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WASHINGTON, Sept. 15 (Xinhua) -- A team of researchers has discovered a planet that orbits around a pair of stars, the U.S. space agency NASA announced Thursday.This is the first instance of astronomers finding direct evidence of a so-called circumbinary planet. A few other planets have been suspected of orbiting around both members of a dual-star system, but the transits of the circumbinary planet have never been detected previously.The team, led by Laurance Doyle of the SETI Institute in California, used photometric data from the NASA Kepler space telescope, which monitors the brightness of 155,000 stars.NASA's Kepler mission has discovered a world where two suns set over the horizon instead of just one. The planet, called Kepler-16b, is the most "Tatooine-like" planet yet found in our galaxy. Tatooine is the name of Luke Skywalker's home world in the science fiction movie Star Wars. In this case, the planet it not thought to be habitable. It is a cold world, with a gaseous surface, but like Tatooine, it circles two stars.They found the binary star system by detecting a system where the stars eclipsed each other from the perspective of the Kepler spacecraft. These stars have two eclipses: A primary eclipse when the larger star is partially blocked by the smaller star and a secondary eclipse where the smaller star is fully blocked by the larger star.But the researchers also noticed other times when the brightness of the two stars dropped, even when they were not in an eclipse position. This pattern suggested that there was likely a third object involved. The fact that these so-called tertiary and quaternary eclipses recurred after varying intervals of time, and were of different depths, indicated that the stars were in different positions in their orbit at each instance. This result showed that the tertiary and quaternary eclipses were being caused by something circling both stars, and not an object circling one or the other star.Measurements of the variations in the timing of all four types of eclipses, resulting from the mutual gravitational interactions of the two stars and the third body, demonstrated that the third object was, indeed, a planet. Their work indicates that the planet is less massive than Jupiter, possibly comparable in mass to Saturn, and that the larger of the two binary stars is smaller than our Sun.Their findings will be published Friday in Science."This discovery confirms a new class of planetary systems that could harbor life," Kepler principal investigator William Borucki said in a statement. "Given that most stars in our galaxy are part of a binary system, this means the opportunities for life are much broader than if planets form only around single stars. This milestone discovery confirms a theory that scientists have had for decades but could not prove until now."

BEIJING, Sept. 21 (Xinhuanet) -- China will launch an unmanned module next week, paving the way for a planned space station, a spokesman for the space program said on Tuesday.Tiangong-1, or "Heavenly Palace 1", will blast off from Jiuquan Satellite Launch Center in Gansu province between Sept 27 and 30, the spokesman said.The 8.5-ton module, and the Long March II-F rocket that will carry it skyward, were positioned onto the launch pad on Tuesday, signaling that the project has entered the final preparation stage."Scientists will conduct final tests in the next few days before injecting propellants for the launch," Cui Jijun, director of the Jiuquan Satellite Launch Center, said.The program spokesman said that Tiangong-1 will serve as "a target spacecraft" for rendezvous and docking experiments.It will also work as "a platform to test long-term unmanned and short-term manned operations", he said.Technical and medical experiments will provide crucial data ahead of the building of the space station (scheduled for 2020).Three rendezvous and docking experiments will be conducted.An unmanned Shenzhou-VIII craft will be launched later this year to dock with Tiangong-1. In 2012, Shenzhou IX and Shenzhou X will blast off to complete at least one manned docking.Jiao Weixin, a space scientist at Peking University, said that rendezvous and docking - vital maneuvers for manned programs - are hard to master."Rendezvous and docking are difficult because it is like asking two racing cars to keep a distance of 1 meter between them," he said.The mission requires two craft, traveling at speeds of 28,000 km/h, to enter the same orbit and connect with precision, he said.The China Manned Space Engineering Office rescheduled the launch of Tiangong-1 after the failed launch of an experimental orbiter last month.The spokesman said that the carrier rocket to blast off with Tiangong-1 atop has been modified.Only the United States and Russia have mastered rendezvous and docking technology, said Pang Zhihao, deputy editor-in-chief of the magazine Space International.Spacecraft developed by Europe and Japan have utilized US and Russian technology to dock with the International Space Station, he added.

BEIJING, Sept. 26 (Xinhuanet) -- Weather forecasts showed that Thursday or Friday might be suitable for launching the Tiangong-1 spacecraft, experts said.The unmanned spacecraft, part of China's first spacecraft rendezvous and docking mission, was set to blast off from the Jiuquan Satellite Launch Center in Northwest China at an appropriate time between Tuesday and Friday.But the latest weather forecast showed that Tuesday and Wednesday would not be suitable for a launch, Cui Jijun, chief commander of the mission's launch site system, was quoted by China National Radio as saying on Sunday.A precondition for launching is that the average wind speed at the launch site should not be faster than 10 meters a second. The upper-level wind, at 300 meters to 25,000 meters above the Earth, should be no faster than 70 meters a second.The 8.5-ton Tiangong-1 spacecraft and the Long March II-F rocket stand at the Jiuquan Satellite Launch Center on Sept 20. The spacecraft is set to blast off at an appropriate time between Tuesday and Friday.If the wind is too strong, the rising rocket carrier could wiggle and pose a danger, experts said."Everything is ready now except for the right weather," Cui said.On Sunday afternoon, all systems of the Tiangong-1 project went through a joint maneuver, he said. Before that, the 8.5-ton spacecraft, and the Long March II-F rocket that will carry it skyward, were positioned onto the launch pad last Tuesday.Engineers carried out checkups on the conditions of the rocket and the spacecraft, among many other tests in the past few days. All preparation work is done except for fuel loading, he said.Wang Xiaoqing, a publicity official at the launch site, said that the fuel loading usually begins one day before the launch. Once the fuel is loaded into the carrier vehicle, the launch becomes "irreversible".Tiangong-1, or Heavenly Palace 1, will serve as "a target spacecraft" for three rendezvous and docking experiments.The spacecraft rendezvous and docking missions are expected to pave the way for the building of a planned space station scheduled for 2020, previous reports said.Following Tiangong-1, an unmanned Shenzhou VIII spaceship will blast off from the Jiuquan Satellite Launch Center later this year.Lu Jinrong, chief engineer of the mission's launch site system, said that it is rare that two launches of China's manned space program are scheduled in half a year."In the past, the launch site carried out one launch a year, or even one every two to three years," he said."We are already in a high-frequency launch period."

BEIJING, Aug. 22 (Xinhuanet) -- U.S. presidential candidate Rick Perry's controversial stem-cell treatment may inspire desperate patients to follow his lead while causing medical and legal concerns, according to media reports Monday.The Texas governor underwent a procedure on July 1 where stem cells, made from fat taken from his body, were put into his bloodstream to see if they might find their way to fix a bad back.The treatment carries potential risks ranging from blood clots to infection to cancer and may even run afoul of federal rules, doctors say. File photo of U.S. Republican presidential candidate Texas Governor Rick Perry."As a highly influential person of power, Perry’s actions have the unfortunate potential to push desperate patients into the clinic of quacks,” Harvard’s stem cell expert George Daley told the Associated Press.Worries about the safety and wisdom of this treatment are widespread among stem cell researchers as such a treatment has not been thoroughly vetted by researchers or approved by the FDA.

BEIJING, Sept. 4 (Xinhua) -- Officials and delegations from China and African countries have gathered at a seminar being held in Beijing to discuss rural development and economic growth.The seven-day seminar kicked off on Sunday, attracting representatives from China and 11 African countries to exchange views and experiences related to the seminar's theme of "agriculture and rural development."Justin Lin Yifu, chief economist and senior vice president of the World Bank, said at the seminar's opening ceremony that African countries should take cues from China's experience in creating a series of policies to bolster agricultural and rural development, as these policies have also facilitated the country's economic growth.Hu Jinglin, assistant to China's Minister of Finance, said improved agricultural cooperation between China and Africa will help enhance global grain security.China has worked on 142 cooperative agricultural projects with 14 African countries to date. In addition, it has sent 104 agricultural experts to 33 African countries to train more than 4,200 local agricultural technicians.

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