Astronomers Track Newly Discovered Interstellar Comet 3I/ATLAS

Astronomers are closely monitoring a newly discovered comet, designated 3I/ATLAS, which is the third known interstellar object to visit our solar system. This comet was first identified on July 2, 2025, using the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Rio Hurtado, Chile. NASA has confirmed that this comet exhibits a trajectory consistent with an origin beyond our solar system, traveling at an impressive speed of approximately 37 miles (60 kilometers) per second towards the center of the Milky Way galaxy.

Currently, 3I/ATLAS is located around 420 million miles (670 million kilometers) from Earth. Dr. Larry Denneau, a University of Hawaii astronomer and co-principal investigator for ATLAS, stated, "Beyond that we do not know very much, and there are many efforts underway to observe this object with larger telescopes to determine its composition."

The two previous interstellar visitors observed by astronomers include 1I/'Oumuamua, detected in 2017, and 2I/Borisov, discovered in 2019. According to Dr. Denneau, 3I/ATLAS shares some characteristics with 2I/Borisov, particularly its icy nature. However, it is significantly larger, with an estimated diameter of about 10 kilometers (6.2 miles).

As the comet approaches the Sun, astronomers anticipate that its faint coma—a cloud of gas and dust surrounding the nucleus—will expand, potentially becoming more visible. 3I/ATLAS is expected to reach its closest approach to the Sun around October 30, 2025, when it will be approximately 130 million miles (210 million kilometers) away from our star, well within the orbit of Mars. Importantly, astronomers have confirmed that the comet poses no threat to Earth, with its closest distance being over 150 million miles (240 million kilometers).

The ATLAS network is a NASA-funded initiative operated by the University of Hawaii, comprising five telescopes positioned worldwide that continuously scan the night sky for any objects that might pose a risk to Earth. As the study of 3I/ATLAS continues, astronomers remain hopeful that further observations will yield more insights into the composition and origin of this intriguing celestial visitor.