| June 21, 2025 |
First spotted in old images (Rubin Observatory) |
Astronomers later realized, “Hey, we actually caught it on camera before we even knew it was here!” |
| July 1, 2025 |
Official discovery by ATLAS telescope in Chile |
Confirmed to be interstellar — a true visitor from another star system, only the third ever found (after ʻOumuamua and Borisov). |
| Mid-July 2025 |
Hubble & Gemini snap photos |
Pictures show a glowing cloud of dust around it — proof it’s “alive” like a comet, not just a dead rock. |
| Summer 2025 |
Global telescopes & JWST study it |
Scientists find it’s pumping out lots of CO₂ gas, way more than typical comets. Translation: it’s weird, different, and exotic. |
| Through Sept 2025 |
Still visible from Earth’s telescopes |
Amateurs and pros alike can track it before it ducks behind the Sun. Brightness is steady, no crazy flare-ups (yet). |
| Oct 3, 2025 |
Close pass by Mars |
Like a cosmic drive-by. Mars orbiters may grab epic close-ups that Earth telescopes can’t. |
| Oct 29–30, 2025 |
Perihelion — closest to the Sun |
This is the “big moment.” If it’s going to put on a show, this is when. Think of it as the comet’s spotlight performance. |
| Late Oct 2025 |
Lost in Sun’s glare |
From Earth we can’t see it — too close to the Sun in the sky. Astronomers twiddle thumbs and wait. |
| Early Nov 2025 |
Returns to view in morning sky |
Should reappear before sunrise. Nobody knows if it’ll be brighter or fainter — that’s the suspense. |
| Dec 19, 2025 |
Closest to Earth (~270 million km) |
That’s still far, but close enough for telescopes to grab lots of data. It won’t be naked-eye bright, but science teams will feast on the view. |
| March 2026 |
Passes near Jupiter |
A possible cameo for Juno or ESA’s JUICE probe. If they catch it, we’d get the first ever spacecraft look at an interstellar comet. |
| Beyond 2026 |
Gone forever |
After this, 3I/ATLAS sails back into interstellar space. No second chances. This is a once-in-a-lifetime visitor. |