Astronomical observations of young protostars indicate that early planetary systems evolved from the dust in a protoplanetary disk very quickly - in under five million years. Such short timescales require very efficient mechanism(s) to transport material inward towards the central star, but the mechanism(s) that do this are uncertain. Several have been invoked, however, in which magnetic fields play a key role, either in the stellar wind or in the disk itself.
Astronomers cannot currently directly measure magnetic field strengths in planet-forming regions, but experiments on meteoritic materials in our own Solar system can potentially constrain the strength of early Solar nebular magnetic fields. Chondrules are millimeter-sized constituents of primitive meteorites that formed in brief heating events in the young solar nebula. They probably constitute a significant fraction of the mass of asteroids and even of terrestrial planet precursors. The formation of chondrules, therefore, very likely occurred during a key stage in the evolution of the early solar system. If a stable field was present during their cooling off phase, they should themselves have become slightly magnetized. Determining their magnetic fields should therefore not only constrain models of their formation, but of the disk's evolution as well.