Story perspectives

NASA’s Juno Reveals Jupiter’s Surprising Size Discrepancies

2/5/2026

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Summary

Story summary

NASA's Juno mission shows Jupiter is smaller and flatter, with an equatorial diameter of 142,976 km and a polar diameter of 133,684 km.
The study, led by the Weizmann Institute, challenges nearly 50 years of consensus on Jupiter's dimensions.
Professor Yohai Kaspi of the Weizmann Institute notes measurement methods have evolved and textbooks should be updated.
The findings will inform models of Jupiter's atmosphere and formation.

History

Historical Context

NASA's Pioneer 10 spacecraft made history in December 1973 as the first to fly by Jupiter, revealing crucial data about the planet's atmosphere and magnetic field. Subsequent missions, including the Voyager probes in 1979, expanded our understanding of Jupiter's structure and its moons. Recent findings from the Weizmann Institute, measuring Jupiter's equatorial diameter at 142,976 km, challenge earlier data and enhance our knowledge of gas giants.

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Story summary

NASA's Juno mission shows Jupiter is smaller and flatter, with an equatorial diameter of 142,976 km and a polar diameter of 133,684 km.
The study, led by the Weizmann Institute, challenges nearly 50 years of consensus on Jupiter's dimensions.
Professor Yohai Kaspi of the Weizmann Institute notes measurement methods have evolved and textbooks should be updated.
The findings will inform models of Jupiter's atmosphere and formation.

1 / 2