Photo: NASA
Scientists have found that Jupiter is slightly smaller and more flattened than previously believed, according to new research reported by Live Science.
The team analyzed data from NASA’s Juno spacecraft to refine measurements of the Solar System’s largest planet. Although the differences are small, the updated figures will improve models of Jupiter’s internal structure and enhance our understanding of gas giants beyond the Solar System.
“Textbooks will need updating. Jupiter itself hasn’t changed, but the way we measure it has,” said study co-author Yohai Kaspi, a planetary scientist at the Weizmann Institute of Science in Israel.
Until now, scientists relied on six measurements taken by the Voyager missions and Pioneer 10 and 11 about 50 years ago, using radio signals. Those values became the standard reference for Jupiter’s size and shape.
Since arriving at Jupiter in 2016, Juno has collected far more detailed radio data, especially over the past two years. This allowed researchers to refine Jupiter’s dimensions to within about 400 meters in each direction.
“By knowing Jupiter’s distance and tracking its rotation, you can estimate its size and shape, but truly precise measurements require more sophisticated techniques,” Kaspi explained.
In the new study, scientists tracked how Juno’s radio signals were distorted as they passed through Jupiter’s atmosphere before being cut off when the planet blocked the signal. This enabled the team to account for Jupiter’s powerful winds, which slightly alter the planet’s shape, and to calculate more accurate dimensions.
Based on the new data, Jupiter’s polar radius is now estimated at 66,842 kilometers — about 12 kilometers smaller than previously thought — while its equatorial radius is 71,488 kilometers, around 4 kilometers smaller than earlier estimates.
