Exploring Jovian Worlds

Based on what we are learning from the exoplanet surveys of the past decade, our galaxy is the home of an immense number of Jovian-size gas giant planets.  There are countless “hot Jupiters”–gas giants located close to their stars which whip around and around their orbits in ridiculously short “years”.  There are frigid slow gas giants and super massive ones—practically brown dwarves– which are larger than Jupiter.  There is an endless proliferation of Uranus and Neptune type giants. Imagine them all glittering in strange colors with weird shapes.  They are cloaked in alien clouds and covered in mysterious storms.  Who knows what lies beneath?

All of these billions of giant planets seem pretty hypothetical to me as I sit here at my cramped & cluttered desk on solid little Earth.  Yet they exist.  They are out there in numbers too vast to comprehend. However, right now, NASA is conducting the most comprehensive exploration yet of the gas giant we can access.  Juno’s mission is just getting underway in earnest, and the largest gas giant in our own backyard should reveal lots about all of the billions which are out of reach.

I am sad that I can neither understand nor convey the loftiness of this crazy ongoing mission. It is an astonishing undertaking—but we are so inundated by with murky political battles and vulgar popular drivel, that it is hard to see the utterly astonishing nature of this undertaking.

Maybe I can put it in perspective somewhat. Imagine back to the year 1609 AD when Henry Hudson was first seeing the river which was later named after him. Before him was an exquisite expanse of islands, bays, and sparkling river. The vast waterway flowed down from unknown mountains into a bay surrounded by lovely islands.  The whole expanse was filled with flocks of unknown birds and schools of fish. Beyond the thriving marshes, mysterious forests were filled with moving shadows.

Now multiply that a billion times: replace Henry Hudson with a tiny fragile robot and replace the Hudson River with luminous gas oceans large enough to entirely submerge scores of Earths.  That is what is happening right now.  As you sit reading this on a little glowing screen, we are making fundamental discoveries about a whole planet.

On August 27, 2016, Juno executed the first of 36 orbital flybys over Jupiter. The doughty spacecraft was only 4,200 kilometers (2,500 miles) above Jupiter’s atmosphere. It sent back the first detailed images of the north pole of Jupiter—and it is unlike the rest of the planet.

The North Pole of Jupiter as seen by Juno [NASA]

To quote Scott Bolton, one of the lead scientists of the Juno mission, “[The] first glimpse of Jupiter’s north pole…it looks like nothing we have seen or imagined before….It’s bluer in color up there than other parts of the planet, and there are a lot of storms. There is no sign of the latitudinal bands or zone and belts that we are used to — this image is hardly recognizable as Jupiter. We’re seeing signs that the clouds have shadows, possibly indicating that the clouds are at a higher altitude than other features.”

Jupiter’s clouds contain whole continent-like regions of air which are different than the rest of the planet’s storms and whirls.  We don’t yet know why or how, but we are finding out.  As we do so, we are peeling back a layer of mystery which surrounds all such worlds.

Solar Radiation Streaming over the North Pole of Jupiter

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