New measurements show Jupiter is slightly smaller and more flattened than experts once thought.
NASA’s Juno spacecraft delivers the most precise data yet. Researchers analyzed radio occultation from multiple flybys. They tracked how signals bend through the thick atmosphere. This method maps temperature, density, and shape accurately.
The updated figures come from a study in Nature Astronomy. At the 1-bar pressure level, Jupiter’s polar radius measures 66,842 km. Its equatorial radius stands at 71,488 km. These values shrink the planet by about 12 km at the poles. They also reduce it by 4 km at the equator compared to 1970s estimates.
Old data came from Pioneer and Voyager missions. Scientists then relied on just six occultation measurements. Those early readings left room for error. They missed strong zonal winds that distort the atmosphere.
Juno changes everything. The probe provided far more observations. Advanced processing techniques handle wind effects better. As a result, the planet appears more squashed with a pronounced equatorial bulge.
Experts say these tweaks matter a lot. Precise dimensions improve models of Jupiter’s interior. Better models also help understand other gas giants in distant systems.
In related space news, astronomers recently watched a massive star in the Andromeda galaxy collapse quietly into a black hole. It faded without a supernova explosion.
Scientists continue to refine our view of the solar system. Juno’s ongoing work reveals hidden details. Jupiter remains the largest planet, yet now we know it more exactly.