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LOS ANGELES, June 23 (Xinhua) -- The sun and its inner planets may have formed differently than previously thought, NASA's Jet Propulsion Laboratory (JPL) said on Thursday.Data revealed differences between the sun and planets in oxygen and nitrogen, which are two of the most abundant elements in our solar system, said JPL in Pasadena, Los Angeles.Although the difference is slight, the implications could help determine how our solar system evolved, JPL said.NASA researchers drew the conclusion after analyzing samples returned by NASA's 2004 Genesis mission, according to JPL.The air on Earth contains three different kinds of oxygen atoms which are differentiated by the number of neutrons they contain. Nearly 100 percent of oxygen atoms in the solar system are composed of O-16, but there are also tiny amounts of more exotic oxygen isotopes called O-17 and O-18. Researchers studying the oxygen of Genesis samples found that the percentage of O-16 in the sun is slightly higher than on Earth or on other terrestrial planets. The other isotopes' percentages were slightly lower."We found that Earth, the moon, as well as Martian and other meteorites which are samples of asteroids, have a lower concentration of the O-16 than does the sun," said Kevin McKeegan, a Genesis co-investigator from University of California, Los Angeles (UCLA) and the lead author of one of two papers published this week in Science journal. "The implication is that we did not form out of the same solar nebula materials that created the sun -- just how and why remains to be discovered." Another paper detailed differences between the sun and planets in the element nitrogen. Like oxygen, nitrogen has one isotope, N- 14, that makes up nearly 100 percent of the atoms in the solar system, but there is also a tiny amount of N-15. Researchers studying the same samples saw that when compared to Earth's atmosphere, nitrogen in the sun and Jupiter has slightly more N-14, but 40 percent less N-15. Both the sun and Jupiter appear to have the same nitrogen composition. As is the case for oxygen, Earth and the rest of the inner solar system are very different in nitrogen."These findings show that all solar system objects including the terrestrial planets, meteorites and comets are anomalous compared to the initial composition of the nebula from which the solar system formed," said Bernard Marty, a Genesis co- investigator from Petrographic and Geochemical Research Center in Fracne and the lead author of the other new Science paper. " Understanding the cause of such a heterogeneity will impact our view on the formation of the solar system."Data were obtained from analysis of samples Genesis collected from the solar wind, or material ejected from the outer portion of the sun. This material can be thought of as a fossil of our nebula because the preponderance of scientific evidence suggests that the outer layer of our sun has not changed measurably for billions of years."The sun houses more than 99 percent of the material currently in our solar system, so it's a good idea to get to know it better, " said Genesis Principal Investigator Don Burnett of the California Institute of Technology, Pasadena, California. "While it was more challenging than expected, we have answered some important questions, and like all successful missions, generated plenty more."Genesis was launched in August 2000. The spacecraft traveled to Earth's L1 Lagrange Point about one million miles from Earth, where it remained for 886 days between 2001 and 2004, passively collecting solar-wind samples.JPL managed the Genesis mission for NASA's Science Mission Directorate, Washington. The Genesis mission was part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Alasca.

WASHINGTON, Sept. 27 (Xinhua) -- At least 13 people had been killed amid 72 sickened in 18 states in listeria outbreak traced to Colorado cantaloupes, making it the most deadly U.S. outbreak of food-borne infection since 1998, the Centers for Disease Control and Prevention (CDC) said Tuesday in a statement posted on its website.Of the 13 deaths, four were in New Mexico, two were in Colorado, two were in Texas, and there was one each in Kansas, Maryland, Missouri, Nebraska and Oklahoma.Victims range in age from 35 to 96 years, with an average age of 78. All of the illnesses started on or after July 31.The figures were the latest confirmed as of Monday morning, according to the CDC. But they may well rise in the still-widening outbreak as state and local officials are investigating three additional deaths that may be connected.In 1998, 21 people died from listeria linked to tainted hot dogs, according to a CDC online database.The Food and Drug Administration on Sept. 14 warned consumers not to eat cantaloupes from Colorado's Rocky Ford region shipped by Jensen Farms. The cantaloupes with the brand name Rocky Ford were distributed from July 29 to Sept. 10 in at least 17 states.Listeria is a common bacterium that typically causes mild illness in healthy people, but can cause severe illness in older people and those with compromised immune systems. It also can cause miscarriages and stillbirths in pregnant women and severe infections in new babies.Listeria infections lead to about 1,600 serious illnesses each year and about 260 people die, according to the CDC.The CDC estimates that about 48 million people in the U.S. each year get sick from tainted food, with about 128,000 hospitalized and 3,000 deaths.

CANBERRA, Sept. 23 (Xinhua) -- A genetic study on Friday found Aboriginal Australians are descended from the first people to leave Africa up to 75,000 years ago.Researchers from the University of Western Australia, Murdoch University and an international team analyzed genetic material of a 100-year-old West Australian Aboriginal man's hair, and found he was directly descended from a migration out of Africa into Asia.The study revealed that Australian Aboriginal ancestors split from the first modern human populations to leave Africa, between 64,000 and 75,000 years ago, at least 24,000 years before other human migrations.According to Dr. Joe Dortch, an archaeologist at the University of Western Australia, the discovery rewrites the history of the human species by confirming humans moved out of Africa in waves of migrations rather than in one single out-of-Africa diaspora.It also rewrites the story about how Aborigines arrived in Australia some 50,000 years ago."So far there are no [archaeological] sites that are over 50, 000 years old so it puts a time limit on that and focuses our future efforts," he said in a statement released on Friday.Dr. Dortch believes the finding will foster a sense of pride in modern Australian Aborigines."No-one else in the world can say 'I am descended from people who have been here 75,000 years'."Associate Professor Darren Curnoe, leader of the Human Evolutionary Biology Lab in the School of Biological, Earth & Environmental Sciences at the University of New South Wales, said the study powerfully confirms that Aboriginal Australians are one of the oldest living populations in the world, certainly the oldest outside of Africa."Australians are truly one of the world's great human populations and a very ancient one at that, with deep connections to the Australian continent and broader Asian region. About this now there can be no dispute," he told Xinhua in an email note.Meanwhile, Professor Alan Cooper, Director of the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, said while this is a major step forward, the key unresolved question remains the unique story of Aboriginal history within Australia, such as what has happened in those 50,000 years of life in the harsh Australian environment."Unfortunately, the information from a single individual tells us very little about this fascinating, and critically important part of human history. Aborigines are one of the oldest continuous human populations outside Africa, as they note in the paper, and due to the geographic isolation and limited archaeological records remain one of the most mysterious chapters in human history," he told Xinhua on Friday.The study is published on Friday in the journal Science.Indigenous Australians are the original inhabitants of the Australian continent and nearby islands. They together make up more than 2.5 percent of Australia's population.

WASHINGTON, July 8 (Xinhua) -- U.S. space shuttle Atlantis lifted off on Friday morning from Kennedy Space Center in Florida, on the 135th and final flight in NASA's shuttle program.The shuttle blasted off at about 11:29 a.m. EDT (1529 GMT) on a tower of flame, NASA TV showed.Before taking flight, shuttle Commander Christopher Ferguson saluted all those who contributed over the years to the shuttle program."The shuttle is always going to be a reflection of what a great nation can do when it dares to be bold and commits to follow through,'' he said. "We're not ending the journey today ... we're completing a chapter of a journey that will never end.''In this photo released by NASA, space shuttle Atlantis lifts off from NASA's Kennedy Space Center in Florida, the United States, July 8, 2011. U.S. space shuttle Atlantis lifted off at about 11:29 a.m. EDT (1529 GMT) on Friday from Kennedy Space Center in Florida, on the 135th and final flight in NASA's shuttle program.Atlantis's primary payload is an Italian-built cargo hauler named Raffaello which is loaded with 8,640 pounds (3,919 kgs) of food, clothing, supplies and science equipment to sustain space station operations after the shuttles are retired.Only four astronauts take to the skies because there is no shuttle available for a rescue flight should anything go wrong. Normally NASA sends six or seven astronauts on space shuttle flights -- with the last four-person shuttle crew launched 28 years ago.But Atlantis' status as the final flight means there is no other space shuttle on standby and the U.S. would have to call on Russia for any rescue operation. The Russian Soyuz capsules hold just three astronauts and at least one must be Russian, so two crew members would have to fly up and bring home the Americans from the International Space Station one at a time.The crew will also return an ammonia pump that recently failed on the station. Engineers want to understand why the pump failed and improve designs for future spacecraft. One spacewalk is planned during Atlantis' mission, though it will be conducted by NASA's two resident space station astronauts, rather than the shuttle crew.It is the 33rd voyage for Atlantis. Its return to the earth later this month will mark the end of the 30-year shuttle program.Atlantis will be the last shuttle to be retired. Discovery was first in March, followed by Endeavour at the beginning of June. Each shuttle will head to a museum.When the U.S. space shuttle program officially ends later this year, the Russian space program's Soyuz capsule will be the only method for transporting astronauts to and from the station.Space shuttles have made great contributions to U.S. space exploration. They allowed astronauts to not only launch satellites, but to grab and repair them and put them back into service. Most remarkably, they allowed NASA to regularly rejuvenate the Hubble Space Telescope, which for 21 years has produced images that are transforming astronomers' understanding of the universe. With their enormous cargo bays, the shuttles also enabled the United States and its partners to build the International Space Station.However, high costs, risks, policy shift force the U.S. to quit the space shuttle program.NASA originally estimated the program would cost about 90 billion U.S. dollars. However, its actual cost stands at about 200 billion dollars, compared with the 151 billion dollars spent on Apollo which took Americans to the moon in 1969.Seven astronauts perished when Challenger exploded about a minute after launch in 1986. Nearly two decades after the Challenger explosion, a new catastrophe shocked NASA when the shuttle Columbia disintegrated moments before landing in 2003.One out of every 67 flights ended in death. Based on deaths per million miles traveled, the space shuttle is 138 times riskier than a passenger jet.The panel that investigated the 2003 Columbia accident concluded: "It is in the nation's interest to replace the Shuttle as soon as possible.''The Obama administration wants to spur private companies to get into the space taxi business, freeing NASA to focus on deep space exploration and new technology development.During his first-ever Twitter town hall meeting on Wednesday, Obama said NASA needs new technology breakthroughs to revitalize its mission to explore the universe."The shuttle did some extraordinary work in low-orbit experiments, the International Space Station, moving cargo. It was an extraordinary accomplishment. And we're very proud of the work that it did," Obama said. "But now what we need is that next technological breakthrough."

MOSCOW, Aug. 26 (Xinhua) -- Russia will carry out two unmanned test launches of Soyuz carrier rockets in the coming fall before delivering crews to the International Space Station (ISS), local media reported on Friday.Citing a source, RIA Novosti news agency said that one of the Soyuz rockets was scheduled to send a new Progress M-13M space freighter to the ISS.On Wednesday, a Progress M-12M cargo ship failed to reach the orbit after the engine of a Soyuz-U carrier rocket turned off during the ascend. Soon after the accident, Russia announced it will temporarily ground all Soyuz rockets.Due to the accident, Russian space authorities have put off Thursday's launch of a Soyuz-2 carrier rocket from the Plesetsk Space Center in northern Russia and a launch of a manned space ship from Baikonur space center in Kazakhstan.After the retirement of the U.S. shuttle fleet, Russia's Soyuz spacecrafts have become the only way for astronauts to reach the ISS until at least the middle of the decade.

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