NASA Juno finds Jupiter’s Jet-Streams Are Unearthly

Data collected by
NASA’s Juno mission to Jupiter indicate that
the atmospheric winds of the
gas-giant planet run deep into
its atmosphere and last longer than similar
processes found here on Earth. The findings will improve
understanding of Jupiter’s interior structure, core mass and,
eventually, its

Other Juno science
results released today include that the
massive cyclones that surround Jupiter’s
north and south poles
are enduring atmospheric features and unlike anything
encountered in our solar system. The
findings are part of a
four-article collection on Juno science results being
published in the March 8 edition of the journal Nature.

“These astonishing science results are yet
another example of
Jupiter’s curve balls, and a testimony to the value of
exploring the unknown from a new perspective with
next-generation instruments.Juno’s unique
orbit and
evolutionary high-precision radio science and infrared
enabled these paradigm-shifting discoveries,”
said Scott Bolton, principal
investigator of Juno from the
Southwest Research Institute, San Antonio. “Juno
is only about
one third the way through its primary mission, and already we
seeing the beginnings of a new Jupiter.”

For hundreds of years, this gaseous giant planet appeared
shrouded in colorful bands of clouds extending from dusk to
dawn, referred to as zones and belts. The bands were thought to
be an expression of Jovian weather, related to winds blowing
eastward and westward at different speeds. This animation
illustrates a recent discovery by Juno that demonstrates these
east-west flows, also known as jet-streams penetrate deep into
the planet’s atmosphere, to a depth of about 1,900 miles (3,000
kilometers). Credits: NASA/JPL-Caltech

The depth to which the roots of Jupiter’s
famous zones and
belts extend has been a mystery for decades. Gravity
measurements collected by Juno during its close flybys of the
planet have now
provided an answer.

“Juno’s measurement of Jupiter’s gravity field
indicates a
north-south asymmetry, similar to the asymmetry observed in
zones and belts,” said Luciano Iess, Juno co-investigator
from Sapienza University of
Rome, and
lead author on a Nature
paper on Jupiter’s gravity field.

On a gas planet, such an asymmetry can only
come from flows
deep within the planet; and on Jupiter, the visible eastward
and westward jet streams are likewise asymmetric north and
south. The deeper
the jets, the more mass they contain,
leading to a stronger signal expressed in
the gravity field.
Thus, the magnitude of the asymmetry in gravity determines
deep the jet streams extend.

“Galileo viewed the stripes on Jupiter more
than 400 years
ago,” said Yohai Kaspi, Juno co-investigator from the Weizmann
Institute of Science, Rehovot, Israel,and lead author
of a
Nature paper on Jupiter’s deep weather layer. “Until now, we
only had a
superficial understanding of them and have been
able to relate these stripes to
cloud features along Jupiter’s
jets. Now, following the Juno gravity
measurements, we know
how deep the jets extend and what their structure is
the visible clouds. It’s like going from a 2-D picture to a 3-D
in high definition.”

The result was a surprise for the Juno science
team because it
indicated that the weather layer of Jupiter was more massive,
extending much deeper than previously expected. The Jovian
weather layer, from
its very top to a depth of 1,900 miles
(3,000 kilometers), contains about one
percent of Jupiter’s
mass (about 3 Earth masses).

“By contrast, Earth’s atmosphere is less than
one millionth of
the total mass of Earth,” said Kaspi “The fact that Jupiter
has such a massive region rotating in separate east-west bands
is definitely a

The finding is important for understanding the
nature and
possible mechanisms driving these strong jet streams. In
the gravity signature of the jets is entangled with
the gravity signal of

Another Juno result released today suggests
that beneath the
weather layer, the planet rotates nearly as a rigid body.”This
is really an amazing result, and future
measurements by Juno
will help us understand how the transition works between
weather layer and the rigid body below,” said Tristan Guillot,
a Juno
co-investigator from the Université Côte d’Azur, Nice,
France, and lead author
of the paper on Jupiter’s deep
interior. “Juno’s discovery has implications for
other worlds
in our solar system and beyond. Our results imply that the
differentially-rotating region should be at least three
times deeper in Saturn
and shallower in massive giant planets
and brown dwarf stars.”

A truly striking result released in the Nature
papers is the
beautiful new imagery of Jupiter’s poles captured by Juno’s
Jovian Infrared Auroral Mapper (JIRAM)
instrument. Imaging in
the infrared part of the spectrum, JIRAM captures images
light emerging from deep inside Jupiter equally well, night or
day. JIRAM
probes the weather layer down to 30 to 45 miles (50
to 70 kilometers) below
Jupiter’s cloud tops.

“Prior to Juno we
did not know what the weather was like near
Jupiter’s poles. Now, we have been
able to observe the polar
weather up-close every two months,” said Alberto Adriani, Juno
co-investigator from the Institute for
Space Astrophysics and
Planetology, Rome, and lead author of the paper. “Each one of
the northern cyclones is almost as
wide as the distance
between Naples, Italy and New York City — and the
ones are even larger than that. They have very
violent winds,
reaching, in some cases, speeds as great as 220 mph (350 kph).
Finally, and perhaps most remarkably, they are very
together and enduring. There is nothing else like it that we
know of in
the solar system.”

Jupiter’s poles are a stark contrast to the
more familiar
orange and white belts and zones encircling the planet at
latitudes. Its north pole is dominated by a central
cyclone surrounded by eight
circumpolar cyclones with
diameters ranging from 2,500 to 2,900 miles (4,000 to 4,600
kilometers) across.
Jupiter’s south pole also contains a
central cyclone, but it is surrounded by
five cyclones with
diameters ranging from 3,500 to 4,300 miles (5,600 to 7,000
kilometers) in diameter. Almost all the polar cyclones, at both
poles, are so
densely packed that their spiral arms come in
contact with adjacent cyclones.
However, as tightly spaced as
the cyclones are, they have remained distinct,
with individual
morphologies over the seven months of observations detailed in
the paper.

“The question is,
why do they not merge?” said Adriani. “We
know with Cassini data that Saturn
has a single cyclonic
vortex at each pole. We are beginning to realize that not
gas giants are created equal.”

Abstracts of the
March 8 Juno papers can be found online:

The measurement of Jupiter’s asymmetric gravity

Jupiter’s atmospheric jet-streams extending
thousands of
kilometers deep:

A suppression of differential rotation in
Jupiter’s deep

Clusters of Cyclones Encircling Jupiter’s

To date, Juno has
completed 10 science passes over Jupiter and
logged almost 122 million miles
(200 million kilometers),
since entering Jupiter’s orbit on July 4, 2016.
Juno’s 11th
science pass will be on April 1.

Juno launched on Aug. 5,
2011, from Cape Canaveral, Florida.
During its
mission of exploration, Juno soars low over the
planet’s cloud tops — as close
as about 2,200 miles (3,500
kilometers). During these flybys, Juno is probing
beneath the
obscuring cloud cover of Jupiter and studying its auroras to
more about the planet’s origins, structure, weather
layer and magnetosphere.

NASA’s Jet
Propulsion Laboratory, Pasadena, California,
manages the Juno mission for the principal
investigator, Scott
Bolton, of the Southwest Research Institute in San Antonio.
Juno is part of NASA’s New Frontiers Program, which is managed
at NASA’s Marshall
Space Flight Center in Huntsville, Alabama,
for NASA’s Science Mission
Directorate. The Italian Space
Agency (ASI), contributed two instruments, a
Ka-band frequency
translator (KaT) and the Jovian Infrared Auroral Mapper
Lockheed Martin Space, Denver, built the spacecraft.

The public can follow the
mission on Facebook and Twitter at:

More information on Jupiter
can be found at:

News Media Contact

DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.

Dwayne Brown / Laurie Cantillo
NASA Headquarters, Washington
202-358-1726 / 202-358-1077 /


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