NASA's Juno spacecraft sweeps over Jupiter's Great Red Spot and makes a 3D map of the giant storm. The findings could shed light on gas giant exoplanets in distant solar systems.



Jupiter is the biggest planet in our solar system. It's also home to the biggest storm. The Great Red Spot has been visible for centuries, but we still don't know much about it. But because of a spacecraft launched a decade ago, we are now finally getting a look inside Jupiter's storm. From member station WMFE in Orlando, Brendan Byrne reports.

BRENDAN BYRNE, BYLINE: The Great Red Spot is like a storm here on Earth but of cosmic proportions.

PAUL BYRNE: It's basically clouds.

B BYRNE: Paul Byrne is a planetary scientist at Washington University in St. Louis.

P BYRNE: It's not all that dissimilar to the kinds of things we know as cyclones or hurricanes or typhoons on Earth.

B BYRNE: The Great Red Spot is the largest storm in our Solar System and has been continually observed for around 200 years, but it's been around for much longer. From the top down, Scott Bolton says, scientists have been able to track changes in the spot. It's getting more circular and tinier.

SCOTT BOLTON: We believe this thing is really old. How it lasts that long is a mystery.

B BYRNE: Bolton is the principal investigator of the Juno mission. That spacecraft launched from Florida back in 2011 and arrived at Jupiter in 2016, hoping to answer that question. In 2019, the spacecraft changed course slightly and passed over the Great Red Spot twice. Bolton and his team used microwave sensors to slice into the depths of the storm, getting the first 3D model of the Great Red Spot.

BOLTON: It's a pancake because it's so wide at the top, but it's - the depth of it, that pancake is much thicker than what we would have anticipated.

B BYRNE: The storm is so massive, the spacecraft could actually feel the changes in gravity as it passed over the spot, almost like bumps in the road.


B BYRNE: The radio waves get squeezed and stretched by the gravitational bumps of the storm. Scientists analyzed these waves and found that the Great Red Spot extended some 300 miles into Jupiter's atmosphere. For comparison, the International Space Station is about 150 miles above our heads. Even though the storm is wide and deep, scientists have found that the spot has been shrinking. So can the Juno mission shed any light as to why or when it might disappear? Bolton says it's too soon to tell what the Great Spot's ultimate fate may be. These early data may give them some clues as to what's driving some of the changes.

BOLTON: We're starting to see that there are elements of the dynamics that are telling us that.

B BYRNE: While it's still too soon to say when the Spot will disappear, Bolton says the findings revealed the Great Red Spot is actually trapped between powerful conveyor belts of wind on the planet that are stabilizing the storm, meaning it could be around much longer for us to see from here on Earth. For NPR News, I'm Brendan Byrne in Orlando.