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Title: When did the giant-planet orbital instability happen?
Plain: Models suggest Jupiter, Saturn, Uranus and Neptune once went through a violent rearrangement of their orbits. Whether this happened within the first 100 million years or about 700 million years later is still debated.
Precise: Determine the epoch of the giant-planet instability relative to gas-disk dispersal: early (within about 100 Myr) or late (about 500 to 700 Myr), using constraints from Jupiter trojan binaries, asteroid and meteorite impact ages, terrestrial-planet orbital excitation and lunar basin chronology. An answer is an instability time with uncertainty consistent with all dynamical and chronological constraints.
Settled by: A consistent set of dynamical survival constraints (trojan binaries, terrestrial planet orbits) and radiometric impact ages that exclude one of the two epochs.
Kind: well-posed
Answer type: value
References: (empty)
Literature status: contested
Status note: Most dynamical studies since 2018 favour an early instability, but the interpretation of lunar impact ages remains disputed.
Posed since: (empty)