What are the nine anomalies in 3I/ATLAS? Observations that challenge its natural origins according to Harvard scientist Avi Loeb

The first reported observations of the interstellar object 3I/ATLAS were made by the NASA-funded ATLAS survey telescope in Rio Hurtado, Chile, on July 1, 2025. Since then, the mysterious object has been studied extensively by scientists, who have been trying to understand its nature. 

Various studies and observations have come to light since its discovery, leading scientists to speculate about its origin. 

According to NASA’s official website, 3I/ATLAS is classified as a “comet,” an object from outside the solar system passing through our celestial neighborhood. However, Harvard astrophysicist Avi Loeb gathered data from various reports and studies and listed nine anomalies or unusual patterns, and questioned NASA’s conclusive theory.

While Loeb did not declare 3I/ATLAS to be alien technology or dismiss the possibility that the object is a comet after all, he urged experts to observe the abnormalities and study the object with an open mind.

More details on the nine anomalies in 3I/ATLAS as listed by Avi Loeb

The first point that scientist Loeb brought to light is 3I/ATLAS’ retrograde trajectory, which, according to his research, is aligned to within 5 degrees of Earth’s path around the sun or the ecliptic plane of the planets. 

Loeb argues that there is only a 0.2 percent likelihood of such an occurrence. 

The second anomaly is the “sunward jet” or the “anti-tail” of 3I/ATLAS, which scientists observed during July and August 2025.

Many other comets in the past have developed an “anti-tail,” an optical illusion caused by the observer’s position as the object travels between the Earth and the sun.

However, Loeb argues that so is not the case for 3I/ATLAS.

“That is not an optical illusion from geometric perspective, unlike familiar comets,” he wrote. 

The third anomaly draws attention to the interstellar object’s mass. According to Loeb, 3I/ATLAS is “a million times more massive than 1I/’Oumuamua and a thousand times more massive than 2I/Borisov.” 

Despite being that big, Loeb noted that 3I/ATLAS moves “faster than both.” Based on the numbers, he argues that for a comet to have such a nature is the likelihood of less than 0.1%

The fourth point of anomaly, according to Loeb, is the object’s “fine-tuned” path, which takes it on a course right past Venus, Mars, Jupiter, and “be unobservable from Earth at perihelion.”

Loeb believes the likelihood of such an occurrence is 0.005%

The fifth unusual pattern is 3I/ATLAS’ nickel-to-iron ratio.

According to studies, 3I/ATLAS’ gas plume has an “extreme abundance ratio” of nickel and iron, which makes it stand out from other more familiar solar system comets, including 2I/Borisov.

For the sixth anomaly, researchers examined the data from the Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer to deduce that the gas plume of the interstellar object contains only 4% water by mass.

Instead, it carries a higher proportion of carbon dioxide, which Loeb argues makes 3I/ATLAS an outlier. 

The seventh anomaly shows that 3I/ATLAS has an “extreme negative polarization, unprecedented for all known comets.” 

“The combination of low inversion angle and extreme negative polarization is unprecedented among comets and asteroids, marking 3I/ATLAS the first object known with such polarimetric behavior and representing a previously unobserved population,” Loeb wrote in a Medium post. 

Loeb further suggested that 3I/ATLAS may have emitted the “Wow! Signal,” which was detected in 1977 by the Ohio State University’s Big Ear radio telescope. 

The signal led to speculations about extraterrestrial beings, but it has remained a mystery since. 

Loeb argues it is the eighth anomaly, claiming 3I/ATLAS arrived from a direction coincident with the radio signal.

As the last anomaly, Loeb drew attention to the rapid brightening of the object near perihelion and its turning bluer than the sun, which, to him, was “very surprising,” as comets are expected to redden the scattered sunlight, resulting in having a redder color than the sun. 

However, whether the nine anomalies listed by Loeb hint at a technological origin of 3I/ATLAS remains debatable. 

On the contrary, NASA’s lead scientist, Tom Statler, while speaking with The Guardian last month, stated that 3I/ATLAS looked like a comet and behaved like one. 

Consequently, he dismissed alien theories; however, Loeb urged experts to collect as much data as possible and remain open-minded.