NASA's Juno Mission Just Stared Right Into Jupiter's Angry Red Eye

On Monday, NASA's Juno spacecraft came within 9,000 kilometres (5,600 miles) of one of Jupiter's most iconic features and has started to add a few close-up pics to the holiday album.

These images are what a lot of Jupiter fans have been waiting for. The beast of a hurricane called the Great Red Spot has been swirling among the planet's clouds for centuries, and yet still so much about it remains a mystery. 

"For generations people from all over the world and all walks of life have marvelled over the Great Red Spot," says Juno investigator Scott Bolton from the Southwest Research Institute in San Antonio.

Artist impression: NASA / JPL / Björn Jónsson / Seán Doran

"Now we are finally going to see what this storm looks like up close and personal."

The first confirmed sighting of the spot can be traced back to observations made by Giovanni Cassini around 1665, though oddly no astronomer mentioned it again until 1830.

Maybe it faded away for a few generations, or perhaps it's an entirely different blemish. In either case, Jupiter's angry red eye has drawn our attention ever since.

The numbers are mind blowing. It's an anticyclone that could swallow Earth at around 16,350 kilometres (10,160 miles) across, with winds peaking at just under 645 kilometres per hour (about 400 miles per hour).

The storm's ominous rusty hue is just one of the mysteries researchers hope to eventually solve. Jupiter's upper atmosphere consists largely of ammonia, ammonium hydrosulphide, and water, but it's not entirely clear how these compounds might react to produce reds and oranges.

There are also questions about how the storm maintains its rage. On Earth, the contrast between a liquid and solid surface and the atmosphere means storms typically run out of steam after days or weeks.

Centuries is quite an effort for a single weather system to stick together.

In 2016, astronomers noticed the atmosphere above the spot was also warmer than the surrounding clouds, an observation that could help explain why the temperature of Jupiter's upper atmosphere was comparable with Earth's, in spite of being further from the Sun.

"We could see almost immediately that our maximum temperatures at high altitudes were above the Great Red Spot far below – a weird coincidence or a major clue?" lead researcher James O'Donoghue from Boston University said at the time.

The researchers speculated that acoustic and gravitational waves stirred by the storm crashed against the gases in the atmosphere, causing heat to radiate through the clouds high above the planet.

It will take more than a few detailed images to answer the multitude of questions we have about the Great Red Spot, and Juno has been collecting as much data as it can from its suite of tools to get a better look at the processes boiling away beneath the top layers.

"Now we have the best pictures ever of this iconic storm. It will take us some time to analyse all the data from not only JunoCam, but Juno's eight science instruments, to shed some new light on the past, present and future of the Great Red Spot," says Bolton.

The images that are being uploaded here are raw and unprocessed, just how a lot of Jupiter fans like them. You can also find plenty of examples of images being processed by an army of citizen scientists.

"It is always exciting to see these new raw images of Jupiter as they arrive. But it is even more thrilling to take the raw images and turn them into something that people can appreciate. That is what I live for," says graphic designer Jason Major.

NASA and other enthusiasts are in the process of polishing them up to provide some stunning art of the Solar System's most notorious hurricane in the near future, so these definitely won't be the last time we'll see Jupiter eye-to-eye.

NASA / JPL-Caltech / SwRI / MSSS / Roman Tkachenko

NASA/Daniela Bustamante

NASA / Phablo Araujo / Universidade Federal de Goiás

NASA/Soumya Nanda

NASA/SwRI/MSSS/Michael Galindo