| 1972 | Discovery of extensive magnetism of lunar surface |
| 1975 | Discovery of conducting lunar core (with B. Goldstein) |
| 1977 | Discovery of absorption of solar wind by Venus atmosphere |
| 1978 | Established that Mars had no significant magnetic dipole moment |
| 1979 | Discovery of lightning on Venus (with F. L. Scarf) |
| 1980 | Established that Venus had no significant magnetic dipole moment |
| 1981 | Discovered the induced magnetotail of Venus |
| 1984 | Discovered disturbances in interplanetary magnetic field correlated with passage of asteroid 2201 Olijato |
| 1985 | Discovery of flux transfer events at the magnetopause of Mercury and Jupiter (with R. J. Walker) |
| 1988 | Discovery of mirror mode fluctuations in the coma of comet Halley |
| 1989 | Discovery of ULF waves in the magnetosphere of Mercury |
| 1995 | Confirmed that Mars had no significant magnetic dipole moment |
| 1998 | Discovery of substorm-like behavior in the magnetosphere of Jupiter |
| 2000 | Discovery of the variable composition of Io's atmosphere |
| 2000 | Determined the processes enabling the plasma circulation of the jovian magnetosphere |
| 2001 | Used in situ magnetometry to determine the rotation period of Jupiter |
| 2001 | Explained the formation of the torus in terms of ENA production in the Io exosphere |