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Our Pale Blue Dot Imaged by Various Spacecrafts. Image Credits: From Quarks to Quasars, jaxa/nhk, Cassini, MESSENGER, NASA, Juno, JPL.

, #Earth #pale blue dot #from quarks to quasars #apollo 4 #apollo 17 #juno #mars global surveyor #MESSENGER #cassini #voyager 1 #astrophotography #earth'smoon #moon

NASA’s Cassini Spacecraft Obtains Best Views of Saturn Hexagon via NASA 

Image Credits [Top to bottom, left to right]: First & second images, NASA/JPL-Caltech/SSI/Hampton. Third & fourth images, NASA/JPL-Caltech/University of Arizona.

NASA’s Cassini spacecraft has obtained the highest-resolution movie yet of a unique six-sided jet stream, known as the hexagon, around Saturn’s north pole.

This is the first hexagon movie of its kind, using color filters, and the first to show a complete view of the top of Saturn down to about 70 degrees latitude. Spanning about 20,000 miles (30,000 kilometers) across, the hexagon is a wavy jet stream of 200-mile-per-hour winds (about 322 kilometers per hour) with a massive, rotating storm at the center. There is no weather feature exactly, consistently like this anywhere else in the solar system.

"The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable," said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. "A hurricane on Earth typically lasts a week, but this has been here for decades — and who knows — maybe centuries."

Weather patterns on Earth are interrupted when they encounter friction from landforms or ice caps. Scientists suspect the stability of the hexagon has something to do with the lack of solid landforms on Saturn, which is essentially a giant ball of gas.

Better views of the hexagon are available now because the sun began to illuminate its interior in late 2012. Cassini captured images of the hexagon over a 10-hour time span with high-resolution cameras, giving scientists a good look at the motion of cloud structures within.

They saw the storm around the pole, as well as small vortices rotating in the opposite direction of the hexagon. Some of the vortices are swept along with the jet stream as if on a racetrack. The largest of these vortices spans about 2,200 miles (3,500 kilometers), or about twice the size of the largest hurricane recorded on Earth.

Scientists analyzed these images in false color, a rendering method that makes it easier to distinguish differences among the types of particles suspended in the atmosphere — relatively small particles that make up haze — inside and outside the hexagon.

Continue reading …

, #NASA #JPL #Caltech #University of Arizona #science #Saturn #Saturn's hexagon #hexagon #astronomy #astronomyfacts #Cassini #Cassini spacecraft #astrophotography #Saturn's north pole

spaceplasma:

Intense Colors on Rhea

These intense false-color views highlight and enhance color variations across the intensely cratered and cracked surface of Rhea.

To create the false-color view, ultraviolet, green and infrared images were combined into a single black and white picture that isolates and maps regional color differences. This “color map” was then superposed over a clear-filter image. The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition or the sizes of grains making up the icy soil.

Credit: NASA/JPL/Space Science Institute

, #astronomy #astronomyfacts #Saturn's moon #rhea #Cassini #Cassini mission #space #cosmos #NASA #moon

astronemma: procyonvulpecula: GOOD NEWS! MOST OF NASA’S PLANETARY MISSIONS ARE...

procyonvulpecula:

GOOD NEWS! MOST OF NASA’S PLANETARY MISSIONS ARE STILL OPERATING!

That’s because they’re run from JPL or APL, privately run facilities that are under contract to NASA. So missions that won’t be affected by the shutdown include all the important ones like Curiosity; Opportunity; Odyssey; Mars Reconnaissance Orbiter; Cassini; Dawn; Juno; Spitzer; the Voyagers; WISE; MESSENGER and New Horizons, amongst others. Given the size of that list, I’d like to see a list of missions that are affected!

Source: http://www.planetary.org/blogs/emily-lakdawalla/2013/10010929-shutdown-jpl-operating.html

For those of you who were unsure as to what is closed for now and what isn’t, CNN has provided a comprehensive, albeit long, and descriptive list of what government services and agencies are closed, partially closed, and open here: http://tinyurl.com/qbf4k84.

You can also find a list of general services affected here: http://tinyurl.com/ozbs4w3, and here: http://tinyurl.com/l4gbhlu.

, #news #humanactions #United States #NASA #JPL #APL #Curiosity #opportunity #Odyssey #mars reconnaissance orbiter #Cassini

discoverynews:

Distant Earth: A History of ‘Pale Blue Dots’

NASA’s Cassini spacecraft may have done it, but it certainly wasn’t the first space mission to image Earth from deep space. So, let Discovery News’ space historian

, #science #astronomyfacts #pale blue dot #earth #NASA #Cassini

thekidshouldseethis:

Selecting over 200,000 photos from Cassini–Huygens’ eight years of image-taking, Fabio Di Donato animates Around Saturn to Jazz Suite No.2: VI. Waltz 2 by Dmitri Shostakovich.

The Cassini program is an international cooperative effort involving NASA, the European Space Agency (ESA) and the Italian space agency, Agenzia Spaziale Italiana (ASI), as well as several separate European academic and industrial contributors. The Cassini partnership represents an undertaking whose scope and cost would not likely be borne by any single nation, but is made possible through shared investment and participation. Through the mission, about 260 scientists from 17 countries hope to gain a better understanding of Saturn, its stunning rings, its magnetosphere, Titan and its other icy moons.

This is the third video made with Cassini imagery that has gone viral over the last few years — the others: Cassini Mission by Chris Abbas and Outer Space by Sander van den Berg. Perhaps that popularity reflects just how incredible it is to see these up close glimpses of the sixth planet from 900 million miles away.

Also, this, just in case the kids didn’t see it. 

via The Verge.

, #science #Cassini #NASA #Saturn #video
Cassini Releases Image of Earth Waving at Saturn  Image credit: NASA/JPL-Caltech  

From more than 40 countries and 30 U.S. states, people around the world shared more than 1,400 images of themselves as part of the Wave at Saturn event organized by NASA’s Cassini mission. That event on July 19, 2013, marked the day the Cassini spacecraft turned back toward Earth to take our picture as part of a larger mosaic of the Saturn system. The images came via Twitter, Facebook, Flickr, Instagram, Google+ and email. The mission has assembled this collage from the shared images, using an image of Earth as the base image. 
People around the world shared more than 1,400 images of themselves as part of the Wave at Saturn event organized by NASA’s Cassini mission on July 19 — the day the Cassini spacecraft turned back toward Earth to take our picture. The mission has assembled a collage from those images. The collage is online here. "Thanks to all of you, near and far, old and young, who joined the Cassini mission in marking the first time inhabitants of Earth had advance notice that our picture was being taken from interplanetary distances," said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. "While Earth is too small in the images Cassini obtained to distinguish any individual human beings, the mission has put together this collage so that we can celebrate all your waving hands, uplifted paws, smiling faces and artwork." The images came from 40 countries and 30 U.S. states via Twitter, Facebook, Flickr, Instagram, Google+ and email. From its perch in the Saturn system, Cassini took a picture of Earth as part of a larger set of images it was collecting of the Saturn system. Scientists are busy putting together the color mosaic of the Saturn system, which they expect will take at least several more weeks to complete. The scientists who study Saturn’s rings are poring over visible-light and infrared data obtained during that campaign. 
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. 
For more information on the Wave at Saturn campaign, visit here. 
For more information about the Cassini mission, visit here and here.

Cassini Releases Image of Earth Waving at Saturn  Image credit: NASA/JPL-Caltech  

From more than 40 countries and 30 U.S. states, people around the world shared more than 1,400 images of themselves as part of the Wave at Saturn event organized by NASA’s Cassini mission. That event on July 19, 2013, marked the day the Cassini spacecraft turned back toward Earth to take our picture as part of a larger mosaic of the Saturn system. The images came via Twitter, Facebook, Flickr, Instagram, Google+ and email. The mission has assembled this collage from the shared images, using an image of Earth as the base image. 

People around the world shared more than 1,400 images of themselves as part of the Wave at Saturn event organized by NASA’s Cassini mission on July 19 — the day the Cassini spacecraft turned back toward Earth to take our picture. The mission has assembled a collage from those images. The collage is online here

"Thanks to all of you, near and far, old and young, who joined the Cassini mission in marking the first time inhabitants of Earth had advance notice that our picture was being taken from interplanetary distances," said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. "While Earth is too small in the images Cassini obtained to distinguish any individual human beings, the mission has put together this collage so that we can celebrate all your waving hands, uplifted paws, smiling faces and artwork." 

The images came from 40 countries and 30 U.S. states via Twitter, Facebook, Flickr, Instagram, Google+ and email. 

From its perch in the Saturn system, Cassini took a picture of Earth as part of a larger set of images it was collecting of the Saturn system. Scientists are busy putting together the color mosaic of the Saturn system, which they expect will take at least several more weeks to complete. The scientists who study Saturn’s rings are poring over visible-light and infrared data obtained during that campaign. 

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. 

  • For more information on the Wave at Saturn campaign, visit here
  • For more information about the Cassini mission, visit here and here.
, #Cassini #Earth #Saturn #cassini-huygens #NASA #JPL #science #humanactions

Sneak Peeks of the Earth and Saturn Panorama from Cassini on July 19 via Universe Today by KEN KREMER.[Click images to enlarge.]

Breathtaking raw images of the Earth and Saturn system snapped by NASA’s Cassini spacecraft on July 19 during the worldwide ‘Wave at Saturn’ campaign are streaming back across 1 billion miles of interplanetary space.

Science team members are now busily processing the images to create individual color composites and a panoramic view of the ‘pale blue dot’ and the entire Saturnian system.

NASA just released the first individual color composite focusing on Earth – see above. And its spectacular!

To capture all of Saturn and its wide swath of rings, Cassini’s wide angle camera snapped a mosaic of 33 footprints.

“At each footprint, images were taken in different spectral filters for a total of 323 images,” says Carolyn Porco, Cassini Imaging Team leader of the Space Science Institute in Boulder, Colo.

Cassini took the pictures of Earth between 2:27 and 2:42 p.m. PDT on Friday, July 19 from a distance of about 898 million miles (1.44 billion kilometers) away from the home to every human being that has ever lived.

Continue reading…

  • First image: ”Partial context mosaic of the Earth and Saturn taken by NASA’s Cassini orbiter on July 19, 2013. This mosaic was assembled from five wide angle camera raw images and offers a sneak peek of the complete panorama.” View full image here. Credit: NASA/JPL-Caltech/Ken Kremer/Marco Di Lorenzo.
  • Second image: ”The Day the Earth Smiled: Sneak Preview - In this rare image taken on July 19, 2013, the wide-angle camera on NASA’s Cassini spacecraft has captured Saturn’s rings and our planet Earth and its moon in the same frame.” View full image here. Credit: NASA/JPL-Caltech/Space Science Institute.
, #science #Saturn #Cassini #NASA #pale blue dot #earth #astrophotography #astronomyfacts #astronomy

NASA Releases Images of Earth by Distant Spacecraft [Click images to enlarge & read descriptions - Image Credit: NASA/JPL-Caltech/Space Science Institute.]

Color and black-and-white images of Earth taken by two NASA interplanetary spacecraft on July 19 show our planet and its moon as bright beacons from millions of miles away in space. 

NASA’s Cassini spacecraft captured the color images of Earth and the moon from its perch in the Saturn system nearly 900 million miles (1.5 billion kilometers) away. MESSENGER, the first probe to orbit Mercury, took a black-and-white image from a distance of 61 million miles (98 million kilometers) as part of a campaign to search for natural satellites of the planet. 

In the Cassini images Earth and the moon appear as mere dots — Earth a pale blue and the moon a stark white, visible between Saturn’s rings. It was the first time Cassini’s highest-resolution camera captured Earth and its moon as two distinct objects. 

It also marked the first time people on Earth had advance notice their planet’s portrait was being taken from interplanetary distances. NASA invited the public to celebrate by finding Saturn in their part of the sky, waving at the ringed planet and sharing pictures over the Internet. More than 20,000 people around the world participated. 

"We can’t see individual continents or people in this portrait of Earth, but this pale blue dot is a succinct summary of who we were on July 19," said Linda Spilker, Cassini project scientist, at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. "Cassini’s picture reminds us how tiny our home planet is in the vastness of space, and also testifies to the ingenuity of the citizens of this tiny planet to send a robotic spacecraft so far away from home to study Saturn and take a look-back photo of Earth." 

Pictures of Earth from the outer solar system are rare because from that distance, Earth appears very close to our sun. A camera’s sensitive detectors can be damaged by looking directly at the sun, just as a human being can damage his or her retina by doing the same. Cassini was able to take this image because the sun had temporarily moved behind Saturn from the spacecraft’s point of view and most of the light was blocked. 

A wide-angle image of Earth will become part of a multi-image picture, or mosaic, of Saturn’s rings, which scientists are assembling. This image is not expected to be available for several weeks because of the time-consuming challenges involved in blending images taken in changing geometry and at vastly different light levels, with faint and extraordinarily bright targets side by side. 

Read more here.

, #Earth #Saturn #Cassini #astrophotography #Messenger #JPL #NASA #astronomy #astronomyfacts #science

carolynporco:

How sweet it is! Richard Branson plans to smile on July 19 w/ the rest of us!!

He says:

"One of my favourite images is the Pale Blue Dot, a photo taken in 1990 that captured the Earth as a tiny speck of light from beyond the orbit of Neptune.

Then in 2006 Cassini took this awe-inspiring image of Earth from within the shadow of Saturn. Can you spot us?

Now it is time for an updated version of the Pale Blue Dot. On July 19th, the Cassini cameras will face the sun and capture the Earth, Saturn and its rings. It will be the first time human beings have known in advance their photo will be taken from a billion miles away.”

Richard is also promoting the two contests we are running at Diamond Sky Productions. If you are a photography buff who has thought about communication with extraterrestrials, or you are a music composer, consider entering!

Richard’s Blog - Virgin.com: Pale Blue Dot

, #science #humanactions #Cassini

jtotheizzoe:

You guys like Saturn, right? Here’s a whole gallery of Saturn GIFs, from rings to moons, captured by the Cassini spacecraft. They’re part modern art and part science.

Next to the Voyager twins, I think Cassini might be the best satellite NASA ever launched. Certainly takes the best pictures. Tumblr’s own staceythinx  has an iPad app called Cassini HD that features even more photos, plus color, plus science.

(GIFs by framesandflames)

, #gif #saturn #cassini #space #astronomy #astronomyfacts #Astronomy

electricspacekoolaid:

Cassini Shapes First Global Topographic Map of Titan

Image: Using data from NASA’s Cassini spacecraft, scientists have created the first global topographic map of Saturn’s moon Titan, giving researchers a 3-D tool for learning more about one of the most Earthlike and interesting worlds in the solar system

Scientists have created the first global topographic map of Saturn’s moon Titan, giving researchers a valuable tool for learning more about one of the most Earth-like and interesting worlds in the solar system. The map was just published as part of a paper in the journal Icarus.

Titan is Saturn’s largest moon - at 1,600 miles (2,574 kilometers) across it’s bigger than planet Mercury - and is the second-largest moon in the solar system. Scientists care about Titan because it’s the only moon in the solar system known to have clouds, surface liquids and a mysterious, thick atmosphere. The cold atmosphere is mostly nitrogen, like Earth’s, but the organic compound methane on Titan acts the way water vapor does on Earth, forming clouds and falling as rain and carving the surface with rivers. Organic chemicals, derived from methane, are present in Titan’s atmosphere, lakes and rivers and may offer clues about the origins of life.

“Titan has so much interesting activity - like flowing liquids and moving sand dunes - but to understand these processes it’s useful to know how the terrain slopes,” said Ralph Lorenz, a member of the Cassini radar team based at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., who led the map-design team. “It’s especially helpful to those studying hydrology and modeling Titan’s climate and weather, who need to know whether there is high ground or low ground driving their models.”

Titan’s thick haze scatters light in ways that make it very hard for remote cameras to “see” landscape shapes and shadows, the usual approach to measuring topography on planetary bodies. Virtually all the data we have on Titan comes from NASA’s Saturn-orbiting Cassini spacecraft, which has flown past the moon nearly 100 times over the past decade. On many of those flybys, Cassini has used a radar imager, which can peer through the haze, and the radar data can be used to estimate the surface height.

“With this new topographic map, one of the most fascinating and dynamic worlds in our solar system now pops out in 3-D,” said Steve Wall, the deputy team lead of Cassini’s radar team, based at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “On Earth, rivers, volcanoes and even weather are closely related to heights of surfaces - we’re now eager to see what we can learn from them on Titan.”

Read

Image credit: NASA/JPL-Caltech/ASI/JHUAPL/Cornell/Weizmann 

, #space #tech #Cassini #NASA #astronomy #Solar System #Titan #Saturn #astronomy facts #Cassini spacecraft #spacecraft #astronomyfacts
Cassini Probe to Take Photo of Earth From Deep Space
[Image credit: NASA/JPL-Caltech]
“NASA’s Cassini spacecraft, now exploring Saturn, will take a picture of our home planet from a distance of hundreds of millions of miles on July 19. NASA is inviting the public to help acknowledge the historic interplanetary portrait as it is being taken. 
Earth will appear as a small, pale blue dot between the rings of Saturn in the image, which will be part of a mosaic, or multi-image portrait, of the Saturn system Cassini is composing. "While Earth will be only about a pixel in size from Cassini’s vantage point 898 million [1.44 billion kilometers] away, the team is looking forward to giving the world a chance to see what their home looks like from Saturn," said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. "We hope you’ll join us in waving at Saturn from Earth, so we can commemorate this special opportunity." Cassini will start obtaining the Earth part of the mosaic at 2:27 p.m. PDT (5:27 p.m. EDT or 21:27 UTC) and end about 15 minutes later, all while Saturn is eclipsing the sun from Cassini’s point of view. The spacecraft’s unique vantage point in Saturn’s shadow will provide a special scientific opportunity to look at the planet’s rings. At the time of the photo, North America and part of the Atlantic Ocean will be in sunlight. Unlike two previous Cassini eclipse mosaics of the Saturn system in 2006, which captured Earth, and another in 2012, the July 19 image will be the first to capture the Saturn system with Earth in natural color, as human eyes would see it. It also will be the first to capture Earth and its moon with Cassini’s highest-resolution camera. The probe’s position will allow it to turn its cameras in the direction of the sun, where Earth will be, without damaging the spacecraft’s sensitive detectors.”
Continue reading…
To learn more about the public outreach activities associated with the taking of the image, visit:http://saturn.jpl.nasa.gov/waveatsaturn . For more information about Cassini, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Cassini Probe to Take Photo of Earth From Deep Space

[Image credit: NASA/JPL-Caltech]

NASA’s Cassini spacecraft, now exploring Saturn, will take a picture of our home planet from a distance of hundreds of millions of miles on July 19. NASA is inviting the public to help acknowledge the historic interplanetary portrait as it is being taken. 

Earth will appear as a small, pale blue dot between the rings of Saturn in the image, which will be part of a mosaic, or multi-image portrait, of the Saturn system Cassini is composing. 

"While Earth will be only about a pixel in size from Cassini’s vantage point 898 million [1.44 billion kilometers] away, the team is looking forward to giving the world a chance to see what their home looks like from Saturn," said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. "We hope you’ll join us in waving at Saturn from Earth, so we can commemorate this special opportunity." 

Cassini will start obtaining the Earth part of the mosaic at 2:27 p.m. PDT (5:27 p.m. EDT or 21:27 UTC) and end about 15 minutes later, all while Saturn is eclipsing the sun from Cassini’s point of view. The spacecraft’s unique vantage point in Saturn’s shadow will provide a special scientific opportunity to look at the planet’s rings. At the time of the photo, North America and part of the Atlantic Ocean will be in sunlight. 

Unlike two previous Cassini eclipse mosaics of the Saturn system in 2006, which captured Earth, and another in 2012, the July 19 image will be the first to capture the Saturn system with Earth in natural color, as human eyes would see it. It also will be the first to capture Earth and its moon with Cassini’s highest-resolution camera. The probe’s position will allow it to turn its cameras in the direction of the sun, where Earth will be, without damaging the spacecraft’s sensitive detectors.”

Continue reading…

To learn more about the public outreach activities associated with the taking of the image, visit:http://saturn.jpl.nasa.gov/waveatsaturn . 

For more information about Cassini, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

, #science #Earth #Saturn #astronomy #astronomyfacts #Cassini #NASA
spaceplasma:

Saturn’s magnetosphere changes with the seasons  
This is an artist’s concept of the Saturnian plasma sheet based on data from Cassini magnetospheric imaging instrument. It shows Saturn’s embedded “ring current,” an invisible ring of energetic ions trapped in the planet’s magnetic field.
Saturn is at the center, with the red “donut” representing the distribution of dense neutral gas outside Saturn’s icy rings. Beyond this region, energetic ions populate the plasma sheet to the dayside magnetopause filling the faintly sketched magnetic flux tubes to higher latitudes and contributing to the ring current. The plasma sheet thins gradually toward the nightside. The view is from above Saturn’s equatorial plane, which is represented by grid lines. The moon Titan’s location is shown for scale. The location of the bow shock is marked, as is the flow of the deflected solar wind in the magnetosheath.
Researchers working with data from NASA’s Cassini spacecraft have discovered one way the bubble of charged particles around Saturn — known as the magnetosphere — changes with the planet’s seasons. The finding provides an important clue for solving a riddle about the planet’s naturally occurring radio signal. The results might also help scientists better understand variations in Earth’s magnetosphere and Van Allen radiation belts, which affect a variety of activities at Earth, ranging from space flight safety to satellite and cell phone communications.
The paper, just published in the Journal of Geophysical Research, is led by Tim Kennelly, an undergraduate physics and astronomy major at the University of Iowa, Iowa City, who is working with Cassini’s radio and plasma wave science team.
In data collected by Cassini from July 2004 to December 2011, Kennelly and his colleagues examined “flux tubes,” structures composed of hot, electrically charged gas called plasma, which funnel charged particles in towards Saturn. Focusing on the tubes when they initially formed and before they had a chance to dissipate under the influence of the magnetosphere, the scientists found that the occurrence of the tubes correlates with radio wave patterns in the northern and southern hemisphere depending upon the season. This seasonal effect is roughly similar to the way Earth’s northern lights appear more frequently in the spring and autumn months.
Radio emissions have been used to measure Jupiter’s rotation period reliably, and scientists thought it would also help them determine Saturn’s rotation period. To their chagrin, however, the pattern has varied over the visits by different spacecraft and even in radio emissions originating in the northern and southern hemispheres. The new results could help scientists hone in on why these signals vary the way they do.
For more on the finding, go to: http://now.uiowa.edu/2013/03/telling-time-saturn .

spaceplasma:

Saturn’s magnetosphere changes with the seasons

This is an artist’s concept of the Saturnian plasma sheet based on data from Cassini magnetospheric imaging instrument. It shows Saturn’s embedded “ring current,” an invisible ring of energetic ions trapped in the planet’s magnetic field.

Saturn is at the center, with the red “donut” representing the distribution of dense neutral gas outside Saturn’s icy rings. Beyond this region, energetic ions populate the plasma sheet to the dayside magnetopause filling the faintly sketched magnetic flux tubes to higher latitudes and contributing to the ring current. The plasma sheet thins gradually toward the nightside. The view is from above Saturn’s equatorial plane, which is represented by grid lines. The moon Titan’s location is shown for scale. The location of the bow shock is marked, as is the flow of the deflected solar wind in the magnetosheath.

Researchers working with data from NASA’s Cassini spacecraft have discovered one way the bubble of charged particles around Saturn — known as the magnetosphere — changes with the planet’s seasons. The finding provides an important clue for solving a riddle about the planet’s naturally occurring radio signal. The results might also help scientists better understand variations in Earth’s magnetosphere and Van Allen radiation belts, which affect a variety of activities at Earth, ranging from space flight safety to satellite and cell phone communications.

The paper, just published in the Journal of Geophysical Research, is led by Tim Kennelly, an undergraduate physics and astronomy major at the University of Iowa, Iowa City, who is working with Cassini’s radio and plasma wave science team.

In data collected by Cassini from July 2004 to December 2011, Kennelly and his colleagues examined “flux tubes,” structures composed of hot, electrically charged gas called plasma, which funnel charged particles in towards Saturn. Focusing on the tubes when they initially formed and before they had a chance to dissipate under the influence of the magnetosphere, the scientists found that the occurrence of the tubes correlates with radio wave patterns in the northern and southern hemisphere depending upon the season. This seasonal effect is roughly similar to the way Earth’s northern lights appear more frequently in the spring and autumn months.

Radio emissions have been used to measure Jupiter’s rotation period reliably, and scientists thought it would also help them determine Saturn’s rotation period. To their chagrin, however, the pattern has varied over the visits by different spacecraft and even in radio emissions originating in the northern and southern hemispheres. The new results could help scientists hone in on why these signals vary the way they do.

For more on the finding, go to: http://now.uiowa.edu/2013/03/telling-time-saturn .

, #NASA #Astronomy #saturn #Cassini #plasma #magnetosphere #astronomyfacts
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