galaxy news: Saturns

‏إظهار الرسائل ذات التسميات Saturns. إظهار كافة الرسائل

الخميس، 6 سبتمبر 2012

Image of the Day: Stunning New Views of Saturn's Titan

Image of the Day: Stunning New Views of Saturn's Titan
Image of the Day: Stunning New Views of Saturn's TitanThe Daily Galaxy --Great Discoveries Channel: Sci, Space, TechFollow the Daily Galaxy Add Daily Galaxy to igoogle page

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August 30, 2012 Image of the Day: Stunning New Views of Saturn's Titan

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A wide-angle view in today’s package captures Titan passing in front of Saturn, as well as the planet’s changing colors. Upon Cassini’s arrival at Saturn eight years ago, Saturn’s northern winter hemisphere was an azure blue. Now that winter is encroaching on the planet’s southern hemisphere and summer on the north, the color scheme is reversing: blue is tinting the southern atmosphere and is fading from the north.

The other three images depict the newly discovered south polar vortex in the atmosphere of Titan, reported recently by Cassini scientists. Cassini's visible-light cameras have seen a concentration of yellowish haze in the detached haze layer at the south pole of Titan since at least March 27. Cassini's visual and infrared mapping spectrometer spotted the massing of clouds around the south pole as early as May 22 in infrared wavelengths.

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After a June 27 flyby of the moon, Cassini released a dramatic image and movie showing the vortex rotating faster than the moon's rotation period. The four images being released today were acquired in May, June and July of 2012.

Some of these views, such as those of the polar vortex, are only possible becauseCassini's newly inclined -- or tilted -- orbits allow more direct viewing of the polar regions of Saturn and its moons.Scientists are looking forward to seeing more of the same -- new phenomena like Titan’s south polar vortex and changes wrought by the passage of time and seasons -- during the remainder of Cassini’s mission.

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“Cassini has been in orbit now for the last eight years, and despite the fact that we can’t know exactly what the next five years will show us, we can be certain that whatever it is will be wondrous," said Carolyn Porco, imaging team lead based at the Space Science Institute in Boulder, Colo.Launched in 1997, Cassini went into orbit around Saturn on July 1, 2004. It is in its second mission extension, known as the Solstice Mission, and one of its main goals is to analyze seasonal changes in the Saturn system.

The Daily Galaxy via http://saturn.jpl.nasa.gov/

Posted at 08:45 AM | Permalink

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الاثنين، 27 أغسطس 2012

"Saturn's Titan is Capable of Creating the Molecules that Make Up DNA" (Today's Most Popular)

"Saturn's Titan is Capable of Creating the Molecules that Make Up DNA" (Today's Most Popular)
"Saturn's Titan is Capable of Creating the Molecules that Make Up DNA" (Today's Most Popular)The Daily Galaxy --Great Discoveries Channel: Sci, Space, TechFollow the Daily Galaxy Add Daily Galaxy to igoogle page

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August 20, 2012 "Saturn's Titan is Capable of Creating the Molecules that Make Up DNA" (Today's Most Popular)

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Saturn's moon Titan has many of the components for life without liquid water. But the orange hydrocarbon haze that shrouds the planet's largest moon could be creating the molecules that make up DNA without the help of water – an ingredient widely thought to be necessary for the molecules formation according to a 2011 international study.

Paul Davies, a leading authority in astrobiology, director of BEYOND: Center for Fundamental Concepts in Science and co-director of the ASU Cosmology Initiative, says: "To the best of our knowledge, the original chemicals chosen by known life on Earth do not constitute a unique set; other choices could have been made, and maybe were made if life started elsewhere many times."

Researchers warn however that although Titan's atmosphere is creating these molecules, that doesn't mean that the molecules are combining to form life, But the finding could entice astrobiologists to consider a wider range of extrasolar planets as potential hosts for at least simple forms of organic life, the team of scientists from the US and France suggests.

The findings also suggest that billions of years ago Earth's upper atmosphere – not just the so-called primordial soup on the surface – may have been the sources for these "prebiotic" molecules, amino acids and the so-called nucleotide bases that make up DNA.

"We're really starting to get a sense for what kind of chemistry an atmosphere is capable of" performing, says Sarah Hörst, a graduate student in planetary science at the University of Arizona, who led the research effort.

NASA's Cassini spacecraft, which has detected large molecules at altitudes of some 600 miles above Titan's surface. But the molecules are so far unidentified because of limitations to the craft's instruments. The Cassini research team replicated Titan's atmosphere in a large chamber at the temperatures present in the moon's upper atmosphere. To play the role of the sun's ultraviolet light hitting Titan's atmosphere, they used radio energy at a power level comparable to a modestly bright light bulb. The UV light is critical because it breaks up molecules such as molecular nitrogen or carbon monoxide in Titan's atmosphere, leaving the individual atoms to choose up different partners, forming new molecules.

The experiment yielded tiny aerosol particles. The team ran the particles through a sensitive mass spectrometer, which showed the chemical formulas for the molecules that made up the aerosols.Hörst then ran the formulas past a roster of molecules biologically important for life on Earth. She got 18 hits, including the four nucleotides whose combinations form an organism's genetic information encoded in DNA. It appears to be less important that water is present to form these molecules than it is for some form of oxygen to be present in the mix of ingredients, she concluded.

On Earth, oxygen early in the planet's pre-life history would come in the form of carbon dioxide and carbon monoxide from volcanic activity, as well as from water released by volcanism and through meteor and comet impacts. On Titan, the oxygen appears to be coming from Enceladus, an ice-bound moon of Saturn in its own right because of icy geysers spewing into space from near its south pole. Some researchers think the geysers hint at a possible global subsurface sea and a potential habitat for life.

In 2011, researchers showed how water molecules ejected as part of Enceladus's geysers can be carried great distances through the Saturn system, with some oxygen-bearing molecules finding their way to Titan.

The Daily Galaxy via NASA and csmonitor.com

Posted at 11:03 AM | Permalink

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A discovery on the cards maybe ?

Posted by:Android Application Development |August 21, 2012 at 04:06 AM

It'd be silly to think that chemicals would only form on Earth for some reason and that other planets and moons don't have the exact same processes happening on them. Rather than looking for Earth-like planets, it would make more sense to exclude planets and moons that have conditions that could PREVENT these processes.

Posted by:Fedge |August 23, 2012 at 09:03 AM

الأحد، 29 يوليو 2012

The Rivers of Saturn's Titan --"A Weirdly Earth-like Place"

The Rivers of Saturn's Titan --"A Weirdly Earth-like Place"
The Rivers of Saturn's Titan --"A Weirdly Earth-like Place"The Daily Galaxy --Great Discoveries Channel: Sci, Space, TechFollow the Daily Galaxy Add Daily Galaxy to igoogle page

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July 21, 2012 The Rivers of Saturn's Titan --"A Weirdly Earth-like Place"

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In 2004, the Cassini-Huygens spacecraft — a probe that flies by Titan as it orbits Saturn — penetrated Titan’s orange haze, providing scientists with their first detailed images of the surface. Radar images revealed an icy terrain carved out over millions of years by rivers of liquid methane, similar to how rivers of water have etched into Earth’s rocky continents. The image above from the Cassini mission show river networks draining into lakes in Titan's north polar region.

While images of Titan have revealed its present landscape, very little is known about its geologic past. Now researchers at MIT and the University of Tennessee at Knoxville have analyzed images of Titan’s river networks and determined that in some regions, rivers have created surprisingly little erosion. The researchers say there are two possible explanations: either erosion on Titan is extremely slow, or some other recent phenomena may have wiped out older riverbeds and landforms.

“It’s a surface that should have eroded much more than what we’re seeing, if the river networks have been active for a long time,” says Taylor Perron, the Cecil and Ida Green Assistant Professor of Geology at MIT. “It raises some very interesting questions about what has been happening on Titan in the last billion years.”

“It’s a weirdly Earth-like place, even with this exotic combination of materials and temperatures,” Perron says. “And so you can still say something definitive about the erosion. It’s the same physics.”

Compared to most moons in our solar system, Titan is relatively smooth, with few craters pockmarking its facade. Titan is around four billion years old, about the same age as the rest of the solar system. But judging by the number of craters, one might estimate that its surface is much younger, between 100 million and one billion years old.

What might explain this moon’s low crater count? Perron says the answer may be similar to what happens on Earth. * “We don’t have many impact craters on Earth,” Perron says. “People flock to them because they’re so few, and one explanation is that Earth’s continents are always eroding or being covered with sediment. That may be the case on Titan, too.”

For example, plate tectonics, erupting volcanoes, advancing glaciers and river networks have all reshaped Earth’s surface over billions of years. On Titan, similar processes — tectonic upheaval, icy lava eruptions, erosion and sedimentation by rivers — may be at work.

But identifying which of these geological phenomena may have modified Titan’s surface is a significant challenge. Images generated by the Cassini spacecraft, similar to aerial photos but with much coarser resolution, are flat, depicting terrain from a bird’s-eye perspective, with no information about a landform’s elevation or depth.

“It’s an interesting challenge,” Perron says. “It’s almost like we were thrown back a few centuries, before there were many topographic maps, and we only had maps showing where the rivers are.”

Perron and MIT graduate student Benjamin Black set out to determine the extent to which river networks may have renewed Titan’s surface. The team analyzed images taken from Cassini-Huygens, and mapped 52 prominent river networks from four regions on Titan. The researchers compared the images with a model of river network evolution developed by Perron. This model depicts the evolution of a river over time, given variables such as the strength of the underlying material and the rate of flow through the river channels. As a river erodes slowly through the ice, it transforms from a long, spindly thread into a dense, treelike network of tributaries.

Black compared his measurements of Titan’s river networks with the model, and found the moon’s rivers most resembled the early stages of a typical terrestrial river’s evolution. The observations indicate that rivers in some regions have caused very little erosion, and hence very little modification of Titan’s surface.

“They’re more on the long and spindly side,” Black says. “You do see some full and branching networks, and that’s tantalizing, because if we get more data, it will be interesting to know whether there really are regional differences.”* Going a step further, Black compared Titan’s images with recently renewed landscapes on Earth, including volcanic terrain on the island of Kauai and recently glaciated landscapes in North America. The river networks in those locations are similar in form to those on Titan, suggesting that geologic processes may have reshaped the moon’s icy surface in the recent past.

TheDaily Galaxy via http://web.mit.eduImage credit: NASA/JPL/USGS

Posted at 09:00 AM | Permalink

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Posted by:manos |July 22, 2012 at 06:40 AM

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Posted by:mr |July 22, 2012 at 05:47 PM