The universe occasionally sends us rare messengers from beyond our solar system. One such extraordinary visitor is Interstellar Comet 3I/ATLAS, a cosmic object that has captured the attention of astronomers worldwide. Discovered by a NASA funded telescope in Chile, this comet is not just another icy body drifting through space, it may be older than the Sun itself.

As only the third confirmed interstellar object (ISO) ever detected, 3I/ATLAS provides a once in a generation opportunity to study ancient material from the Milky Way and better understand how planetary systems form across the galaxy.

What Is Interstellar Comet 3I/ATLAS?

Interstellar Comet 3I/ATLAS is a celestial object that originated outside our solar system and is currently passing through it on a one time journey. Unlike typical comets bound by the Sun’s gravity, this object follows a hyperbolic orbit, meaning it will eventually leave the solar system forever.

Key Discovery Details

• Discovery Date: July 1, 2025.

• Facility: The Asteroid Terrestrial impact Last Alert System (ATLAS) telescope in Río Hurtado, Chile.

• Official Designations: 3I/ATLAS and C/2025 N1 (ATLAS).

• Age: Estimated to be at least 7 billion years old, potentially making it older than our own solar system.

Why the Name “3I/ATLAS”

• 3I: Indicates it is the third interstellar object ever confirmed
• ATLAS: Discovered by the Asteroid Terrestrial impact Last Alert System, a NASA survey

Before 3I/ATLAS, only two interstellar visitors were known:

1. 1I/Oumuamua (2017) – the first detected interstellar object
2. 2I/Borisov (2019) – the first confirmed interstellar comet

Physical Characteristics & Behaviour

3I/ATLAS is particularly unique because it has displayed several “mysterious” features that have puzzled astronomers:

Active Cometary Behavior

Unlike ʻOumuamua, which showed no classic comet features, 3I/ATLAS is an active comet:

• Displays a visible coma, a cloud of ice and dust around the nucleus
• Expected to develop a tail as it approaches the Sun

Size and Appearance

• Estimated nucleus diameter: 10–30 km
• Significantly larger than earlier interstellar objects
• Exhibits a reddish hue, suggesting complex surface chemistry

Discovery of 3I/ATLAS

Where and How Was It Found?

The comet was first observed by a NASA supported ATLAS telescope located in Rio Hurtado, Chile. The ATLAS survey is designed to detect near Earth objects, but it also plays a key role in identifying rare cosmic travellers like 3I/ATLAS.

Astronomers quickly noticed its unusual speed and trajectory, confirming that it was not gravitationally bound to the Sun.

Trajectory and Speed of Interstellar Comet 3I/ATLAS: Proof of Interstellar Origin

Hyperbolic Orbit Explained

3I/ATLAS moves along an open ended hyperbolic orbit, that meaning:

• It approaches the Sun
• Reaches a closest point called perihelion
• Then exits the solar system permanently

Exceptional Velocity

• Travels at 57–68 km/s relative to the Sun
• This extreme speed exceeds what solar gravity can capture

Such motion is a clear signature of an object arriving from interstellar space rather than forming within our solar system.

Origin and Age: Older Than the Solar System?

One of the most fascinating aspects of 3I/ATLAS is its possible age and birthplace.

A Rare Galactic Origin

• Likely originated from the Milky Way’s thick disk
• The thick disk is home to ancient stars, unlike the thin disk where our Sun resides
• This makes 3I/ATLAS different from ʻOumuamua and Borisov, which likely came from the thin disk

Could It Be Over 7 Billion Years Old?

Advanced simulations using the Ōtautahi–Oxford model suggest:

• A 70% probability that 3I/ATLAS is over 3 billion years older than our solar system
• Estimated total age: more than 7 billion years

If confirmed, this would make 3I/ATLAS the oldest comet ever observed by humanity.

Chemical Composition: Water and Organic Compounds

Detection of Water

In a major recent development, NASA astronomers confirmed the chemical fingerprint of water on 3I/ATLAS. This discovery strengthens its classification as a true comet.

Complex Organics Present

Spectral analysis indicates:

• Presence of water ice
• Possible complex organic molecules

These materials are essential building blocks for planets and life, making 3I/ATLAS especially valuable for scientific study.

Chemical Signature: A “Friendly Interstellar Gardener”?

Data from the James Webb Space Telescope (JWST) and the Hubble Space Telescope have revealed a chemical makeup that differs significantly from local comets:

• Carbon Dioxide Overload: The ratio of carbon dioxide and water is nearly eight times higher than what we see in local Oort Cloud comets.
• Volatile Richness: High concentrations of methanol, hydrogen cyanide, and even traces of hydrogen sulfide have been detected.
• The “Gardener” Hypothesis: Some scientists have noted that the high ratio of methanol (a precursor to complex organic molecules) relative to cyanide suggests this comet could be a “carrier” of the ingredients for life, leading to the nickname “interstellar gardener.”

Feature	3I/ATLAS	Local Solar System Comets
Origin	Outside our Solar System	Oort Cloud / Kuiper Belt
Orbit Shape	Hyperbolic (Open)	Elliptical (Closed)
Color	Shifted from Red to Green	Mostly Grey/White/Green
Carbon dioxide Ratio	Extremely High	Moderate to Low

Why Interstellar Comet 3I/ATLAS Is Scientifically Important

1. First ISO from the Milky Way’s Thick Disk

3I/ATLAS is the first interstellar object traced to the thick disk, offering insights into:

• Ancient galactic environments
• Early star and planet formation processes

2. Window into Primordial Galactic Material

Because it formed billions of years before the Sun, the comet acts like a time capsule, preserving conditions from the early Milky Way.

3. Implications for Panspermia

The presence of water and organic compounds raises intriguing questions:

• Could interstellar objects transport life-building molecules between star systems?
• Did similar objects contribute to the chemical foundations of life on Earth?

What Are Interstellar Objects?

Definition

Interstellar objects (ISOs) are celestial bodies that:

• Originate outside the solar system
• Are not bound to any star
• Travel through space on hyperbolic trajectories

How Do They Form?

ISOs are typically ejected from their home systems due to:

• Planetary collisions
• Gravitational slingshots by massive planets or stars

Once expelled, they wander through interstellar space until they encounter another star system like ours.

What Happens Next to 3I/ATLAS?

3I/ATLAS will:

• Make a brief passage near the Sun
• Continue shedding material due to solar heating
• Eventually exit the solar system permanently

Although its visit is temporary, the data collected will fuel research for decades.

Conclusion

Interstellar Comet 3I/ATLAS is far more than a passing object it is a rare messenger from an ancient part of the Milky Way. Its immense age, chemical richness and unique origin make it one of the most scientifically valuable objects ever observed.

As technology improves and future missions are planned to intercept similar visitors, 3I/ATLAS reminds us that our solar system is not isolated. Instead, it is part of a vast, dynamic galaxy where material and possibly the seeds of life travels freely between the stars.

Interstellar Comet 3I/ATLAS, Frequently Asked Question (FAQ)