Nasa's Juno spacecraft is sending back images from its trip to scrape by Jupiter and take pictures of the Great Red Spot on its surface. That swirling red image – created by a storm bigger than the Earth on the planet's surface – has fascinated people for centuries, and they may now get a look at how and why it happens.

The Juno spacecraft flew a mere 5,600 miles over the planet's surface, taking images and readings as it did so.

But it will take days for all of the pictures to travel through the solar system back to Nasa scientists on Earths. And it will take weeks, months or even years to know the full implications of what we can see there.

Scientists hope the exercise will help unlock such mysteries as what forces are driving the storm, how long it has existed, how deeply it penetrates the planet's lower atmosphere and why it appears to be gradually dissipating.

Astronomers also believe a greater understanding of the Great Red Spot may yield clues to the structure, mechanics and formation of Jupiter as a whole.

"This is a storm bigger than the entire Earth. It's been there for hundreds of years. We want to know what makes it tick," said Steve Levin, the lead project scientist for the Juno mission at JPL.

Levin said the storm is believed to be powered by energy oozing from Jupiter's interior combined with rotation of the planet, but the precise inner workings are unknown.

Some of the most valuable data from Monday's flyby is expected to come from an instrument designed to peer into the red spot at six different depths, Levin said.

The churning cyclone ranks as the largest known storm in the solar system, measuring about 10,000 miles in diameter with winds clocked at hundreds of miles an hour around its outer edges. It appears as a deep, red orb surrounded by layers of pale yellow, orange and white.

The red spot has been continuously monitored from Earth since about 1830, though observations believed to have been of the same feature date back more than 350 years.

Once wide enough to swallow three Earth-sized planets, the famed Jovian weather system has been shrinking for the past 100 years and may eventually disappear altogether.

Still, the spot remains the most prominent characteristic of the solar system's largest planet, a gargantuan ball of gas – mostly hydrogen and helium – 11 times the diameter of Earth with more than twice as much mass as all the other planets combined.

Monday's encounter with the Great Red Spot was the latest of 12 flyby missions currently scheduled by NASA for Juno, which is to make its next close approach to Jupiter's cloud tops on 1 September.

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