general

No Clear Cometary tail in Post-Perihelion Images of 3I/ATLAS - Avi Loeb – Medium

Lau Chi Fung

— 2 min read

Interstellar Object 3I/ATLAS: A Rare Glimpse into the Cosmos

On November 5, 2025, astronomers at the R. Naves Observatory captured a post-perihelion image of the interstellar object 3I/ATLAS, providing scientists with a unique opportunity to study this rare visitor from beyond our solar system.

What is Interstellar Object 3I/ATLAS?

Interstellar object 3I/ATLAS (short for "Atlas") is an asteroid or comet that has traveled more than 4 billion kilometers from its home in the outer reaches of the solar system. It was discovered on October 8, 2020, by astronomers at the Haleakala Observatory in Hawaii, and was later named after the survey telescope that first spotted it.

The Journey of 3I/ATLAS

On January 28, 2021, 3I/ATLAS passed within 11 million kilometers of Earth, offering scientists a fleeting glimpse into its composition and behavior. This close approach provided valuable insights into the object's size, shape, and orbital characteristics.

The Perihelion Passage

As 3I/ATLAS approached the inner solar system, it underwent a process known as perihelion passage. During this time, the object's distance from the Sun is at its closest point in its orbit. On November 5, 2025, astronomers captured an image of 3I/ATLAS just hours after its perihelion passage.

The Image

The post-perihelion image of 3I/ATLAS shows a fuzzy ball of light with a diameter of approximately 300-400 meters. The Sunward direction is towards the bottom left corner, indicating that the object had passed closest to the Sun at its perihelion point.

Characteristics of 3I/ATLAS

Scientists have been studying 3I/ATLAS since its discovery in 2020, and their findings suggest that it is a rare type of interstellar object. Here are some key characteristics:

  • Size: 300-400 meters in diameter
  • Shape: Estimated to be an ellipsoid or irregular shape
  • Composition: Unknown, but believed to be primarily rock or ice
  • Orbital Characteristics: Highly elliptical orbit that takes it from the outer solar system to the inner solar system

Significance of 3I/ATLAS

The discovery and study of interstellar objects like 3I/ATLAS offer scientists a unique opportunity to explore the outer reaches of our solar system and beyond. These objects can provide insights into the formation and evolution of our solar system, as well as the possibility of life on other planets.

  • Understanding Interstellar Space: The study of 3I/ATLAS helps scientists understand the properties of interstellar space, including the behavior of small bodies in the outer solar system.
  • Cometary Origins: The object's composition and orbital characteristics suggest that it may be a comet, providing insights into the origins of comets in our solar system.
  • Potential for Life: The discovery of 3I/ATLAS raises questions about the possibility of life on other planets, particularly those with similar asteroid or comet populations.

Future Research Directions

As scientists continue to study 3I/ATLAS and other interstellar objects, researchers are exploring new avenues of investigation. Some potential areas of research include:

  • Orbital Dynamics: Studying the orbital characteristics of 3I/ATLAS can provide insights into the gravitational interactions between our solar system and nearby stars.
  • Cometary Composition: Analyzing the composition of 3I/ATLAS can help scientists understand the origins of comets in our solar system and their potential for life-bearing environments.
  • Technological Advancements: The study of 3I/ATLAS is driving technological advancements, including improved asteroid detection and tracking systems.

Conclusion

The post-perihelion image of interstellar object 3I/ATLAS offers scientists a rare glimpse into the behavior of this enigmatic visitor from beyond our solar system. As researchers continue to study 3I/ATLAS and other interstellar objects, we can expect new insights into the outer reaches of our solar system and the potential for life on other planets.

Additional Resources:

Read more