What were the odds: two articles in Nature Astronomy, and they aren’t even high energy/compact objects. In the August “issue” (vol. 8, #8):
Edwards, G. H. Keller, C. B. Newton, E. R. An early giant planet instability recorded in asteroidal mete…
10.1038/s41550-024-02340-6
This research group used meteorites, for the most part assumed to be samples of asteroids. Such chondrite meteorites have preserved chemical signatures from their formation, for the most part assumed to be pretty early on in the new Solar System of ours. And what do those chemistries say? For the most part, chemical signatures indicate conditions, like initial and maximum temperatures, and formation reservoirs (chemical pools, vs. different source pools). And what do those temperatures and reservoirs say? In short, the early Solar System (for the most part) was a “shooting gallery” of dislodged asteroids, all crashing here and there. And what does that gonzo shooting gallery say? For the most part, a dislodger was necessary, likely the migration of Jupiter and other giant planets.
By now you may have noticed my cagey language. This chain of evidence is long, and full of assumptions. So how do we know it’s not all a pedagogical rat’s nest, a train-of-thought train wreck? Because there are multiple, independent lines of evidence for this migration of planets in the early Solar System. Most directly, we see other Systems (“exoplanets”) that pretty clearly had ‘their Jupiter’ migrate. Other Systems, with “hot Jupiters,” had that giant planet form at a distance, then spiral in. In the course of spiraling into its host star, it dislodged many small bodies (asteroids, comets, nascent comet-like things, and whatevers between categories). Our own Solar System has odd properties for Uranus and Neptune; the most direct explanation is that Uranus actually formed further out, and the two switched places into what we see today. There’s also the Late Heavy Bombardment, a putative ultra-storm of impactors into the Earth and inner Solar System. The scars of such a LHB are visible on the planets. Between multiple, parallel investigations, it’s clear that something happened. That the details aren’t lining up exactly (for one, the LHB is a hot debate in the field) is a matter of the details; it’s not up for debate that bombardment (small-B) did happen.
Asteroids- and their happenstance samples, the meteorites- record, preserve, and signify the history of our Solar System, and to an extent a pre-Solar environ, and to some extent how Systems typically form. We study asteroids to give context and depth to our meteorite studies; we study meteorites to give detail and decimal places on our asteroid studies. And, by extension, we study both, to give context, detail, and comprehension to our place in the cosmos.