Potentially ‘Alien’ Comet Zooms Toward Close Encounter With the Sun

Comet 96P/Machholz as seen in 2007.
NASA

A few days after bright green Comet C/2022 E3 (ZTF) makes its closest pass by Earth in 50,000 years, a bigger and stranger comet will buzz by the sun for 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 on Twitter. 

Battams has been tracking 96P’s progress towards the sun using SOHO, NASA’s solar observatory, providing some pretty striking visuals.

Here’s the latest view of comet 96P in the non-standard LASCO C3 90-sec exposure orange filter images. These were processed using pretty much that same basic (9 line!) python algorithm I talked about yesterday. I added a splash of color here to make it look a tad prettier ☄️☀️🛰️ pic.twitter.com/G7EFLo0Clb

— Karl Battams (@SungrazerComets) January 30, 2023

Most sun-grazing comets don’t survive a close pass by the sun, but 96P is big enough to potentially make it. That said, Battams has already tracked what might be fragments breaking off the nucleus several days before the moment of closest approach, or perihelion, which is expected on Feb. 7.

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 says his project is running a special observing program on 96P to gather as much data as possible.

“We’re trying to science the heck out of it.”