NASA discovers the third known interstellar object to pass through the Solar System

▲ The image shows interstellar object A11pI3Z, located in the constellation of Sagittarius. It is estimated to be 20 kilometers in diameter and is the third ever detected. Photo AFP / David Rankin, Saguaro Observatory

AP and Europa Press

La Jornada Newspaper, Friday, July 4, 2025, p. 6

Florida. NASA's Asteroid Terrestrial-impact Last Alert System (ATLAS) has discovered the third known interstellar object to pass through the Solar System.

Initially named A11pl3Z and originating in the constellation of Sagittarius, it is estimated to be about 20 kilometers in diameter, much larger than Oumuamua and Borisov, the two known interstellar objects.

Being monitored by telescopes around the world, according to ESA, this object is currently approximately 670 million kilometers from the Sun and is hurtling toward our inner system. It is moving at nearly 68 kilometers per second and will pass close to Mars and the Sun later this year.

The International Astronomical Union's Minor Planet Center has already classified the object as a comet, with the designation 3I/ATLAS, and it could contain clues to another star system.

Pascal Lee, a planetary scientist at the SETI Institute, commented on his X account that it is already in Jupiter's orbit. Its closest approach to the Sun is expected on October 29, and its closest approach to Earth will be on October 30 at 1.35 astronomical units, so there is no risk of impact.

3I/ATLAS should remain visible to ground-based telescopes until September, after which it will pass too close to the Sun to be observed. It is expected to reappear on the far side of the Sun in early December, allowing for further observations, according to NASA.

Its light curve has not yet been published, so there is no information yet on its shape or rotation.

Astrophysicist Josep Trigo-Rodríguez of the Institute of Space Sciences near Barcelona, ​​Spain, believes it is an interstellar object based on its strange trajectory and extreme speed as it passes through the solar system. He estimates its size to be approximately 40 kilometers (25 miles) in diameter.

The first confirmed interstellar visitor was in 2017. Nicknamed Oumuamua , which means explorer in Hawaiian, after the observatory in Hawaii that discovered it. Initially classified as an asteroid, the elongated Oumuamua has since shown signs of being a comet.

The second object to deviate from another star system toward ours is 21/Borisov, discovered in 2019.