An interstellar object named 3I/ATLAS has attracted widespread attention from the scientific community and the public in recent weeks, sparking a new round of heated debate between the scientific community and various non-mainstream theories regarding its origin.

   On October 29, 3I/ATLAS, known as the "third interstellar visitor," will pass through perihelion. Perihelion is usually the best position to study the composition of a comet, as solar heating vaporizes the various types of ice inside it. This is when comets are most active and brightest, making it a prime period for scientific observations.

The discovery of 3I/ATLAS has once again brought to mind the prophecy of the enigmatic oracle Baba Wanja that humanity would make contact with extraterrestrial civilizations in 2025. Meanwhile, its enormous size, unusual chemical activity, and unprecedented release of nickel vapor have further excited scientists. The scientific community generally believes that the scientific secrets behind 3I/ATLAS may be even more fascinating than the extraterrestrial tales.

Interstellar Visitors Arrive Again

3I/ATLAS was initially observed as a tiny point-like object in the night sky by the NASA-funded Asteroid Impact Warning System (ATLAS). On July 1st, ATLAS recorded the object traveling at an astonishing speed of approximately 210,000 kilometers per hour, at a distance of about 670 million kilometers from Earth. Within 24 hours, astronomers confirmed that 3I/ATLAS is an interstellar object. Its hyperbolic orbit, unbound by the Sun's gravity, is crucial evidence of its extrasolar origin.

Preliminary observations of 3I/ATLAS show that the object has a faint coma and a short tail, thus classifying it as a comet and giving it the nickname "cosmic snowball".

Subsequent observations revealed that 3I/ATLAS is enormous, with an estimated diameter of 10-20 kilometers, equivalent to the size of Manhattan Island, and larger than the asteroid that caused the extinction of the dinosaurs. Its mass is at least 3.3 billion tons, thousands to millions of times greater than the previous two interstellar visitors, 'Oumuamua' and '2I/Borisov'.

The scientific research website IFLScience reported on the 25th that 3I/ATLAS is particularly active compared to the other two. It releases about 180 kilograms of dust per second, more than double the rate of 2I/Borisov. 3I/ATLAS's orbit is higher and faster, and it may be older than the solar system itself, perhaps even twice as old.

Glowing nickel vapor in the coma

According to a report by Space.com on October 27, an international team used the Very Large Telescope in Chile to detect luminous nickel vapor in the coma of comet 3I/ATLAS. This indicates that it is undergoing a series of chemical activation processes, and the released nickel may be related to its complex molecular structure rather than traditional high-temperature metal vaporization.

Scientists also observed spectral lines of cyanide gas, a common molecular emission from comets in the solar system. Notably, no iron was detected within the observation range. Scientists speculate that nickel may exist in molecular form, perhaps combined with carbon monoxide or other organic compounds, which decompose under sunlight, releasing nickel atoms, rather than directly vaporizing at high temperatures.

Combined with observations from the James Webb Space Telescope, the chemical composition of 3I/ATLAS is more complex. The Webb telescope discovered that its coma contained significantly more carbon dioxide than water ice, and also detected water ice particles and carbon monoxide gas, indicating that various frozen substances were gradually warming, thus creating the active comet phenomenon observed. Scientists believe that nickel may be present in these decomposing molecules, along with the release of other gases; the release mechanism and the presence of other metals are still under further investigation.

The scientific community responds to non-mainstream speculation

Soon after 3I/ATLAS was discovered, rumors circulated online that it might be a "mothership" sent by an alien civilization, using the sun's gravity to accelerate or decelerate and hide behind the sun. This speculation was put forward by Harvard University astronomer Avi Loeb.

This isn't the first time Loeb has proposed a similar idea. Back in 2017, he proposed that 'Oumuamua might be an alien probe, publishing a best-selling book that sparked global discussion. This time, he suggests that 3I/ATLAS might be a sign of another alien visit. He speculates that the alien spacecraft might be using the gravity of a star to perform a "gravitational slingshot" maneuver, with the Sun providing the necessary acceleration.

But the mainstream view in the scientific community is almost unanimous that Loeb's speculation lacks evidence.

Since its initial discovery, NASA has closely studied 3I/ATLAS using both ground-based and space telescopes and has clearly stated that it poses no risk to Earth. Tom Statler, lead scientist for NASA's Small Solar System Bodies Program, emphasized that virtually all evidence indicates that 3I/ATLAS is a natural object with characteristics consistent with a well-known comet.

"All comets, not just interstellar comets, can exhibit unusual properties," Statler noted. "Comets are a mixture of dust and ice that are heated by the sun, and that heating can change their state, and how they react is sometimes difficult to predict."

Chris Lintott, professor of astrophysics at the University of Oxford in the UK, bluntly stated that Loeb's theory is "complete nonsense" and said that "there is no doubt that it is a comet."

At the same time, Loeb also admitted in his blog that "the simplest hypothesis is that 3I/ATLAS is a comet," and he proposed alternative possibilities more to challenge inherent ideas.

Despite the clear scientific evidence, the topic of "alien motherships" continues to spread rapidly online. Indeed, compared to "comets," alien spaceships obviously inspire more imagination. An "intelligent visitor from beyond the galaxy" generates more traffic and discussion than "floating ice." However, while science allows for imagination, it doesn't mean it can ignore evidence.

Currently, numerous telescopes and solar observatories around the world are closely tracking 3I/ATLAS. As it approaches perihelion, scientists are analyzing its brightness fluctuations, ejection rate, and wake shape to determine its internal structure and composition. These studies may change scientists' understanding of the chemical composition of interstellar comets and other solar system objects, and provide new insights into the origin of planetary systems throughout the Milky Way.