Universe Today » Saturn

Fabulous! Enceladus Raw Flyby Images

Nancy Atkinson — Tue, 03 Nov 2009 02:37:39 +0000

Carolyn Porco, the lead for Cassini's imaging team, warned on Twitter that the flyby of Saturn's moon Enceladus performed by the spacecraft on Nov. 2 wasn't really an "imaging" flyby, and that we might have to wait until the Nov. 21 flyby for really good images. But just take a look the images returned so far, with stunning looks at the jets shooting from the moon! Another image takes a close look at the surface. These are raw, unprocessed images, but what images they are! This is the second image from today's flyby returned by the spacecraft. See below for more.
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Happy Halloween From Saturn

Nancy Atkinson — Fri, 30 Oct 2009 21:20:18 +0000

Happy Halloween from the Cassini team

The Cassini team posted this image today, sending "bats wishes" for a happy, healthy and fun Halloween. And this give all of us here at Universe Today a chance to wish everyone a fun, safe, almost-full-Moon-lit, eat-your-favorite-treats, happy Hallow's Eve. Click the image for a larger version.

Also, as a heads up, Cassini will be flying by the moon Enceladus next week, on Nov. 2, approaching within about 100 kilometers (62 miles) of the surface. The spacecraft has gone closer during a previous flyby (25 kilometers or 15 miles), but this time it will be going deep into the heart of the plume from the geysers on the tiger-striped moon. The objective is to analyze the particles in the plume with instruments that can detect the size, mass, charge, speed and composition. This will happen at about 7:40 a.m. UTC and the spacecraft will spend only about a minute in the plume.

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Now Watch This: Saturn Aurora Movie

Nancy Atkinson — Tue, 13 Oct 2009 16:00:02 +0000

Wow! This is really neat! We've long known that Saturn has aurorae, and the Cassini team recently took a series of images to see if they could catch an aurora in action near Saturn's north pole. As always, the folks at UnmannedSpaceflight.com are always on the lookout for the latest images being beamed back to Earth, and one of the UMSFer's, Astro0, saw this image series, realized what the Cassini team was trying to do, and used the images to put together this movie. You'll see Saturn's limb, moving stars, streaks that are likely cosmic ray hits, and flaring aurorae, or "curtains of light" that can sometimes rise 1,200 miles (2,000 km) above the cloud tops near Saturn's poles. Astronomers say that while aurorae on Earth shine for a few hours at most, on Saturn they can last for days. Additionally, if you were on Saturn, the aurora would look like a faint red glow. Most of the energy in Saturn's aurora is not in the form of visible light, though and instead they mostly glow in ultraviolet (UV) or infrared wavelengths. Read our previous article about the infrared aurorae at Saturn.

Thanks Astro0, (with H/T to Emily Lakdawalla)!

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Spitzer Sees Giant Ring Around Saturn

Nancy Atkinson — Wed, 07 Oct 2009 14:18:07 +0000

Artist concept of the new Saturnian Ring. Image courtesy Anne Verbiscer

The Spitzer Space Telescope has spied an enormous ring around Saturn, the largest and farthest distant band around this ringed world. Just how big is this ring? "If you had infrared eyes like Spitzer," said Anne Verbiscer, research astronomer at the University of Virginia, Charlottesville, "from Earth, it would look like one full moon on either side of Saturn." That's incredibly huge! The bulk of its material starts about six million kilometers (3.7 million miles) away from the planet and extends outward roughly another 12 million kilometers (7.4 million miles). A billion Earths could fit in the volume of space this ring occupies.

So, why hasn't this gigantic structure been detected previously?
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Amazing Ring Ripples

Nancy Atkinson — Mon, 05 Oct 2009 18:50:55 +0000

Two shepherding moons continue to affect Saturn's F ring in this amazing image captured by Cassini. Pandora on the outside of the ring and Prometheus on the inside, periodically create what are called "streamer-channels," seen here in the F ring. The potato-shaped Prometheus pulls a streamer of material from the ring and leaves behind a dark channel. During its 14.7-hour orbit of Saturn, Prometheus (102 kilometers, or 63 miles across) reaches the point in its elliptical path, called apoapse, where it is farthest away from Saturn and closest to the F ring, and the moon's gravity is just strong enough to draw a "streamer" of material out of the core region of the F ring.
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The Saturn System: A Feast for the Eyes

Nancy Atkinson — Thu, 24 Sep 2009 16:11:12 +0000

The Cassini team released some incredible images earlier this week of the Saturn system during equinox, and followed up with this beauty of a crescent moon Rhea beneath the rings of Saturn. NASA has also put together a multimedia presentation of recent pictures of Saturn, set to music, and it is stunning. Run, don't walk and click here to watch. (Flash required)

With these great images, it is no wonder that the leader of the Cassini imaging team, Carolyn Porco has been presented with an award for her work, the Lennart Nilsson Award for photography for capturing "worlds that are otherwise hidden from human sight." The award committee's citation reads:
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New Equinox Stunners From Cassini

Nancy Atkinson — Tue, 22 Sep 2009 03:48:28 +0000

Every 14.8 Earth years, equinox occurs at Saturn. But this is the first time there has been a spacecraft in situ to watch what happens when the sun is directly overhead at the equator, illuminating the rings directly edge-on. New images compiled from the Cassini spacecraft show a rare and breathtaking display of nature: the setting of the sun on Saturn's rings. The image above — a mosaic of 75 different images — shows the beauty of this ringed world, but the most surprising revelation from these new images are that newly discovered lumps and bumps in the rings are as high as the Rocky Mountains.
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New Wallpaper for Star Trek, Cassini Fans

Nancy Atkinson — Wed, 16 Sep 2009 01:20:39 +0000

Star Trek fan? Like Cassini and Saturn? The very busy planetary scientist Carolyn Porco also has a visual graphics company, Diamond Sky Productions and they have created some new wallpapers featuring scenes from the latest Star Trek motion picture. The images are copyrighted, so we can't post them here, but no doubt you'll want to take a look at these spectacular images over at Diamond Sky's website. Enjoy!

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Super Cell Lightning Storm Raging on Saturn Since January

Nancy Atkinson — Tue, 15 Sep 2009 00:05:26 +0000

The Cassini spacecraft has been in orbit around Saturn since 2004 and during its mission, has watched nine different lightning storms rage on the planet. But this latest one is the longest lasting and most powerful storm yet: it has been going on since mid-January 2009 with no end in sight. It broke the storm duration record of 7.5 months set by another thunderstorm observed by Cassin between November 2007 and July 2008. Lightning discharges in Saturn's atmosphere emit very powerful radio waves which are about 10,000 times stronger than their terrestrial counterparts and the huge thunderstorms in Saturn's atmosphere have diameters of about 3,000 km.
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Temporary Radiation Belt Discovered at Saturn

Nancy Atkinson — Mon, 14 Sep 2009 00:08:12 +0000

A new, temporary radiation belt has been detected at Saturn, located about 377,000 km from the center of the planet, near the orbit of the moon Dione. The temporary radiation belt was short-lived and formed three times in 2005. It was observed as sudden increases in the intensity of high energy charged particles in the inner part of Saturn's magnetosphere, in the vicinity of the moons Dione and Tethys, and likely was caused by a change in the intensities of cosmic rays at Saturn.
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Naked Saturn

Nancy Atkinson — Thu, 13 Aug 2009 16:32:58 +0000

Here's one of the first raw images of Saturn taken by the Cassini spacecraft just after equinox, on August 12, 2009. The planet sure looks naked without its rings! But not to fear, the rings are still there; we just can't see them very well — only a thin line. That's because the sun was shining directly straight-on at the rings at Saturn's equinox, and the spacecraft was in the right place, too. Equinox occurs every half-Saturn-year which is equivalent to about 15 Earth years. The illumination geometry that accompanies equinox lowers the sun's angle to the ringplane and causes out-of-plane structures and some moons to cast long shadows across the rings. The ring shadows themselves have become a rapidly narrowing band cast onto the planet. Below, see another image with the rings visible as the spacecraft changed its angle.
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More Equinox Oddities in Saturn's Rings

Nancy Atkinson — Tue, 11 Aug 2009 22:37:03 +0000

Today, August 11, 2009, is Saturn's equinox. As we've been saying for a few months, the rings are going to disappear — at least from our vantage point on Earth. "Whenever equinox occurs on Saturn, sunlight will hit Saturn's thin rings, the ring plane, edge-on," said Linda Spilker, deputy project scientist for the Cassini spacecraft at Saturn. "The light reflecting off this extremely narrow band is so small that for all intents and purposes the rings simply vanish." But even from the view at Saturn, weird things are happening in the rings, and the Cassini spacecraft has a front row seat watching it all take place. Above is one of the latest raw images sent back from Cassini, taken on August 7, 2009 showing how the sunlight is hitting the edge of the rings. It is a gorgeous shot. Below, see some of the strange sights Cassini has been seeing, including a buzzsaw, a blasted ring, and tell-tale moon shadows. For more about Saturn's equinox, check out today's 365 Days of Astronomy podcast with Emily Lakdawalla of the Planetary Society and she'll tell you all about the weird and beautiful play of light and shadow going on at Saturn.
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Titan Shaping Up to Look a Lot Like Pre-Life Earth

Anne Minard — Thu, 06 Aug 2009 17:54:47 +0000

It's more than a billion kilometers (759 million miles) away, but the more astronomers learn about Titan, the more it looks like Earth.

That's the theme of two talks happening this week at the International Astronomical Union meeting in Rio de Janeiro, Brazil. Two NASA researchers, Rosaly Lopes and Robert M. Nelson of the Jet Propulsion Laboratory in Pasadena, California, are reporting that weather and geology have very similar actions on Earth and Titan — even though Saturn's moon is, on average, 100 degrees C (212 degrees F) colder than Antarctica (and certainly much more frigid than either California or Brazil; lucky astronomers).

The researchers are also reporting a tantalizing clue in the search for life: Titan hosts chemistry much like pre-biotic conditions on Earth.

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Saturn Sees Days Shorter Than Thought, Winds Like Jupiter — Sort of

Anne Minard — Thu, 30 Jul 2009 15:49:15 +0000

A new estimate of Saturn's rotation rate reveals days on the gas giant are five minutes shorter than previously believed — and that Saturn's atmosphere has much in common with that of its planetary neighbor, Jupiter.

The new results appear today in the journal Nature.

(Image caption: Saturn as photographed by Cassini-Huygens. Credit: NASA)

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Vertical Structures Tower Above Saturn's Rings

Nancy Atkinson — Tue, 16 Jun 2009 15:39:57 +0000

Cassini has imaged towering vertical structures in the planet’s otherwise flat rings that come from the gravitational effects of a small nearby moon. This is the first time these structures have been seen. They reach up over one kilometer high, and are visible now as the sun nears "high noon" directly overhead at the planet's equator, as Saturn approaches its equinox.
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Book Your Tours of Titan and Enceladus Today!

Nancy Atkinson — Tue, 02 Jun 2009 15:04:42 +0000

Now's the time to book your Cassini tour!

Looking to go somewhere far-flung and exotic? Now is the time to book your excursion, and the Cassini spacecraft has several flyby tours of the moons Titan and Enceladus scheduled for the next few months. Major tour operators say the cost of long-haul flights and summer holidays prices are at an all time low. But with Cassini, you can travel for FREE! just by following the along with Universe Today and the Cassini website. Thrill with some of the closest flybys ever of the mystery moon Titan, and delight in explorations of the geyser plumes of Enceladus. As a special bonus, if you book today, you can experience Saturn's solar equinox, as in August the sun crosses from the southern hemisphere to the north. Wonderful worlds are beckoning – come away starting June 6 with Cassini! It's a worry free vacation. See below for available tour dates! Destination fees do not apply.
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Latest from Saturn: Pastel Rings and Moons by the Bunch

Nancy Atkinson — Tue, 28 Apr 2009 22:16:59 +0000

The latest images from the Cassini spacecraft include this gorgeous natural color view of Saturn's inner rings. Visible are the different degrees of transparency of the rings, which appear almost pastel in color. The dark shadows of the rings separate Saturn's southern hemisphere in the bottom of the image from the north. The innermost D ring is invisible, laid over the planet's northern hemisphere. The translucent C ring runs through the middle of the image. The denser B ring stretches across the top of the image. See below for more info on this image, as well as a challenge to "find the moons" on another Cassini image.
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Electrically Charged Particles Found in Enceladus' Plumes

Nancy Atkinson — Wed, 22 Apr 2009 01:24:29 +0000

Plumes of Enceladus. Credi: NASA/JPL

A team of planetary scientists working on the Cassini-Huygens mission has discovered tiny, icy particles in the plume from Saturn’s moon Enceladus that offer a tantalizing glimpse of the interior of this enigmatic world. The spectrometer on Cassini, the Cassini Plasma Spectrometer (CAPS) discovered a surprise: the ice particles are electrically charged.

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Cassini's Indirect Image of Boulders and Moonlets in Saturn's Rings

Nancy Atkinson — Mon, 13 Apr 2009 02:51:13 +0000

Take a look at this — it is absolutely stunning. A couple of weeks ago, Anne wrote an article about moon shadows on Saturns rings. Because Saturn is approaching its equinox, in August the rings will "disappear" from our view from Earth, as the rings will be exactly edge-on. But as the rings ease into alignment with the sun, Saturn's moons cast their shadows across the rings, growing longer as equinox approaches. See in the image above, a shadow is cast on the rings, likely by either the moon Mimas or Tethys. But the eagle-eyed folks over at UnmannedSpaceflight.com also noticed something else in this raw image from the Cassini spacecraft. Notice the area right near the middle of the image where the rings look kind of fuzzy? That's not just camera blur; those are more shadows, created by thousands of boulders or moonlets in the ring! Amazing! We've never actually seen the small objects that make up the rings — and we still haven't — but we're seeing the shadows they are creating! Let's zoom in for a closer look:
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Moonshadows on Saturn's Rings Are Harbingers of Spring

Anne Minard — Mon, 23 Mar 2009 17:31:58 +0000

Moonshadows on Saturn's rings are foretelling the planet's equinox, when the sun will be exactly aligned with the planet's equator and rings — and then will shift north from the southern hemisphere, kickstarting northern spring.

NASA's Cassini spacecraft has captured, for the first time, the tell-tale moonshadows - sort of like groundhogs on Earth.

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Hubble Snaps Rare Moon Parade Across Saturn

Anne Minard — Tue, 17 Mar 2009 14:09:20 +0000

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Once every 15 years, Saturn flashes its paper-thin rings in edge-on formation relative to Earth.

Because the orbits of Saturn's major satellites are in the ring plane, too, this alignment gives astronomers a rare opportunity to capture a spectacular parade of celestial bodies crossing Saturn's surface.

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Cassini Switches to Backup Thrusters

Anne Minard — Thu, 12 Mar 2009 17:52:41 +0000

Artist's rendering of the Cassini spacecraft. Credit: NASA

NASA's Cassini spacecraft successfully switched to a backup set of propulsion thrusters late Wednesday, which will allow the long-lived machine to continue scoping out Saturn and its moons.

The swap was performed because of degradation in the performance of the primary thrusters, which had been in use since Cassini’s launch in 1997. This is only the second time in Cassini’s 11 years of flight that the engineering teams have gone to a backup system.

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Moonlet Could Be Source of Saturn's G Ring

Nancy Atkinson — Tue, 03 Mar 2009 18:32:48 +0000

Saturn's G ring has been the ring without a moon, until now. In trying to understand the mysterious G ring, Cassini scientists have taken every opportunity they can to take a closer look at what could be creating the ring. In 2007, scientists identified a possible source of the G ring as relatively large, icy particles that resided within a bright arc on the ring's inner edge. But the researchers thought there had to be more than just these particles "shepherding" the ring, and concluded that there had to be larger, yet-unseen bodies hiding in the arc. Their persistence has now paid off, as a small moonlet has been found within the ring. "Before Cassini, the G ring was the only dusty ring that was not clearly associated with a known moon, which made it odd," said Matthew Hedman, a Cassini imaging team associate at Cornell University in Ithaca, N.Y. "The discovery of this moonlet, together with other Cassini data, should help us make sense of this previously mysterious ring." The sequence of three images above, obtained by NASA’s Cassini spacecraft over the course of about 10 minutes, shows the path of the moonlet in a bright arc of Saturn's faint G ring.
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Titan Dunes Turn Climate Models Upside Down

Anne Minard — Fri, 27 Feb 2009 14:55:48 +0000

Scientists have mapped vast dune fields on Titan that may align with the wind on Saturn’s biggest moon — flowing opposite the way climate models had predicted.

The maps, as above, represent four years of radar data collected by the Cassini spacecraft. They reveal rippled dunes that are generally oriented east-west, which means Titan’s winds probably blow toward the east instead of the west. If so, Titan’s surface winds blow opposite the direction suggested by previous global circulation models. On the example above, the arrows indicate the general wind direction. The dark areas without arrows might have dunes but have not yet been imaged.

“At Titan there are very few clouds, so determining which way the wind blows is not an easy thing, but by tracking the direction in which Titan’s sand dunes form, we get some insight into the global wind pattern,” says Ralph Lorenz, Cassini radar scientist at Johns Hopkins University in Maryland. “Think of the dunes sort of like a weather vane, pointing us to the direction the winds are blowing.”

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Jupiter, Saturn Plowed Through Asteroids, Study Says

Anne Minard — Wed, 25 Feb 2009 18:01:16 +0000

When Mars and Jupiter migrated to their present orbits around 4 billion years ago, they left scars in the asteroid belt that are still visible today.

The evidence is unveiled in a new paper in this week's issue of the journal Nature, by planetary scientists David Minton and Renu Malhotra from the University of Arizona in Tucson.

The asteroid belt has long been known to harbor gaps, called Kirkwood gaps, in distinct locations. Some of these gaps correspond to unstable zones, where the modern-day gravitational influence of Jupiter and Saturn eject asteroids. But for the first time, Minton and Malhotra have noticed that some clearings don't fit the bill.

"What we found was that many regions are depleted in asteroids relative to other regions, not just in the previously known Kirkwood gaps that are explained by the current planetary orbits," Minton wrote in an email. In an editorial accompanying the paper, author Kevin Walsh added, "Qualitatively, it looks as if a snow plough were driven through the main asteroid belt, kicking out asteroids along the way and slowing to a stop at the inner edge of the belt."

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