In the vastness of our cosmic neighborhood, a few visitors, that do not belong to our Solar System, sometimes appear. One of them is 3I/ATLAS, the third interstellar object identified so far, whose behavior continues to astonish the astronomical community all around the world.
After its closest approach to the Sun, recorded on October 30th, observations from Hubble and the James Webb confirmed an extraordinary speed: 57 kilometers per second (205,200 km/h), more than twice the speed reached by Oumuamua in 2017.
Such speed would be impossible for an object trapped by the Sun’s gravity; however, since 3I/ATLAS is not bound by the gravity of the Solar System, its behavior is completely different.
Precisely that freedom is what sets it apart from bodies that are born near the Sun. It’s trajectory reveals that it did not originate here and that it is only passing through this region before disappearing into deep space.
The distinction between a local comet and an interstellar visitor lies in the shape of its orbit. While objects in the Solar System move in closed, generally elliptical paths, external travelers follow hyperbolic or open orbits, which means they will never return.
That is exactly the case of 3I/ATLAS, whose path clearly shows that its passage is temporary.
Calculated data show that its kinetic energy at all times exceeds the influence of the Sun. This means that it approaches, changes direction, and leaves without anything being able to stop it. Far from slowing it down, the Sun’s gravity acts as an additional boost that further increases its speed as it leaves the region.
What would happen if an interstellar object like 3I/ATLAS collided with Earth?
On November 24, a study was released that explored an extremely improbable but scientifically valid scenario: what would happen if an interstellar object like this were to impact Earth?
To do this, researchers generated 26 billion synthetic trajectories, based on the motions of nearby dwarf stars and solar gravitational adjustments, and then allowed millions of virtual paths to collide with Earth in a purely statistical model.
The result was surprising: a body similar to 3I/ATLAS would collide with our planet at a speed close to 72 km/s, far above most meteoroids in the Solar System, which reach between 11 and 30 km/s.
At such speeds, even small fragments would have a remarkable destructive potential. Fortunately, the likelihood of an actual impact from 3I/ATLAS is ruled out.
Until a few years ago, the idea that objects from other stars could enter our environment seemed more theoretical than real.
Oumuamua opened the discussion, Borisov cemented it, and now 3I/ATLAS suggests that these visitors might be more common than previously imagined, only they are too fast or too faint to be easily detected.
According to the study, many would follow patterns influenced by the Sun’s motion through the galaxy, which explains why they cross our space like fleeting messengers.
If nothing alters its journey, 3I/ATLAS will continue to accelerate as it moves away, since it has no orbit to follow nor cycle to repeat.
Its visit is a reminder that the Solar System is not an isolated refuge, but rather a waypoint within a much larger galactic map.
As 3I/ATLAS moves away, a somewhat unsettling question arises: how many interstellar objects may have passed near Earth without our knowing it? And more than that, how many could be crossing our cosmic neighborhood right now without being detected?
Why do some experts believe that 3I/ATLAS is much more than a simple comet?
The comet 3I/ATLAS became the subject of speculation due to a series of highly unusual characteristics that defy conventional explanations.
Its anomalies include an exceptionally large nongravitational acceleration that cannot be fully explained by normal ice outgassing (the “rocket effect”), which would require an implausible loss of mass.
In addition, its chemical composition is atypical, showing unusual levels of carbon dioxide and nickel compared to other elements, suggesting that it formed in a very different chemical environment and with an estimated age of up to 7 billion years or more, making it older than the Solar System itself.
All of the above, together with its unusual extra boost, the absence of a large gas cloud that would justify the acceleration, and the jet of material (anti-tail) pointing toward the Sun, led some scientists, such as astrophysicist Avi Loeb, to consider more speculative hypotheses, proposing that this could be a structure of artificial or technological origin.
What is certain is that, after NASA’s press conference, this hypothesis has been completely ruled out; nonetheless, experts emphasize that, since it comes from outside the Solar System, this is a celestial body that behaves in a unique and anomalous way.
Research and the release of images will continue as new data are obtained.
When will comet 3I/ATLAS be at its closest approach to Earth?
The date of its closest approach (perigee) to Earth will be:
- Date: December 19, 2025
- Distance: Approximately 1.8 Astronomical Units (AU), which is about 270 million kilometers.
This distance is almost twice the average distance between Earth and the Sun, so the comet is very far away and poses no danger to our planet.
What will happen on December 19, the date of the comet 3I/ATLAS’s closest approach to Earth?
December 19, 2025, will be the date of the closest approach to Earth of the interstellar comet 3I/ATLAS.
The importance of this day lies in the fact that it will be the best time to attempt to observe this cosmic traveler. The comet is expected to be visible in the morning sky, moving near constellations such as Virgo and Leo.
Although it is unlikely to be visible to the naked eye, amateur astronomers with small telescopes will have an excellent opportunity to capture data and images of this high-speed comet.
Once it passes this point, 3I/ATLAS will continue its journey toward the outer reaches of the Solar System, leaving it permanently.
