Archive for ringed planet

Saturn’s Moons: Facts About the Ringed Planet’s Satellites

The moons of Saturn — 62 in all — come in a variety of sizes and compositions.

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NASA Spacecraft Photographs Venus as Seen from Saturn




Venus Peeks Through Saturn's Rings


Venus appears as a bright dot shining through Saturn’s rings in this image, taken on Nov. 10, 2012, by NASA’s Cassini spacecraft. Cassini was about 498,000 miles from the ringed planet at the time.
CREDIT: NASA/JPL-Caltech/Space Science Institute


Venus gleams over Saturn’s enormous shoulder in two stunning new photos captured by NASA’s Cassini spacecraft, which is orbiting the ringed planet.

Earth’s hellishly hot “sister planet” peeks through Saturn’s iconic rings in one image, which Cassini took last November when it was in Saturn’s shadow. Because of the vast gulf between the two worlds, the Earth-size Venus appears as a bright white dot, just above and to the right of the picture’s center.

When it took the photo, Cassini was about 498,000 miles (802,000 kilometers) from Saturn and looking toward the unlit side of the rings from slightly below the ring plane, researchers said. Each pixel in the image covers about 28 miles (44 km).

Venus Shines Near Saturn's Edge

Cassini captured the other image on Jan. 4, when the probe was approximately 371,000 miles (597,000 km) from Saturn. Venus appears near the top of the photo, sandwiched between Saturn’s bright, curving limb and its G ring. The scale in this view is 20 miles (32 km) per pixel. [Gallery: The Rings and Moons of Saturn]

The broad, fuzzy streak lower down is Saturn’s E ring, which was generated by the icy plume of particles erupting from geysers on the planet’s enigmatic moon Enceladus. The luminous point to the left of the E ring is a distant star, researchers said.

This isn’t the first time Cassini has seen a planet from the inner solar system from its vantage point around Saturn. In 2006, the spacecraft snapped an amazing view of Earth as it appeared from the ringed planet. That photo, called “In Saturn’s Shadow,” is one of the most popular Cassini images taken to date, researchers said.

Though Venus is about the same size as Earth and has a similar rocky composition, conditions on the two planets’ surfaces are very different. Astronauts walking around on Venus would experience pressures 100 times greater than those on Earth’s surface and temperatures around 870 degrees Fahrenheit (466 degrees Celsius) — hot enough to melt lead.

Both of these extremes are a result of Venus’ thick, carbon-dioxide-dominated atmosphere, which has created a runaway greenhouse effect on the second planet from the sun.

The $3.2 billion Cassini mission is a joint effort involving NASA, the European Space Agency and the Italian Space Agency. Cassini launched in 1997 and arrived at the Saturn system in 2004. It is now studying the ringed planet and its many moons on an extended mission that runs through at least 2017.

Follow SPACE.com senior writer Mike Wall on Twitter @michaeldwall or SPACE.com @Spacedotcom. We’re also on Facebook and Google+This article was first published on SPACE.com.

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Spectacular New Images Showcase Saturn's Rings

Spectacular New Images Showcase Saturn's Rings

Article source: http://www.space.com/20053-venus-photo-from-saturn-cassini.html

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Saturn’s time to shine

Saturn-Dec2012_PeachSaturn-finder-chartSaturn-moonsJupiter dominated the night sky in early 2013, but now it shares the spotlight with our solar system’s other gas giant, Saturn, as the ringed world puts on a show in April. The planet reaches its peak when it lies opposite the Sun in our sky April 28, which means it rises near sunset and remains visible all night. At opposition, Saturn also shines brighter and appears larger through a telescope than at any other time of the year.

Start looking for the ringed planet in early April, when it hangs low in the east-southeast around 10 p.m. local daylight time. The bright star Spica (Alpha [α] Virginis) works as a guide, as Saturn lies 15° east of the luminary among the much fainter background stars of Libra. The planet shines at magnitude 0.2, noticeably brighter than the 1st-magnitude star.

By opposition, Saturn rises earlier and provides great telescopic views by midnight local daylight time. It also brightens slightly to magnitude 0.1. “Saturn will look stunning through any size telescope near opposition,” says Astronomy Senior Editor Richard Talcott. “The planet’s rings are more open than they have been since 2006, so now is a great time to explore their structure.”

Through a telescope, Saturn’s disk spans 19″ across its equator while its rings cover 43″ and tilt 18° to our line of sight. “You’ll easily spot the Cassini Division that separates the outer A ring from the brighter B ring,” Talcott says. “And on nights with steady viewing conditions, you should even be able to spot the semitransparent C ring that lies closest to Saturn as well.”

And if you can peel your eyes away from the planet’s gorgeous rings, Saturn’s moons also offer a show. For example, many of the satellites are on parade April 28. Magnitude 8.4 Titan and magnitude 11.8 Enceladus pass close to the north of the planet while Dione, Tethys, and Rhea (magnitudes 10.4, 10.3, and 9.7, respectively) lie east of Saturn that same evening. “Titan shows up easily through any instrument, but a 4-inch or larger telescope should reveal the three to the east,” Talcott says. “Enceladus is more challenging and will require a larger scope because it’s so close to the brilliant rings.”

Fast facts

  • Saturn is the second-largest planet in the solar system, and more than 750 Earths could fit inside it.
  • Saturn is the only planet in our solar system that’s less dense than water, and it weighs only 95 times as much as Earth. As such, the planet would float in water.
  • It takes Saturn about 29 years to orbit the Sun but a little less than 11 hours to rotate completely.
  • Saturn’s quick rotation flattens it slightly, so its polar diameter is only 89 percent of its equatorial diameter.
  • Saturn’s rings can be as thin as 33 feet (10 meters) thick and are made almost entirely of ice.

Article source: http://www.astronomy.com/~/link.aspx?_id=7f08f4a5-d06b-455c-b693-5ee56f7c9b8b

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Massive swirling Saturn vortex filmed

This spectacular photo of a polar storm on Saturn was taken by NASA's Cassini spacecraft on Tuesday. It is a raw and unprocessed image.Amazing new photos from NASA’s Cassini probe orbiting Saturn reveal a dizzying glimpse into a monster storm raging on the ringed planet’s north pole.

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Enormous Vortex On Saturn Snapped By Spacecraft | Video

NASA’s Cassini mission beamed back stunning imagery of a swirling storm on the ringed planet on November 27th, 2012.

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Saturn’s Temperature: One Cool Planet

Most of ringed planet’s heat comes from within, rather than from the sun.

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Violent origin of Saturn’s weird moons explained

Saturn’s icy moon Enceladus hangs below the gas giant’s rings while Titan lurks in the background, in this new image taken by the Cassini spacecraft on March 12, 2012. Saturn’s icy medium-size moons were born when a few much bigger satellites collided to form the ringed planet’s huge moon Titan, a new study suggests.

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NASA snaps stunning shots of Saturn and Titan

(SPACE.com) NASA’s Cassini probe has beamed home stunning images of Saturn and Titan, the ringed planet’s largest moon.

The new natural-color Cassini photos, which were unveiled Wednesday (Aug. 29), capture the Saturn system as it undergoes a seasonal shift. The ringed planet and its many moons look quite different today than they did when Cassini arrived on the scene eight years ago, researchers said.

“As the seasons have advanced, and spring has come to the north and autumn to the south throughout the Saturn system, the azure blue in the northern winter Saturnian hemisphere that greeted Cassini upon its arrival in 2004 is now fading; and it is now the southern hemisphere, in its approach to winter, that is taking on a bluish hue,” Cassini imaging team leader Carolyn Porco, of the Space Science Institute in Boulder, Colo., said in a statement.

“This change is likely due to the reduced intensity of ultraviolet light and the haze it produces in the hemisphere approaching winter, and the increasing intensity of ultraviolet light and haze production in the hemisphere approaching summer,” Porco added. [More Spectacular Photos of Saturn by Cassini]

NASAs Cassini spacecraft looks toward the night side of Saturns moon Titan and sees sunlight scattering its atmosphere, forming a colorful ring. The images were acquired on June 6, 2012, when Cassini was about 134,000 miles from Titan.

NASA’s Cassini spacecraft looks toward the night side of Saturn’s moon Titan and sees sunlight scattering its atmosphere, forming a colorful ring. The images were acquired on June 6, 2012, when Cassini was about 134,000 miles from Titan.

(Credit:
NASA/JPL-Caltech/Space Science Institute)

One of the photos showcases Saturn, its rings and Titan, which at 3,200 miles (5,150 kilometers) wide is larger than the planet Mercury. The edge-on ring system forms a thin line directly behind the huge moon while its shadow projects a series of dark bands onto the planet’s southern half.

Another photo shows Titan’s south polar vortex — an odd mass of swirling gas that Cassini noticed earlier this year — in clear and dramatic detail. The formation of the vortex is likely related to the seasonal changes occurring on Saturn, Titan and its other moons, scientists have said.

The south polar vortex of Saturn's moon Titan stands out in this natural-color view from NASA's Cassini spacecraft, snapped on July 25, 2012.

The south polar vortex of Saturn’s moon Titan stands out in this natural-color view from NASA’s Cassini spacecraft, snapped on July 25, 2012.

(Credit:
NASA/JPL-Caltech/Space Science Institute)

The last photo shows a circle of light around Titan, making the haze-shrouded moon look like a dazzling ring floating in the blackness of space. The effect is created by sunlight scattering through the periphery of Titan’s thick, nitrogen-dominated atmosphere, researchers said.

Cassini launched in 1997 and has been studying Saturn and its rings and moons since it arrived in orbit around the planet in 2004. Cassini’s primary mission ended in 2008, but the probe’s activities have been extended twice, most recently through 2017. 

NASA, the European Space Agency and the Italian Space Agency have worked together on the mission over the years.

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

Copyright 2012 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Article source: http://www.cbsnews.com/8301-205_162-57503300/nasa-snaps-stunning-shots-of-saturn-and-titan/

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NASA has solved the mystery of Saturn’s jet streams


Robert T. Gonzalez

NASA has solved the mystery of Saturn's jet streamsSaturn’s atmosphere is constantly swimming with turbulent jet streams — but where do they get their energy to form in the first place? This has been one of the biggest mysteries about Saturn for decades.

Now, using data acquired from the Agency’s Cassini spacecraft, NASA scientists think they have the answer: the energy for the jet streams comes from within the planet itself.

“We know the atmospheres of planets such as Saturn and Jupiter can get their energy from only two places: the sun or the internal heating,” explains NASA Goddard’s Tony Del Genio, lead author on the paper describing the team’s findings, published in the latest issue of the journal Icarus. “The challenge has been coming up with ways to use the data, so that we can tell the difference.”

Del Genio’s team met this challenge, by analyzing seven years’ worth of photos of the ringed planet with automated cloud tracking software. This allowed the researchers to determine close to 120,000 wind vectors from 560 images, giving them the biggest, most detailed picture yet of the planet’s atmospheric dynamics. By capturing these photos with filters that allowed Cassini to see near-infrared light, the researchers were able to get their first detailed look at atmospheric disturbances — called eddies — that give rise to jet streams, accelerating them “like rotating gears driving a conveyor belt.” According to NASA:

By seeing for the first time how these eddies accelerate the jet streams at two different altitudes, scientists found the eddies were weak at the higher altitudes where previous researchers had found that most of the sun’s heating occurs. The eddies were stronger deeper in the atmosphere. Thus, the authors could discount heating from the sun and infer instead that the internal heat of the planet is ultimately driving the acceleration of the jet streams, not the sun.

The mechanism that best matched the observations would involve internal heat from the planet stirring up water vapor from Saturn’s interior. That water vapor condenses in some places as air rises and releases heat as it makes clouds and rain. This heat provides the energy to create the eddies that drive the jet streams.

“Understanding what drives the meteorology on Saturn, and in general on gaseous planets, has been one of our cardinal goals since the inception of the Cassini mission,” said Carolyn Porco,head of Cassini’s imaging team, in a statement. “It is very gratifying to see that we’re finally coming to understand those atmospheric processes that make Earth similar to, and also different from, other planets.” [NASA]

Top image NASA/JPL-Caltech/SSI

Article source: http://io9.com/5921792/nasa-has-solved-the-mystery-of-saturns-jet-streams

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Haunting photos of Saturn’s moons snapped

This raw image from NASA's Cassini spacecraft was taken on Wednesday. The camera was pointing toward Saturn's moon Dione at about 49,087 miles (78,998 kilometers) away.NASA’s workhorse Saturn orbiter Cassini has just beamed back stunning new views of the ringed planet’s dazzling moons, including the probe’s closest-ever pass over the ice geysers of Enceladus.

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