Juno’s first close-up images of Jupiter reveal a very different gas giant
by Ryan Whitwam
We’ve all seen images of Jupiter enough to pick it out of a planetary lineup — it’s the big one with the wavy clouds and a big red spot. NASA’s Juno probe reached the planet several weeks ago, and has just sent back its first close-up photos. They reveal a planet that looks very different from the one we’ve seen so far. It’s the same Jupiter, of course, but seen from completely new angles.
Juno was launched in the summer of 2011 and took nearly five years to reach Jupiter. The harsh radiation emanating from the gas giant could be harmful to the probe’s systems over long periods, so Juno is in a highly elliptical polar orbit. This allows the spacecraft to spend as little time as possible in the planet’s heavy radiation belts. The polar orbit also lets Juno spy on different areas of the planet on each orbit as it rotates.
Juno’s eccentric orbit means that it only just made its first low pass over Jupiter after reaching the planet on July 4th. That’s why there’s been relatively little news on the mission in recent weeks. In the image above, Juno caught a glimpse of Jupiter’s southern aurorae in infrared using the Jovian Infrared Auroral Mapper (JIRAM) camera. Scientists have never seen them from this angle, and certainly not so close up.
Below, you can see a visual spectrum image of Jupiter’s north polar region with storms and cloud formations unlike anything else in the solar system. The north pole appears to lack the striated belts of clouds seen at lower latitudes. Instead, there’s a sea of giant cyclones. One thing scientists were interested to see Jupiter does not have is a hexagonal cloud formation at the north pole. That’s a very prominent feature on Saturn. Juno did, however, pick up radio emissions from Jupiter’s northern polar aurorae, which scientists hope can help us understand what makes them so massive.
The photo above was captured from an altitude of 120,000 miles, but Juno got as close as 2,500 miles during this first pass. It sent back 6MB of data over the course of its six-hour transit. Later this year, Juno will use its engines to reduce the eccentricity of its orbit, bringing the orbital period to just 14 days. It will also get as low as 1,200 miles above the cloud tops. Its 37 planned orbits should be finished in another 18 months, at which time NASA will let the probe drop into the Jovian atmosphere.
Originally published at www.extremetech.com.
