NASA’s Juno probe just sent back the best and most detailed images ever of Jupiter’s polar regions. I’m sure you’ll agree they’re wonderful eye candy. They were made during the spacecraft’s first flyby of the planet during its long looping orbit. The photos show a chaos of whirling storms and weather activity and a notable lack of the planet’s most familiar feature, its dark belts.
Juno’s “stay safe” orbit around Jupiter. Notice that when the probe is close to the planet, it orbits much faster than when further out
Juno keeps a healthy distance from the gas giant and its toxic radiation environment during most of its long, looping orbit. But for a few hours each orbit, it zips about 2,500 miles (4,200 km) above Jupiter’s swirling clouds to take close up photos and make other measurements of the atmosphere.
“First glimpse of Jupiter’s north pole, and it looks like nothing we have seen or imagined before,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. “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.”
Along with JunoCam snapping pictures during the flyby, all eight of Juno’s science instruments were energized and collecting data. Some of the most remarkable images were made using the Jovian Infrared Auroral Mapper (JI-RAM) and show fantastic detail in Jupiter’s southern auroral oval, a feature never seen before from Earth or space probe. Both of Jupiter’s ovals — north and south — bear a great similarity to the auroral ovals that hover like pale green doughnuts over our own planet’s geomagnetic poles. It’s here that the solar wind streams in along both planets’ magnetic field lines, strikes atoms and molecules in the atmosphere and sets the air to glow with the northern and southern lights.
Scientists were a little surprised not to see the hexagon-shaped cloud pattern structure photographed by Voyager mission in 1981 and again in greater detail by the Cassini probe in 2006 at Saturn’s north pole. Instead, photos show a delightful chaos of spinning storms, each far more powerful than a hurricane on Earth. Jupiter’s polar regions are truly unique, and we have 36 more flybys to eyeball them until Juno’s mission ends in 2018.
Give a listen to Juno’s recording of Jupiter’s auroras. The frequencies have been shifted into human hearing range.
During the probe’s first scientific sweep by Jupiter, the Radio/Plasma Wave Experiment (Waves) recorded ghostly- sounding transmissions emanating from above the planet. These radio emissions from Jupiter have been known about since the 1950s but had never been analyzed from such a close vantage point. “Waves detected the signature emissions of the energetic particles that generate the massive auroras which encircle Jupiter’s north pole,” said Bill Kurth, co-investigator for the Waves instrument from the University of Iowa, Iowa City. “These emissions are the strongest in the solar system. Now we are going to try to figure out where the electrons come from that are generating them.”
See how Jupiter glows in infrared (heat) light. We see it in two different wavelengths (colors) of infrared.
Both Jupiter and Saturn have distinctive parallel cloud belt that correspond to bands of powerful winds that whip the clouds around at hundreds of miles an hour. But at the poles, the belts disappear and are replaced by individual storms. I’m no expert, but I wonder if this isn’t related to how fast planets rotate at their equatorial regions compared to polar. On Earth, a person standing at the equator is moving at more than 1,000 miles per hour. At the north and south pole, their speed drops to zero. Perhaps the drop in speed prevents formation of latitudinal belts in windier temperature and tropical zones.
While Juno’s photos are far more detailed and the probe will examine the polar regions in depth, they aren’t the first photos taken of Jupiter’s top and bottom. That honor goes to NASA’s Pioneer 11 mission which flew by the gas giant 42 years ago in December 1974 and got a somewhat good look at the south polar area and much better one of the planet’s north pole. It’s interesting to compare them to the new images.
Take some time to marvel at Jupiter. After three nights in a row of aurora viewing here in Minnesota along with the recent spate of storms and hurricanes raging along the Atlantic and Gulf coasts, it’s easy to feel a connection to this colossal planet half a billion miles away.