Jupiter Surprises With Massive Magnetism And A ‘Fuzzy’ Core

This enhanced color view of Jupiter’s south pole was created by citizen scientist Gabriel Fiset using data from the JunoCam instrument on NASA’s Juno spacecraft. Oval storms dot the cloudscape. Approaching the pole, the planet’s familiar belts and zones transition into clusters of unorganized, puddle-like structures, streams of air that resemble giant tangled strings. The image was taken on Dec. 11, 2016 from an altitude of about 32,400 miles (52,200 km) above the planet’s beautiful cloud tops. Credit: NASA/JPL-Caltech/SwRI/MSSS/Gabriel Fiset

I look out at night and see Jupiter and wonder how much we don’t know about the solar system’s biggest planet. Scientific investigation increases our knowledge of the universe but never reaches an endpoint. Who would want it to? There’s an infinite complexity to everything we might investigate, and the hunt’s half the fun. Always another layer, another surprise.

I smile whenever I read that a new study “changes everything.” Some of that’s breathless hype, but change is part of the game when as we come come closer to understanding how things work in the world. Whether you’re a scientist or just someone who appreciates the results of science, however tentative in places, you can revel in the study and appreciation of the natural world as long as you live. Which makes me want to live forever.

This enhanced color picture of Jupiter was taken by Juno on March 27, 2017 during its close flyby  of just 12,400 miles (20,000 km). The details in the clouds is nothing short of incredible. Credit:  NASA/JPL-Caltech/SwRI/MSSS/Bjorn Jonsson

Good examples of new and unexpected discoveries are happening right now at Jupiter. NASA’s Juno spacecraft has been monitoring the planet from up close during each of it long-winded orbits, gathering information about its deep interior, stripey clouds and monster magnetic field. Like Earth, Jupiter’s a planet-sized bar magnet with north and south magnetic poles and an invisible magnetic field that controls the motion and direction of atoms and ions (an atom that’s gained or lost an electron) that stray by.

The curved lines represent Jupiter’s magnetic field which concentrates in the north and south polar regions. Particles from Io stream in a loop toward Jupiter to create bright, auroral hot spots at either pole. Credit: John Spencer, Southwest Research Institute

Thanks to Juno we’re discovering that Jupiter’s magnetic field is stronger and more irregular than first thought. The strength of the magnetic field was previously estimated to be about 5 gauss compared to Earth’s 0.25 to 0.60 gauss at the surface, but Juno found that it might be as high as 8-9 gauss. It also dips in intensity over different regions of the planet, indicating that it may not originate in Jupiter’s core as does Earth’s field but higher up closer to the surface. That would be, well … weird.

What we think Jupiter’s interior looks like. Deep inside, pressure’s so great that hydrogen is compressed into a “metallic” form that conducts electricity. Heat from the core powers winds and helps create clouds in Jupiter’s atmosphere. Credit: NASA

Scientists had also assumed Jupiter internal structure was uniform. That deep beneath cloudy atmosphere, maybe halfway to the core, immense pressure and heat turned hydrogen gas (Jupiter’s main ingredient) into a metallic liquid that conducts electricity just like a metal. Helium, a heavier element, separates from the hydrogen and rains down towards a deeper layer of hydrogen at the center of which is a small, solid core composed of we-don’t-know-what-yet 43,000 miles down. But Juno’s data indicates that the interior isn’t so cleanly divided as thought, and that the core isn’t solid but “fuzzy” and mingled with the overlying, sloshy hydrogen.

Even the planet’s clouds are yielding surprises. We’ve known for a long time that Jupiter has clouds made of ammonia (pew!), but Juno found there’s a dense, deep zone of ammonia gas around the equator which no one expected. Also the amount of ammonia varies across the atmosphere.

This image, taken by the JunoCam imager on NASA’s Juno spacecraft, highlights a feature on Jupiter where multiple atmospheric conditions appear to collide. The ghostly bluish streak across the right half of the image is a long-lived storm; the egg-shaped spot on the lower left is where incoming small dark spots make a hairpin turn. Credit:
NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko

“We’ve known there’s a spike at the equator, but the new microwave data is showing that the spike goes way, way down into the abyss, 300 km (186 miles) below the cloud,” said Leigh Fletcher of the University of Leicester, UK. “It suggests ammonia is being distributed by a weather system that penetrates much deeper than anyone expected.”

There much more to come. Juno’s next closest approach to Jupiter will be on May 19 and include a flyover of the Great Red Spot, Jupiter’s most distinctive feature. What new befuddlement will find there?

2 Responses

  1. Thanks Bob. Like you were saying, at higher magnification Jupiter swims like viewing it from underwater. Will try setting up a few hours earlier to see if that helps. Also have some different kinds of filters and will try those. Weather forecast doesn’t look very good at this time though…of course. lol


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