Jupiter's Great Red Spot, a storm so big it could swallow Earth, extends surprisingly deep beneath the planet's cloud tops, scientists have reported.
Data from NASA's Juno spacecraft is providing a deeper understanding of Jupiter's wondrous and violent atmosphere, including its Great Red Spot, finding the storm extends much further down than first thought.
Despite the storm shrinking, it still has a width of 16,000 kilometres and a depth of between 350 and 500 kilometres.
The planet, known as a gas giant, is composed primarily of hydrogen and helium, with traces of other gases.
The data is giving scientists studying the solar system's largest planet — so big that 1,000 Earths could fit inside it — a three-dimensional account of Jupiter's atmosphere.
An instrument called a microwave radiometer enabled scientists to peer beneath Jupiter's cloud tops and investigate the structure of its numerous vortex storms.
Lead scientist Scott Bolton, from Southwest Research Institute, said there might not be a hard cut-off at the bottom of the storm.
Dr Bolton said assumptions based on how Earth's atmosphere behaves, as well as models produced over the past few decades, had given the impression that the Great Red Spot was a relatively shallow storm.
"Jupiter works in this mysterious way that we're sort of revealing for the first time because this is the first mission that's been able to look inside the planet," Dr Bolton said.
The Juno spacecraft will soon be measuring the depth of the polar cyclones, which might penetrate even deeper beneath the clouds.
The Great Red Spot could be the tallest Jovian storm measured with Juno's microwave and gravity-mapping instruments, Dr Bolton said.
"I wouldn't want to be too quick to guess that we've seen the deepest," he said.
The Great Red Spot has evolved in shape over time and there are indications that it may be shrinking in size.
"It's the biggest storm in the entire solar system. There isn't anything else like it," Dr Bolton said
In 2011, Juno has been orbiting the solar system's largest planet since 2016 obtaining information about its atmosphere, interior structure, internal magnetic field and the region.
Juno also is due to fly by Jupiter's large moons, Europa and Io, and explore the small rings around the planet.
By contrast, some of the surrounding jet streams extend an estimated 3,200 kilometres into Jupiter.
NASA recently extended the mission by another four years, to 2025.
AP/Reuters
