It looks like there might be a small mix-up—what you likely meant is “3I/ATLAS”, not “31/Atlas.” The former refers to 3I/ATLAS, which is the name of the third confirmed interstellar object to pass through our Solar System. Here’s what that means:
What is
3I/ATLAS
?
1. Label Explained:
- “3I” stands for the third interstellar object (“I” designates interstellar) ever detected. The first two were 1I/ʻOumuamua (2017) and 2I/Borisov (2019) .
- “ATLAS” is the name of the survey system—Asteroid Terrestrial‑impact Last Alert System—that discovered the object .
2. Discovery:
- Discovered on July 1, 2025, by the ATLAS telescopes (one of which operates in Chile) .
3. What Makes It Interstellar?
- It follows a hyperbolic trajectory with an orbital eccentricity well above 1, confirming it’s not gravitationally bound to the Sun—i.e., it’s from outside the Solar System .
4. Physical Traits:
- Early size estimates varied widely—from potentially up to ~20 km, later refined to around 1–5 km (Hubble’s observations suggest its nucleus is between 0.32 and 5.6 km in diameter) .
- Its movement and chemical composition indicate an origin from the Milky Way’s thick disk, a region populated by very old stars, making it possibly several billion years old—some estimates range from 3 to over 10 billion years .
5. Observation Timeline:
- Closest approach to the Sun (perihelion): October 29, 2025 .
- It will be visible through September, then temporarily obscured due to solar alignment in October, before reappearing and becoming observable again in November and December .
In Summary
- “3I/ATLAS” is an interstellar comet—the third confirmed—to enter our Solar System.
- Discovered in July 2025 by the ATLAS survey.
- Likely Ancient, possibly older than our Solar System, and quite fast-moving.
- Has been and will continue to be observed by many telescopes across the world and in space.
If you were referencing something different, feel free to clarify!
Is the 3I/Atlas dangerous to the Earth? (ChatGPT, 2025-8-31)
No — 3I/ATLAS is not dangerous to Earth.
Here’s why:
1.
Trajectory
- Its orbit is hyperbolic, meaning it will just pass through the Solar System and continue back out into interstellar space.
- Current calculations show no risk of collision with Earth (or any planet). It will stay far away from our orbit.
2.
Closest Approaches
- To the Sun (perihelion): October 29, 2025 — it will swing closest to the Sun but still at a safe distance.
- To Earth: It never comes anywhere near close enough to be hazardous. It remains far outside any danger zone.
3.
Size vs. Risk
- Even though it could be a few kilometers across (estimates: 0.3–5 km nucleus), size doesn’t matter here because its path keeps it millions of kilometers away from Earth.
- For comparison, NASA tracks thousands of near-Earth objects (NEOs) that cross or approach our orbit; 3I/ATLAS is not classified as one.
4.
Scientific Opportunity
- Rather than a threat, it’s a rare gift: only the third confirmed interstellar object after ʻOumuamua and Borisov.
- Astronomers are eager to study its composition, brightness, and activity because it carries information about other planetary systems and the Milky Way’s thick disk.
✅ Bottom line: 3I/ATLAS is harmless to Earth — it’s a visitor just passing through, and a fascinating chance for science, not a threat.
Would you like me to show you a sky chart (month-by-month guide) of when and where it can be seen in 2025?
