International Space Agencies – Missions and Discoveries

3I/ATLAS: A Possible 7-Billion-Year-Old Interstellar Comet Discovered

Why in the News?

Recently astronomers using the ATLAS telescope in Chile discovered 3I/ATLAS, the third known interstellar object and possibly the oldest comet ever detected, estimated to be over 7 billion years old.

About 3I/ATLAS:

  • Discovery: It was detected on July 1, 2025, by the ATLAS telescope in Río Hurtado, Chile; confirmed interstellar due to its hyperbolic orbit and high speed (57–68 km/s).
  • Significance: It is likely the oldest comet ever observed — possibly 7.6–14 billion years old, older than our 4.5-billion-year-old solar system.
  • Nature: It appeared like an interstellar comet, showing signs of activity including a coma (cloud of dust/ice) and likely a tail as it nears the Sun.
  • Composition: Rich in water ice and complex organic compounds; has a reddish hue indicating ancient, primordial material.
  • Size: Estimated nucleus diameter is 10–30 km — larger than previous interstellar objects like 1I/ʻOumuamua and 2I/Borisov.
  • Trajectory:
    • Closest to Earth: ~270 million km (no threat).
    • Closest to Sun: ~210 million km (Oct 29–30, 2025).
    • Will exit the solar system permanently after perihelion.
  • Scientific Importance:
    • It offers rare opportunity to study materials from another star system.
    • It can reveal clues about the formation of the Milky Way, other solar systems, and early star formation processes.

Back2Basics: ATLAS Telescope

  • ATLAS (Asteroid Terrestrial-impact Last Alert System) is a NASA-funded early warning project for detecting small near-Earth objects (NEOs).
  • It is developed and operated by the University of Hawaii’s Institute for Astronomy.
  • As of 2025, ATLAS operates five telescopes in Hawaii, South Africa, Chile, and the Canary Islands.
  • Each telescope has a 0.5-meter Wright-Schmidt design, a 1-meter focal length, and a 110 MP CCD detector with a 7.4° field of view.
  • The system scans 20,000 square degrees of sky three times per night and provides 1–3 week warnings for asteroids 45–120 meters wide.
  • In addition to asteroids, ATLAS also discovers supernovae, comets, dwarf planets, and variable stars.

What are Interstellar Objects?

  • Overview: Celestial bodies that originate outside the solar system and travel through it on open-ended (hyperbolic) orbits.
  • Key Characteristics:
    • Not gravitationally bound to the Sun.
    • Travel at very high speeds, often unaffected by solar gravity.
    • Do not return once they pass through the inner solar system.
  • Known Interstellar Visitors:
    1. 1I/ʻOumuamua (2017) – Asteroid-like, no coma or tail.
    2. 2I/Borisov (2019) – Active comet with typical cometary features.
  • 3I/ATLAS (2025) – Discussed above.
  • How are they Identified:
    • Hyperbolic trajectory confirmed via orbital calculations.
    • Speed at great distances exceeds gravitational escape velocity.
  • Scientific Value:
    • Provide direct clues about planetary formation beyond our solar system.
    • Can reveal chemical signatures from other star systems.
    • Allow us to study primordial matter from distant parts of the galaxy.
    • Act as natural probes from unknown regions of the Milky Way.
[UPSC 2011] What is the difference between asteroids and comets?

1. Asteroids are small rocky planetoids, while comets are formed of frozen gases held together by rocky and metallic material. 2. Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and mercury. 3. Comets show a perceptible glowing tail, while asteroids do not.

Which of the statements given above is/are correct?

Options: (a) 1 and 2 only (b) 1 and 3 only* (c) 3 only (d) 1, 2 and 3

 

Get an IAS/IPS ranker as your 1: 1 personal mentor for UPSC 2024

Attend Now

Subscribe
Notify of
0 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments

JOIN THE COMMUNITY

Join us across Social Media platforms.