Gas giants exert a major control on solar system architecture. Observations of disks like those by the Atacama Large Millimeter/submillimeter Array (ALMA) reveal early stages of planet formation in far-away stellar systems. But timing of giant planet formation processes can best be traced via detailed investigations possible in our solar system. A commentary by Weiss and Bottke  closely examines Jupiter formation, using clues preserved in the meteorite record. They find current data are consistent with an initial “slow growth” phase for Jupiter that created separate isotopic reservoirs for meteorite parent bodies. Subsequently, paleomagnetic data suggest rapid dissipation of the nebular field, most easily explained by rapid (greater than 30 times) growth of Jupiter, which supports a core accretion physical model for giant planets. The case is not closed, however. Weiss and Bottke propose further observations and physical modeling to establish the pacing of Jupiter formation and its effects on the architecture of our solar system.
Story Image: Weiss and Bottke  review the evidence from meteorite isotopes (green line) that indicate Jupiter slowly grew to sufficient mass, expressed relative to Earth mass, to create a gap in the solar nebula’s isotopic reservoirs by 1.3-3.46 billion years after formation of calcium aluminum inclusions (CAIs) in the early solar system. They then propose a >30x increase in the rate of Jupiter accretion, suggesting it drove dissipation of the carriers of the nebular magnetic field because the field is recorded in meteorites before 3.94 billion years but not after (red line). A period of slow followed by rapid growth is consistent with core accretion physical models for gas giants. Credit: Weiss and Bottke , Figure 1b