NASA Revises Jupiter Size Using Juno Mission Data

Jupiter, the largest planet in the solar system, is slightly smaller and more flattened than scientists previously believed, according to new findings based on data from NASA’s Juno spacecraft. The revised measurements offer the most precise picture yet of the gas giant’s size and shape, helping researchers better understand its internal structure and formation history.

More Precise Measurements Of Jupiter

Using advanced radio science data from NASA’s Juno mission, scientists calculated Jupiter’s equatorial diameter at 88,841 miles (142,976 km). This is about 5 miles smaller than estimates made using Voyager and Pioneer spacecraft data in the late 1970s. The planet’s polar diameter was measured at 83,067 miles (133,684 km), roughly 15 miles smaller than earlier calculations.

Greater Flattening At The Poles

The new analysis confirms that Jupiter is more oblate than previously known. The planet is about 7% wider at the equator than from pole to pole, a result of its rapid rotation and fluid composition. By comparison, Earth’s equatorial diameter exceeds its polar diameter by only about 0.33%. This enhanced flattening provides fresh insights into how mass is distributed inside Jupiter.

How Juno Enabled High-Precision Results

The measurements were made possible when the Juno spacecraft passed behind Jupiter relative to Earth, allowing its radio signals to travel through the planet’s atmosphere. According to planetary scientist Eli Galanti of the Weizmann Institute of Science, changes in the signal revealed details about Jupiter’s atmospheric density and temperature, enabling scientists to calculate its size and shape with exceptional accuracy. These observations were conducted after NASA extended the Juno mission in 2021.

Important Facts for Exams

• Jupiter is the fifth planet from the Sun and the largest in the solar system.
• The Juno mission has been orbiting Jupiter since 2016.
• Jupiter is primarily composed of hydrogen and helium.
• Its rapid rotation causes significant equatorial bulging.

Why Jupiter’s Size Matters For Science

Accurate measurements of Jupiter’s radius are crucial for models of its interior and atmosphere. As the most massive planet, Jupiter played a central role in shaping the solar system’s evolution. Scientists believe it formed early and influenced the distribution of material and delivery of volatile compounds, such as water and ammonia, to the inner solar system, including Earth.