Back in July and August of 2025, the interstellar object 3I/ATLAS was inferred to rotate with a period of 16.16 (+/-0.01) hours (as derived here).

Last week, preliminary images revealed a network of jets around 3I/ATLAS (as discussed here and here). These observed jets from 3I/ATLAS should have been smeared by the rotation. Instead, the image taken by F. Niebling and M. Buechner on November 9, 2025, shows tightly-collimated jets extending to distances larger than a million kilometers. At the expected thermal speed of sublimated volatiles from a natural comet, 400 meters per second, it takes about a month for the material to traverse a million kilometers.

How could these jets maintain their orientation if 3I/ATLAS is rotating every 16.16 hours?

The possibility that outflows slowed down the rotation since July is unlikely because asymmetries in outgassing typically enhance rotation (as discussed here). There is no recent measurement of the rotation period of 3I/ATLAS, but we expect related data in the coming weeks.

Another possibility is that illumination by the Sun induces outgassing only at specific angles relative to the Sun, which are dictated by the orientation of the pockets of ice and the surface topography of the nucleus. For example, ice pockets in deep valleys surrounded by mountains that shadow them will be exposed to direct sunlight and sublimate only when the Sun is at the right angle. This would lead to pulsating outflows from that spot with a period of 16.16 hours, resulting in a jet which looks like peas in a pod separated by a spatial scale of 400 meters per second times 16.16 hours which is 23,270 kilometers. There should be 43 peas on a pod of a million kilometers length and these puffs of gas should all be in the general direction of the Sun as the ice quickly cools when it is not illuminated by sunlight. This sunward orientation effect could not account for jets pointing away from the Sun, as evident in the image of 3I/ATLAS taken by M. Jäger, G. Rhemann and E. Prosperi on November 8, 2025.

Alternatively, the apparent features might represent the evaporated trail of fragments that were ejected from the main nucleus. This would imply that the nucleus exploded near the Sun, in contrast to the single object inference from the image obtained by D. Jewitt and J. Luu on November 11, 2025.

A more speculative possibility is that the jets maintain their directionality because they are produced by technological thrusters which preserve global orientation for navigation purposes.

At any event, the post-perihelion images add a new anomaly to the list, which by now includes 12 mysteries concerning 3I/ATLAS:

1. Its retrograde trajectory is aligned to within 5 degrees with the ecliptic plane of the planets around the Sun, with a likelihood of 0.2% (see here).

2. During July and August as well as in early November of 2025, it displayed a sunward jet (anti-tail) that is not an optical illusion from geometric perspective, unlike familiar comets (see here).

3. Its nucleus is about a million times more massive than 1I/`Oumuamua and a thousand times more massive than 2I/Borisov, while moving faster than both, altogether with a likelihood of less than 0.1% (see here and here).

4. Its arrival time was fine-tuned to bring it within tens of millions of kilometers from Mars, Venus and Jupiter and be unobservable from Earth at perihelion, with a likelihood of 0.005% (see here).

5. Its gas plume contains much more nickel than iron (as found in industrially-produced nickel alloys) and a nickel to cyanide ratio that is orders of magnitude larger than that of all known comets, including 2I/Borisov, with a likelihood below 1% (see here).

6. Its gas plume contains only 4% water by mass, a primary constituent of familiar comets (see here).

7. It shows extreme negative polarization, unprecedented for all known comets, including 2I/Borisov, with a likelihood below 1% (see here).

8. It arrived from a direction coincident with the radio “Wow! Signal” to within 9 degrees, with a likelihood of 0.6% (see here).

9. Near perihelion, it brightened faster than any known comet and was bluer than the Sun (see here).

10. It exhibits sunward and anti-solar jets which require an unreasonably large surface area in order to absorb enough sunlight needed to sublimate enough ice to feed the mass flux of these jets (as calculated here).

11. Near perihelion it exhibits non-gravitational acceleration which requires massive evaporation of at least 13% of its mass (as calculated here), whereas preliminary images indicate that the object maintained its integrity and did not break up (as discussed here).

12. Its tightly-collimated jets maintain orientation across a million kilometers in multiple directions relative to the Sun despite its measured rotation.

So far, I have not updated my rank for 3I/ATLAS on the Loeb Scale (defined here and quantified here), since we expect a flood of new data in the coming weeks. If the measured speed, composition and mass flux of the jets are consistent with sublimation of volatiles from pockets of ice on the surface of a natural comet, I will reduce my Loeb Scale rank. On the other hand, if the speed and mass flux are inconsistent with warming by sunlight of a natural comet, then I will raise the Loeb Scale rank to a higher value than 4. The rank will reach a value of 10 if there is evidence for new objects near Earth or Mars that are related to 3I/ATLAS.

(http://www.autoadmit.com/thread.php?thread_id=5798707&forum_id=2.#49434885)