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by 82_28 » Sat Jul 11, 2015 10:42 am
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by NaturalMystik » Thu Oct 08, 2015 2:19 pm
New Horizons Finds Blue Skies and Water Ice on Pluto
Pluto’s Blue Sky: Pluto’s haze layer shows its blue color in this picture taken by the New Horizons Ralph/Multispectral Visible Imaging Camera (MVIC). The high-altitude haze is thought to be similar in nature to that seen at Saturn’s moon Titan. The source of both hazes likely involves sunlight-initiated chemical reactions of nitrogen and methane, leading to relatively small, soot-like particles (called tholins) that grow as they settle toward the surface. This image was generated by software that combines information from blue, red and near-infrared images to replicate the color a human eye would perceive as closely as possible.
Credits: NASA/JHUAPL/SwRI
The first color images of Pluto’s atmospheric hazes, returned by NASA’s New Horizons spacecraft last week, reveal that the hazes are blue.
“Who would have expected a blue sky in the Kuiper Belt? It’s gorgeous,” said Alan Stern, New Horizons principal investigator from Southwest Research Institute (SwRI), Boulder, Colorado.
The haze particles themselves are likely gray or red, but the way they scatter blue light has gotten the attention of the New Horizons science team. “That striking blue tint tells us about the size and composition of the haze particles,” said science team researcher Carly Howett, also of SwRI. “A blue sky often results from scattering of sunlight by very small particles. On Earth, those particles are very tiny nitrogen molecules. On Pluto they appear to be larger — but still relatively small — soot-like particles we call tholins.”
Scientists believe the tholin particles form high in the atmosphere, where ultraviolet sunlight breaks apart and ionizes nitrogen and methane molecules and allows them to react with one another to form more and more complex negatively and positively charged ions. When they recombine, they form very complex macromolecules, a process first found to occur in the upper atmosphere of Saturn’s moon Titan. The more complex molecules continue to combine and grow until they become small particles; volatile gases condense and coat their surfaces with ice frost before they have time to fall through the atmosphere to the surface, where they add to Pluto’s red coloring.
In a second significant finding, New Horizons has detected numerous small, exposed regions of water ice on Pluto. The discovery was made from data collected by the Ralph spectral composition mapper on New Horizons.Water Ice on Pluto: Regions with exposed water ice are highlighted in blue in this composite image from New Horizons' Ralph instrument, combining visible imagery from the Multispectral Visible Imaging Camera (MVIC) with infrared spectroscopy from the Linear Etalon Imaging Spectral Array (LEISA). The strongest signatures of water ice occur along Virgil Fossa, just west of Elliot crater on the left side of the inset image, and also in Viking Terra near the top of the frame. A major outcrop also occurs in Baré Montes towards the right of the image, along with numerous much smaller outcrops, mostly associated with impact craters and valleys between mountains. The scene is approximately 280 miles (450 kilometers) across. Note that all surface feature names are informal.
Credits: NASA/JHUAPL/SwRI
“Large expanses of Pluto don’t show exposed water ice,” said science team member Jason Cook, of SwRI, “because it’s apparently masked by other, more volatile ices across most of the planet. Understanding why water appears exactly where it does, and not in other places, is a challenge that we are digging into.”
A curious aspect of the detection is that the areas showing the most obvious water ice spectral signatures correspond to areas that are bright red in recently released color images. “I’m surprised that this water ice is so red,” says Silvia Protopapa, a science team member from the University of Maryland, College Park. “We don’t yet understand the relationship between water ice and the reddish tholin colorants on Pluto's surface.”
The New Horizons spacecraft is currently 3.1 billion miles (5 billion kilometers) from Earth, with all systems healthy and operating normally.
https://www.nasa.gov/nh/nh-finds-blue-s ... e-on-pluto
by freemason9 » Thu Oct 08, 2015 8:48 pm
by NaturalMystik » Thu Oct 08, 2015 9:34 pm
by 82_28 » Sat Jun 02, 2018 5:26 am
For decades, researchers have debated about how to classify Pluto. Is it a planet? Is it a dwarf planet? Or is it something else entirely?
Now, scientists from the Southwest Research Institute suggest it may fall into the third category. As Neel V. Patel reports for Popular Science, Pluto could be made up of billions of comets all mashed together. The researchers present their ideas in a study published in the journal Icarus.
Scientists had long believed the dwarf planet Pluto was formed the way planets come to be: they start as swirling dust that’s gradually pulled together by gravity. But with the realization that Pluto was a Kuiper belt dwarf planet, researchers began speculating about the origins of the icy world.
In recent decades, scientists have tossed around the idea that Pluto could be a giant comet. But they had no way to test these speculations. That is, until the summer of 2015, when New Horizons zipped by the tiny world. The historic flyby yielded breathtaking images, spectacular data—and the possibility of testing out the wild comet proposal.
The researchers turned to Sputnik Planitia—the western lobe of the massive heart-shaped icy expanse stamped on Pluto’s side—for the task. As Christopher Glein, lead author of the paper and researcher at the Southwest Research Institute, explains to Patel, the researchers used the data from New Horizons on this icy expanse to estimate the amount of nitrogen on Pluto and the amount that’s escaped from its atmosphere.
The researchers then pulled together composition data gathered by the European Space Agency’s Rosetta mission. The craft orbited Comet 67P/Churyumov-Gerasimenko for two years before purposefully crash-landing into its surface in 2016.
“[W]e used the nitrogen abundance from Rosetta, and scaled that up to the mass of Pluto,” Glein says. Both analyses gave surprisingly similar estimates.
Glein explains the conclusions in a statement: “We found an intriguing consistency between the estimated amount of nitrogen inside the [Sputnik Planitia] glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P, the comet explored by Rosetta.”
The conclusions are far from definitive but hint that the comet idea is an intriguing possibility. However, there are still a few caveats. For one, researchers aren’t sure that comet 67P has an average comet composition, Patel reports. For another, New Horizons only captured information about Pluto at a specific point in time, which means nitrogen rates could have changed over the last billions of years. As Mike Walls writes for Space.com, there’s also still the possibility Pluto formed “from cold ices with a chemical composition closer to that of the sun.”
One big challenge to the theory is the low amounts of carbon monoxide on the dwarf planet—a find that runs counter to the situation of most comets. But that doesn’t preclude the comet idea: Carbon monoxide may be buried deep under the glacier, or even trapped in a below-surface ocean.
Despite these uncertainties, Caltech planetary scientist James Tuttle Keane, who was not involved in the study, tells Gizmodo’s George Dvorsky the study still adds to the important conversation about how the solar system formed.
“This paper is an exciting example of the science that can be achieved when combining data from different, international, planetary science missions,” he says. “There’s been long debate about the role and significance of comets in the construction of planets… This study represents a new piece to this long-standing puzzle.”
As Patel reports, there’s only one way to confirm the new theory: Land on Pluto to gather more data.
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