WebProNews

Tag: saturn’s moon

  • Propylene Found on Saturn’s Moon Titan

    Propylene Found on Saturn’s Moon Titan

    Of all the Saturnian moons examined by NASA’s Cassini probe, Titan is consistently the most interesting. Researchers have observed large lakes on the moon’s surface, a vortex that formed rapidly, possible hydrocarbon sand deposits, and what appears to be a solid ice shell.

    This week, NASA further revealed the mysteries of Titan, announcing that propylene has been found on the moon’s surface. The hydrocarbon was detected in Titan’s lower atmosphere by the Cassini spacecraft’s infrared spectrometer.

    “This chemical is all around us in everyday life, strung together in long chains to form a plastic called polypropylene,” said Conor Nixon, a planetary scientist at NASA’s Goddard Space Flight Center and lead author of a paper on the discovery published today in the Astrophysical Journal Letters. “That plastic container at the grocery store with the recycling code 5 on the bottom – that’s polypropylene.”

    Though this discovery marks the first plastic ingredient to be found outside the Earth, astronomers have known for decades that Titan contains many hydrocarbons. Methane is abundant in Titan’s atmosphere, and sunlight breaks the gas down into other hydrocarbons such as ethane and propane, both of which have been confirmed on Titan in the past.

    “I am always excited when scientists discover a molecule that has never been observed before in an atmosphere,” said Scott Edgington, deputy project scientist for Cassini at NASA’s Jet Propulsion Laboratory . “This new piece of the puzzle will provide an additional test of how well we understand the chemical zoo that makes up Titan’s atmosphere.”

    (Image courtesy NASA)

  • Saturn’s Moon Titan May Have Solid Ice Shell

    Saturn’s Moon Titan May Have Solid Ice Shell

    Saturn’s Moon Titan has consistently been one of the most fascinating objects in our solar system. In just the past two years, astronomers have found large bodies of water on the moon, seen the satellite’s weather form a seasonal vortex, and detected hydrocarbon sand on Titan’s surface.

    This week, researchers announced that odd gravitational measurements of Titan’s surface taken by the Cassini spacecraft suggest that the moon’s ice shell is rigid. Moreover, bumps in the surface of the shell could indicate large roots of ice that extend deep into the planet’s oceans. This hypothesis was based on the fact that areas of higher topography on Titan’s shell were found to have lower gravity readings, suggesting that they may cover large ice columns that would be less dense than the surrounding water.

    “Normally, if you fly over a mountain, you expect to see an increase in gravity due to the extra mass of the mountain,” said Francis Nimmo, a co-author of a paper on the findings published in the journal Nature. “On Titan, when you fly over a mountain, the gravity gets lower. That’s a very odd observation.”

    Though the ice column explanation is suitable for Titan’s gravity readings, it could conflict with other observations of the moon. According to NASA, the hypothesis would mean a lack of ice volcanoes, which other researchers have suggested exist on Titan. Also, a fixed ice shell would suggest no plate tectonic action on the moon’s suface.

    “It’s like a big beach ball under the ice sheet pushing up on it, and the only way to keep it submerged is if the ice sheet is strong,” said Douglas Hemingway, lead author of the paper and a planetary scientist at the University of California at Santa Cruz. “If large roots under the ice shell are the explanation, this means that Titan’s ice shell must have a very thick rigid layer.”

    (Image courtesy ESA/NASA/JPL/University of Arizona)

  • Ice May Float on Titan’s Seas, Finds New Study

    Ice May Float on Titan’s Seas, Finds New Study

    Scientists have published a new study that concludes Saturn’s moon Titan might have ice floating in its seas. The presence of hydrocarbon ice in Titan’s methane lakes and seas could explain the mixed readings NASA‘s Cassini probe has seen while recording the reflectivity of the moon’s surface.

    “One of the most intriguing questions about these lakes and seas is whether they might host an exotic form of life,” said Jonathan Lunine, co-author of the research and a Cassini interdisciplinary Titan scientist at Cornell University. “And the formation of floating hydrocarbon ice will provide an opportunity for interesting chemistry along the boundary between liquid and solid, a boundary that may have been important in the origin of terrestrial life.”

    Floating methane ice was thought to be impossible on Titan, since solid methane is more dense than liquid methane, and would sink. The new research considers the interplay between Titan’s lakes and the moon’s atmosphere. Scientists found that the types of methane and ethane ice that might exist on Titan will float if the temperature is below 90.4 kelvins (297 degrees Fahrenheit), methane’s freezing point.

    “We now know it’s possible to get methane-and-ethane-rich ice freezing over on Titan in thin blocks that congeal together as it gets colder — similar to what we see with Arctic sea ice at the onset of winter,” said Jason Hofgartner, lead author of the paper and a Natural Sciences and Engineering Research Council of Canada scholar at Cornell. “We’ll want to take these conditions into consideration if we ever decide to explore the Titan surface some day.”

    Titan is the only other object in our solar system besides Earth known to have bodies of liquid on its surface. Its seas are composed of organic molecules that are believed to have been the building blocks for life on Earth.

  • Cassini Spots “Mini Nile River” on Saturn’s Titan

    The Cassini probe orbiting Saturn and its moons has photographed what the European Space Agency (ESA) is calling a “miniature extraterrestrial version of the Nile river” on Saturn’s moon Titan. The formation is a river valley on the the moon’s surface that runs for over 400 km (248 miles) from its source to a large sea. The radar image is the first time such a long river system has been photographed in high resolution anywhere except Earth.

    “Though there are some short, local meanders, the relative straightness of the river valley suggests it follows the trace of at least one fault, similar to other large rivers running into the southern margin of this same Titan sea,” said Jani Radebaugh, a Cassini radar team associate at Brigham Young University. “Such faults – fractures in Titan’s bedrock – may not imply plate tectonics, like on Earth, but still lead to the opening of basins and perhaps to the formation of the giant seas themselves.”

    Researchers explained that they believe the river is filled with liquid because it is dark along its entire extent in the image. This indicates a smooth surface, and Titan is the only other object in the solar system known to have stable liquid on its surface. The liquid likely isn’t water, though. Titan’s environment contains liquid hydrocarbons, such as ethane and methane.

    “This radar-imaged river by Cassini provides another fantastic snapshot of a world in motion, which was first hinted at from the images of channels and gullies seen by ESA’s Huygens probe as it descended to the moon’s surface in 2005,” said Nicolas Altobelli, ESA’s Cassini Project Scientist.

    The Cassini probe recently celebrated its 15th birthday since launch. In its time around Saturn, the probe has found lakes on Titan, signs of water ice on Enceladus, and followed huge storms in Saturn’s atmosphere.

    (Image courtesy NASA/JPL–Caltech/ASI)

  • Titan’s Atmosphere Shifts Abruptly, South Pole Vortex Forms

    New data from NASA’s Cassini spacecraft shows that a shift in seasonal sunlight has resulted in an abrupt, wholesale reversal in the circulation of the atmosphere of Saturn’s moon Titan. According to researchers, the data shows “definitive” evidence for sinking air at the moon’s south pole where previously the air was upwelling. A paper on the data published today in the journal Nature states that the “key” to air circulation in Titan’s atmosphere is the moon’s tilt in relation to the sun.

    “Cassini’s up-close observations are likely the only ones we’ll have in our lifetime of a transition like this in action,” said Nick Teanby, the study’s lead author and a Cassini team associated at the University of Bristol. “It’s extremely exciting to see such rapid changes on a body that usually changes so slowly and has a ‘year’ that is the equivalent of nearly 30 Earth years.”

    Titan is interesting to researchers because is is one of only a few objects in our solar system, along with Earth, Venus, and Mars, that has both a solid surface and substantial atmosphere. Models of Titan’s atmosphere have predicted atmosphere circulation changes for almost 20 years, but the Titan pole that is currently undergoing winter is normally pointed away from Earth. Cassini is finally observing the circulation changes directly.

    “Understanding Titan’s atmosphere gives us clues for understanding our own complex atmosphere,” said Scott Edgington, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory. “Some of the complexity in both places arises from the interplay of atmospheric circulation and chemistry.”

    NASA also stated that Cassini has detected complex chemical production in Titan’s atmosphere at up to 600 kilometers (400 miles) above the moon’s surface. This means that atmospheric circulation extends to about 100 kilometers (60 miles) higher than scientists expected. The compression of that air as it sank lower created a “hot spot” high above Titan’s south pole. That suggested that changes would be coming to the moon’s atmosphere, and that a layer of haze first detected by NASA’s Voyager spacecraft may not be as “detached” as was previously thought. The haze, instead, may be where small haze particles combine into larger aggregates that drop in Titan’s atmosphere and give the moon it’s orange color.

    “Next, we would expect to see the vortex over the south pole build up,” said Mike Flasar, Cassini’s composite infrared spectrometer principal investigator at NASA’s Goddard Space Flight Center. “As that happens, one question is whether the south winter pole will be the identical twin of the north winter pole, or will it have a distinct personality? The most important thing is to be able to keep watching as these changes happen.”

    (Image courtesy ESA)

  • NASA Spots Pac-Man-Shaped Thermal Pattern on Saturn Moon

    Scientists working on NASA‘s Cassini mission have spotted a second feature shaped like Pac-Man on one of Saturn’s Moon. The pattern appears in thermal data from the moon Tethys, taken using Cassini’s composite infrared spectrometer. A similar thermal pattern was spotted on Saturn’s moon Mimas back in 2010.

    “Finding a second Pac-Man in the Saturn system tells us that the processes creating these Pac-Men are more widespread than previously thought,” said Carly Howett, lead author of a paper about the phenomenon that was recently published in the journal Icarus. “The Saturn system – and even the Jupiter system – could turn out to be a veritable arcade of these characters.”

    The current hypothesis about the Pac-Men holds that high energy electrons bombard low latitudes on the sides of Mimas and Tethys that face the sun as they orbit Saturn. These electrons turn those sections of the surface into hard-packed ice, causing them to resist heating or cooling more than the rest of the surface. Also, since Tethys is bombarded by icy particles from Enceladus, the thermal pattern suggests to researchers that the surface alteration is occurring more quickly than the particles can re-coat the object’s surface. The Pac-Man pattern can actually be seen subtly in visible-light images of Tethys’ surface, appearing as a dark lens-shaped region.

    “Studies at infrared wavelengths give us a tremendous amount of information about the processes that shape planets and moons,” said Mike Flasar, the Cassini spectrometer’s principal investigator at NASA’s Goddard Space Flight Center. “A result like this underscores just how powerful these observations are.”

    When the Cassini data was taken, the daytime temperatures inside the “mouth” of the Pac-Man pattern were 29 degrees Fahrenheit cooler than their surroundings. The warmest temperature recorded on Tethys was -300 degrees Fahrenheit.

    “Finding a new Pac-Man demonstrates the diversity of processes at work in the Saturn system,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory. “Future Cassini observations may reveal other new phenomena that will surprise us and help us better understand the evolution of moons in the Saturn system and beyond.”

    (Image courtesy NASA/JPL-Caltech/GSFC/SWRI)