BO




USE TWITTER-@webjump21-@GLOBENEWSWEB-@DAILYTIMES21-@NEWSBOOK21-@BRASILNEWS21- CALENDAR 2016-CALENDARIO 2016-GLOBE NEWS-GLOBE NEWS-GLOBE NEWS USE TWITTER @GLOBENEWSWEB UŻYWAJ na twojej komórce-تستخدم على الجوال-Die Verwendung auf Ihrem MOBILE-あなたの携帯電話で利用-USE ON YOUR MOBILE-使用您MOBILE-USAR en tu móvil-UTILISER sur votre mobile-Использовать на вашем MOBILE-USE IN-FACEBOOK-News Paper Globe News.NEWSWEEK NEWS-BULGARIAN NEWS-COLOMBIA REPORTS-HAWAII NEWS NOW-THE LOCAL GERMANY-GAZETA POLSKA- KYIVPOST- NEWS JAPAN TODAY NEWS-CBS NEWS- G1 GLOBO-BRASIL NEWS-THE WALL STREET JOURNAL-LE MONDE-FRANCE -TORONTO SUN-THE HINDU-ARAB NEWS-ALJAZEERA-GULFNEWS-VIETNAM NEWS- JAKARTA POST-MOSCOW NEWS-CORRIERE DELLA SERA -NORWAY NEWS-TURKEY NEWS-UKRAINE NEWS-JAKARTA POST-JAPAN TIMES-AL ARABIYA NEWS-DAILY RECORD-KUALA LUMPUR POST-MALAYSIA-MADAGASCAR TRIBUNE-MOROCCO WORLD NEWS ABS -CBN-NEWS-PHILLIPINES NEWS-THE IRISH TIMES-IRELAND NEWS-THE NEWS YORK TIMES-CAMBODIA POST-ALASKA NEWS-SOUTH AFRICA-WELLINGTON NEWS TIMES-ADELAIDE NEWS-THE ADVERTISER-WELLIGTON NEWS-BEIJING NEWS CHINA-MASHABLE-BANGKOK POST-TAILAND NEWS->

sábado, 28 de maio de 2016

NASA WEB-NASA DISCOVERY-NASA Radar Finds Ice Age Record in Mars' Polar Cap

,NASA WEB-NASA DISCOVERY-Chandra Movie Captures Expanding Debris from a Stellar Explosion

NASA WEB´-NASADISCOVERY-Europa's Ocean May Have An Earthlike Chemical Balance

NASA JPL latest news release
NASA Radar Finds Ice Age Record in Mars' Polar CapScientists using radar data from NASA's Mars Reconnaissance Orbiter (MRO) have found a record of the most recent Martian ice age recorded in the planet's north polar ice cap.
The new results agree with previous models that indicate a glacial period ended about 400,000 years ago, as well as predictions about how much ice would have been accumulated at the poles since then.
The results, published in the May 27 issue of the journal Science, help refine models of the Red Planet's past and future climate by allowing scientists to determine how ice moves between the poles and mid-latitudes, and in what volumes.
Mars has bright polar caps of ice that are easily visible from telescopes on Earth. A seasonal cover of carbon-dioxide ice and snow is observed to advance and retreat over the poles during the Martian year. During summertime in the planet's north, the remaining northern polar cap is all water ice; the southern cap is water ice as well, but remains covered by a relatively thin layer of carbon dioxide ice even in southern summertime.
But Mars also undergoes variations in its tilt and the shape of its orbit over hundreds of thousands of years. These changes cause substantial shifts in the planet's climate, including ice ages. Earth has similar, but less variable, phases called Milankovitch cycles.
Scientists use data from MRO's Shallow Subsurface Radar (SHARAD) to produce images called radargrams that are like vertical slices though the layers of ice and dust that comprise the Martian polar ice deposits. For the new study, researchers analyzed hundreds of such images to look for variations in the layer properties.
The researchers identified a boundary in the ice that extends across the entire north polar cap. Above the boundary, the layers accumulated very quickly and uniformly, compared with the layers below them.
"The layers in the upper few hundred meters display features that indicate a period of erosion, followed by a period of rapid accumulation that is still occurring today," said planetary scientist Isaac Smith, the study's lead author. Smith led the work while at Southwest Research Institute in Boulder, Colorado, but is now at the Planetary Science Institute in Tucson, Arizona.
On Earth, ice ages take hold when the polar regions and high latitudes become cooler than average for thousands of years, causing glaciers to grow toward the mid-latitudes. In contrast, the Martian variety occurs when -- as a result of the planet's increased tilt -- its poles become warmer than lower latitudes. During these periods, the polar caps retreat and water vapor migrates toward the equator, forming ground ice and glaciers at mid-latitudes. As the warm polar period ends, polar ice begins accumulating again, while ice is lost from mid-latitudes. This retreat and regrowth of polar ice is exactly what Smith and colleagues see in the record revealed by the SHARAD radar images.
An increase in polar ice following a mid-latitude ice age is also expected from climate models that show how ice moves around based on Mars' orbital properties, especially its tilt. These models predict the last Martian ice age ended about 400,000 years ago, as the poles began to cool relative to the equator. Models suggest that since then, the polar deposits would have thickened by about 980 feet (300 meters).
The upper unit identified by Smith and colleagues reaches a maximum thickness of 1,050 feet (320 meters) across the polar cap, which is equivalent to a 2-foot-thick (60-centimeter-thick) global layer of ice. That is essentially the same as model predictions made by other researchers in 2003 and 2007.
"This suggests that we have indeed identified the record of the most recent Martian glacial period and the regrowth of the polar ice since then. Using these measurements, we can improve our understanding of how much water is moving between the poles and other latitudes, helping to improve our understanding of the Martian climate," Smith said.
After 10 years in orbit, Mars Reconnaissance and its six science instruments are still in excellent shape. "The longevity of the mission has enabled more thorough and improved radar coverage of the Martian poles," said Richard Zurek, the mission's project scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. "Our long life in orbit and powerful 3-D analysis tools are allowing scientists to unravel Mars' past climate history."
The Italian Space Agency provided the SHARAD instrument on Mars Reconnaissance Orbiter and Sapienza University of Rome leads its operations. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems of Denver built the orbiter and supports its operations.

quarta-feira, 18 de maio de 2016

NASA WEB´-NASADISCOVERY-Europa's Ocean May Have An Earthlike Chemical Balance

Europa's varied surface features

A submersible rests on the seafloor above a region of active serpentinization near the Lost City hydrothermal vent field in the mid-Atlantic Ocean.
This enhanced-color view from NASA's Galileo spacecraft shows an intricate pattern of linear fractures on the icy surface of Jupiter's moon Europa. Image Credit: NASA/JPL-Caltech/ SETI Institute
› Full image and caption
A new NASA study modeling conditions in the ocean of Jupiter's moon Europa suggests that the necessary balance of chemical energy for life could exist there, even if the moon lacks volcanic hydrothermal activity.
Europa is strongly believed to hide a deep ocean of salty liquid water beneath its icy shell. Whether the Jovian moon has the raw materials and chemical energy in the right proportions to support biology is a topic of intense scientific interest. The answer may hinge on whether Europa has environments where chemicals are matched in the right proportions to power biological processes. Life on Earth exploits such niches.
In a new study, scientists at NASA's Jet Propulsion Laboratory, Pasadena, California, compared Europa's potential for producing hydrogen and oxygen with that of Earth, through processes that do not directly involve volcanism. The balance of these two elements is a key indicator of the energy available for life. The study found that the amounts would be comparable in scale; on both worlds, oxygen production is about 10 times higher than hydrogen production.
The work draws attention to the ways that Europa's rocky interior may be much more complex and possibly earthlike than people typically think, according to Steve Vance, a planetary scientist at JPL and lead author of the study. "We're studying an alien ocean using methods developed to understand the movement of energy and nutrients in Earth's own systems. The cycling of oxygen and hydrogen in Europa's ocean will be a major driver for Europa's ocean chemistry and any life there, just as it is on Earth."
Ultimately, Vance and colleagues want to also understand the cycling of life's other major elements in the ocean: carbon, nitrogen, phosphorus and sulfur.
As part of their study, the researchers calculated how much hydrogen that could potentially be produced in Europa's ocean as seawater reacts with rock, in a process called serpentinization. In this process, water percolates into spaces between mineral grains and reacts with the rock to form new minerals, releasing hydrogen in the process. The researchers considered how cracks in Europa's seafloor likely open up over time, as the moon's rocky interior continues to cool following its formation billions of years ago. New cracks expose fresh rock to seawater, where more hydrogen-producing reactions can take place.
In Earth's oceanic crust, such fractures are believed to penetrate to a depth of 3 to 4 miles (5 to 6 kilometers). On present-day Europa, the researchers expect water could reach as deep as 15 miles (25 kilometers) into the rocky interior, driving these key chemical reactions throughout a deeper fraction of Europa's seafloor.
The other half of Europa's chemical-energy-for-life equation would be provided by oxidants -- oxygen and other compounds that could react with the hydrogen -- being cycled into the Europan ocean from the icy surface above. Europa is bathed in radiation from Jupiter, which splits apart water ice molecules to create these materials. Scientists have inferred that Europa's surface is being cycled back into its interior, which could carry oxidants into the ocean.
"The oxidants from the ice are like the positive terminal of a battery, and the chemicals from the seafloor, called reductants, are like the negative terminal. Whether or not life and biological processes complete the circuit is part of what motivates our exploration of Europa," said Kevin Hand, a planetary scientist at JPL who co-authored the study.
Europa's rocky, neighboring Jovian moon, Io, is the most volcanically active body in the solar system, due to heat produced by the stretching and squeezing effects of Jupiter's gravity as it orbits the planet. Scientists have long considered it possible that Europa might also have volcanic activity, as well as hydrothermal vents, where mineral-laden hot water would emerge from the sea floor.
According to Vance, researchers previously speculated that volcanism is paramount for creating a habitable environment in Europa's ocean. If such activity is not occurring in its rocky interior, the thinking goes, the large flux of oxidants from the surface would make the ocean too acidic, and toxic, for life. "But actually, if the rock is cold, it's easier to fracture. This allows for a huge amount of hydrogen to be produced by serpentinization that would balance the oxidants in a ratio comparable to that in Earth's oceans," he said.
The results are published online this week in the journal Geophysical Research Letters.
NASA is currently formulating a mission to explore Europa and investigate in depth whether the icy moon might be habitable. This new model is part of a large body of evidence that is guiding the mission's development. Some time in the 2020s, NASA would send a highly capable, radiation-tolerant spacecraft into a long, looping orbit around Jupiter to perform repeated close flybys of Europa. During these flybys, the mission would take high-resolution images; determine the composition of the icy moon's surface and faint atmosphere; and investigate its ice shell, ocean and interior.

quinta-feira, 12 de maio de 2016

NASA WEB-NASA DISCOVERY-Chandra Movie Captures Expanding Debris from a Stellar Explosion

THE WASHINGTON POST-Brazil’s president suspended from office, effectively tossing leftist party from power


Chandra Movie Captures Expanding Debris from a Stellar Explosion

Animations of Chandra observations from 2000 through 2015 of the Tycho supernova remnant’s X-ray evolution over time.
When the star that created this supernova remnant exploded in 1572, it was so bright that it was visible during the day. And though he wasn’t the first or only person to observe this stellar spectacle, the Danish astronomer Tycho Brahe wrote a book about his extensive observations of the event, gaining the honor of it being named after him.
In modern times, astronomers have observed the debris field from this explosion − what is now known as Tycho’s supernova remnant − using data from NASA’s Chandra X-ray Observatory, the NSF’s Karl G. Jansky Very Large Array (VLA) and many other telescopes. Today, they know that the Tycho remnant was created by the explosion of a white dwarf star, making it part of the so-called Type Ia class of supernovas used to track the expansion of the Universe.
Since much of the material being flung out from the shattered star has been heated by shock waves − similar to sonic booms from supersonic planes − passing through it, the remnant glows strongly in X-ray light. Astronomers have now used Chandra observations from 2000 through 2015 to create the longest movie of the Tycho remnant’s X-ray evolution over time, using five different images. This shows the expansion from the explosion is still continuing about 450 years later, as seen from Earth’s vantage point roughly 10,000 light years away.
By combining the X-ray data with some 30 years of observations in radio waves with the VLA, astronomers have also produced a movie, using three different images. Astronomers have used these X-ray and radio data to learn new things about this supernova and its remnant.
The researchers measured the speed of the blast wave at many different locations around the remnant. The large size of the remnant enables this motion to be measured with relatively high precision. Although the remnant is approximately circular, there are clear differences in the speed of the blast wave in different regions. The speed in the right and lower right directions is about twice as large as that in the left and the upper left directions. This difference was also seen in earlier observations.
This range in speed of the blast wave’s outward motion is caused by differences in the density of gas surrounding the supernova remnant. This causes an offset in position of the explosion site from the geometric center, determined by locating the center of the circular remnant. The astronomers found that the size of the offset is about 10% of the remnant’s current radius, towards the upper left of the geometric center. The team also found that the maximum speed of the blast wave is about 12 million miles per hour.
Offsets such as this between the explosion center and the geometric center could exist in other supernova remnants. Understanding the location of the explosion center for Type Ia supernovas is important because it narrows the search region for a surviving companion star. Any surviving companion star would help identify the trigger mechanism for the supernova, showing that the white dwarf pulled material from the companion star until it reached a critical mass and exploded. The lack of a companion star would favor the other main trigger mechanism, where two white dwarfs merge causing the critical mass to be exceeded, leaving no star behind.
The significant offset from the center of the explosion to the remnant’s geometric center is a relatively recent phenomenon. For the first few hundred years of the remnant, the explosion’s shock was so powerful that the density of gas it was running into did not affect its motion. The density discrepancy from the left side to the right has increased as the shock moved outwards, causing the offset in position between the explosion center and the geometric center to grow with time. So, if future X-ray astronomers, say 1,000 years from now, do the same observation, they should find a much larger offset.
A paper describing these results has been accepted for publication in The Astrophysical Journal Letters and is available online. The authors are Brian Williams (NASA’s Goddard Space Flight Center), Laura Chomiuk (Michigan State University), John Hewitt (University of North Florida), John Blondin (North Carolina State University), Kazimierz Borkowski (NCSU), Parviz Ghavamian (Towson University), Robert Petre (GSFC), and Stephen Reynolds (NCSU).
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Image credits: X-ray: NASA/CXC/GSFC/B. Williams et al; Optical: DSS; Radio: NSF/NRAO/VLA

quarta-feira, 4 de maio de 2016

NASA WEB-Found: Clues about Volcanoes Under Ice on Ancient Mars

IRELAND NEWS-THE IRISH TIMES- Kenny hopes talks with Independents can be concluded by tomorrow

OGLOBO-FALTA VACINA ,DINHEIRO E VERGONHA NA CARA DOS POLITICOS.


Evidence Builds for Old Under-Ice Volcanoes on Mars
This graphic illustrates where Mars mineral-mapping from orbit has detected minerals that can indicate where a volcano erupted beneath an ice sheet. The site is far from any ice sheet on modern Mars, in an area where unusual shapes have been interpreted as a possible result of volcanism under ice. Image credit: NASA/JPL-Caltech/JHUAPL/ASU
› Full image and caption
Volcanoes erupted beneath an ice sheet on Mars billions of years ago, far from any ice sheet on the Red Planet today, new evidence from NASA's Mars Reconnaissance Orbiter suggests.
The research about these volcanoes helps show there was extensive ice on ancient Mars. It also adds information about an environment combining heat and moisture, which could have provided favorable conditions for microbial life.
Sheridan Ackiss of Purdue University, West Lafayette, Indiana, and collaborators used the orbiter's mineral-mapping spectrometer to investigate surface composition in an oddly textured region of southern Mars called "Sisyphi Montes." The region is studded with flat-topped mountains. Other researchers previously noted these domes' similarity in shape to volcanoes on Earth that erupted underneath ice.
"Rocks tell stories. Studying the rocks can show how the volcano formed or how it was changed over time," Ackiss said. "I wanted to learn what story the rocks on these volcanoes were telling."
When a volcano begins erupting beneath a sheet of ice on Earth, the rapidly generated steam typically leads to explosions that punch through the ice and propel ash high into the sky. For example, the 2010 eruption of ice-covered Eyjafjallajökull in Iceland lofted ash that disrupted air travel across Europe for about a week.
Characteristic minerals resulting from such subglacial volcanism on Earth include zeolites, sulfates and clays. Those are just what the new research has detected at some flat-topped mountains in the Sisyphi Montes region examined with the spacecraft's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), providing resolution of about 60 feet (18 meters) per pixel.
"We wouldn't have been able to do this without the high resolution of CRISM," Ackiss said.
The Sisyphi Montes region extends from about 55 degrees to 75 degrees south latitude. Some of the sites that have shapes and compositions consistent with volcanic eruptions beneath an ice sheet are about 1,000 miles (about 1,600 kilometers) from the current south polar ice cap of Mars. The cap now has a diameter of about 220 miles (about 350 kilometers).
The Mars Reconnaissance Orbiter Project has been using CRISM and five other instruments on the spacecraft to investigate Mars since 2006. The project is managed by NASA's Jet Propulsion Laboratory, Pasadena, California, for the agency's Science Mission Directorate, Washington. The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, provided and operates CRISM. Lockheed Martin Space Systems in Denver built the orbiter and supports its operations.
NASA has three active orbiters and two rovers at Mars that are advancing knowledge about the Red Planet that is useful in planning future missions that will take humans there.