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  Cassini-Huygens at Saturn: Questions, comments (Page 7)

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Author Topic:   Cassini-Huygens at Saturn: Questions, comments
dss65
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posted 03-14-2011 09:15 PM     Click Here to See the Profile for dss65   Click Here to Email dss65     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by DChudwin:
An incredible animation of Cassini flying around Saturn and through its rings can be found here.
Magnificent!

alcyone
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posted 03-15-2011 02:49 PM     Click Here to See the Profile for alcyone     Edit/Delete Message   Reply w/Quote
Thank you for posting this wonderful view of the Saturnian system.

DChudwin
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posted 03-17-2011 10:07 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
NASA has issued a press release confirming that methane rain on Titan has pooled on its surface. New photos show the seasonal change in the clouds above Titan and surfaces differences likely due to liquid methane. The photos can be found here on the CICLOPS site.
As spring continues to unfold at Saturn, April showers on the planet's largest moon, Titan, have brought methane rain to its equatorial deserts, as revealed in images captured by NASA's Cassini spacecraft. This is the first time scientists have obtained current evidence of rain soaking Titan's surface at low latitudes.

Extensive rain from large cloud systems, spotted by Cassini's cameras in late 2010, has apparently darkened the surface of the moon. The best explanation is these areas remained wet after methane rainstorms. The observations released today in the journal Science, combined with earlier results in Geophysical Research Letters last month, show the weather systems of Titan's thick atmosphere and the changes wrought on its surface are affected by the changing seasons.

"It's amazing to be watching such familiar activity as rainstorms and seasonal changes in weather patterns on a distant, icy satellite," said Elizabeth Turtle, a Cassini imaging team associate at the Johns Hopkins University Applied Physics Lab in Laurel, Md., and lead author of today's publication. "These observations are helping us to understand how Titan works as a system, as well as similar processes on our own planet."

DChudwin
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posted 03-22-2011 08:03 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
Besides imaging Titan and Saturn's icy moons and moonlets, Cassini also has been keeping an eye on Saturn itself. The spacecraft sent back today beautiful raw images of a large storm which has been raging on Saturn's surface.

DChudwin
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posted 06-11-2011 08:37 AM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
The CICLOPS website features an instructive picture showing how Saturn dwarfs its moons. This image shows Rhea and Dione, the second and third largest moons, with Saturn and its rings in the background. The huge new storm in Saturn's northern hemisphere is also visible.

DChudwin
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posted 09-03-2011 09:12 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
The Cassini spacecraft flew within 15,500 miles of Saturn's moon Hyperion on August 25. Hyperion is a bizarrely-shaped moon 168 miles in diameter which rotates chaotically. Certainly one of the strangest objects in the solar system.

Here are some of the still frames of Hyperion as shown on the CICLOPS website.

A movie has been made of the approach pictures.

DChudwin
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posted 09-18-2011 10:23 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
Cassini made another pass near Saturn's moon Enceladus on September 13 and sent back images received on September 15. This image was taken 42,000 km from Enceladus and shows the grooves and craters on its icy surface.

DChudwin
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posted 10-09-2011 10:52 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
Cassini had another close encounter October 1 with Encealdus, flying just 62 miles above the icy moon of Saturn. Back-lit images were returned of the geysers of water vapor and ice shooting from the south polar regions of Enceladus. The spacecraft flew through the plumes and also obtained better data about the surface composition of the area from which the geysers arise.

DChudwin
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posted 11-18-2011 07:21 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
NASA has released a series of remarkable images detailing the development of the major storm on Saturn since December, 2010. The series of true and false-color images were taken by the Cassini spacecraft orbiting Saturn.

DChudwin
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posted 12-22-2011 08:28 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
Cassini Delivers Holiday Treats From Across The Solar System

No team of reindeer was necessary for these holiday treats from NASA's Cassini spacecraft. A beam of radio signals, from clear across the solar system, has delivered a Christmas package of glorious images of Saturn's largest, most colorful ornament, Titan, and other icy baubles in orbit around this splendid planet. These treats are being featured today in a public release from the mission's imaging team.

The release includes images of satellite conjunctions in which one moon passes in front of or behind another. Cassini scientists regularly make these observations to study the ever-changing orbits of the planet's moons. But even in these routine images, the Saturnian system shines. A few of Saturn's stark, airless, icy moons appear to dangle next to the orange orb of Titan, the only moon in the solar system with a substantial atmosphere. Titan's atmosphere is of great interest because of its great similarities to the atmosphere believed to exist long ago on the early Earth.

While it may be Christmastime and wintry in Earth's northern hemisphere, it is currently northern spring in the Saturnian system and will remain so for several Earth years. Current plans to extend the Cassini mission through 2017 will surely beget a continued bounty of scientifically rewarding and majestic views of Saturn and its moons and rings, as we spectators are treated to the passage of northern spring and the final arrival of summer in May 2017.

"As another year traveling this magnificent sector of our solar system draws to a close, all of us on Cassini wish all of you a very happy and peaceful holiday season," said Carolyn Porco, Cassini imaging team lead at the Space Science Institute, Boulder, Colo.

gliderpilotuk
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posted 12-23-2011 06:40 AM     Click Here to See the Profile for gliderpilotuk   Click Here to Email gliderpilotuk     Edit/Delete Message   Reply w/Quote
Oh W-O-W! Photography as art, for sure.

DChudwin
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posted 01-13-2012 07:10 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
Cassini continues to send back spectacular pictures from its orbit around Saturn. This stunning image shows Titan (on the left) and Tethys (on the right) with Saturn's rings transversing Cassini's view of the moons.

The CICLOPS website features an imaging diary and new pictures are put up each week. Dr. Carolyn Porco and her imaging team have done a great job, both scientifically and artistically.

DChudwin
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posted 03-10-2012 06:07 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
Saturn's moon Enceladus is one of the most fascinating objects in the solar system. Observations by the Cassini spacecraft have shown features such as geysers of liquid water shooting out of cracks in Enceladus' surface.

Proposed budget cuts in NASA's planetary program will reduce funds available to study the next outer planet mission. The three leading contenders are missions to Europa, Uranus or Enceladus. While all would be worthwhile, an Enceladus orbiter and lander/probe would be my first choice.

Bjorn Jonsson has posted this stunning animation "Flight Over Enceladus." Based on Cassini images, this nearly 7 minute animation shows what a flyby around Enceladus would look like. Great job, Bjorn!

DChudwin
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posted 03-30-2012 11:53 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
New images of Saturn's moons Enceladus, Janus and Dione were taken on March 27 and 28, 2012, by NASA's Cassini spacecraft.

Cassini passed Enceladus first on March 27, coming within about 46 miles (74 kilometers) of the moon's surface. The encounter was primarily designed for Cassini's ion and neutral mass spectrometer, which "tasted" the composition of Enceladus' south polar plume. Other instruments, including the Cassini plasma spectrometer and composite infrared spectrometer, also took measurements.

Before the closest approach of this encounter, Cassini's cameras imaged the plume, which is comprised of jets of water ice and vapor, and organic compounds emanating from the south polar region. Later, the cameras captured a nine-frame mosaic of the surface of the moon's leading hemisphere as the spacecraft left the moon.

After the Enceladus encounter, Cassini passed the small moon Janus with a closest approach distance of 27,000 miles (44,000 kilometers). The planet was in the background in some of these views.

Early on March 28, the spacecraft flew by Dione at a distance of 27,000 miles (44,000 kilometers) and collected, among other observations, a nine-frame mosaic depicting the side of the moon that faces away from Saturn in its orbit.

All of Cassini's raw images can be seen here.

DChudwin
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posted 04-30-2012 09:07 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
From a new NASA release about Saturn's moon Phoebe:
Cassini images suggest Phoebe originated in the far-off Kuiper Belt, the region of ancient, icy, rocky bodies beyond Neptune's orbit. Data show Phoebe was spherical and hot early in its history, and has denser rock-rich material concentrated near its center. Its average density is about the same as Pluto, another object in the Kuiper Belt. Phoebe likely was captured by Saturn's gravity when it somehow got close to the giant planet.

Saturn is surrounded by a cloud of irregular moons that circle the planet in orbits tilted from Saturn's orbit around the sun, the so-called equatorial plane. Phoebe is the largest of these irregular moons and also has the distinction of orbiting backward in relation to the other moons. Saturn's large moons appear to have formed from gas and dust orbiting in the planet's equatorial plane. These moons currently orbit Saturn in that same plane.

"By combining Cassini data with modeling techniques previously applied to other solar system bodies, we've been able to go back in time and clarify why it is so different from the rest of the Saturn system," said Jonathan Lunine, a co-author on the study and a Cassini team member at Cornell University, Ithaca, N.Y.

Analyses suggest that Phoebe was born within the first 3 million years of the birth of the solar system, which occurred 4.5 billion years ago. The moon may originally have been porous but appears to have collapsed in on itself as it warmed up. Phoebe developed a density 40 percent higher than the average inner Saturnian moon.

Objects of Phoebe's size have long been thought to form as "potato-shaped" bodies and remained that way over their lifetimes. If such an object formed early enough in the solar system's history, it could have harbored the kinds of radioactive material that would produce substantial heat over a short timescale. This would warm the interior and reshape the moon.

"From the shape seen in Cassini images and modeling the likely cratering history, we were able to see that Phoebe started with a nearly spherical shape, rather than being an irregular shape later smoothed into a sphere by impacts," said co-author Peter Thomas, a Cassini team member at Cornell.

Phoebe likely stayed warm for tens of millions of years before freezing up. The study suggests the heat also would have enabled the moon to host liquid water at one time. This could explain the signature of water-rich material on Phoebe's surface previously detected by Cassini.

The new study also is consistent with the idea that several hundred million years after Phoebe cooled, the moon drifted toward the inner solar system in a solar-system-wide rearrangement. Phoebe was large enough to survive this turbulence.

More than 60 moons are known to orbit Saturn, varying drastically in shape, size, surface age and origin. Scientists using both ground-based observatories and Cassini's cameras continue to search for others.

A beautiful 2004 picture of Phoebe can be found here.

gliderpilotuk
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posted 05-01-2012 11:41 AM     Click Here to See the Profile for gliderpilotuk   Click Here to Email gliderpilotuk     Edit/Delete Message   Reply w/Quote
Someone's going to have to put together a coffee table book like Full Moon with all these stunning images. Trouble is: the images just keep coming!

DChudwin
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posted 05-21-2012 09:49 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
An egg in orbit around Saturn? Cassini has just sent back its first close-up images of Saturn's small moon Methone. It appears to be egg-shaped and remarkably smooth. Cassini also imaged Tethys on this pass.

According to CICLOPS (Cassini Imaging Central Laboratory for Operations):

With a close-approach distance of about 1,200 miles (1,900 kilometers), this was Cassini's closest flyby of the 2-mile-wide (3-kilometer-wide) Methone.

Earlier on May 20, Cassini flew by the larger moon Tethys at a distance of about 34,000 miles (54,000 kilometers), and several images from that encounter are included here. Tethys is 660 miles, or 1,062 kilometers, across.

Between 2004 and 2007, Cassini discovered Methone and two other small moons, Pallene and Anthe, between the orbits of Mimas and Enceladus. The three tiny moons, called the Alkyonides group, are embedded in Saturn's E ring and their surfaces are sprayed by ice particles originating from the jets of water ice, water vapor and organic compounds emanating from the south polar area of the moon Enceladus. The best previous Cassini images of Methone were taken on June 8, 2005, at a distance of about 140,000 miles (225,000 kilometers) and barely resolved this object.

Cassini went into orbit around Saturn on July 1, 2004. Now, almost 8 years later, Cassini continues to provide us with new information about the Saturn system and spectacular images through CICLOPS headed by Dr. Carolyn Porco.

DChudwin
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posted 07-10-2012 08:33 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
I'm running out of superlatives for the images sent back by Cassini. The latest wonder is this true-color image of a vortex over the south pole of Titan. Cassini flew past Titan again on June 27.

DChudwin
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posted 09-07-2012 07:35 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
While the public is rightfully focused on the exploits of Curiosity on Mars for the last month, the Cassini spacecraft continues in orbit around Saturn, sending back new images and scientific information. Cassini's mission has been extended to 2017, allowing it to view Saturn, its rings and moons over many years to understand changes with time.

Here is a recent beautiful picture in true color of Saturn and Titan.

gliderpilotuk
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posted 09-08-2012 02:09 PM     Click Here to See the Profile for gliderpilotuk   Click Here to Email gliderpilotuk     Edit/Delete Message   Reply w/Quote
David, thanks for keeping us aware. I wouldn't ordinarily search for Cassini-Huygens updates, but this is just gorgeous and need not be overshadowed by Curiosity.

ilbasso
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posted 09-08-2012 02:47 PM     Click Here to See the Profile for ilbasso   Click Here to Email ilbasso     Edit/Delete Message   Reply w/Quote
I'm a JPL Solar System Ambassador, and I just did a presentation on Cassini/Huygens to a local astronomy club last week. It was great fun to go through all of the recent findings and photos from this spectacular mission to put together the presentation.

Cassini continues to rack up big discoveries. In the past year alone, these have included such things as:

  • Evidence of possible cryo-volcanic activity on Dione
  • Determination of the fine structure of Enceladus' plumes by watching them occult two stars in Orion's Belt
  • Using RADAR to image Enceladus and compare the results to Titan (using a radar signature of an object with a known composition to compare with Titan to try to understand what's going on there)
  • "Hot spot" detected on Enceladus
  • Determination that the leading hemispheres of Mimas and Tethys are colder than expected, possibly due to alteration of the surface composition from protons liberated from Saturn's cloudtops
  • Determination that the icy satellites do not share the same chemical signatures as the rings (possible nano-iron or PAHs causing the rings to be redder than pure ice)
  • Auroral hiss and electron beams around Enceladus; "van Allen"-like belts around Saturn with cavities in the field caused by the inner icy moons
  • Observations of the "propeller" features in the outer A ring (clumps of ring material squeezed or stretched by unseen objects embedded in the rings). Observation that some propellers were not where they were expected to be after 2 years
  • Material clumping in the F ring into strands and moonlets, which subsequently were pulled apart
  • Determination of particle size distribution in the rings based on occultations of stars
  • Seasonal variation in the bowl-shaped E ring
And that's just the non-Titan findings so far this year! The Titan findings will be summarized at another review later this month.

So Cassini is still doing a LOT of science. And it continues to send back beautiful images. In the latest extension of the mission, the orbit has once again been pushed up at an angle to the ring plane, so Cassini can observe the rings again, after two years in the ring plane.

DChudwin
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posted 12-18-2012 08:18 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
For the holidays, Carolyn Porco and her Cassini imaging team have released a new mosaic image of a backlit Saturn. I am at loss for superlatives to describe the beauty of the ringed planet as shown from this vantage point.

carl walker
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posted 01-14-2013 04:25 PM     Click Here to See the Profile for carl walker     Edit/Delete Message   Reply w/Quote
Posted on the eighth anniversary of Europe's Huygens probe making the most distant landing in our Solar System...
Eight years ago today, ESA's Huygens bounced, slid and wobbled its way to rest on the surface of Saturn's moon Titan, the first time a probe had touched down on an alien world in the outer Solar System.

The animation was created using real data recorded by Huygen's instruments, allowing us to witness this historical moment as if we had been there.

Blackarrow
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posted 01-28-2013 05:11 PM     Click Here to See the Profile for Blackarrow     Edit/Delete Message   Reply w/Quote
The magnificent Cassini images of the Enceladus geysers makes me wonder whether the tiny thrust from these geysers over millions of years will change the orbit of Enceladus. Bear in mind that miniscule Phobos raises enough of a tidal bulge in the rocky crust of Mars to create sufficient tidal drag to place it on a spiral path to impact (or break-up) in ten million years or so.

DChudwin
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posted 02-10-2013 09:58 AM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
One of the most mysterious structures on Saturn is a massive hexagonal pattern on the North Pole of the planet. The hexagon is 8,600 miles on each side, stable (it was first seen by Voyager in 1980-82), and maintains its shape despite (or perhaps because of) cyclonic winds at the North Pole.

This recently released Cassini image is one of the best yet of the pattern. Saturn's rings are also visible in the upper right.

The origin of the hexagon is unknown, although the theory that it is a standing wave pattern is the most credible. Some conspiracy theorists have suggested that the hexagon is a message to us, but from whom or what I am not certain.

Lou Chinal
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posted 02-10-2013 12:36 PM     Click Here to See the Profile for Lou Chinal   Click Here to Email Lou Chinal     Edit/Delete Message   Reply w/Quote
Okay, you got me hooked!

DChudwin
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posted 03-11-2013 09:22 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
The Cassini spacecraft made its final close encounter with Saturn's icy moon Rhea yesterday and sent back some more magnificent images. While the mission will continue until 2017, the spacecraft will not make any further Rhea flybys.

DChudwin
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posted 10-20-2013 04:43 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
NASA has released a new image of Saturn as seen from above by the Cassini spacecraft. The color picture is a mosaic of 12 images, each taken this month with red, green and blue filters.

Interestingly, it was produced by an amateur.

DChudwin
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posted 10-25-2013 02:15 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
Better views of the hydrocarbon lakes on Titan can be seen here.

DChudwin
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posted 12-23-2013 09:56 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
Carolyn Porco and her CICLOPS imaging team have served an end-of-the year assortment of some of the best recent images of Saturn and its moons taken by the venerable Cassini spacecraft.

Ronpur
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posted 12-23-2013 10:06 PM     Click Here to See the Profile for Ronpur   Click Here to Email Ronpur     Edit/Delete Message   Reply w/Quote
Spectacular!

DChudwin
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posted 04-03-2014 10:56 PM     Click Here to See the Profile for DChudwin   Click Here to Email DChudwin     Edit/Delete Message   Reply w/Quote
Here is a Washington Post article about the exciting new findings suggesting a subsurface lake of liquid water on Enceladus.
For years, the motto among astrobiologists — people who look for life in distant worlds, and try to understand what life is, exactly — has been "follow the water." You have to start the search somewhere, and scientists have started with liquid water because it's the essential agent for all biochemistry on Earth.

Now they've followed the water to a small, icy moon orbiting Saturn. Scientists reported Thursday that Enceladus, a shiny world about 300 miles in diameter, has a subsurface "regional sea" with a rocky bottom.


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