NASA will fly closer to Jupiter’s Great Red Spot tonight than ever before — here’s what it could see

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Jupiter’s Great Red Spot storm, as seen by NASA’s Voyager 1 probe on March 4, 1979. NASA/JPL; Björn Jónsson/IAAA
  • Jupiter’s Great Red Spot is a storm about twice as wide as Earth.
  • Using the Juno spacecraft, NASA will take its closest-ever photos of the giant storm on July 10.
  • Business Insider simulated what the best single-frame image might look like.

Jupiter’s Great Red Spot is about twice as wide as Earth and has tumbled in the planet’s atmosphere for at least 350 years.

Despite astronomers’ long-standing fascination with this tempest, however, it’s mysterious: It’s located hundreds of millions of miles away, and only a handful of spacecraft have taken detailed images of it.

That will change on July 10, when the space agency’s Juno probe will fly within a cosmic breath of the Great Red Spot and take its closest-ever images of the super-storm. The flyby is anticipated to occur around 10:06 p.m.

“This will not be the only flyover of Great Red Spot planned for Juno’s [orbits], but it is the closest [Great Red Spot] flyover in the plans,” Candice Hansen, a senior scientist at the Planetary Science Institute, told Business Insider in an email.

How Juno will photograph the Great Red Spot

Juno, a robot the size of a basketball court, settled into orbit around Jupiter on July 4, 2016.

Since then it’s taken the first-ever photos of Jupiter’s poles, discovered atmospheric “rivers” of ammonia, watched 870-mile-wide cyclones swirl, recorded mysterious auroras, and probed deep into the planet’s thick cloud tops for evidence of a solid core, among other feats.

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But Juno has yet to take close-up photos of the Great Red Spot because Jupiter rotates rapidly, about once every 10 Earth hours. The probe’s visits are also fast and infrequent — about every 53.5 days — to prevent it from getting too much exposure to the planet’s electronics-damaging radiation.

The robot’s main camera, called JunoCam, will beam back new images of the Great Red Spot around July 14, Scott Bolton, a planetary scientist at the Southwest Research Institute and the Juno mission’s leader, said in an email to Business Insider.

Scientists like Bolton and Hansen are eagerly looking forward to seeing the unprecedented data.

“Juno and her cloud-penetrating science instruments will dive in to see how deep the roots of this storm go, and help us understand how this giant storm works and what makes it so special,” Bolton said in a NASA statement.

However, taking photos of the Great Red Spot isn’t straightforward. Hansen explained that Juno will fly too close to the storm — about 5,600 miles above it — to capture the whole thing in one view at that point. 

Making the task even more challenging, the probe will zoom by at 34 miles per second. That’s speedy enough to traverse the continental US in a little more than a minute.

As a result, JunoCam will strafe the planet with a series of images.

What Juno’s Great Red Spot photos might look like

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The parts of Jupiter that Juno will photograph on July 10, 2017. NASA; Microsoft/WorldWide Telescope; Business Insider

Hansen said the eastern and western edges of the Great Red Spot will be out of view, and the northern and southern regions “will be foreshortened due to the viewing angle close to the top of the storm.”

This illustration, created by Business Insider based on an image provided by Hansen, shows approximately what JunoCam will see (center) and what it won’t (in red) during its flyby.

As Juno zips away from the planet and into deep space, more distant images should reveal the entire storm (though not in as much detail).

“The closest, most detailed image that JunoCam will return of the Great Red Spot is expected to show more than half of the [storm],” Hansen said.

That single photo will capture a similar level of detail as the JunoCam image below, which is of Jupiter’s wandering Little Red Spot.

Juno took the picture from about 9,000 miles away:

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The much-larger Great Red Spot, however, should fill most of the frame with its eastern and western limbs cropped out.

To get a sense of what the actual photo might look like, we cropped a true-colour image of the Great Red Spot, taken in 1996 by the Galileo probe, to match up to JunoCam’s view. The new spacecraft’s photo will show much more and better detail, however.

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Once all of JunoCam’s raw photo data is verified, processed into full colour, and stitched together as a giant mosaic image of the probe’s flyby, it will be unrivalled in history.

“The first report of a feature on Jupiter which could be the Great Red Spot was about 350 years ago, not long after the first telescopic observations from Galileo,” Bolton told Business Insider. “It is possible the feature has existed considerably longer but there are no recorded observations to provide evidence.”

NASA’s Juno probe won’t fly endlessly around the gas giant. The space agency expects to destroy Juno in 2018 or 2019 by plunging it into the seemingly bottomless, noxious clouds of Jupiter. The goal is to keep Juno from disrupting any aliens — microbial or otherwise — that might live in hidden oceans of water below the icy shells of Jupiter’s moons Europa and Ganymede.