A new visitor from outside our Sistema Solar is crossing space at very high speed. Astrônomos confirmed the passage of comet 3I/Atlas, the third interstellar object ever detected, which travels at an impressive 57 kilometers per second. Sua trajectory and speed are so high that the celestial body will not be captured by Sol’s gravity, making only a single visit before returning to deep space.
Intensive monitoring of 3I/Atlas began in November 2025, when its extrasolar nature was confirmed. Desde then, a global network of observatories follows the comet’s every movement, collecting crucial data to understand its origin and composition.
The object’s main feature is its hyperbolic orbit, an open path that indicates it did not originate in our system. Essa’s distinct trajectory, combined with its speed, offers scientists a rare opportunity to study material formed around another star.
The trajectory that confirms its external origin
The hyperbolic orbit of 3I/Atlas is what fundamentally differentiates it from comets that belong to our Sistema Solar, which follow elliptical orbits and periodically return close to Sol. The interstellar comet’s speed exceeds its so-called escape velocity at any point in its journey, meaning that the gravitational pull of Sol is insufficient to trap it. The gravitational interaction will only slightly alter its direction, acting like a cosmic slingshot that will hurl it back into the interstellar medium.
Precise calculations carried out by space agencies indicate that the comet’s closest approach to Sol, known as perihelion, will occur in the next few days. During this period, observation will be intensified to capture details about the sublimation of gases from its surface, a phenomenon that reveals information about its internal composition. Simulações computations predict that the gravitational deflection will be a short-lived event, completing in a matter of hours before the object continues its journey away from us.
Higher speed than previous visitors
3I/Atlas’ 57 km/s speed puts it in a class of its own when compared to its interstellar predecessors.
The first object of its kind, the enigmatic ‘Oumuamua, detected in 2017, traveled at a speed of about 26 km/s. Já comet 2I/Borisov, identified in 2019, reached approximately 33 km/s.
The significantly faster speed of 3I/Atlas not only reinforces its extrasolar origin, but also poses a challenge to astronomers, as it drastically reduces the time window available for detailed studies.
Chemical composition reveals a distant past
Preliminary spectroscopic analyzes of 3I/Atlas, carried out with cutting-edge telescopes, already reveal a chemical “fingerprint” distinct from that found in comets in our system.
The light reflected by the comet was decomposed to identify the elements present in its coma, the cloud of gas and dust that surrounds it.
The data point to a high concentration of carbon monoxide and molecular hydrogen, as well as traces of methane and ammonia, suggesting that the comet formed in a stellar environment much colder than ours.
The presence of crystalline silicates in the comet’s dust is also an important indicator, providing clues about the temperature and pressure conditions in the nebula where it was born, millions or billions of years ago.
Global telescope network on high alert
Observatório Europeu of Sul (ESO), at Chile, is leading a coordinated observation campaign involving facilities around the world. Powerful Telescópios, such as Very Large Telescope (VLT) and Gemini North, in Havaí, are taking the time to capture high-resolution images and detailed spectra of the comet.
These tracking centers work together, with the VLT focusing on compositional analysis and the Gemini North obtaining infrared images to study the object’s thermal properties. Orbital data is constantly refined to predict your position with maximum accuracy.
[[_0]
Orbital dynamics and the future of interstellar detection
Unlike ‘Oumuamua, which exhibited a slight acceleration not explained by gravity alone, 3I/Atlas follows a path that aligns perfectly with gravitational models. Essa predictability makes its study more direct, allowing scientists to focus on its composition and origin. The detection of three interstellar objects in less than a decade suggests that such visitors are much more common than previously thought. Modelos statistics, which previously predicted one visit every century, are being revised to estimate up to seven passages per year by Sistema Solar, although most are too small to be detected with current technology. Essa new reality drives the development of networks of automated telescopes, such as the future Observatório Vera C. Rubin, which will continuously scan the sky and drastically increase the chances of intercepting these cosmic travelers early.
[[_1]
Opportunity for amateur observers
The cosmic event is not just restricted to large observatories. Astrônomos amateurs with suitable equipment will also have the chance to record the 3I/Atlas passage.
How and when to observe comet 3I/Atlas
The best window of visibility for observers at Hemisfério Sul will occur between November 28th and December 5th. Durante this period, the comet will reach its maximum brightness, with an apparent magnitude of 9.2, making it a challenging but possible target.
For observation, a location with dark skies, away from light pollution from cities, and the use of a telescope with at least 200 mm (8 inches) of aperture are recommended. The best time will be during the early hours of the morning, between 2am and 5am, when the sky is darker and the comet will be in a favorable position.
