What we know so far about 3I/ATLAS: Everything understood to date

3I/ATLAS, the interstellar object, has remained a topic of interest for researchers and space enthusiasts for months. Many discoveries have been made since it was first spotted on July 1, 2025. 

With the latest images released by NASA in November and early December, new information continues to surface about the interstellar object.

Although NASA describes it as an “interstellar comet,” astrophysicists like Avi Loeb from Harvard University have spoken out about its anomalous nature, urging others not to jump to conclusions about its origin or type, but to be open to new details as and when they emerge with studies regarding the object being carried out among space communities across the globe. 

The most recent observations by researchers across Europe and Africa noted that 3I/ATLAS pulsates light jets like a heartbeat, with a period of 16.16 hours.

While many suggested that the change in light was a result of the object’s rotation, Avi Loeb suggested it could be a sign of an artificial propulsion system.

However, his claims remain speculative. 

Everything to know so far about the interstellar object 3I/ATLAS

3I/ATLAS’ discovery

On July 1, 2025, the ATLAS (Asteroid Terrestrial-impact Last Alert System) survey telescope spotted and reported the interstellar object from Rio Hurtado, Chile. 

It is the third observed interstellar object and was noticed when it was approximately 420 million miles away from Earth. 

However, when the discovery became public, reports about its “pre-discovery” began to surface, some dating back to June 14. 

“Since its first report, observations from before the discovery have been gathered from the archives of three different ATLAS telescopes around the world and the Zwicky Transient Facility at the Palomar Observatory in San Diego County, California,” NASA’s official website said. 

NASA also assured people that he interstellar object posed no threat to human life as it would remain hundreds of millions of kilometers away from Earth even during its closest approach. 

What makes 3I/ATLAS stand out?

The interstellar object has remained a topic of discussion, sparking debate within the space community because of its anomalous nature. 

While it resembles the traits of a comet, it also shows signs that challenge those, making its nature – natural or artificial/alien – open for debate. 

From 3I/ATLAS’ “anti-tail” and its composition, which features a strange abundance of nickel as compared to iron, to its “extreme negative polarization” and unusual brightening and non-gravitational acceleration, it shows several signs that make scientists question its origin. 

However, even with the anomalies, summarized by Avi Loeb, 3I/ATLAS cannot be called an alien spacecraft, as much remains unknown.

Where did 3I/ATLAS come from?

While there have been multiple reports about where the interstellar object came from, the actual place of origin remains speculative. However, it is known to have come from beyond Earth’s solar system, which is why it is an interstellar object. 

3I/ATLAS’s size

Since the interstellar object is hundreds of millions of kilometers away from Earth, it has been difficult for researchers to note its exact size. 

The Hubble Space Telescope images of the object captured in August prompted scientists to report that the interstellar object’s nucleus’s diameter may be approximately between 440 meters and 5,600 meters. 

On December 19, 3I/ATLAS will come closest to Earth, but will still remain significantly far from Earth to pose a threat to human life.

3I/ATLAS’ speed

As per NASA’s reports, the interstellar object was initially travelling at a speed of approximately 137,000 miles per hour. However, when it came close to the sun, its speed increased to 153,000 mph. 

NASA expects the interstellar object to return to its original speed by the time it leaves the solar system.

Stay tuned for more updates.