Okay so I'm quoting some important bits in order to clear up the confusion on the dates:
Perihelion is just 2 days before Halloween. Is 3I/ATLAS wearing a custom of a comet or is it a truly icy rock of natural origin?
On November 3, 2025, 3I/ATLAS will come within a distance of 97 million kilometers from Venus. During the same week, it will be observable by the ESA mission, Juice, on its path to Jupiter. On December 19, 2025, 6 days before Christmas, 3I/ATLAS will get to a closest distance of 267 million kilometers from Earth, assuming a purely gravitational trajectory.
This is how we'll know if it's technological:
Thus, perihelion constitutes the acid test of 3I/ATLAS. If it is a natural comet glued together by weak forces, its heating by 770 watts per square meter may break it up into fragments which evaporate more quickly as a result of their larger surface area per unit mass. The resulting fireworks might generate a much brighter cometary plume of gas and dust around it. However, if 3I/ATLAS was technologically manufactured — as suggested by its high abundance of nickel relative to iron, it might maneuver or release mini-probes.
by TheGoldenLeaper