US EditionNASA's Juno Finds Jupiter Is a Tiny Bit Smaller than Previously Thought
Juno data shows Jupiter is up to 15 miles flatter at poles and 8 kilometers slimmer at the equator, improving interior and atmospheric models, study finds.
- Using Juno data, researchers published on Feb. 2, 2026 that Jupiter is slightly smaller and flatter than previously believed, based on new radio-occultation data from NASA's Juno spacecraft and reanalysis techniques.
- Past measurements relied on six radio occultations from Pioneer 10 and 11, Voyager 1 and 2 nearly 50 years ago and omitted strong zonal winds, while Juno's 2021 mission extension enabled behind-Jupiter passes for new occultation data.
- Juno's radio occultations reveal an equatorial diameter of 142,976 km, showing Jupiter is about 5 miles narrower than previously measured.
- Researchers say small shifts in Jupiter's radius let interior‑density models align better with gravity and atmospheric measurements, sharpening its role for textbooks and exoplanet modelers.
- Jupiter remains oblate, with Galanti saying `These few kilometers matter`, and Kaspi adding `This research helps us understand how planets form and evolve`.
42 Articles
42 Articles
The size and shape of Jupiter - Nature Astronomy
Jupiter, the fastest-rotating planet in the Solar System, exhibits a pronounced equatorial bulge, with its equatorial radius exceeding the polar radius by approximately 7%. This oblate shape reflects the combined effects of rapid rotation, complex internal structure and atmospheric winds. Existing estimates of Jupiter’s shape, with uncertainties of about 4 km, are based on a single analysis of Voyager and Pioneer radio occultations from nearly f…
NASA's Juno mission finds Jupiter smaller, flatter than previously thought
Data from NASA's Juno mission show that Jupiter, the largest planet in the solar system, is slightly smaller and more "squashed" than previously believed, the U.S. space agency said on Wednesday.By analyzing radio occultation data from 13 close flybys
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