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SUMMARY:An Early Heavy Bombardment of the Inner Solar System - Craig Walt
 on (ETH)
DTSTART:20250318T130000Z
DTEND:20250318T140000Z
UID:TALK227278@talks.cam.ac.uk
CONTACT:Dr Dolev Bashi
DESCRIPTION:The orbital architecture of planets in the Solar System is tho
 ught to have been set shortly after its birth. However\, ancient asteroid 
 families are highly dispersed\, suggesting that perhaps the Solar System r
 emained chaotic until later in its history. Testing this possibility requi
 res precise dating of the collisions that should have generated such famil
 ies\, but planetary surfaces record little to no information from this tim
 e. The meteorite record of asteroid collisions represents a separate and m
 ore complete archive of Solar System evolution. In this project\, we lever
 aged recent methodological advances to build an extensive record of in-sit
 u meteorite apatite U-Pb ages\, sensitive to collisions that induce parent
  body break-up events. Most asteroid collisions in our record occurred 448
 0 +/- 20 million years ago. Only highly dispersed asteroid families are po
 tentially co-eval with our U-Pb ages\, demonstrating that strong perturbat
 ions modifying the orbital eccentricities and inclinations of asteroids we
 re still operating at 4480 Ma. This is unexpected in scenarios where the p
 lanets completed their growth and acquired their current orbits in a few M
 yr within the dispersal of the protoplanetary disk. Our work provides uniq
 ue evidence that the asteroid belt was still in a state of dynamical chaos
  80 Myr after its formation.
LOCATION:Ryle seminar room + ONLINE - Details to be sent by email
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