摘  要: The suggestions to solve a few problems in the origin of the solar system
and planet formation are presented. The difference in orbital periods between hot Jupiters and giant planets on long-period orbits is caused by two populations of protoplanetary disks. Nonuniform viscosity in the solar nebula interprets large masses of Jupiter and Saturn. The formation, structure, and evolution of the solar nebula are investigated by including nonuniform viscosity and the mass influx from the gravitational collapse of a molecular cloud core. The existence of the surface density minimum in the nebula leads to the low mass of Mars.