31/Atlas Comet Tracker: When and how to watch ATLAS? When does it peak?

31/Atlas Comet LIVE Tracker: 3I/ATLAS is believed to be 7 billion years old, meaning it is likely twice as old as the Earth itself.

NASA has confirmed that the comet will swing just inside Mars’ orbit at a distance of about 1.4 AU (210 million km) on October 30, 2025.

According to NASA, Comet 3I/ATLAS poses no threat to Earth and will remain at a safe distance from our planet. The closest it will approach Earth is about 1.8 astronomical units (about 170 million miles, or 270 million kilometres).

It will reach its closest point to the Sun around October 30.

31/Atlas Comet LIVE Tracker: 3I/ATLAS measures around 14 to 20 kilometers across.

31/Atlas Comet LIVE Tracker: The interstellar comet’s size and physical properties are being investigated by astronomers across the world. 3I/ATLAS should remain visible to ground-based telescopes through September, after which it will pass too close to the Sun to be observed.

It will reappear on the other side of the Sun by early December this year, allowing for renewed observations by astronomers.

3I/ATLAS Interstellar Comet Live Tracker: The interstellar comet is reportedly travelling at the speed of 221,000 km/h (60 km/s), a key clue pointing to its extraterrestrial origin.

Such a velocity is exceptionally high compared to typical, according to reports.

3I/ATLAS Interstellar Comet Live Tracker: The “coma” of the comet, measuring a few thousand kilometres, was "clearly visible" in the image shared by the ESA on October 7.

The ESA had captured a glimpse of the comet as it neared Mars on October 3.

3I/ATLAS Interstellar Comet Live Tracker: Comet 3I/ATLAS is said to be that “slightly fuzzy white dot” moving downwards near the centre of the image.

This dot is the centre of the comet, part of its icy-rocky nucleus and the surrounding coma.

3I/ATLAS Interstellar Comet Live Tracker: 3I/ATLAS will pass about 167 million miles from Earth in December.

This will be its nearest approach since it was first detected entering the solar system in July, before continuing its journey back into interstellar space.

3I/ATLAS Interstellar Comet Live Tracker: The object was reported to the Minor Planet Center on July 1, 2025, after being spotted by ATLAS. Archived data later showed it had been visible since mid-June.

3I/ATLAS Interstellar Comet Live Tracker: The European Space Agency (ESA) ruled out sending a spacecraft due to the comet’s extremely high speed and short approach window. Instead, scientists will study it from afar using telescopes like Hubble and the James Webb Space Telescope to analyse its dust and gas.

3I/ATLAS Interstellar Comet Live Tracker: As 3I/ATLAS nears the Sun, astronomers have detected it releasing a jet of material directed toward the Sun. This happens when solar heat vaporizes the comet’s icy surface. Space.com reported that images show its glowing coma and a bright jet highlighted in purple.

3I/ATLAS Interstellar Comet Live Tracker: A comet is a large icy object that travels around the Sun, forming a glowing tail as sunlight heats it. A meteorite, on the other hand, is a small fragment of rock or metal that enters Earth’s atmosphere, appearing as a shooting star before landing on the ground.

3I/ATLAS Interstellar Comet Live Tracker: Perihelion is the point in an object's orbit when it comes closest to the Sun. For comets, which usually have long, stretched orbits, this point is significant because they heat up and release gas and dust. In contrast, planets have nearly circular orbits, so the difference between their perihelion and aphelion (farthest point) is minor.

3I/ATLAS Interstellar Comet Live Tracker: According to NASA, 3I/ATLAS originated in another star system. It was ejected into interstellar space millions or billions of years ago and has been traveling between stars ever since. It’s now approaching from the direction of the constellation Sagittarius.

3I/ATLAS Interstellar Comet Live Tracker: The name “3I/ATLAS” follows a naming convention: “3” marks it as the third interstellar object, “I” stands for interstellar, and “ATLAS” credits the telescope project that discovered it.

3I/ATLAS Interstellar Comet Live Tracker: ESA is using multiple spacecraft, including Mars Express, the ExoMars Trace Gas Orbiter, and the Jupiter Icy Moons Explorer (JUICE) — to study the comet. These missions will help observe its activity from different points in the Solar System.

3I/ATLAS Interstellar Comet Live Tracker: ESA confirmed that the comet’s fast, inward trajectory and timing make a direct mission impossible. Instead, astronomers are using telescopes like Hubble and James Webb to remotely study its composition and dust plume.

3I/ATLAS Interstellar Comet Live Tracker: NASA’s Hubble Space Telescope captured a dust plume and a trailing tail of ice particles. The James Webb Space Telescope detected carbon dioxide, carbon monoxide, carbonyl sulphide, and water ice — all vaporized as the comet heats up near the Sun.

3I/ATLAS Interstellar Comet Live Tracker: NASA confirmed it’s a comet because it shows a coma, a glowing halo of gas and dust, caused by sunlight heating its icy core. This activity is not seen in asteroids.

3I/ATLAS Interstellar Comet Live Tracker: Observations from Hubble suggest the comet’s nucleus measures between 440 meters and 5.6 kilometers in diameter.

3I/ATLAS Interstellar Comet Live Tracker:

Size: Between a few hundred meters and a few kilometers wide

Speed: Around 210,000 km/h — the fastest known Solar System visitor

Closest approach to Mars: ~30 million km on October 3, 2025

Closest approach to the Sun: ~210 million km on October 30, 2025

Closest approach to Earth: ~270 million km on December 19, 2025

3I/ATLAS Interstellar Comet Live Tracker: After its discovery by NASA’s ATLAS telescope, ESA began tracking it with ground-based observatories and will soon involve spacecraft like Mars Express, ExoMars TGO, and JUICE for deeper study.

3I/ATLAS Interstellar Comet Live Tracker:The comet was first spotted by the NASA-funded ATLAS telescope in Río Hurtado, Chile, on July 1, 2025. Its hyperbolic orbit showed it came from beyond the Solar System.

3I/ATLAS Interstellar Comet Live Tracker: It’s only the third interstellar object ever detected, offering scientists a rare glimpse into materials formed around another star system.