Comet 3I/ATLAS, discovered in July 2025, intrigues astronomers with its peculiar characteristics. Astrophysicist Avi Loeb, from Harvard, argues that the object, with an estimated mass of more than 50 billion tons, could be an alien spacecraft, and not a natural comet. Detected by a telescope in Chile, the interstellar object has jets and speed that, according to Loeb, suggest technological propellants. NASA, however, states that the behavior of 3I/ATLAS is typical of comets.
Recent observations, such as radio signals captured by the MeerKAT telescope, indicate the presence of ice, reinforcing the natural origin of the object. The comet, the third interstellar identified, does not pose a risk to Earth, with its closest passage scheduled for December 19, 2025. New analyzes are scheduled for March 2026, when NASA’s Juno probe will attempt to collect data near Jupiter.
- Estimated diameter: between 320 meters and 5.6 kilometers.
- Speed: around 210 thousand km/h.
- Composition: rich in carbon dioxide, with traces of water and hydroxyl.
- Origin: possibly a cold region of the Milky Way, up to 7 billion years old.
Unusual features of 3I/ATLAS
3I/ATLAS stands out for its atypical chemical composition. Observations from the James Webb Space Telescope revealed a proportion of carbon dioxide eight times greater than that of water, something rare in comets.
This composition suggests that the object wasit formed under conditions different from those of comets in the Solar System. The presence of hydroxyl, detected in October 2025, indicates ice in the nucleus, typical of interstellar comets.
Loeb theory and controversies
Avi Loeb, leader of the Galileo Project, argues that the mass of 3I/ATLAS, exceeding 50 billion tons, is disproportionate for a natural comet. He compares the object to 1I/Oumuamua, suggesting that its jets could be ion thrusters.
Your ideas face skepticism. The scientific community points out that radio signals and ice sublimation align with cometary behaviors.
NASA reinforces that there is no evidence of alien technology. Studies continue to clarify the nature of the object.
Recent scientific observations
The MeerKAT radio telescope in South Africa detected radio waves from 3I/ATLAS on October 24, 2025. The analysis confirmed the presence of hydroxyl, a byproduct of water sublimation.
Telescopes such as Hubble and James Webb have provided detailed images. The comet’s retrograde orbit, almost aligned with the Earth’s plane, is considered rare.
The object passed through perihelion, the closest point to the Sun, on October 29, 2025. Its trajectory does not indicate a risk of collision with Earth.
New observations are planned with the European Space Agency’s JUICE probe, between November 2 and 25, 2025.
Next steps in research
The Juno probe, positioned in Jupiter’s orbit, will attempt to capture radio signals from 3I/ATLAS in March 2026.
The data will help map the composition and trajectory of the object. Astronomers seek to confirm whether it is a natural comet or presents unexplained anomalies.
The global monitoring campaign, coordinated by the International Asteroid Warning Network, runs until January 2026. The objective is to refine orbital calculations.
3I/ATLAS remains visible until September 2026, offering more study opportunities.
Global Comet Monitoring
NASA and other space agencies have monitored 3I/ATLAS since its discovery. The activation of planetary defense protocols is preventive and does not indicate a threat.
The object is the third interstellar identified, after 1I/Oumuamua (2017) and 2I/Borisov (2019). Your visit is a unique chance to study materials from other star systems.
Ongoing scientific debate
Loeb insists that the alien hypothesis must be tested scientifically. He suggests thatthe comet’s trajectory, hidden by the Sun in October 2025, may indicate intentional maneuvers.
Most astronomers refute the theory, highlighting that 3I/ATLAS exhibits typical cometary features. Additional data, such as from the Juno probe, may clarify the debate.
