Interstellar Comet 3I/ATLAS: What It Is and What Its Current Status Is

Liputan6.com, Jakarta The interstellar comet 3I/ATLAS is making headlines among astronomers in October 2025.

This rare celestial object, the third identified interstellar comet, is reaching a crucial moment in its journey through our Solar System.

Later this month, 3I/ATLAS will reach its closest approach to the Sun, or perihelion, a significant event that will enable further observations.

In addition to its approach to the Sun, comet 3I/ATLAS is also making close approaches to several planets, including Mars and Venus.

This event provides a unique opportunity for spacecraft and telescopes to gather valuable data on the composition and behavior of comets originating outside our star system.

Scientists hope to uncover more mysteries about the origins and characteristics of interstellar objects through these intensive observations.

The discovery of 3I/ATLAS by the ATLAS system in July 2025 confirms its status as an interstellar object, following in the footsteps of 1I/ʻOumuamua and 2I/Borisov.

October 2025 marks the peak of visibility and intensive observation before the comet disappears from Earth's view again.

🚨 BREAKING: MYSTERIOUS INTERSTELLAR OBJECT ARRIVES TOMORROW - NASA LOSING CONTROL OF THE NARRATIVEA Manhattan-sized object named 3I/ATLAS is racing toward the Sun right now and it’s moving in ways that no natural object should. NASA just quietly added it to the International… pic.twitter.com/yhH4v5nSWV

— HustleBitch (@HustleBitch_) October 28, 2025

October 2025 will be a crucial period for comet 3I/ATLAS, as it reaches its closest point to the Sun (perihelion) on October 29, 2025, at 11:47 UT.

At a distance of 1.3561 AU (approximately 203 million km), this position lies between the orbits of Earth and Mars, allowing for more intensive observations from various instruments.

In addition to perihelion, 3I/ATLAS will also make a series of close approaches to the planets in the Solar System.

On October 3, 2025, the comet will pass Mars at a distance of 0.19 AU (28 million km).

Spacecraft such as the European Space Agency's ExoMars Trace Gas Orbiter (TGO) and Mars Express, as well as NASA's Mars probes, are preparing to observe the comet directly.

Next, the comet will pass Venus at a distance of 0.65 AU (97 million km) on November 3, 2025.

3I/ATLAS's closest approach to Earth will happened on December 19, 2025, at a distance of 1.80 AU (269 million km), but the comet poses no threat.

On March 16, 2026, the comet will pass Jupiter at a distance of 0.36 AU (54 million km), with ESA's Juice mission planning to make observations in November 2025.

Comet 3I/ATLAS, also known as C/2025 N1 (ATLAS), is the third interstellar object confirmed to be passing through our Solar System.

It was discovered on July 1, 2025, by the NASA-funded Asteroid Terrestrial-Impact Last Alert System (ATLAS) survey telescope in Río Hurtado, Chile.

This discovery was quickly followed by follow-up observations that confirmed its hyperbolic trajectory, a characteristic of objects originating outside the Solar System.

3I/ATLAS's trajectory indicates that the comet is moving too fast to be bound by the Sun's gravity, indicating its origin in another star system.

Scientists suspect it was ejected into interstellar space, likely from the thick disk of the Milky Way Galaxy, making it one of the oldest known comets, with an estimated age of up to 11 billion years.

It must have been drifting through space for millions or even billions of years before arriving in our Solar System.

Initial observations by David Jewitt and Jane Luu using the Nordic Optical Telescope on July 2, 2025, confirmed that 3I/ATLAS exhibited clear activity with a diffuse appearance.

Its status as an interstellar comet provides important insights into the material and conditions beyond the boundaries of the Solar System, as well as the formation and evolution of other star systems.

3I/ATLAS is an active comet consisting of a dense, icy nucleus and a coma, a cloud of gas and icy dust ejected from the nucleus.

However, images from the Hubble Space Telescope indicate its diameter is likely between 0.32 and 5.6 km, with the most likely estimate being less than 1 km.

Observations by the James Webb Space Telescope (JWST) indicate that 3I/ATLAS is rich in carbon dioxide and contains small amounts of water ice, water vapor, carbon monoxide, and carbonyl sulfide.

Furthermore, observations by the Very Large Telescope also detected emissions of cyanide gas and atomic nickel vapor from this comet.

This comet has the highest eccentricity of any of the three interstellar objects known to date, at 6.1374.

Its maximum velocity at perihelion reaches 68 km/s relative to the Sun.

From July to late September 2025, comet 3I/ATLAS can be observed from Earth after sunset.

However, during solar conjunction on October 21, 2025, the comet will be on the opposite side of the Sun from Earth, making it unobservable from October 1 to November 9, 2025.

The comet is expected to reappear on the other side of the Sun in early December 2025, reopening the observation window.

On October 3, 2025, 3I/ATLAS will have a total magnitude of about 12, making it very faint and not bright enough to be visible with binoculars or the naked eye.

NASA's Hubble Space Telescope captured this image of 3I/ATLAS on July 21, 2025, showing a teardrop-shaped dust cocoon.

The James Webb Space Telescope (JWST) also observed it on August 6, 2025.

Two ESA spacecraft, Hera and Europa Clipper, are expected to pass through 3I/ATLAS's tail between October 25 and November 6, 2025, to detect ions from its tail.

ESA's Comet Interceptor mission, due to launch in 2029, is also being prepared to intercept interstellar objects like 3I/ATLAS in the future.