Kuiper

Yeah, I suppose I'm making up for last night's debacle in poasting, that I'd got took by a Matt Drudge trollpoast. Not that I believed any of it ever, but it's embarrassing enough that I'd thought it was worth taking seriously. So, now: Kuiper Belt Objects.

We've been to one - sent a probe thither, anyway. Ultima Thule, as we called it at the time; Arrakoth, now. We seem to be on a hunt to find more closer to home. These n-body systems move about chaotically, and sometimes Kuiper comes closer to us. Triton, dramatically, came to Neptune.

Just in the last week we read that a couple asteroids look Arrakothey. And now, Hokkaido University is looking into a rock that came down to Tagish Lake.

Tagish Lake is metamorphic, as these things go; it got hit (out) by something. Also there was "radiogenic heating" around that time of impact. That means homemade radiation. According to the abstract, the internal radiation happened during the parent asteroid's formation. It had got to 160 km diameter or more, in Kuiper; before the impact, which - they say - probably happened in our Asteroid Belt at, what, 4 AU. I assume Jupiter was mostly formed by then.

They say the impactor was only 10 km across. Doesn't seem enough to vapourise the parent.

Is, then, that parent ex-Kuiper still among us?