An interstellar comet crosses Earth and astronomers suspect it may hold secrets even older than the Sun
Humanity is just getting used to the idea of interstellar visitors. First there was ʻOumuamua, then Borisov, and now a comet with a technical name but a story that seems to come straight out of a cosmic chronicle. Its journey is filled with questions and stellar encounters that are just beginning to unfold.
The comet, known as , is only the third interstellar object ever seen. It comes from beyond our solar system and travels at about 220,000 km/h. Its closest approach to the Sun will be at the end of October, and telescopes like the James Webb are already observing it in detail, along with missions like Mars Express and JUICE.
Despite international attention, no one knew where this comet came from. Researchers turned to data from Gaia, the ESA satellite that maps more than a billion stars. With this data, they traced back the comet’s orbit 10 million years to compare it with possible stellar encounters.
All interactions occurred with main sequence stars, with no traces of encounters with stellar remnants like white dwarfs or neutron stars. The most intense encounter happened about 72,000 years ago with HD 187760, located 84 light years away, although the gravitational effect was minimal.
What makes this comet fascinating is its cometary activity: it releases gases and dust as it approaches the Sun, allowing astronomers to study materials that formed in another corner of the galaxy. While some calculations link it to , its ultimate origin remains unresolved. However, it seems certain that it will not be the last visitor: the Vera Rubin Observatory promises to detect many more in the next decade. Each of them will carry secrets that will test our theories about the cosmos.
