As far as we know, our solar system is unique. It could, in principle, be the only planetary system in the Universe to harbor intelligent life or, indeed, life at all. As such, attempting to reconstruct its history is one of the most fundamental pursuits in the natural sciences. Whereas astronomical observations of star- forming regions provide a framework for understanding the formation of low-mass stars and the early evolution of planetary systems in general, direct information about the earliest solar system can only come from primitive meteorites and their components and some differentiated meteorites that record the birth of the solar system. The main objective of this proposal is to investigate the timescales and processes – including the role of supernovas – leading to the formation of the solar system by measurement of isotopic variations in meteorites. To achieve our objectives, we will integrate long-lived and short-lived radioisotope chronometers with the presence/absence of nucleosynthetic anomalies in various meteorites and meteoritic components. Our isotopic measurements will be obtained using state-of-the-art technologies such as second-generation mass spectrometers housed in laboratories directed by the PI and fully dedicated to cosmochemistry. This will allow us to: 1) define the mechanism and timescale for the collapse of the protosolar molecular cloud and emergence of the protoplanetary disk, 2) constrain the source and locale of chondrule-forming event(s) as well as the nature of the mechanism(s) required to transport chondrules to the accretion regions of chondrites, and 3) provide robust estimates of the timing and mechanism of asteroidal differentiation. We aim to understand how the variable initial conditions imposed by the range of possible stellar environments and protoplanetary disk properties regulated the formation and assemblage of disk solids into asteroidal and planetary bodies comprising our solar system.