Interstellar Comet 3I/Atlas Discovered
Third Cosmic Visitor from Beyond Our Solar System Identified
A remarkable celestial visitor, designated 3I/Atlas, has been officially cataloged as the third known object to traverse interstellar space into our solar system. Its discovery marks a significant moment for astronomy, offering new insights into the vastness and composition of the cosmos.
Groundbreaking Observation
The initial detection of comet 3I/Atlas was reported on July 1, 2025, by the Sideoo System Telescope of Last Alert of Land Impact of Asteroids (Atlas) located in Río Hurtado, Chile. This NASA-funded observatory provided the first alert to the Minor Planet Center. Subsequent analysis of archived data from other Atlas telescopes worldwide, as well as observations from the Zwicky Transient Facility at Caltech’s Palomar Observatory, revealed prior sightings dating back to June 14.
An Interstellar Wanderer
Scientists have classified 3I/Atlas as an interstellar object due to its hyperbolic orbital path, meaning its trajectory is not a closed loop around the Sun. This distinctive orbit indicates that the comet originated from beyond our solar system. Tracing its path backward confirms its journey from the vast expanse between star systems.
Astronomers are actively studying the comet’s size and physical characteristics. It is expected to remain visible to Earth-based telescopes until September 2025. However, due to its proximity to the Sun, it will become unobservable for a period before reappearing on the opposite side in early December 2025, allowing for renewed observations.
Naming Convention Explained
Comets are typically named after their discoverers. In this case, the designation honors the Atlas telescope team. The “I” signifies its interstellar origin, and the “3” marks it as the third such object identified. This follows the naming conventions established by the discoveries of ‘Oumuamua in 2017 and 2I/Borisov in 2019.
Cosmic Identity and Trajectory
The interstellar object 3I/Atlas poses no threat to Earth. Its closest approach will be approximately 1.8 astronomical units (about 270 million kilometers or 170 million miles) from our planet. The comet will reach its closest point to the Sun, known as perihelion, around October 30, 2025, at a distance of about 1.4 AU (210 million kilometers or 130 million miles), well within the orbit of Mars.
Frequently Asked Questions
Where did this interstellar object originate?
Comet 3I/Atlas formed within another star system and was subsequently ejected into interstellar space. It is estimated to have traveled for millions, perhaps billions, of years before reaching our solar system. Its approach originated from the direction of the constellation Sagittarius, home to the Milky Way’s galactic center.
How was its interstellar origin determined?
Observational data revealed that 3I/Atlas is moving at a velocity too high to be bound by the Sun’s gravity. Its trajectory is classified as hyperbolic, meaning it will not enter a stable orbit around the Sun but will continue its journey back into interstellar space.
What are the dimensions and classification of 3I/Atlas?
While its exact size is still under investigation, observations confirm that 3I/Atlas is an active comet, exhibiting an icy composition and a coma—a luminous cloud of gas and dust surrounding the nucleus as it nears the Sun. This activity leads astronomers to classify it as a comet rather than an asteroid.
What is the speed of Comet 3I/Atlas?
The comet is traveling at an impressive speed. At the time of its discovery, it was moving at approximately 221,000 kilometers per hour (about 61 kilometers per second or 137,000 miles per hour). Its velocity is expected to increase as it gets closer to the Sun.
Is there any risk of collision with Earth?
No, there is no danger of 3I/Atlas colliding with Earth. Although its path takes it through the inner solar system, its closest projected distance to our planet is approximately 1.6 AU (about 240 million kilometers or 150 million miles).
