Jupiter 'puts on firework party' before arrival of space probe Juno


Jupiter, the king of planets, appears to be wearing a crown of blazing light in a stunning new image from the Hubble Space Telescope.

The photo shows a vivid aurora, similar to the Northern Lights on Earth, over one of the gas giant's poles.

Auroras occur when high energy sub-atomic particles flying through space are captured by a planet's magnetic field and steered north or south.

Collisions between the particles and molecules in the atmosphere give rise to the spectacular light display.

Jupiter, the largest planet in the Solar System, has an exceptionally powerful magnetic field and its auroras are hundreds of times more energetic than those on Earth.

The picture was released days before an American spacecraft, Juno, is due to reach Jupiter, early on July 5, UK time.

The probe will orbit closer to the planet than any previous spacecraft, flying to within 2,900 miles of its swirling cloud tops.

It carries special shielding to protect its sensitive electronics from the circuit-frying radiation storm generated by Jupiter's magnetic field.

Currently Juno is ploughing through the solar wind - the stream of high energy particles flowing out from the sun - close to Jupiter.

British astronomer Dr Jonathan Nichols, from the University of Leicester, who heads the Hubble team investigating Jupiter's light displays, said: "These auroras are very dramatic and among the most active I have ever seen.

"It almost seems as if Jupiter is throwing a firework party for the imminent arrival of Juno."

To highlight changes in the auroras, which cover areas bigger than the Earth, Hubble is observing Jupiter daily for around a month.

Unlike Earthly auroras, those on Jupiter never cease. While on Earth the phenomenon is caused by charged particles raining down from the sun, Jupiter has an additional aurora "dynamo". Charged particles thrown into space by Jupiter's volcanically active moon, Io, are also captured by the planet's magnetic field.

Juno, which has a planned lifespan of 20 months, will study Jupiter's magnetic field and the source of its raging 384mph winds, and take panoramic colour photos.

Unusually for a robotic space mission, it is carrying passengers - three Lego figures depicting the 17th century Italian astronomer Galileo Galilei, the Roman god Jupiter, and the deity's wife Juno.

Lego made the figures out of aluminium rather than the usual plastic so they could withstand the extreme conditions of space flight.

Juno was launched by the US space agency Nasa from Cape Canaveral, Florida, on August 5 2011.

By the time it reaches Jupiter it will have travelled 1.4 billion miles.