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Showing posts tagged Saturn

The Massive Vertical Structures Towering Above Saturn’s Rings

Ringsnotflat 
This one is a 10 on the Galaxy wow meter: In images made possible only as Saturn nears equinox, NASA’s Cassini spacecraft has uncovered for the first time towering vertical structures in the planet’s otherwise flat rings that are attributable to the gravitational effects of a small nearby moon.

The search for material extending well above and below Saturn’s ring plane has been a major goal of the imaging team during Cassini’s “Equinox Mission,” the two-year period when the sun is seen directly overhead at noon at the planet’s equator. This novel illumination geometry, which occurs every half-Saturn-year, or about 15 Earth years, lowers the sun’s angle to the ring plane and causes out-of-plane structures to cast long shadows across the rings’ broad expanse, making them easy to detect.

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Cassini’s cameras spotted not only the predictable shadows of some of Saturn’s moons, but also the shadows of newly revealed vertical structures in the rings themselves. And these observations have lent dramatic support to the analysis that demonstrates how small moons in very narrow gaps can have considerable and complex effects on the edges of their gaps, and that such moons can be smaller than previously believed.

The Daily Galaxy via NASA/Cassini

 
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Posted at 12:06am
Tagged Saturn Astronomy Cassini

 


Mystery Solved: Water on Saturn Comes From Icy Moon ‘Rain’

by Denise Chow, SPACE.com Staff Writer

Date: 26 July 2011 Time: 01:36 PM ET

Enceladus Rans Water on Saturn

At least four distinct plumes of water ice spew out from the south polar region of Saturn’s moon Enceladus. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 25, 2009.
CREDIT: NASA/JPL/Space Science Institute 
View full size image

An icy moon around Saturn is showering rain water onto its home planet, creating a vast halo of water vapor around the ringed world, a new study finds.

The discovery means that Enceladus, Saturn’s sixth-largest moon, is the only moon in the solar system known to influence the chemical composition of its parent planet, researchers said. It also solves a 14-year mystery that had scientists puzzled over the source of the water in Saturn’s upper atmosphere.

"There is no analogy to this behavior on Earth," said study leader Paul Hartogh, of the Max Planck Institute for Solar System Research in Germany, in a statement. "No significant quantities of water enter our atmosphere from space. This is unique to Saturn."

Enceladus has a frigid, icy surface but an active interior, particularly at its south pole. In this dynamic region, geothermal activity is concentrated at four trenches that are dubbed “tiger stripes,” because of their distinctive surface markings. [Photos: The Rings and Moons of Saturn]

These fissures, which measure approximately 80 miles (130 kilometers) long and 1.2 miles (2 km) wide, form icy geysers that spew plumes of water vapor into space. Enceladus expels roughly 550 pounds (250 kilograms) of water vapor every second through its tiger stripe jets.

Another ring around Saturn

Observations from the European Space Agency’s Herschel space observatory revealed that this water raining from Enceladus creates a doughnut-shaped ring of water vapor around Saturn.

The total width of the water vapor ring is more than 10 times the radius of Saturn, yet it is only about one Saturn radius thick. Enceladus’ elliptical orbit means that the moon’s distance from Saturn varies as ittravels around the ringed planet. But, Herschel’s observations indicate that Enceladus’ jets consistently replenish the water vapor ring throughout its orbit.

Despite the size of the ring, it had not been detected prior to now because water vapor is transparent to visible light, researchers said. Yet, Herschel’s eyes, which are tuned to infrared wavelengths, were able to spot the curious feature.

"These are observations that only Herschel can make," said Göran Pilbratt, ESA Herschel project scientist, in a statement. "ESA’s Infrared Space Observatory found the water vapor in Saturn’s atmosphere. Then NASA/ESA’s Cassini/Huygens mission found the jets of Enceladus. Now Herschel has shown how to fit all these observations together."

A mystery solved

Astronomers have known that Saturn’s atmosphere holds traces of gaseous water in its deepest layers, but the presence of water in the planet’s upper atmosphere had been a mystery. The phenomenon was first reported in 1997 by teams using ESA’s Infrared Space Observatory, but until now, the source of the water was unknown.

Computer models based on the latest findings from Herschel estimate that between three to five percent of the water spewed by Enceladus ends up falling onto Saturn.

While most of Enceladus’ rain is either lost in space, freezes on Saturn’s rings, or potentially even falls onto the planet’s other moons, what does reach the ringed planet is sufficient enough to explain the water in its upper atmosphere.

The water vapor is also responsible for the production of other chemical compounds bearing oxygen, such as carbon dioxide, scientists said.

Eventually, water in the planet’s upper atmosphere will travel to lower levels, where the small amounts will condense into tiny clouds that are ultimately not observable, they added.

via Space.com

 
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Posted at 11:52am
Tagged Space Astronomy Saturn

 


Catching Its Tail

Huge storm churning through the atmosphere in Saturn's northern hemisphere

Image credit: NASA/JPL-Caltech/SSI

The huge storm churning through the atmosphere in Saturn’s northern hemisphere overtakes itself as it encircles the planet in this true-color view from NASA’s Cassini spacecraft.

This picture, captured on Feb. 25, 2011, was taken about 12 weeks after the storm began, and the clouds by this time had formed a tail that wrapped around the planet. Some of the clouds moved south and got caught up in a current that flows to the east (to the right) relative to the storm head. This tail, which appears as slightly blue clouds south and west (left) of the storm head, can be seen encountering the storm head in this view.

This storm is the largest, most intense storm observed on Saturn by NASA’s Voyager or Cassini spacecraft. It is still active today. As scientists have tracked this storm over several months, they have found it covers 500 times the area of the largest of the southern hemisphere storms observed earlier in the Cassini mission (see PIA06197). The shadow cast by Saturn’s rings has a strong seasonal effect, and it is possible that the switch to powerful storms now being located in the northern hemisphere is related to the change of seasons after the planet’s August 2009 equinox.

See PIA12824 for a nearly true-color view taken in December 2010. See PIA12825 for false-color high-resolution views of the storm taken in February 2011.

Huge storms called Great White Spots have been observed in previous Saturnian years (each of which is about 30 Earth years), usually appearing in late northern summer. Saturn is now experiencing early northern spring, so this storm, if it is a Great White Spot, is happening earlier than usual. This storm is about as large as the largest of the Great White Spots, which also encircled the planet but had latitudinal sizes ranging up to 20,000 kilometers (12,000 miles). The Voyager and Cassini spacecraft were not at Saturn for previous Great White Spot appearances.

The storm is a prodigious source of radio noise, which comes from lightning deep in the planet’s atmosphere. The lightning is produced in the water clouds, where falling rain and hail generate electricity. The mystery is why Saturn stores energy for decades and releases it all at once. This behavior is unlike that at Jupiter and Earth, which have numerous storms going on at all times.

This view looks toward the sunlit side of the rings from just above the ring plane.

Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were acquired with the Cassini spacecraft wide-angle camera at a distance of approximately 1.4 million miles (2.2 million kilometers) from Saturn. Image scale is 80 miles (129 kilometers) per pixel.

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 Cassini-Huygens 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 team is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission, visit www.nasa.gov/cassini and saturn.jpl.nasa.gov.

via nasa.gov

Download Full Size Image.

 
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Posted at 12:28am
Tagged Space Astronomy Saturn Solar System NASA

 


Icy Saturn Moon May Be Covering a Salty Sea

Nola Taylor Redd, SPACE.com Contributor

Date: 22 June 2011 Time: 01:01 PM ET

Saturn Moon Riddled with Gushing Geysers, New Images RevealDramatic plumes, both large and small, spray water ice out from many locations along the famed “tiger stripes” near the south pole of Saturn’s moon Enceladus in this image taken by NASA’s Cassini probe on Nov. 21, 2009.
CREDIT: NASA/JPL/Space Science Institute 
View full size image

Saturn’s icy moon Enceladus conceals a salty ocean beneath its frozen surface, scientists now suspect.

Using NASA’s Cassini spacecraft orbiting Saturn, scientists have discovered that the water geysers erupting from Enceladus contain a significant amount of salt — enough to suggest the presence of a subterranean sea.

The finding might have implications for the possibility of life on Enceladus, researchers said.

A team of scientists led by Frank Postberg of the University of Heidelberg used Cassini’s Cosmic Dust Analyzer to directly examine the plumes during three flybys by the Cassini spacecraft. Individual particles were analyzed as they hit a metal target, and the ones closer to the moon’s surface were found to have a high salt content. [Photos: The Rings and Moons of Saturn]

"The salt-rich ice grains are, on average, heavier than the salt-poor ice grains," Postberg told SPACE.com in an email. “Only a relatively small fraction of the salty particles escape into the E ring.” The E ring is the outermost of Saturn’s seven ring groupings, and it is made up of particles ejected by Enceladus’ geyser plumes.

Geysers from Saturn moon

The idea of a salty sea beneath the icy crust of Saturn’s sixth largest moon has been entertained since sodium was first detected in the planet’s E ring. [Video:Enceladus: Saturn’s Refreshing Secret]

But only about 6 percent of the ring particles were salty, suggesting that they were formed by ice that immediately evaporated into water vapor without forming a liquid, a process known as sublimation, researchers said.

Cassini discovered plumes of water vapor shooting from the southern hemisphere of Enceladus in 2005. The geysers erupt from four parallel trenches known as the “tiger stripes.”

While previous studies found a relatively low amount of salt in the Enceladus geyser particles that make up Saturn’s outer ring, the percentage is different when studying the geysers themselves.

"The lower you get to the surface, the more salt-rich grains you see," Postberg said.

In fact, more than 99 percent of the ice around the geysers is salt-rich.

"This makes a much stronger case for liquid water," Postberg said.

Earth’s oceans get their salt from the rocks that enclose them. The same is true of any other body with an ocean. On Enceladus, pressure would push bubbles of ocean spray into space, where they would quickly freeze before they could break apart. These bubbles would become samples of the ocean they escaped.

The geysers of Enceladus are fed by at least one reservoir of water a few hundred feet below the surface. Whether it is a single large lake or several smaller pools is unknown, but in order for the spray to form, a total water-surface area of several hundred square miles must exist.

Geysers from all four tiger stripes are heavy in salt, so the reservoirs must at least be large enough to cover the area under these fissures.

Based on the scientists’ study, these reservoirs connect to a larger ocean about 50 miles (80 km) underground. Calculations limit it to the southern hemisphere, but how wide it extends is unknown.

Theoretically, the geysers could be fed directly by a shallow ocean, but geophysicists consider that unlikely because an enormous amount of heat would be needed to keep such a large body from freezing.

The research is detailed in the online June 22 edition of the journal Nature.

Probing for life

Scientists searching for extraterrestrial life have long considered liquid water a primary requirement for its existence, so an ocean under Enceladus’ surface provides another potential target.

Postberg pointed out that, unlike other unseen oceans in the solar system, the water on Enceladus is fairly easy to reach. Jupiter’s moon Europa, for instance, could have an ocean under a layer of ice, but retrieving it would require significant effort. By contrast, the geysers on Enceladus pull material — and potentially life, should it exist there — from its ocean and shoot it into space.

"The water samples are thrown in front of your spacecraft by the plumes," he said. "You don’t have to drill deep to analyze ocean material."

Similarly, as astronomers pinpoint bodies outside the solar system where life might thrive, they tend to focus on planets close to stars, where temperatures are warm enough for liquid water to form at the surface.

But Enceladus, orbiting a planet about 891 million miles (1.4 billion km) from the sun, is cold and frigid on its surface.

"The fact that water is on such a remote and unlikely place surely has implications for the general likelihood of life in the universe," Postberg said.

Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

via www.space.com

 
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Posted at 10:37pm
Tagged Saturn NASA Cassini Solar System Astronomy

 


Cassini: Unlocking Saturn’s Secrets

In Saturn’s Shadow

 In Saturn

With giant Saturn hanging in the blackness and sheltering Cassini from the sun’s blinding glare, the spacecraft viewed the rings as never before, revealing previously unknown faint rings and even glimpsing its home world.

This marvelous panoramic view was created by combining a total of 165 images taken by the Cassini wide-angle camera over nearly three hours on Sept. 15, 2006. The full mosaic consists of three rows of nine wide-angle camera footprints; only a portion of the full mosaic is shown here. Color in the view was created by digitally compositing ultraviolet, infrared and clear filter images and was then adjusted to resemble natural color.

The mosaic images were acquired as the spacecraft drifted in the darkness of Saturn’s shadow for about 12 hours, allowing a multitude of unique observations of the microscopic particles that compose Saturn’s faint rings.

Ring structures containing these tiny particles brighten substantially at high phase angles: i.e., viewing angles where the sun is almost directly behind the objects being imaged.

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/home/index.cfm. The Cassini imaging team homepage is at http://ciclops.org.

Image credit: NASA/JPL/Space Science Institute

Full slide show of amazing hand-picked Saturn images HERE

 
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Posted at 10:10pm
Tagged NASA Astronomy Saturn Cassini

 


The Fountains of Enceladus

One of many of Saturn’s Moons.

This has to be one of the greatest, most alien images ever taken from robotic spacecraft. It approaches how I might expect Enceladus to be depicted if it were in a Star Trek movie. As if the plumes at the edge of the disk back-lit by the Sun were not enough… the trail of smaller plumes breaking through the darkness is absolutely fantastic. The above is a real image but the color is an artistic interpretation by someone would know. Considering how little color is usually found at Enceladus, we can image this is really as good as if it were compiled from a full RGB set of filters. A larger monotone of the same image here.

This image was compiled by Astro0 on unmannedspaceflight.com. Also one of the best views staring down the length of one of Enceladus’ “tiger stripes”.

Ever so sharp look straight down on the South Pole of Enceladus from 1,855 km.

 
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Posted at 1:04pm
Tagged Saturn Enceladus

 


A short film about Cassini mission with soundtrack by Nine Inch Nails.

(Source: fabilipo)

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Posted at 12:59pm
Reblogged (Video reblogged from itsfullofstars)
Tagged Cassini Saturn Nine Inch Nails

 




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