Oumuamua left the solar system in 2017. The trajectory data has been updated several times since then, and the updated models are more interesting than the original ones — not because they confirm anything exotic, but because they narrow the range of explanations in ways that make the remaining explanations harder to dismiss.
The original anomaly was the non-gravitational acceleration. Oumuamua was accelerating away from the sun faster than solar radiation pressure alone could account for. The leading explanation was outgassing — cometary activity releasing gas that acted as a propellant. The problem was that no outgassing was detected. No coma. No tail. Nothing that looked like a comet behaving like a comet.
The updated trajectory models, incorporating additional observations from the period before Oumuamua left the detectable range, have refined the acceleration profile. It's not uniform. There are variations in the acceleration that are consistent with a tumbling object — which Oumuamua was, based on its light curve — but the variations don't map cleanly onto any simple outgassing model. The gas would have to be coming from a very specific location on the object, in a very specific direction, with very specific timing.
This doesn't mean it's a spacecraft. It means the outgassing explanation requires more specificity than the original version did, and more specificity means more assumptions, and more assumptions means more ways to be wrong.
The hydrogen iceberg hypothesis — proposed in 2020 — would explain the acceleration without outgassing, because hydrogen ice sublimates invisibly. The problem is that hydrogen icebergs shouldn't survive interstellar travel. The math on that is fairly clear. So that explanation has its own problems.
What the updated data actually shows is that we have a well-characterized anomaly and a set of explanations that each require some special pleading. That's not a mystery in the dramatic sense. It's a gap in our models. Gaps in models are normal. They're also where the interesting science happens.
There's more on this at AI divination — the relationship between anomalous data and the models we use to explain it. The specific challenge of Oumuamua is that it's gone, so we can't get more data. We're working with what we have, and what we have is genuinely strange.
The fringe interpretations get more attention than they deserve, and the mainstream interpretations get less scrutiny than they need. The actual situation is more interesting than either: a well-documented object that doesn't fit cleanly into any existing category, and a scientific community that's being appropriately careful about what it claims to know.
More on anomalous space data at outer-band transmissions. The question of what the data actually shows versus what gets reported is something the commentary has been tracking. And the maker's perspective has more on the fringe theory landscape around interstellar objects.