Universe Today
When the
Juno
mission reached Jupiter on July 5th, 2016, it became the second mission in history to establish orbit around the Solar System's largest planet. And in the course of it conducting its many orbits, it has revealed some interesting things about Jupiter. This has included information about its atmosphere, meteorological phenomena, gravity, and its powerful magnetic fields.
And just yesterday - on
Monday, July 10th
at 7:06 p.m. PDT (11:06 p.m. EDT) - just days after the probe celebrated its first year of orbiting the planet, the
Juno
mission passed directly over Jupiter's most famous feature - the
Great Red Spot
. This massive anticyclonic storm has been a focal point for centuries, and
Juno's
scheduled flyby was the closest any mission has ever come to it.
Jupiter's Great Red Spot was first observed during the late 17th century, either by Robert Hooke or Giovanni Cassini. By 1830, astronomers began monitoring this anticyclonic storm, and have noted periodic expansions and regressions in its size ever since. Today, it is 16,000 kilometers (10,000 miles) in diameter and reaches wind speeds of 120 meters per second (432 km/h; 286 mph) at the edges.
[caption id="attachment_129321" align="aligncenter" width="580"]
The Juno spacecraft isn't the first one to visit Jupiter. Galileo went there in the mid 90's, and Voyager 1 snapped a nice picture of the clouds on its mission. Credit: NASA
[/caption]
As part of its sixth orbit of Jupiter's turbulent cloud tops,
Juno
passed close to Jupiter's center (aka. perijove), which took place at 6:55 p.m. PDT (9:55 p.m. EDT). Eleven minutes later - at 7:06 p.m. PDT (10:06 p.m. EDT) - the probe flew over the Great Red Spot. In the process,
Juno
was at a distance of just 9,000 km (5,600 miles) from the anticyclonic storm, which is the closest any spacecraft has ever flown to it.
During the flyby,
Juno
had all eight of its scientific instruments (as well its imager, the
JunoCam
) trained directly on the storm. With such an array aimed at this feature, NASA expects to learn more about what has been powering this storm for at least the past three and a half centuries. As Scott Bolton, the principal investigator of
Juno
at the
Southwest Research Institute
(SwRI), said prior to the event in a NASA
press release
:
This perijove and flyby of the Giant Red Spot also comes just days after Juno celebrated its first anniversary around Jupiter. This took place on July 4th at 7:30 p.m. PDT (10:30 p.m. EDT), at which point, Juno had been in orbit around the Jovian planet for exactly one year. By this time, the spacecraft had covered a distance of 114.5 million km (71 million mi) while orbiting around the planet.
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This artist's illustration shows Juno's Microwave Radiometer observing deep into Jupiter's atmosphere. The image shows real data from the 6 MWR channels, arranged by wavelength. Credit: NASA/SwRI/JPL
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The information that
Juno
has collected in that time with its advanced suite of instruments has already provided fresh insights into Jupiter's interior and the history of its formation. And this information, it is hoped, will help astronomers to learn more about the Solar System's own history of formation. And in the course of making its orbits, the probe has been put through its paces, absorbing radiation from Jupiter's powerful magnetic field.
As Rick Nybakken, the project manager for
Juno
at NASA's Jet Propulsion Laboratory,
put it
:
The
Juno
mission is set to conclude this coming February, after completing 6 more orbits of Jupiter. At this point, and barring any mission extensions, the probe will be de-orbited to burn up in Jupiter's outer atmosphere. As with the
Galileo
spacecraft, this is meant to avoid any possibility of impact and biological contamination with one of Jupiter's moons.
Further Reading: NASA
