomer has suggested that one interstellar visitor may have been artificial

Battams tweeted that his project has run a special observing program on 96P to gather as much data as possible.

"We're trying to science the heck out of it."

Correction, Jan. 31: The perihelion date has been fixed. It is Jan. 31.