Final countdown to British scientists’ date with Jupiter

SCIENCE EDITOR THE mystery of what lies beneath the swirling storm clouds of Jupiter will soon be solved as Nasa’s Juno spacecraft arrives at the planet this week.

Little is known about the gas giant, which is so big it can be seen from Earth without a telescope, and which produces the most spectacular auroras in the solar system.

Scientists are not even sure if there is a solid core under its turbulent atmosphere or what drives the huge magnetic field which surrounds the planet. If the invisible magnetosphere glowed in visible light, it would appear twice the size of the full moon from Earth.

The Juno spacecraft, named after the Roman goddess and wife of Jupiter, is packed with nine instruments capable of peering into the planet’s heart. It will fly 2,600 miles above the cloud tops, 3,000 miles closer to the surface than any other mission has ever been.

For Prof Stan Cowley and Prof Emma Bunce of the University of Leicester, the mission marks the culmination of more than 15 years of work.

In 2001, the pair produced a groundbreaking paper suggesting that the spectacular auroras over Jupiter’s poles were driven by a combination of the planet’s rapid rotation and volcanic material spewed out from its moon, Io.

The research came to the attention of mission controllers at Nasa who invited the Leicester team on board to help plan the project. Now they will finally see if their theory was accurate.

“Jupiter produces the most incredible auroras in the solar system, many times brighter than on Earth,” said Prof Bunce. “This is the first opportunity we will have to test out theoretical ideas and see if they were correct.

“Juno is an incredibly ambitious project. We don’t know the details of [Jupiter’s] interior, whether or not it has a core, and how much water is contained in the atmosphere.”

The Juno spacecraft has spent the past five years travelling the 1.7 million miles to Jupiter and will arrive tomorrow.

The entry into orbit – Jupiter Orbital Insertion – is the trickiest part of the mission. Nobody knows if the spacecraft can survive the turbulence of being so close to Jupiter, and the craft has been fitted with a titanium vault to protect sensitive instruments. Nasa’s Juno spacecraft has spent five years travelling the 1.7 million miles to Jupiter. Yet its true success depends on how it survives the gas giant’s famously turbulent atmosphere