Seven Reasons 3i Atlas is the Most Important Visitor

Updates

Cindy Sheehan

Oct 14, 2025

1. An ancient, interstellar time capsule

3i/ATLAS may be up to 10 billion years old, potentially older than our solar system.
Its material is a time capsule, offering a glimpse into the formation of the universe billions of years ago and providing clues about the composition and evolution of other planetary systems.

2. An unusual chemical composition

Initial observations from the James Webb Space Telescope revealed a high ratio of carbon dioxide to water ice.
It has also shown an “extreme abundance ratio” of nickel and iron, metals not typically found in such high quantities in cometary comas.

3. A source of pristine, untouched material

As an interstellar object, it carries pristine material from another star system that has not been exposed to our sun.
Studying this material can reveal the conditions under which planets and comets form in other solar systems.

4. A source of unique data on interstellar object formation

Its existence implies that planetesimals (tiny planets) existed in the galaxy a long time ago and contained heavier elements than just hydrogen and helium.
Analyzing its trajectory and composition can help scientists better understand how interstellar objects are ejected from their home systems and how planetary systems evolve.

5. Its large size makes it easier to study

Measuring up to 20 kilometers wide, 3I/ATLAS is significantly larger than the two previous interstellar objects, ‘Oumuamua and Borisov. Its enormous coma, almost twice the diameter of Earth, is also much larger and brighter than expected. This makes it an easier target for telescopes to observe, allowing for higher-resolution data collection.

6. It showcases the diverse behavior of interstellar comets

3I/ATLAS has surprised astronomers by releasing water vapor even while still very far from the sun. This behavior challenges traditional assumptions about comets and reveals that interstellar objects possess a wider range of properties. This provides valuable insights into how cometary activity works in extreme environments.

7. It offers a benchmark for future detections

As telescopes like the Vera Rubin Observatory come online, astronomers will expect to find many more interstellar visitors. 3I/ATLAS can serve as a reference object, helping scientists to refine search strategies, detection algorithms, and classification systems for the next wave of interstellar visitors, ushering in a new era of interstellar object studies.