Hubble’s planetary portrait captures changes in Jupiter’s Great Red Spot
13 October 2015
Scientists using the NASA/ESA Hubble
Space Telescope have produced new maps of Jupiter that show the
continuing changes in its famous Great Red Spot. The images also reveal a
rare wave structure in the planet’s atmosphere that has not been seen
for decades. The new image is the first in a series of annual portraits
of the Solar System’s outer planets, which will give us new glimpses of
these remote worlds, and help scientists to study how they change over
time.
In this new image of
Jupiter
a broad range of features has been captured, including winds, clouds
and storms. The scientists behind the new images took pictures of
Jupiter using Hubble’s
Wide Field Camera 3
over a ten-hour period and have produced two maps of the entire planet
from the observations. These maps make it possible to determine the
speeds of Jupiter’s winds, to identify different phenomena in its
atmosphere and to track changes in its most famous features.
The new images confirm that the huge storm, which has raged on
Jupiter’s surface for at least three hundred years, continues to shrink,
but that it may not go out without a fight. The storm, known as the
Great Red Spot,
is seen here swirling at the centre of the image of the planet. It has
been decreasing in size at a noticeably faster rate from year to year
for some time. But now, the rate of shrinkage seems to be slowing again,
even though the spot is still about 240 kilometres smaller than it was
in 2014.
The spot’s size is not the only change that has been captured by
Hubble. At the centre of the spot, which is less intense in colour than
it once was, an unusual wispy filament can be seen spanning almost the
entire width of the vortex. This filamentary streamer rotates and twists
throughout the ten-hour span of the Great Red Spot image sequence,
distorted by winds that are blowing at 540 kilometres per hour.
There is another feature of interest in this new view of our giant
neighbour. Just north of the planet’s equator, researchers have found a
rare wave structure, of a type that has been spotted on the planet only
once before, decades ago by the Voyager 2 mission, which was launched in
1977. In the
Voyager 2
images the wave was barely visible and astronomers began to think its
appearance was a fluke, as nothing like it has been seen since, until
now.
The current wave was found in a region dotted with cyclones and anticyclones. Similar waves — called
baroclinic waves — sometimes appear in the Earth’s atmosphere where
cyclones
are forming. The wave may originate in a clear layer beneath the
clouds, only becoming visible when it propagates up into the cloud deck,
according to the researchers.
The observations of Jupiter form part of the Outer Planet Atmospheres
Legacy (OPAL) programme, which will allow Hubble to dedicate time each
year to observing the outer planets. In addition to Jupiter,
Neptune and
Uranus have already been observed as part of the programme and maps of these planets will be placed in the public archive.
Saturn
will be added to the series later. The collection of maps that will be
built up over time will help scientists not only to understand the
atmospheres of giant planets in the Solar System, but also the
atmospheres of our own planet and of the planets that are being
discovered around other stars.
Notes
The findings are described in an
Astrophysical Journal paper First results from the Hubble OPAL program: Jupiter in 2015, available online.
Notes for editors
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
More information
Image credit: NASA, ESA, A. Simon (GSFC), M. Wong (UC Berkeley), and G. Orton (JPL-Caltech)
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