Recent solar flares on the far side of the Sun, accompanied by powerful plasma ejections, may have affected the trajectory and speed of the interstellar object 3I/ATLAS, according to specialists from the Solar Astronomy Laboratory of the Space Research Institute (IKI RAS). The comet, which arrived from the depths of space, is showing unusual behavior that could be linked to solar activity — and it is expected to make its closest approach to Earth in December.

Solar Flares and Their Effect on the Interstellar Visitor

According to IKI RAS astronomers, between October 23 and 27, the object 3I/ATLAS was likely struck by at least five major coronal mass ejections (CMEs) — streams of plasma and magnetic fields. The most significant impact probably occurred on October 24, triggered by a powerful X-class flare detected two days earlier on the side of the Sun not visible from Earth.
These events may have disrupted the comet’s tail dynamics, altered the outgassing of dust and gas from its surface, and caused additional non-gravitational acceleration.

“The reported non-gravitational acceleration of the interstellar object 3I/ATLAS may have been caused by the plasma clouds ejected by the Sun about ten days ago, during the object’s approach to perihelion,” noted researchers at the laboratory.

The comet passed its perihelion — the closest point to the Sun — on October 29, at a distance of about 203 million kilometers. Both NASA and ESA confirm that such encounters with CMEs are rare but can temporarily alter comet behavior — as seen with Comet Encke in 2007.

What We Know About 3I/ATLAS: An Ancient Visitor With Anomalies

The interstellar object 3I/ATLAS (C/2025 N1) was discovered on July 1, 2025, by the ATLAS telescope in Chile. It is the third confirmed interstellar visitor after ʻOumuamua (2017) and 2I/Borisov (2019).

  • Nucleus diameter: 440 m to 5.6 km
  • Speed: ~137,000 mph (221,000 km/h)
  • Estimated age:6–14 billion years — up to 3 billion years older than the Sun
  • Orbit: hyperbolic, with eccentricity >6, meaning it is not gravitationally bound to our star

The comet exhibits several anomalies:

  • An unusual blue-glowing coma, possibly caused by ionized carbon monoxide or some “hot engine”-like process.
  • A sudden acceleration after perihelion.
  • A tail and coma about 24 km

Harvard astronomer Avi Loeb has identified nine anomalies, including the unexplained acceleration, joking that “perhaps 3I/ATLAS isn’t a comet at all — but a probe with an engine.”
Both ESA and NASA are observing it with Hubble, JWST, Mars Express, and ExoMars.

Closest Approach in December: A “Holiday Gift”?

On December 19, 2025, 3I/ATLAS will approach Earth at a safe distance of 267 million kilometers (1.8 AU) — close enough for detailed observation but posing no danger. By that time, astronomers expect to determine whether it’s a natural or artificial object.

Loeb joked, “Maybe the comet will send mini-probes as Christmas presents for humanity.”
In December, it will move through the Virgo and Leo constellations, and its brightness will drop below magnitude 12.

Monitoring continues: Parker Solar Probe and SOHO are tracking post-perihelion changes. Chinese astronomers ended observations after the comet passed Mars on October 3, at a distance of 30 million km.

In Short

Solar flares — including at least five CMEs between October 23–27, one of them X-class on October 24 — may have accelerated the interstellar comet 3I/ATLAS, causing non-gravitational motion, according to IKI RAS.
Discovered in July 2025, the object is the third interstellar visitor, roughly 10 billion years old, with anomalies such as blue emission, a bright tail, and a velocity of 221,000 km/h.
It will make its closest approach on December 19 at 267 million km.
Avi Loeb jokes about “alien probes,” but for now, it’s safe yet fascinating — and still under observation by Hubble and Mars Express.