Astronomers say that the newly discovered interstellar visitor 3I/ATLAS is “very likely” to be the oldest comet ever seen by humanity, with some estimates suggesting it could be around 7 billion years old. The object was discovered on July 1, 2025, and comes from a part of the galaxy that has never been seen up close before.
The thick disk of stars in the Milky Way is thought to be the origin of 3I/ATLAS, which would make it one of the oldest objects formed in the galaxy. This theory also suggests that 3I/ATLAS could be rich in water ice, which would explain its unusual composition and behavior.
As 3I/ATLAS approaches the sun, it will undergo a process called sublimation, where frozen ices turn to gas, creating a cometary aura and tail. Observations have already shown that 3I/ATLAS is bursting with cometary activity, and scientists are excited to study its behavior further.
The discovery of 3I/ATLAS has implications for the Legacy Survey of Space and Time (LSST), which aims to detect up to 50 interstellar objects passing through the solar system. The Vera C. Rubin Observatory will be one of the telescopes observing 3I/ATLAS, providing scientists with a unique opportunity to study this ancient comet.
Matthew Hopkins, an astronomer at the University of Oxford, led the research that suggests 3I/ATLAS could be around 7 billion years old. The Ōtautahi–Oxford Model used in the research was developed by Hopkins as part of his doctoral thesis and has been tested on 3I/ATLAS for the first time.
The discovery of 3I/ATLAS is a significant find, providing insights into the history of our galaxy and the formation of comets. Scientists are eager to continue studying this ancient comet to learn more about its composition, behavior, and place in the universe.
Source: https://www.space.com/astronomy/asteroids/astronomers-say-new-interstellar-visitor-3i-atlas-is-very-likely-to-be-the-oldest-comet-we-have-ever-seen