The passage of comet 3I/ATLAS through the closest point to the Sun: what time was it, what happened and when will it reach Earth

He 3I/ATLAS It has been the focus of space researchers since July, when it was first detected.

This is because the cometalthough it is not the first known interstellar, it has a series of characteristics that make it unique.

Therefore, its journey is closely followed, and one of the most important milestones will occur this October 29when the phenomenon reaches its closest point to the Sun, while its passage through the orbit of our planet is also eagerly awaited. planet.

Consequences of the passage of 3I/ATLAS through the Sun: can it be seen?

The comet in question was reported for the first time on July 1, 2025, after being detected by the ATLAS study telescope, funded by the NASAlocated in Río Hurtado, Chile.

It is about the third interstellar object known (hence its name «3» «I»), after the discovery of 1I/Oumuamua, in 2017, and 2I/Borisov, in 2019. However, this comet presents some particularities that make it a phenomenon never before observed.

The clearest image of comet 3I/ATLAS captured by the Hubble Space Telescope. Photo: Archive

Among these anomalies is that, in principle, it had a «tail» directed towards the sun, when comets typically point their jet in the opposite direction.

Likewise, its diameter, which could be more than 11 kilometers, transforms it into an object up to a thousand times more massive than its predecessors, and the same thing happens with its speed: it travels at more than 220,000 kilometers per hourmuch faster than previous interstellar objects.

Furthermore, 3I/ATLAS not only comes from another system other than the solar system (hence its «interstellar» characterization), but it also has a hyperbolic trajectory, that is, it will pass just once near the Sun and then it will be gone forever of the system. That is why interested parties ask When will this event occur?

NASA reported that the comet will reach its closest point to the Sun (known as perihelion) around October 30, 2025, when it will be located at a distance of approximately 210 million kilometers from the star.

However, various media, including some specialized in the subject, such as Universe Today, They stated that in reality this would have happened this Wednesday October 29 around the 11:47 Universal Time (UT). It is estimated that the United States aerospace agency did not issue a statement in this regard due to the government paralysis of that country.

The placement of 3I at its perihelion could trigger consequences such as increased chemical activity and an increase in the speed at which the object travels.

Furthermore, as a consequence of the intense solar heat, the expansion of the coma (gaseous cloud that surrounds the nucleus) and the tail (flows of gas and dust leaving the coma) of the comet will occur. This makes the phenomenon more visible and, although specialists assure that It cannot be observed with the naked eye by humans.it can be visualized using sophisticated telescopes.

When will 3I/ATLAS pass near Earth and the danger it means

According to NASA, the closest 3I/ATLAS will pass to our planet is about 270 million kilometers.

He also estimates that this will happen in December 2025and, although the comet will not be visible to the human eye, it will be the moment when specialized teams will be able to observe it more clearly.

The 3I and its trajectory. Photo: Gemini Observatory/NOIRLab/NSF/AURA/K. Meech (IfA/U. Hawaii)

The organization, also, due to the “inexplicable” behavior of 3I, activated its planetary defense protocol.

The mechanism was made official through the MPEC bulletin (Minor Planet Electronic Circulars), published by Minor Planet Center from Harvard, an organization that operates under the authority of the International Astronomical Union (IAU) and is funded by NASA.

However, the agency announced that, because the object will circulate so far from the planet, does not pose a threat for this one.