October 26, 2016
Mysterious Hexagon on Saturn’s
North Pole Changes Color


Credit: NASA

Mysterious hexagon on Saturn’s north pole changes colour
OCTOBER 26, 2016 2:47PM
Nick Whigham news.com.au


A HUGE section of Saturn’s surface appears to have changed colour.

Quote:
A mysterious hexagon shape at the northern pole of the planet has changed from blue to gold, scientists say.

It didn’t happen overnight though. Images captured by NASA’s Cassini spacecraft which has been observing the planet since 2004 shows how Saturn’s surface gradually changed its tone from November 2012 to September 2016.

The hexagon essentially looks like a rotating cloud pattern and it’s believed the shape may be produced by differences in the speeds of Saturn’s winds.

Saturn is the sixth planet from the Sun and the second-largest in the Solar System, behind Jupiter.
Like Jupiter, Saturn is a giant gas planet and is composed of similar gases including hydrogen, helium and methane.

The change in its colour is thought to be a result of the changing seasons on the planet and the result of the greater level of sunlight producing aerosols in the atmosphere.
“In particular, the change from a bluish colour to a more golden hue may be due to the increased production of photochemical hazes in the atmosphere as the north pole approaches summer solstice in May 2017,” NASA said.

According to the US space agency, the hexagon shape might act as a kind of protective shell with the “six-sided jetstream” working to prevent particles produced outside the planet from entering.

Whatever its purpose, it sure looks pretty cool — and we now know it comes in both blue and gold.



Saturn is turning golden in preparation for Summer.
Picture: NASA/JPL-Caltech/Space Science Institute/Hampton University


SOURCE: News Australia



PIA21049: Changing Colors in Saturn's North



These two natural color images from NASA's Cassini spacecraft show the changing appearance of Saturn's north polar region between 2012 and 2016.

Scientists are investigating potential causes for the change in color of the region inside the north-polar hexagon on Saturn. The color change is thought to be an effect of Saturn's seasons. In particular, the change from a bluish color to a more golden hue may be due to the increased production of photochemical hazes in the atmosphere as the north pole approaches summer solstice in May 2017.

Researchers think the hexagon, which is a six-sided jetstream, might act as a barrier that prevents haze particles produced outside it from entering. During the polar winter night between November 1995 and August 2009, Saturn's north polar atmosphere became clear of aerosols produced by photochemical reactions -- reactions involving sunlight and the atmosphere. Since the planet experienced equinox in August 2009, the polar atmosphere has been basking in continuous sunshine, and aerosols are being produced inside of the hexagon, around the north pole, making the polar atmosphere appear hazy today.

Other effects, including changes in atmospheric circulation, could also be playing a role. Scientists think seasonally shifting patterns of solar heating probably influence the winds in the polar regions.

Both images were taken by the Cassini wide-angle camera.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. The Cassini imaging team homepage is at http://ciclops.org.

Image Credit:
NASA/JPL-Caltech/Space Science Institute/Hampton University

Image Addition Date:
2016-10-21



 
PIA17652: In Full View: Saturn's Streaming Hexagon


Credit: NASA Photo Journal

This colorful view from NASA's Cassini mission is the highest-resolution view of the unique six-sided jet stream at Saturn's north pole known as "the hexagon." This movie, made from images obtained by Cassini's imaging cameras, is the first to show the hexagon in color filters, and the first movie to show a complete view from the north pole down to about 70 degrees north latitude.

Scientists can see the motion of a wide variety of cloud structures that reside within the hexagon in this movie. There is a massive hurricane tightly centered on the north pole, with an eye about 50 times larger than the average hurricane eye on Earth. (More information about that Saturn hurricane is at PIA14947.) Numerous small vortices are also present, which appear as reddish ovals. Some of these vortices spin clockwise while the hexagon and hurricane spin counterclockwise. Some of those smaller features are swept along with the jet stream of the hexagon, as if on a racetrack. The biggest of these vortices, seen near the lower right corner of the hexagon and appearing whitish, spans about 2,200 miles (3,500 kilometers), approximately twice the size of the largest hurricane on Earth.



The differences in this version of the movie, in which different wavelengths of light from ultraviolet to visible to infrared have been assigned colors, show a distinct contrast between the types of atmospheric particles inside and outside the hexagon. Inside the hexagon there are fewer large haze particles and a concentration of small haze particles, while outside the hexagon, the opposite is true. The jet stream that makes up the hexagon seems to act like a barrier, which results in something like the "ozone hole" in the Antarctic.

This movie shows a view from directly over the north pole, keeping up with the rotation of the planet so that all the motion seen on the screen is the motion of the hexagonal jet stream or the storms inside of it, without any added motion from the spinning of the planet itself. The original images were re-projected to show this polar view.

High-resolution views of the hexagon have only recently become possible because of the changing of the seasons at Saturn and changes in the Cassini spacecraft's orbit. The north pole was dark when Cassini first arrived in July 2004. The sun really only began to illuminate the entire interior of the hexagon in August 2009, with the start of northern spring. In late 2012, Cassini began making swings over Saturn's poles, giving it better views of the hexagon.



The eight frames of the movie were captured over 10 hours on Dec.10, 2012. Each of the eight frames consists of 16 map-projected images (four per color filter, and four filters per frame) so the movie combines data from 128 images total.

In this color scheme, scientists assigned red to the 0.750-micron part of the light spectrum (near infrared). This part of the spectrum penetrates the high-altitude haze layer to sense the top of tropospheric cloud deck. They assigned green to the 0.727-micron part of the light spectrum that senses the upper tropospheric haze (a near-infrared wavelength corresponding to a methane absorption band). They assigned blue to the sum of blue and ultraviolet broadband filters -- combined, this blue channel covers between 0.400 and 0.500 microns (covering very near ultraviolet to blue in visible light). This part of the spectrum is sensitive to small aerosols.

To human eyes, the hexagon and north pole would appear in tones of gold and blue. See PIA14945 for a still image of the area in natural color.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. The Cassini imaging team homepage is at http://ciclops.org.

Image Credit:
NASA/JPL-Caltech/SSI/Hampton University

Image Addition Date:
2013-12-04


SOURCE: NASA Photo Journal




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Mysterious Hexagon on Saturn’s North Pole Changes Color