How can a 1 kilometer body (3i/Atlas) flip 180 degrees suddenly?

[Julian_M]

[Mentor Note: OP advised that his acceptable reference in this OP does not support his assertions, and his references in subsequent posts are not acceptable per the PF rules. They have been requested to post acceptable references that support their assertions.]

I want to know the classical physics of how a large body can rotate 180 degrees suddenly, like what forces involved.

Brief summary: Before and after Perihelion (closest distance to sun). 3i/Atlas rotation axis aligns to the sun. See above. What happened right at Perihelion when earth blocked the view? Did 3i/atlas flip 180 degrees so the other side of the rotation axis aligns with sun or did 3i/Atlas slowly rotate to maintain the rotation axis sun alignment in the journey? If it flipped, how can it just rotate 180 degrees? what forces are involved? Unfortunately, at precisely that moment at Perihelion, it hides behind the sun.

Paper reference: https://www.aanda.org/articles/aa/pdf/2026/01/aa58072-25.pdf

Longer explanation.

Anomaly 14:

Recent observations of 3I/ATLAS reveal a highly unusual geometric configuration that is difficult to reconcile with standard cometary behavior. Measurements show that the object’s rotation axis aligns directly with the Sun, while a narrow anti-tail jet originates from within eight degrees of one rotational pole. Such a precise alignment is statistically rare and already places the object outside what would normally be expected from random surface outgassing.

What makes the situation more extraordinary is what happens after perihelion. As 3I/ATLAS moves away from the Sun, its orientation flips, placing the previously illuminated pole into darkness. Despite this reversal, the anti-tail remains perfectly aligned with the Sun, implying that a second jet becomes active at the opposite pole when it faces sunlight. Both polar regions, independently, produce the same highly collimated geometry under different orbital conditions.

This is just 1 of the 18 anomalies. In March 16, 2026. It will pass right at the edge of Jupiter Hill Radius (the boundary between the Sun and Jupiter gravitational influence).

 

[Bandersnatch]

The paper provided doesn't support any of the statements in the OP. Can you provide a different source or sources as the basis for a discussion?

 

[DaveC426913]

I am curious where this image came from. It displays a highly-elongated object along one axis - more than 4x longer than its other axes. One might almost call it cigar-shaped.

There is no indication that 3I/Atlas has such a shape. Does the artist of this renditon have an overly-active imagination?

And let's not even ask what "activates polar jets" might mean.



My spidey-sense is tingling.

 

[Julian_M]

The image was drawn by an artist just illustrating 1 of the 18 anomalies. That paper was about pre-perihelion which occurs before Oct 29, 2025. But after Perihelion, the same phenomenon occurs, So either the orientation moved with respect to sun or it flips at 180 degrees during perihilion. The papers after post-perihelion are being written by the Hubble and James Webb principal investigators but the preliminary findings are reported by the following astrophysicist:



Here are the 18 anomalies now. Can anyone debunk all of them in an hour or less? Please do because for many it is consuming many months of our time.

Geometric Coincidences:

1. The retrograde trajectory of 3I/ATLAS is aligned to within 5 degrees with the orbital plane of the planets around the Sun, with a probability of 0.2% (as discussed here). The Milky-Way disk is misaligned with the ecliptic plane by about 60 degrees. This suggests that the trajectory of 3I/ATLAS may have been planned.

2. The arrival time of 3I/ATLAS was fine-tuned to bring it to minimum distances of 29 and 54 million kilometers from Mars and Jupiter, respectively, and be unobservable from Earth at perihelion (as discussed here).

3. The forecasted perijove distance of 3I/ATLAS during its encounter with Jupiter on March 16, 2026 is 53.6 million kilometers, is very close to Jupiter’s Hill radius, 53.5 million kilometers (as discussed here). The rare coincidence might mean that 3I/ATLAS intends to release technological devices as satellites near Jupiter’s Lagrange points — where fuel requirements are minimal.

4. Analysis of the Hubble Space Telescope image of 3I/ATLAS from July 21, 2025 (as discussed here) suggests that the anti-tail before perihelion must have been in the form of a collimated jet towards the Sun that is about ten times longer than it is wide. This is similar to the collimation observed in post-perihelion images out to several hundred thousand kilometers. No known comet exhibited a physical sunward jet of this length that is not a perspective effect. For a technological object, a beam of particles might be used to block the solar wind from impacting the nucleus surface at a relative speed of order 500 kilometers per second. In addition, the veil of dust around 3I/ATLAS is just of the right column needed to block sunlight from hitting the nucleus surface (as discussed here).

5. At large distances, the initial rotation axis of 3I/ATLAS was aligned to within 8 degrees with the sunward direction when it entered the solar system (as reported here). The probability for that is 0.5%.

6. The observed wobble of the pre-perihelion jet in the direction of the Sun (as reported here during July and August 2025) requires the base of the jet to be within 8 degrees from the sun-facing pole, with probability of 0.5%.

7. The existence of a prominent jet towards the Sun on the way of 3I/ATLAS out of the solar system requires a similar coincidence near the opposite pole of the rotation axis. The fact that a collimated jet appears as the sunward anti-tail both before and after perihelion (while reversing direction at perihelion relative to the direction of motion), has a tiny probability of occurring at random, equal to the square of 0.5% or 0.000025.

8. Processing of the Hubble Space Telescope Images from January 14, 2026 by the Larson-Sekanina filter — which removes the circularly-symmetric glow round the nucleus, reveals a system of three mini-jets which are symmetrically separated by 120 degrees from each other (as discussed here).

9. The launch base of the post-perihelion anti-tail jet resided on the nightside of 3I/ATLAS before perihelion and the base of the pre-perihelion anti-tail jet is now on the nightside of 3I/ATLAS after perihelion. For these bases to be active only when facing the Sun, they must be well insulated on the nightside for a period longer than several months. Heat naturally flows by conduction throughout the body of a natural comet, making this insulation requirement difficult to satisfy.

10. The gravitational deflection of 3I/ATLAS by 16 degrees at perihelion (as discussed here), is exactly twice the opening angle of the anti-tail before perihelion. This coincidence allows the wobbling jet around the rotation axis to generate an anti-tail in the direction of the Sun before perihelion and a counter jet on the opposite pole after perihelion, with a jet opening angle of 8 degrees on both poles.

11. On January 22, 2026, 3I/ATLAS will align with the Sun-Earth axis to within an extraordinarily small angle of 0.69 degrees (as discussed here). At that time its anti-tail will be pointing at Earth.

12. 3I/ATLAS arrived from a direction coincident with the radio “Wow! Signal” to within 9 degrees, with a probability of 0.6% (as discussed here).

Composition Anomalies of the Gas Shed by 3I/ATLAS:

13. The gas plume surrounding 3I/ATLAS 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 for thousands of known comets, including 2I/Borisov (as reported here). This might indicate a technological origin for these abundances.

14. The anti-tail is capable of penetrating hundreds of thousands of kilometers through the solar wind and the solar radiation. In order not to be stopped, the dust particles must be much larger than common sub-micron particles of interstellar dust (as discussed here). However, if the particles are bigger than a millimeter, then they must carry an untenable amount of mass in order to account for 99% of the scattered sunlight around 3I/ATLAS, as observed in the Hubble images.

15. Data from the SPHEREx space observatory indicated the existence of icy fragments around 3I/ATLAS before perihelion (as reported here in August 2025). However, the spectral signature of ice disappeared in the SPHEREx data after perihelion, taken during December 2025 (as reported here), when abundant organic molecules in gas phase, such as CH3OH, H2CO, CH4, and C2H6, were discovered, along with an enhancement by a factor of ~20 in the water production rate. To survive cosmic-ray bombardment along an interstellar journey that lasted billions of years, these organic molecules must have been buried under a thick layer of material, at least 10-meters in depth.

Unusual Physical Properties:

16. The nucleus of 3I/ATLAS is more massive than 1I/`Oumuamua and 2I/Borisov, while moving faster than both (as discussed here and here). This suggests that 3I/ATLAS might have targeted the inner solar system rather than being drawn at random from the reservoir of interstellar icebergs.

17. 3I/ATLAS shows extreme negative polarization, unprecedented for all known comets, including 2I/Borisov (as discussed here and here). This unusual polarization may be related to its unusual anti-tail.

18. Near perihelion, 3I/ATLAS brightened faster than any known comet and was bluer than the Sun (as discussed here).

 

[DaveC426913]

Please do because for many it is consuming many months of our time.

Who is "us"? Why is it consuming anyone's time, except for fun?

The arrival time of 3I/ATLAS was fine-tuned to bring it to minimum distances of 29 and 54 million kilometers from Mars and Jupiter, respectively

"Fine-tuned" suggests it was tuned deliberately. Is this part of what is consuming so much time?

 

[Bandersnatch]

Oh, lordy. It's Avi Loeb's brainchild. I'm not touching this.

 

[berkeman]

Thread is closed temporarily pending Mentor review.

 

[berkeman]

OP -- please post acceptable references that support your assertions in your OP. Thread is reopened provisionally.