3I/ATLAS shows perihelion burst and radial-only non-gravitational acceleration
12 comments
·November 7, 2025boothby
m4rtink
By this point it looks like they are not that rare. Lets just hope the next one does not have enough delta-v to change its trajectory to intercept us - at a couple dozen km/s. ;-)
CamperBob2
Meanwhile, in this life, some dogs and cats were apparently being eaten, so we get this: https://www.space.com/space-exploration/nasa-is-sinking-its-...
Muromec
That just means that the first people making contact with the object will not be speaking English, not that it will not happen at all
yodon
> For the layman: These plots show a sudden burst of acceleration on the object, and the push points mostly in one steady direction within the orbital plane. A normal comet warms up and ramps its outgassing gradually, and breaking apart would look chaotic with the direction of thrust changing randomly.
> Here we see one short, powerful jet, like a sealed pocket finally venting, so the speed jumps sharply while the path stays in the same plane; it accelerates but it surprisingly doesn’t change direction.
> It resembles what a single thruster would do (what an incredible prospect!), but it can technically still be explained by a natural rupture of volatile ices in an ancient space rock.
tummler
Seems odd to me that there would be one short, powerful jet of a natural explanation. Why hasn’t this thing been outgassing like crazy the whole time?
HPsquared
Maybe it was cooking away like a sealed food container in a microwave, internal pressure building, then the seal is breached and the internal pressure is released in a single event.
aaroninsf
Current speculation is that it's a novel object type, unlike the conglomerate iceballs we call "comets," with a different origin and history.
Unfortunately we did not make the heroic effort it would have taken to get a close look, so as with 1I/ʻOUMUAMUA we'll be left with enigmas and uncertainty.
Unless of course it brakes hard into a parking orbit. :)
bigbuppo
I guess the aliens are here to watch the AI bubble pop.
null
HPsquared
Solar heating and outgassing on the side facing the sun.
Breathless speculation aside, I think it would be extremely cool if we could identify, intercept and sample an extrasolar object at some point in my lifetime.