NASA Reveals Images of Interstellar Comet 3I/Atlas

NASA recently released new images of Comet 3I/Atlas, an interstellar object billions of years old. The images come from several NASA missions including the Perseverance Mars rover, MAVEN orbiter, Psyche and Lucy asteroid missions, and the sun-observing PUNCH spacecraft. First spotted on 1 July 2025 by the ATLAS telescope in Chile, 3I/Atlas was about 670 million km from the Sun. It will make its closest approach to Earth on 19 December 2025 at 170 million miles, nearly twice the Earth-Sun distance. This comet is the third confirmed interstellar object after 1I/ʻOumuamua and 2I/Borisov discovered in 2017 and 2019 respectively.

What Are Interstellar Objects?

Interstellar objects are celestial bodies that originate outside our Solar System. They travel through it but are not gravitationally bound to the Sun or any star here. These objects can be ejected from other star systems by collisions or gravitational slingshots from massive planets or stars. Although suspected for decades, they were only recently observed due to technological advances and powerful telescopes.

How Are Interstellar Objects Identified?

Scientists determine if an object is interstellar by analysing its orbit. Solar System bodies follow closed elliptical orbits around the Sun. They speed up near the Sun (perihelion) and slow down as they move away (aphelion). Interstellar objects follow open hyperbolic trajectories. Their speed is too high for the Sun’s gravity to capture them, so they escape the Solar System. Key indicators include unusually high speeds at large distances from the Sun and hyperbolic orbital paths.

Trajectory of Comet 3I/Atlas

3I/Atlas was observed moving at 60 km/s when 670 million km from the Sun. This speed is high for such a distance, indicating it came from outside the Solar System with initial velocity. Its hyperbolic path confirms its interstellar origin. Unlike typical comets, it will pass through the Solar System once and continue into interstellar space.

Scientific Importance of Studying Interstellar Objects

Interstellar objects provide unique vital information about planetary systems beyond our own. By analysing their chemical makeup, scientists learn about the conditions in their home star systems. For example, a comet rich in ice suggests formation far from a star and ejection by a massive planet. Such studies help understand planetary formation and the diversity of materials in the galaxy. These objects offer a rare chance to study matter from other star systems directly.

Role of NASA Missions in Observing 3I/Atlas

Multiple NASA missions contributed to imaging and studying 3I/Atlas. The Perseverance rover and MAVEN orbiter provided planetary science data. Psyche and Lucy missions, designed for asteroid exploration, added context on small bodies. The PUNCH spacecraft, studying the Sun’s corona and solar wind, helped observe the comet’s interaction with solar particles. This multi-mission approach enhances understanding of interstellar visitors.

Future Prospects

Interstellar objects like 3I/Atlas may become more frequently observed as telescope technology improves. They offer a tangible connection to the broader galaxy. Studying them could eventually inform future interstellar exploration and deepen knowledge about the formation and evolution of planetary systems beyond our own.

Questions for UPSC:

1. Critically analyse the significance of hyperbolic trajectories in identifying interstellar objects and their implications for understanding the Solar System boundaries.
2. Explain the role of advanced space missions like NASA’s Perseverance rover and PUNCH spacecraft in enhancing knowledge of celestial bodies beyond Earth.
3. What are the challenges in detecting interstellar objects? Discuss the technological advancements that have enabled recent discoveries with suitable examples.
4. With suitable examples, comment on how studying interstellar objects can contribute to our understanding of planetary formation and the diversity of materials in the galaxy.

Answer Hints:

1. Critically analyse the significance of hyperbolic trajectories in identifying interstellar objects and their implications for understanding the Solar System boundaries.

1. Hyperbolic trajectories indicate objects are not gravitationally bound to the Sun, confirming interstellar origin.
2. Solar System bodies follow closed elliptical orbits; hyperbolic orbits differ by being open-ended with no aphelion.
3. High inbound and outbound speeds on hyperbolic paths show objects can escape Solar System gravity.
4. Identification via hyperbolic orbits helps define the effective boundary of the Solar System’s gravitational influence.
5. About these trajectories aids in studying the exchange of material between star systems and interstellar space.
6. Examples – 3I/Atlas moving at 60 km/s at 670 million km confirms hyperbolic orbit and interstellar origin.

2. Explain the role of advanced space missions like NASA’s Perseverance rover and PUNCH spacecraft in enhancing knowledge of celestial bodies beyond Earth.

1. Perseverance rover provides planetary science data and imaging capabilities that can capture transient objects like comets.
2. MAVEN orbiter studies Mars atmosphere but also aids in observing interplanetary and interstellar objects passing near Mars orbit.
3. PUNCH spacecraft studies the Sun’s corona and solar wind, helping understand how solar particles interact with passing comets.
4. Psyche and Lucy missions contribute data on small bodies, improving context for comet composition and dynamics.
5. Multi-mission collaboration enables comprehensive observations across different environments and distances.
6. These missions expand knowledge of object trajectories, compositions, and solar interactions beyond Earth-centric views.

3. What are the challenges in detecting interstellar objects? Discuss the technological advancements that have enabled recent discoveries with suitable examples.

1. Interstellar objects are typically small, faint, and move rapidly, making detection difficult with older telescopes.
2. They spend limited time in the inner Solar System, requiring timely and sensitive observation capabilities.
3. Advanced wide-field survey telescopes like ATLAS enable early detection by scanning large sky areas frequently.
4. Improved imaging sensors and data processing allow detection of faint, fast-moving objects (e.g., 3I/Atlas discovered by ATLAS telescope).
5. Space-based and multi-mission observations increase detection chances and enable detailed study.
6. Technological progress in computational orbit determination confirms hyperbolic trajectories efficiently.

4. With suitable examples, comment on how studying interstellar objects can contribute to our understanding of planetary formation and the diversity of materials in the galaxy.

1. Chemical composition analysis reveals conditions of their original star systems (e.g., ice-rich comets indicate formation far from stars).
2. Studying ejected material helps understand planetary system dynamics, such as planetary migration and gravitational interactions.
3. Interstellar objects provide samples of matter formed in diverse galactic environments unlike our Solar System.
4. Examples – 1I/ʻOumuamua’s unusual shape and 2I/Borisov’s cometary composition expanded knowledge on planetary debris diversity.
5. These studies inform models of planet formation, migration, and the distribution of organic and inorganic materials across the galaxy.
6. They offer rare direct vital information about extrasolar system evolution before human interstellar travel is feasible.