Comet 3I/ATLAS: NASA Unveils New Photos of the Third Interstellar Object Ever Detected
- TPP
- Nov 22, 2025
- 5 min read
Captured by NASA’s PUNCH, Perseverance, Lucy, Psyche, and MAVEN, the rare interstellar comet exposes material formed billions of years ago in a distant planetary system.
NASA has released striking new pictures of Comet 3I/ATLAS, an interstellar object that astronomers say is billions of years old and only the third known object from outside our Solar System to pass through it. The images come from a wide range of NASA missions, including the Perseverance Mars rover, Mars Atmosphere and Volatile Evolution (MAVEN) orbiter, asteroid missions Psyche and Lucy, and the Sun-studying Polarimeter to Unify the Corona and Heliosphere (PUNCH) spacecraft.
One of the standout visuals shows PUNCH observations of Comet 3I/ATLAS between September 28 and October 10, 2025, when the comet was between 231 million and 235 million miles from Earth. Each frame is a daily stacked image made from multiple observations. As the comet moves across the sky, background stars appear as streaks of light.
What Do NASA’s New Observations Reveal About Comet 3I/ATLAS?
According to NASA, the comet was discovered on July 1, 2025, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Río Hurtado, Chile, when it was about 670 million km from the Sun. The comet will make its closest approach to Earth on December 19, coming within 170 million miles (270 million km)—about 1.8 astronomical units (AU), nearly twice the Earth-Sun distance.
Based on Hubble Space Telescope observations from August 20, 2025, astronomers estimate that the nucleus is not less than 1,400 feet (440 m) and not greater than 3.5 miles (5.6 km) in diameter.
When discovered, 3I/ATLAS was traveling at 137,000 mph (221,000 km/h). As it moved closer to the Sun, its speed increased—reaching 153,000 mph (246,000 km/h) at perihelion, its closest approach to the Sun, on October 30, 2025, at a distance of 130 million miles (210 million km) or 1.4 AU, just outside Mars’ orbit. Earth was on the opposite side of the Sun at that time.
NASA confirms there is no danger to Earth.
What Makes an Interstellar Object Different From a Solar System Object?
Interstellar objects are celestial bodies originating outside our Solar System. Unlike planets, asteroids, or comets within the Solar System, which follow closed elliptical orbits, interstellar objects travel on open hyperbolic orbits.
A hyperbolic orbit means:
there is a perihelion (closest point to the Sun)
but no aphelion (farthest point)because the object’s speed is too high for the Sun’s gravity to hold it.
Scientists determine if an object is interstellar by calculating its trajectory, speed, and its motion relative to background stars. Solar System objects move slower the farther they are from the Sun. In the case of 3I/ATLAS, at 670 million km, it was moving at 60 km/h in observational motion—far too fast for a typical Solar System object at that distance. This indicates it entered the Solar System with significant initial velocity, confirming its interstellar nature.
How Exactly Do Scientists Confirm That an Object Is Interstellar?
To classify a body as interstellar, astronomers examine:
Its orbital shape (hyperbolic = interstellar)
Its excess speed (too fast to remain gravitationally bound)
Its motion against background stars
Its acceleration due to solar gravity
3I/ATLAS:
Follows a hyperbolic trajectory
Moves too fast to be bound by the Sun
Is simply passing through the Solar System
Will exit at the same speed at which it entered
Even though cometary outgassing (gas released when solar heat sublimates ice) can cause small trajectory changes, NASA notes the perturbations are very small and fully consistent with normal comet behavior.
How Was 3I/ATLAS Discovered and Named?
3I/ATLAS was discovered by the ATLAS telescope, part of NASA’s planetary defense network, on July 1, 2025, and reported to the Minor Planet Center.
The name 3I/ATLAS means:
3I → the third interstellar object ever found
ATLAS → discovered by the ATLAS survey system
The first two interstellar objects were:
1I/ʻOumuamua (2017)
2I/Borisov (2019)
What Are the Physical Features and Activity of Comet 3I/ATLAS?
Astronomers confirm that 3I/ATLAS is indeed a comet, not an asteroid, because it is active. Its features include:
an icy nucleus
a glowing coma of gas and dust
characteristic color
predictable speed and direction
increasing activity as it approaches the Sun
Comets heat up as they near the Sun, causing ice to sublimate and release gas—a process known as outgassing.
This comet is now on its outbound journey, slowing down as it leaves the Sun’s gravitational influence.
Where Did This Interstellar Object Come From?
3I/ATLAS is approaching from the general direction of the constellation Sagittarius, near the central region of the Milky Way Galaxy.
Scientists believe it formed in a distant star system before being ejected—possibly due to:
collisions
gravitational interactions with a massive planet (like Jupiter or Neptune)
disruptions in its home star system
It then drifted through interstellar space for millions or billions of years until arriving at our Solar System.
Is There Any Danger to Earth From Comet 3I/ATLAS?
No. The comet will come no closer than 170 million miles (270 million km) from Earth—nearly twice the Earth-Sun distance.
Its path brought it just inside Mars’ orbit, but never anywhere near Earth’s.
How Fast Is 3I/ATLAS Moving, and How Has Its Speed Changed?
137,000 mph (221,000 km/h) when discovered
153,000 mph (246,000 km/h) at perihelion on Oct. 30, 2025
Now decreasing in speed as it moves away from the Sun
Will exit the Solar System at the same inbound speed
These speeds are typical for interstellar objects, which retain their original velocity because they are not gravitationally bound to our star.
Can Skywatchers See 3I/ATLAS From the Ground?
Yes. After briefly passing behind the Sun, the comet became observable again starting October 31, 2025.
It can be viewed with a small telescope in the pre-dawn sky, and will remain visible until spring 2026.
Why Are Interstellar Objects Like 3I/ATLAS Important for Astronomy?
Interstellar objects offer direct samples of material formed around other stars, giving scientists rare evidence of:
how other solar systems form
what chemical environments exist elsewhere
what kind of planets those systems might contain
For example:
A comet rich in ice suggests it formed far from its star, then was ejected—possibly by a giant planet.
The European Space Agency notes:
“Interstellar comets offer a tantalising opportunity for us to touch something truly otherworldly… a rare, tangible connection to the broader galaxy.”
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