NASA's Juno Mission Reveals Jupiter's Slightly Smaller Size
NASA's Juno spacecraft has provided new measurements indicating Jupiter is marginally smaller and more oblate than previously estimated.
Recent data from NASA's Juno mission indicate that Jupiter, the largest planet in our solar system, is slightly smaller and more oblate than earlier measurements suggested. By analyzing radio occultation data from 13 close flybys and accounting for the effects of zonal winds, scientists determined that Jupiter's equatorial diameter is approximately 8 kilometers narrower, and its polar flattening is about 24 kilometers more pronounced than previously believed.
Radio occultation allows researchers to probe through Jupiter's dense cloud cover to study its internal structure. During these experiments, Juno transmitted radio signals to NASA's Deep Space Network on Earth. As Juno passed behind Jupiter from Earth's perspective, its radio signal traversed the planet's atmosphere before reaching Earth. This process enabled scientists to measure changes in the signal caused by Jupiter's atmospheric composition, density, and temperature, leading to precise determinations of the planet's size and shape.
Eli Galanti, a planetary scientist at the Weizmann Institute of Science in Israel and lead author of the study, noted that this specific geometrical configuration did not occur during Juno's primary mission, so these experiments were not originally planned.
Accurate measurements of Jupiter's dimensions are crucial for calibrating models of giant exoplanets in other star systems. A refined understanding of Jupiter's shape aids astronomers in better interpreting observations of distant planets as they transit their host stars.