Why in news?

• NASA recently released new images and data from various missions (like Mars Perseverance and the Lucy spacecraft) tracking 3I/ATLAS, confirming its interstellar origin and providing valuable details on its trajectory and structure.​
• Radio signals and further analysis have confirmed 3I/ATLAS as a natural comet, settling debates around its true nature.​

Meaning and Features

• An interstellar object refers to asteroids, comets, or similar small bodies that were once part of another star’s planetary system but became unbound, entering interstellar space.​
• These objects are identified by their hyperbolic orbits and excess velocities that show they cannot have originated in the solar system.​
• Unlike planets or stars, they do not orbit the Sun and typically pass through the solar system on erratic, fleeting paths.​
• Their study helps astronomers understand planetary formation processes and galactic dynamics, revealing how stellar and planetary systems evolve.​

Notable Examples

• Only three interstellar objects have been officially recorded passing through our solar system, each providing unique opportunities for scientific study:​
  • 1I/ʻOumuamua (2017): The first detected interstellar object, noted for its mysterious elongated shape and lack of a typical comet tail.​
  • 2I/Borisov (2019): The second, observed as a more traditional, active comet from deep space.​
  • 3I/ATLAS (2025): The most recent, a comet-like body whose age has been estimated at over 4.6 billion years, making a close approach to Earth in December 2025.​

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