Nasa spacecraft finds storm on Jupiter deeper than expected

WASHINGTON • Data from the US National Aeronautics and Space Administration's (Nasa) Juno spacecraft is providing a deeper understanding of Jupiter's wondrous and violent atmosphere, including its Great Red Spot, finding that this immense swirling storm extends much farther down than expected.

Researchers said on Thursday that the Great Red Spot plunges between roughly 350km and 500km below the cloud tops on Jupiter, based on microwave and gravity measurements obtained by Juno.

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.

The planet, known as a gas giant, is composed primarily of hydrogen and helium, with traces of other gases. Stripes and a few storms such as the Great Red Spot dominate the colourful appearance of Jupiter, the fifth planet from the Sun with a diameter of about 143,000km.

The Great Red Spot is a storm roughly 16,000km wide churning in Jupiter's southern hemisphere, boasting crimson-coloured clouds that spin counterclockwise at high speeds. It is one of the marvels of the solar system and has been in existence for centuries, but scientists until now have had little understanding of what lies below its surface.

"From a scientific point of view, it's puzzling how the storm can last so long and be so big," said Dr Scott Bolton, principal investigator of the Juno mission at the Southwest Research Institute in Texas and lead author on one of two Jupiter studies published in the journal Science on Thursday.

An instrument called a microwave radiometer enabled scientists to peer beneath Jupiter's cloud tops and investigate the structure of its numerous vortex storms including the Great Red Spot, showing that they exist very deep in Jupiter's atmosphere, much deeper than expected.

Rather than being confined to the upper-most parts of Jupiter's atmosphere, the Great Red Spot's roots plunge to regions beyond where water condenses and clouds form, and below where any sunlight reaches.

Juno data previously showed that jet streams in Jupiter's atmosphere reach down even farther, to depths of about 3,200km. Assumptions based on how Earth's atmosphere behaves, as well as models produced over past few decades, had given the impression that the Great Red Spot was a relatively shallow storm, said Dr Bolton.

Juno has been orbiting Jupiter since 2016, obtaining information about its atmosphere, interior structure, internal magnetic field and the region around it created by its internal magnetism.

Juno also is due to fly by Jupiter's large moons Europa and Io and explore the small rings around the planet.


A version of this article appeared in the print edition of The Straits Times on October 30, 2021, with the headline 'Nasa spacecraft finds storm on Jupiter deeper than expected'. Subscribe