NASA Cassini spacecraft provides new view of Saturn and Earth

Nov. 12, 2013 — NASA has released a natural-color image of Saturn from space, the first in which Saturn, its moons and rings, and Earth, Venus and Mars, all are visible.

The new panoramic mosaic of the majestic Saturn system taken by NASA's Cassini spacecraft, which shows the view as it would be seen by human eyes, was unveiled at the Newseum in Washington on Tuesday.

Cassini's imaging team processed 141 wide-angle images to create the panorama. The image sweeps 404,880 miles (651,591 kilometers) across Saturn and its inner ring system, including all of Saturn's rings out to the E ring, which is Saturn's second outermost ring. For perspective, the distance between Earth and our moon would fit comfortably inside the span of the E ring.

"In this one magnificent view, Cassini has delivered to us a universe of marvels," said Carolyn Porco, Cassini's imaging team lead at the Space Science Institute in Boulder, Colo. "And it did so on a day people all over the world, in unison, smiled in celebration at the sheer joy of being alive on a pale blue dot."

The mosaic is part of Cassini's "Wave at Saturn" campaign, where on July 19, people for the first time had advance notice a spacecraft was taking their picture from planetary distances. NASA invited the public to celebrate by finding Saturn in their part of the sky, waving at the ringed planet and sharing pictures over the Internet.

An annotated version of the Saturn system mosaic labels points of interest. Earth is a bright blue dot to the lower right of Saturn. Venus is a bright dot to Saturn's upper left. Mars also appears, as a faint red dot, above and to the left of Venus. Seven Saturnian moons are visible, including Enceladus on the left side of the image. Zooming into the image reveals the moon and the icy plume emanating from its south pole, supplying fine, powder-sized icy particles that make up the E ring.

The E ring shines like a halo around Saturn and the inner rings. Because it is so tenuous, it is best seen with light shining from behind it, when the tiny particles are outlined with light because of the phenomenon of diffraction. Scientists who focus on Saturn's rings look for patterns in optical bonanzas like these. They use computers to increase dramatically the contrast of the images and change the color balance, for example, to see evidence for material tracing out the full orbits of the tiny moons Anthe and Methone for the first time.

"This mosaic provides a remarkable amount of high-quality data on Saturn's diffuse rings, revealing all sorts of intriguing structures we are currently trying to understand," said Matt Hedman, a Cassini participating scientist at the University of Idaho in Moscow. "The E ring in particular shows patterns that likely reflect disturbances from such diverse sources as sunlight and Enceladus' gravity."

Cassini does not attempt many images of Earth because the sun is so close to our planet that an unobstructed view would damage the spacecraft's sensitive detectors. Cassini team members looked for an opportunity when the sun would slip behind Saturn from Cassini's point of view. A good opportunity came on July 19, when Cassini was able to capture a picture of Earth and its moon, and this multi-image, backlit panorama of the Saturn system.

"With a long, intricate dance around the Saturn system, Cassini aims to study the Saturn system from as many angles as possible," said Linda Spilker, Cassini project scientist based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Beyond showing us the beauty of the Ringed Planet, data like these also improve our understanding of the history of the faint rings around Saturn and the way disks around planets form -- clues to how our own solar system formed around the sun."

Launched in 1997, Cassini has explored the Saturn system for more than nine years. NASA plans to continue the mission through 2017, with the anticipation of many more images of Saturn, its rings and moons, as well as other scientific data.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team is based at the Space Science Institute, Boulder, Colo.

To view the image, visit: http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA17172 .

A new version of the collage of photos shared by the public, with the Saturn system as backdrop, is available at: http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA17679 .

More information about Cassini is available at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

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Is this my finger? Sensory illusion study provides new insight for body representation brain disorders

Sep. 22, 2013 — People can be easily tricked into believing an artificial finger is their own, shows a study published today [23 September] in The Journal of Physiology. The results reveal that the brain does not require multiple signals to build a picture body ownership, as this is the first time the illusion has been created using sensory inputs from the muscle alone.

The discovery provides new insight into clinical conditions where body representation in the brain is disrupted due to changes in the central or peripheral nervous systems e.g. stroke, schizophrenia and phantom limb syndrome following amputation.

Professor Simon Gandevia, Deputy Director of Neuroscience Research Australia (NeuRA), says: "It may seem silly to ask yourself whether your index finger is part of your body. However, our current findings demonstrate that this question has led to important insights into key brain functions.

"These findings could lead to new clinical interventions where the addition or the removal of specific sensory stimuli is used to change someone's body image."

In the experiment, subjects held an artificial finger with their left hand that was located 12 cm above their right index finger. Vision was eliminated and anaesthesia was used to numb the skin and remove feelings of joint movement. When the artificial finger and the right index finger were moved synchronously, subjects reported they were holding their own index finger: the brain incorrectly incorporated the artificial finger into its internal body representation.

The human brain uses sensory signals to maintain and update internal representation of the body, to plan and generate movements and interact with the world. The study gives new understanding as to how the brain decides what is part of our own body and where it is located. Contrary to previous theories which used multiple sensory inputs including touch and vision, these results demonstrate that messages coming from muscle receptors are enough to change the internal body representation.

The team additionally found a new type of sensory 'grasp illusion' in which perceived distances between index fingers decreases when subjects hold an artificial finger. This implies that the brain generates possible scenarios and tests them against available sensory information.

Professor Gandevia says: "Grasping the artificial finger induces a sensation in some subjects that their hands are level with one another, despite being 12 cm apart. This illusion demonstrates that our brain is a thoughtful (yet at times gullible!) decision maker: it uses available sensory information and memories of past experiences to decide what scenario is most likely (i.e. 'my hands are level')."

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Study provides insights on protecting world's poor from climate change

Sep. 11, 2013 — The worst impacts of climate change on the world's poorest fishing communities can likely be avoided by careful management of the local environment and investing in the diversification of options for local people, according to the Wildlife Conservation Society and James Cook University.

Climate change is already putting pressure on fishers who depend on nature for their livelihoods. In a new study, scientists found large differences in the potential to adapt based on the local mixture of social and environmental characteristics, requiring a variety of management approaches for each situation.

The paper appears today in the online journal PLOS ONE. The authors include: Joshua E. Cinner, Cindy Huchery, Nicholas Graham, and Christina Hicks of the ARC Centre of Excellence for Coral Reef Studies, James Cook University; Emily Darling of Simon Fraser University and Austin Humphries of Rhodes University; Nadine Marshall of CSIRO; and Tim McClanahan of the Wildlife Conservation Society.

The study undertaken by an international team of scientists, focused on 12 poor fishing communities along the coast of Kenya -- a poor country that has been identified as one of the most vulnerable to the impacts of climate change. The scientists found that, even among the poor, there were considerable differences in how climate change was likely to affect the communities based on the existing social conditions and how each community cared for its marine resources.

"Despite the fact that all of the communities we studied were geographically close, they were vulnerable in very different ways," said lead author Dr. Joshua Cinner. "Some communities really lacked the assets to invest in new opportunities; others lacked the diversity of livelihood opportunities and skills to make a change, while some lacked the social networks and connections that people can rely on in times of need."

The team also looked at how the local coral reefs were holding up to a changing climate. "There are a number of studies that look at how climate change will affect either ecosystems or society, but in this study we really brought both of these together to get a more complete picture" says co-author Dr. Tim McClanahan, a Senior Conservation Zoologist from the Wildlife Conservation Society. "We conducted rigorous studies of reef ecology, the types of fish people were catching, and local socioeconomic conditions." Consequently, the study provides the most detailed and comprehensive examination of both social and ecological aspects of climate change impacts on coral reef fisheries to date.

The authors noted that climate change is already exerting significant pressure on the fishing communities of coastal Kenya; the 1998 El Nino Southern Oscillation resulted in widespread coral mortality along the coast. In areas where overfishing was rampant, communities lacked the potential to recover quickly from disturbances. These same areas tended to have fish species that were more sensitive to coral loss than areas that were protected from fishing by local communities and the government.

Overall, the authors found that communities and coastal managers can find ways of reducing the impacts of climate change on fragile coral reef ecosystems. Just as important, the authors maintain, will be formulating adaptation solutions combining ecological and socio-economic factors.

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