More reports on our extrasolar boulder:
Astrophysics > Earth and Planetary Astrophysics www.arxiv.org/abs/2511.16247
[Submitted on 20 Nov 2025]
Ahuja, G. Ganesh, S. Dynamical simulation of the Interstellar Comet 3I/ATLAS
Using Newton’s laws (plus a little of Kepler’s), with the path of the comet (from its July discovery, and even before), up until the current solar conjunction, the authors calculate the trajectory (NOT orbit) of 3I/ATLAS. Unfortunately, as the authors themselves admit, they do not take into account nongravitational forces (“jetting”). We already have initial observations showing some nongravitational force, as the emissions from a comet (now including this one) have no reason to be perfectly symmetrical around the nucleus. If anything, it’s perfectly symmetrical outgassing that would be weird. Since the comet is spurting eccentrically (it appears, in the sunward direction), the trajectory is not strictly calculable using gravity alone- even including the gravities of Mars (pretty negligible) and Jupiter (no, not negligible).
I wouldn’t call this exercise a total waste of time and effort. Knowing the purely gravitational track, one might better calculate the jetting, from comparison with the actual, observed track. This is close to what happened with 1I/‘Oumuamua, with activity below the visible threshold.