Overview
- Jupiter’s equatorial radius is now measured at 71,488 km and its polar radius at 66,842 km, about 4 km smaller at the equator and 12 km flatter at the poles than earlier estimates.
- The updated dimensions come from repeated radio occultation passes by NASA’s Juno spacecraft that traced how radio signals bend through the planet’s atmosphere.
- A 2021 orbit change placed Juno behind Jupiter from Earth’s viewpoint, enabling regular, higher-quality occultation measurements with improved processing.
- Researchers incorporated the effects of powerful zonal winds, yielding a slightly more oblate shape and tighter uncertainties that better match gravity and atmospheric data.
- The findings replace sizes inferred from only six 1970s Voyager and Pioneer measurements, and the improved precision informs models of Jupiter’s interior and other gas giants.