Interstellar Comet 3I ATLAS Latest News and General Information
This year, we’re welcoming a rare guest in our skies – the interstellar comet 3I/ATLAS! It’s only the third interstellar object ever discovered, making it a once-in-a-lifetime visitor. But some argue we shouldn’t dismiss a wilder possibility: could it be an alien probe passing through our Solar System? Whatever you believe, you can track 3I/ATLAS in the Sky Tonight app. On its way out of the Solar System, it will approach the Earth on December 19, 2025. Also, it is still visible in the sky, and if you want to see it, you need to hurry up. Learn when and how to see it, and plan your perfect observing moment!
Contents
- What is 3I/ATLAS?
- Comet 3I ATLAS latest news: will 3I ATLAS hit Earth?
- December 11: 3I/ATLAS will soon approach Earth. Are we safe?
- December 10: A giant solar active region is aligned with comet 3I/ATLAS
- December 10: new beautiful image of comet 3I/ATLAS
- December 1: New 3I/ATLAS images suggest it may be covered in ‘ice volcanoes’
- December 1: Is 3I/ATLAS pulsing like a ‘heartbeat’?
- 3I ATLAS news recap: September-November 2025
- Comet 3I ATLAS live tracking: where is 3I ATLAS now, and how to see it
- Frequently asked questions about the comet 3I/ATLAS
- 31 ATLAS, 3AI ATLAS, ATLAS 3I, 3 Eye Atlas: what’s the correct name?
- Comet 3I/ATLAS discovery
- Comet 3I/ATLAS: to sum up
What is 3I/ATLAS?
3I/ATLAS is the third known interstellar object — a rare visitor from beyond our Solar System. It was first spotted on July 1, 2025, by the ATLAS survey telescope in Chile. The official view, supported by NASA, ESA, and most astronomers, is straightforward: 3I/ATLAS is a natural comet — the third interstellar object ever confirmed, after ‘Oumuamua and comet 2I/Borisov. But not everyone is convinced, and some argue that its unusual properties leave room for more exotic explanations.
Is 3I/ATLAS an alien ship or a comet? Harvard professor vs scientific community
Ever since its discovery, Harvard astronomer Avi Loeb has questioned whether 3I/ATLAS is a normal comet at all. He points to its unusual brightness, precise path through the Solar System, and lack of clear cometary outgassing early on — arguing that it doesn’t behave like a comet. In later updates, Loeb noted its unexpected stability and high mass, speculating that if the object ever changed course near the Sun, this could hint at technological propulsion rather than natural forces. He even joked that people should “take their vacation before October 29,” when the comet reaches perihelion — in case it’s something far stranger than expected.
Most astronomers, however, are unconvinced. Observations from Hubble, SPHEREx, and ESA’s Mars orbiters show signs of a classic comet: a small icy nucleus, a carbon-dioxide-rich coma, bursts of water vapor, and even a rare anti-tail caused by viewing geometry. The evidence shows that 3I/ATLAS is a remarkable natural comet, now giving scientists an unprecedented look at the chemistry of interstellar objects.
Comet 3I ATLAS latest news: will 3I ATLAS hit Earth?
So much has happened since the interstellar comet 3I/ATLAS burst onto the scene that it’s easy to lose track. Has it changed color again? Shifted course? Does it pose a danger to our planet? Here’s everything we know so far about what’s happening with this mysterious visitor from another star system.
December 11: 3I/ATLAS will soon approach Earth. Are we safe?
Interstellar comet 3I/ATLAS is heading for its closest approach to Earth on December 19, but NASA stresses there is no danger whatsoever. The comet will pass at a distance of about 1.8 AU — that’s nearly twice the distance from Earth to the Sun.
At that enormous distance, the comet can’t influence our planet in any noticeable way — not physically, not gravitationally, not electromagnetically — and it absolutely will not hit Earth.
Still, this flyby is scientifically exciting: it’s the best chance for observatories on Earth — and for spacecraft like Hubble and JWST — to capture high-quality data before 3I/ATLAS disappears into deep space forever.
December 10: A giant solar active region is aligned with comet 3I/ATLAS
A massive sunspot complex 4294–4296–4298 — one of the largest in the past decade and the biggest of the current solar cycle — has rotated into a position where its eruptions can now be directed straight toward the interstellar comet 3I/ATLAS. The comet’s trajectory will intersect the potential paths of coronal mass ejections (CMEs) coming from this enormous active region.
What makes AR 4294–4296–4298 interesting is its behavior. Despite its colossal size — over 2000 micro-hemispheres, placing it among the biggest recorded — the region stayed strangely quiet from December 1 to 7, producing no M- or X-class flares. Then, on December 8, it suddenly unleashed an X1.1 flare followed by eight M-class flares in rapid succession. For a sunspot complex of this magnitude, such prolonged silence followed by a burst of activity looks unusual. The next 24–48 hours put 3I/ATLAS in the zone where it could be struck by plasma from these eruptions — just as happened during the solar storm predicted back in late September.
Whether or not these solar flares add another twist to the comet’s story, astronomers will certainly be watching closely.
December 10: new beautiful image of comet 3I/ATLAS
Comet 3I/ATLAS remains visible in the sky, still accessible for both observation and imaging. Recently, astrophotographer Osama Fathi captured a striking view of the comet drifting above the volcanic hills of Egypt’s Black Desert, highlighting its delicate, fading glow against the stark landscape.
To reveal the comet’s structure and faint gas halo, the scene was stacked from 60 exposures of 60 seconds at ISO 1500, then 60 exposures of 30 seconds.
December 1: New 3I/ATLAS images suggest it may be covered in ‘ice volcanoes’
New images of interstellar comet 3I/ATLAS have revealed something spectacular: spiraling jets bursting from its surface. Some astronomers think these could be cryovolcanoes – ‘ice volcanoes’ that shoot gas and dust into space as the comet warms near the Sun.
The idea still needs to be confirmed, but if it holds up, 3I/ATLAS may be very different from the comets we’re used to. In fact, it may have more in common with the icy worlds of the outer Solar System – like Pluto or Triton – than with typical comets we see closer to home.
December 1: Is 3I/ATLAS pulsing like a ‘heartbeat’?
Harvard astronomer Avi Loeb, who has been pointing out oddities in 3I/ATLAS since the day it was discovered, now notes another one: the comet’s brightness seems to rise and fall every 16 hours. Normally, such variations could be explained by a rotating nucleus – but in this case, almost all the light we see comes from the coma, not the nucleus, so the usual explanation doesn’t quite work.
Loeb suggests another possibility: the comet’s jets may be firing in pulses, creating a repeating ‘heartbeat’ pattern. Each burst of gas and dust makes the coma flare up, then fade, then flare again. This could still be natural – for example, a volatile patch on the surface releasing gas once per rotation. But Loeb points out that if the jets don’t always aim toward the Sun, or if their timing seems too precise, it starts looking less ‘comet-like’ and more... unnatural. In that case, he argues, we may be seeing signs of an artificial mechanism with a controlled exhaust system.
For now, it’s just another mystery, and astronomers are racing to capture more data to figure it out.
3I ATLAS news recap: September-November 2025
It’s been a busy few months for our interstellar visitor. If you’ve lost track of this fast-moving interstellar drama — don’t worry. Here’s your quick catch-up on everything 3I/ATLAS has been up to lately:
- Sep 20: Astronomers spot a mysterious green glow around 3I/ATLAS — likely caused by unusual gases.
- Sep 23: New theory suggests 3I/ATLAS could be a “planet-forming seed,” a remnant that helps build worlds in young star systems.
- Sep 23: A solar storm is predicted to hit the comet — the first-ever such event involving an interstellar visitor.
- Sep 25: Avi Loeb notes the comet shows no non-gravitational acceleration and could be anomalously massive — or even propelled.
- Sep 28: Loeb links 3I/ATLAS to the legendary “Wow! Signal” from 1977, as the comet passes through the same region of the sky.
- Sep 29: The comet survives a solar storm unscathed, unlike many of its Solar System cousins.
- Sep 30: 3I/ATLAS slips behind the Sun, vanishing from view until late November.
- Oct 1: The comet approaches Mars, giving NASA orbiters and rovers a chance to observe it up close.
- Oct 5: A new Mars orbit photo confirms the comet’s faint glow.
- Oct 7: ESA’s ExoMars and Mars Express missions capture new images, showing the comet’s delicate coma.
- Oct 7: NASA’s Swift observatory detects water vapor — the first confirmed detection of water vapor from an interstellar comet at such a large heliocentric distance using space-based ultraviolet observations.
- Oct 19: Keck Observatory spots a rare anti-tail, appearing to point toward the Sun due to viewing geometry.
- Oct 21: As the comet hides behind the Sun, Loeb hints it could use the Oberth effect to change course unseen.
- Oct 29: 3I/ATLAS survives its close pass to the Sun, suddenly brightening.
- Nov 2: 3I/ATLAS returns into view after being lost in the Sun’s glare.
- Nov 4:The interstellar comet 3I/ATLAS appears to be changing color again – recent images show the visitor turning to a bluish hue.
- Nov 5: As comet 3I/ATLAS left perihelion, researchers noted a small deviation in the comet’s trajectory (about 4 arcseconds off from predictions) that gave rise to rumors that the comet had changed course.
- Nov 10: The latest images from Spain clearly show two distinct tails on 3I/ATLAS: one “smoky” tail spanning about 30 arcminutes (roughly the apparent diameter of the Full Moon), and the anti-tail made of dust particles about 10 arcminutes long, extending towards the Sun.
- Nov 10: The MeerKAT radio telescope in South Africa detected a radio signal emanating from 3I/ATLAS – a steady background emission typical of gas and dust in space, not a modulated signal carrying information. Similar emissions were first recorded from comets in the 1970s.
- Nov 11: New observations suggest that 3I/ATLAS has been transformed by galactic cosmic rays during its long journey between the stars. In other words, what we see now might not be the comet’s original surface at all, but a kind of “burnt shell” hiding the ancient ices and dust from the system where it was born.
- Nov 11: Harvard astronomer Avi Loeb assumed that 3I/ATLAS might not have survived its close brush with the Sun (and if it did, it might not be a comet at all).
- Nov 20: NASA has finally unveiled the long-anticipated images of 3I/ATLAS taken during its close flyby of Mars in early October — a release delayed for weeks by the U.S. government shutdown.
- Nov 25: The International Asteroid Warning Network (IAWN) has announced its special comet astrometry campaign for 3I/ATLAS that will last from November 27, 2025, through January 27, 2026.
Comet 3I ATLAS live tracking: where is 3I ATLAS now, and how to see it
Want to catch a glimpse of a traveler from another star system? Comet 3I/ATLAS is passing through our cosmic neighborhood, and with the right timing and equipment, you can spot it for yourself. Below, we’ll walk you through how bright it will get, when and where to look, and how to avoid common pitfalls (like the glare of the Moon) to maximize your chances.
Comet 3I ATLAS brightness: what you’ll see?
When it was first discovered, the comet was extremely dim, shining at about magnitude 18. By September 2025, it had brightened into the magnitude 14–15. As 3I/ATLAS approached the Sun in late October, it surprised astronomers by brightening much faster than expected: it suddenly became visible to space observatories at magnitude 9–10. This outburst likely came from water ice becoming active as sunlight reached deeper layers beneath the surface — proof that 3I/ATLAS is far more dynamic than early models suggested.
By November 2025, after emerging from solar conjunction, 3I/ATLAS was holding steady around magnitude 11–13, matching the more cautious brightness forecasts.
By December 2025, however, the comet had faded after its unexpected post-perihelion surge. As it pulls away from the Sun and its dust production declines, 3I/ATLAS now shines at roughly magnitude 13–15, depending on aperture and sky conditions. This places it just within reach of medium-sized amateur telescopes, while smaller instruments struggle to detect its diffuse coma. Unless another outburst occurs, 3I/ATLAS will continue to fade through early 2026.
Even at these levels, the comet remains the brightest interstellar object ever observed, though now primarily a target for dedicated comet observers rather than casual stargazers.
When and where to see comet 3I/ATLAS?
The orbit of comet 3I/ATLAS lies almost in the plane of the planets (inclination ≈5° to the ecliptic), which means it can be observed from both hemispheres.
The best observation window was in November 2025, when the comet finally reemerged from behind the Sun and reached its peak brightness. As of December 2025, 3I/ATLAS is dashing through the constellation Leo, still visible in the early morning hours. However, its brightness has dropped to about magnitude 14 and fainter, and it will continue to fade away. As the year ends, the comet will drift away, leaving the Solar System behind. Starting in January–February 2026, the comet will be observable only by professional astronomers.
Comet 3I/ATLAS observing tips: how to see it?
3I/ATLAS has already passed its peak brightness. Now fading, the comet appears as a very faint, diffuse glow, yet remains observable for patient observers with amateur instruments. To see it, plan carefully:
- Observe before dawn, up to 2 hours before sunrise.
- Find a dark site with a clear view toward the eastern horizon.
- Use low magnification (20–60×) to boost contrast and reveal the faint coma.
- Avoid bright moonlight. The Moon’s glare can easily wash out such a dim object, so aim for New Moon night of December 20.
For convenient planning, see the Moon phase calendar on our website.
3I/ATLAS tracking: where is 3I ATLAS now?
Right now, the interstellar comet 3I/ATLAS is gliding through the constellation Leo, steadily moving away from the Sun after its recent close approach. You can use the free Sky Tonight app as a comet tracker to pinpoint its exact location in the sky:
- Launch the app and tap the magnifying glass icon at the bottom of the screen;
- Type “3I ATLAS” into the search bar, then tap the blue target icon — the comet will appear on the sky map.
- Point your device toward the sky and simply follow the white arrow on the screen until it guides you to comet 3I/ATLAS above your location.
Frequently asked questions about the comet 3I/ATLAS
Why is comet 3I/ATLAS special?
To begin with, it’s a true interstellar object, meaning it didn’t form in our Solar System but came from another star system entirely. Such objects are incredibly rare, so each new one causes a stir. On top of that, early estimates suggest its core could be up to 5 kilometers across, making it one of the largest interstellar bodies we’ve ever spotted. And the best part is that this cosmic traveler will actually be visible in the sky this year.
Is comet 3I/ATLAS the only interstellar object found so far?
Nope! In fact, 3I/ATLAS is the third confirmed interstellar object to enter our Solar System. The very first was the oddly shaped object called ‘Oumuamua, discovered in 2017 — an elongated rock, which some thought looked like an alien spaceship. Then came 2I/Borisov in 2019, which behaved like a typical comet with a bright coma and tail.
How do we know that 3I/ATLAS is not from our Solar System?
Its unusual trajectory was the first big clue — it wasn’t closed, but had a hyperbolic shape, so astronomers suspected the comet wasn't local. Later, orbital calculations confirmed it: 3I/ATLAS follows a clearly hyperbolic path, with a speed and excess energy characteristic of interstellar objects and too high for an orbit gravitationally bound to the Sun.
Will the comet 3I/ATLAS hit Earth?
No need to worry — comet 3I/ATLAS will pass through the inner part of our planetary system, but it will remain very far from Earth. Its closest approach to our planet will occur on December 19, 2025. The distance between the two bodies will be about 1.8 AU — that’s roughly 269 million km, nearly twice the average Earth–Sun distance.
When will 3I/ATLAS leave the Solar System?
After its closest approach to the Sun in late October 2025, 3I/ATLAS has begun its journey back into interstellar space. Traveling at around 30 km/s on a clearly hyperbolic trajectory, it’s moving fast enough to escape the Sun’s gravity entirely. On its way out, the comet will reach perigee (closest to Earth) on December 19, 2025, and cross beyond Jupiter’s orbit by March 16, 2026. By the early 2030s, it will have left the planetary region of the Solar System — continuing its silent voyage through the galaxy, just as it once arrived.
Is 3I/ATLAS for sure a comet? Can it be an alien spaceship?
Most likely, 3I/ATLAS is a comet. It has an icy nucleus, produces gas and dust, and grows a coma and tail — textbook comet behavior (you can check our special article about comets and see for yourself). We might have hoped for alien friends, but not this time.
People want to believe, which is why so many ordinary things get mistaken for UFOs: from balloons to human-made satellites in the night sky. To help you out, we’ve collected the most common mix-ups in our infographic. Don’t let yourself be fooled!
31 ATLAS, 3AI ATLAS, ATLAS 3I, 3 Eye Atlas: what’s the correct name?
If you’ve seen people online calling it “31 ATLAS,” “3AI ATLAS,” or “3 Eye Atlas,” don’t worry — they all mean the same thing. The comet’s real designations are C/2025 N1 (ATLAS) and 3I/ATLAS, which may look different but refer to one and the same interstellar comet.
C/2025 N1 (ATLAS) is the comet’s provisional designation, following standard naming rules by the IAU:
- C/ — non-periodic comet.
- 2025 — the year of discovery.
- N1 — the first object discovered in the first half of July (the “N” period).
- ATLAS — the discovery project.
3I/ATLAS is the other designation, which also follows the IAU naming system, but emphasizes the comet’s interstellar nature:
- 3I shows it’s the third confirmed interstellar object (after 1I/‘Oumuamua and 2I/Borisov).
- ATLAS again refers to the discovery project.
So, C/2025 N1 (ATLAS) places the comet in the catalog of Solar System comets, while 3I/ATLAS emphasizes its unique status as an interstellar visitor. Both names are correct — they just tell the story from different angles.
Comet 3I/ATLAS discovery
The comet was discovered on July 1, 2025, by an automated telescope of the ATLAS project in Chile, which was created to search for potentially hazardous asteroids. In the images, the object appeared as a very faint 20th-magnitude star, located about 4.5 billion kilometers from the Sun. Already the next day, calculations showed that its trajectory was not closed and had a hyperbolic shape. This meant the body had arrived from beyond the Solar System. On July 2, the Minor Planet Center officially confirmed its interstellar status.
Initially, the object was thought to be an asteroid, but subsequent observations revealed signs of cometary activity, including a small coma and a short tail. Over the following weeks, its brightness increased slowly, and it became clear that this was a full-fledged comet.
Why are interstellar comets like 3I/ATLAS so rare?
Most comets we see in the night sky belong to the Solar System. They were born billions of years ago in distant regions such as the Oort Cloud or Kuiper Belt and follow long, elliptical orbits around the Sun. Sometimes planetary gravity tweaks their paths, but they remain bound to our star.
An interstellar comet, however, has a completely different story. It forms in another planetary system and then receives such a strong gravitational “kick” from planets or passing stars that it is ejected forever. From that moment, it drifts through the galaxy for millions or even billions of years, until by sheer chance it passes through the Solar System. That chance is vanishingly small — which is why only three interstellar objects have been identified so far, with 3I/ATLAS among them.
Why do astronomers pay so much attention to interstellar objects?
Interstellar visitors like 3I/ATLAS are priceless to science because they act as natural messengers from other star systems. Unlike local comets, which were born in our own Solar System, these objects formed around entirely different stars and then wandered across the galaxy for millions or even billions of years before reaching us.
Studying them lets astronomers compare how planets and comets form under different conditions. Observations of 3I/ATLAS show that its composition most certainly includes water and carbon dioxide – the same ingredients we see in many Solar System comets. This suggests that the recipe for building comets, and perhaps even the raw materials for planets, may be surprisingly similar across the galaxy.
Comet 3I/ATLAS: to sum up
Comet 3I/ATLAS (C/2025 N1) is only the third interstellar object ever spotted in our Solar System, after ‘Oumuamua and 2I/Borisov. It’s large — with a nucleus estimated at 0.6–5.6 km across — and fast, racing along at about 210,000 km/h. On December 19, the comet will make its closest approach to Earth, passing at a distance roughly twice the Earth–Sun separation. Don’t miss your chance to track a messenger from another star system! With the free Sky Tonight app, you can find comet 3I/ATLAS in seconds, plan your observing sessions, and follow its journey across the constellations.
Visible right now: explore the other comets drawing everyone’s attention
Even though 3I/ATLAS is no longer at its prime, it’s still observable with amateur telescopes. Also, there are other comets visible in the sky in December! Check our regularly updated article about the best comets to see right now to stay up to date with all the sky’s brightest travelers.
