Looking Up (and Down) at Jupiter
June 9, 2017
Jupiter, our solar system’s largest planet, is slowly giving up its secrets. Last month, astronomers and planetary scientists of NASA’s Juno Mission to Jupiter released spectacular new images of the planet along with scientific papers fueled by the mission’s newly gathered data. The Juno probe has been in orbit around Jupiter since July 2016. NASA launched the spacecraft, named for the wife of the god Jupiter in Roman mythology, in August 2011. Juno is managed by the Jet Propulsion Laboratory in Pasadena, California.
Jupiter’s south pole, as seen by the Juno spacecraft from an altitude of 32,000 miles (52,000 kilometers). The oval features are massive cyclones up to 600 miles (1,000 kilometers) in diameter. Credit: NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles
Juno circles Jupiter in an unusual elongated (stretched out) orbit. Juno flies as far as 5 million miles (8 million kilometers) away from the planet and dives as close as 3,000 miles (5,000 kilometers) above Jupiter’s turbulent cloud tops. Rather than orbiting at or near the planet’s equator, Juno circles over Jupiter’s north and south poles. This orbit helps Juno avoid Jupiter’s radiation belt, which emanates from the planet’s waistline like an invisible ring. The intense radiation of this region would quickly destroy Juno’s electronic circuits and scientific instruments.
Spectacular storms cluster around Jupiter’s turbulent north pole. Credit: MSSS/SwRI/JPL-Caltech/NASA
Juno’s polar orbit has given scientists (and everyone else) new views of Jupiter. Unlike the rest of the planet’s atmosphere, which is famous for its banded structure (as we see in our familiar side view of the planet), Jupiter’s poles resemble bubbling cauldrons. Cyclonic storms many times larger than the largest hurricanes on Earth pockmark these regions, whose grayish-blue hues contrast with the tans, oranges, and reds found elsewhere on the planet. Scientists await further images to determine if these polar storms are short lived or if they may last years, decades, or even centuries—as has Jupiter’s famous and stormy Great Red Spot.
The familiar side view of Jupiter reveals its varied color bands and the Great Red Spot just south of the planet’s equator. Credit: Johns Hopkins U. APL/SWRI/NASA
One of Juno’s primary objectives is to study Jupiter’s internal makeup and determine if the planet has a solid, rocky core. The data returned so far suggest that Jupiter does indeed have a solid core, but that it is “fuzzy.” Data from future orbits of the probe will help scientists understand the makeup of the core and why it appears to have an undefined boundary.
Launched from Earth in 2011, the Juno spacecraft arrived at Jupiter in 2016. Credit: NASA/JPL
In addition to providing new looks at Jupiter, Juno has forced scientists to reconsider several previously believed notions of the giant planet. The probe has detected more ammonia in Jupiter’s atmosphere than was previously thought to be there. The ammonia is also spread unevenly, with much of it concentrating near Jupiter’s equator. Juno has discovered that the planet’s magnetic field is about as twice as strong as previously thought, and that the magnetism is “lumpy,” having stronger and weaker pockets. The magnetic field is also generated much closer to the planet’s surface than scientists had earlier guessed. Further measurements from Juno are needed to help understand how the field is generated. (Scientists think Earth’s magnetic field comes from the liquid core at our planet’s center.)
Juno still has more than 30 dives to collect information on Jupiter, providing numerous opportunities to further rewrite the book on our distant, gassy, and giant planetary neighbor.
