About 3I/ATLAS
3I/ATLAS is a mythic comet. It swings within 1.356 AU of the Sun at perihelion.
A visitor from another star system — it doesn't belong to our Sun at all. Only a couple have ever been caught passing through.
Mythic comet 175 EP
3I/ATLAS
Position computed live · sbdb
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Live ephemeris
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Score breakdown
· 6 badgesMythic Top tier reached ✦
- Interstellar visitor +80
- 3I/ATLAS, the third interstellar visitor +55
- Hyperbolic comet (one pass, then gone) +18
- Retrograde orbit +8
- Has a proper name +8
- Comet +6
Total score 175
Badges
- Comet · +6
- Interstellar visitor · +80
- Retrograde orbit · +8
- Has a proper name · +8
- Hyperbolic comet (one pass, then gone) · +18
- 3I/ATLAS, the third interstellar visitor · +55
Trivia
What makes it special
- Interstellar. A visitor from another star system — it doesn't belong to our Sun at all. Only a couple have ever been caught passing through.
Hard to believe
- Against the traffic. It goes round the Sun backwards, against the direction every planet and almost everything else travels.
What it actually is
- Its orbit family. On a hyperbolic orbit: it is moving too fast for the Sun's gravity to hold on to it.
- Closest approach. At its nearest it comes within 1.36 AU of the Sun — inside the orbit of Mars.
- One-way trip. On a hyperbolic path — it will leave the Solar System and never return.
Standing on it
- Growing a tail. Once inside roughly the orbit of Mars the ice starts turning straight to gas, blowing out the coma and tail that make a comet a comet.
- Tail. Its tail always points away from the Sun, never trailing behind its motion — it is blown, not dragged.
By the numbers
- Made of. A comet is a dirty snowball: water ice, frozen carbon dioxide and dust, held together loosely enough that some simply crumble when the Sun warms them.
Properties
- designation
- 3I
- eccentricity
- 6.1414
- full name
- C/2025 N1 (ATLAS)
- inclination
- 175.12
- interstellar
- yes
- mean motion deg day
- 7.273
- moid au
- 0.365
- name
- 3I/ATLAS
- named
- yes
- orbit class
- HYP
- perihelion au
- 1.356
- semi major au
- -0.2638
How to see it
Like any astronomical target, 3I/ATLAS is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. Because it moves against the background stars, the live position panel on this page tracks where it is right now. The visibility panel above works out tonight's viewing window for your saved location.
Why 3I/ATLAS is a mythic comet
3I/ATLAS scores 175 points on Spacedle's rarity scale, which places it in the mythic tier.
That score comes from 6 science badges — Comet, Interstellar visitor, Retrograde orbit, Has a proper name, Hyperbolic comet (one pass, then gone) and 3I/ATLAS, the third interstellar visitor — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.