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BEIJING, June 28 (Xinhuanet) -- A truck-sized asteroid passed over the Atlantic Ocean within 7,500 miles of the Earth on Monday, according to NASA's Jet Propulsion Laboratory.The space rock, called asteroid 2011 MD, is the second space rock to zip extremely close to the Earth this year.The asteroid, with latest size estimates ranging from 16 to 66 feet (5 to 20 meters) wide, was discovered just last week on June 22, but there was never any risk of it impacting the Earth, NASA scientists said. That means asteroid 2011 MD would likely be too small to survive the fiery plunge through the Earth's atmosphere, let alone reach the surface, NASA scientists said. Asteroids this size can be expected to buzz Earth with close shaves about once every six years, they added.The space rock flew well below geosynchronous satellites, which orbit 22,236 miles (35,786 km) above the Earth, but well above the 220-mile (354-km) altitude of the International Space Station.There was little chance that the asteroid would hit a satellite because of the vastness of space and relatively small number of satellites, experts said.

CHICAGO, Aug. 25 (Xinhua) -- Gold futures on the COMEX Division of the New York Mercantile Exchange on Thursday bounced off the biggest drop since March 2008, as the weakness in stock market enhanced appeal of gold as a safe-have investment.The most active gold contract for Dec. delivery gained 5.9 U.S. dollars, or 0.3 percent, to 1,763.2 dollars per ounce. The metal suffered on Wednesday the biggest one-day drop since March 19, 2008.Market analysts said that gold extended losses in earlier trading, hit by a margin-requirement increase, but the drop in global stock market gave a push to the metal. Both Dow Jones industrial average and S&P 500 declined on Thursday after a 3-day rise as a government report showed U.S. jobless claims rose last week.Besides, market hearsay went that Germany might be next to get a sovereign-debt downgrade, adding to the positive tone on gold market. German equity market also suffered sharp drop in the day.Many market watchers remained long-term bullish attitude toward gold although they said the precious metal could correct further in the short term. A trader noted that the fundamental factors driving uncertainty and fears are all still there.Expectations are growing that the Federal Reserve Chairman Ben Bernanke would not provide any form of stimulus in a speech scheduled for Friday at a yearly gathering of central bankers in Jackson Hole.Silver for Sept. delivery also rose 1.583 dollars, or four percent, to 40.745 dollars per ounce. Platinum for Oct. delivery lost 3.9 dollars, or 0.2 percent, to 1822.4 dollars per ounce.

HONG KONG, Sept. 9 (Xinhua) -- The Hong Kong Polytechnic University (PolyU) announced Friday that its surveying experts had successfully developed methodologies for precise mapping of the Moon, after intensive analysis of the data captured by the Chinese lunar orbiter ChangE-1 and other lunar exploration missions.According to the PolyU, the team has made significant contributions to lunar mapping. Their efforts culminated in the development of a unique and innovative approach to the creation of accurate 3D models of the lunar surface.The team has produced the most updated parameters of the lunar figure (the shape of the moon), which is essential for lunar mapping using 17.5 million laser altimetry measurements from the ChangE-1and the Japanese SELENE missions.In addition, they also used the new topographic and gravity models to calculate improved crustal thickness and mass distribution of the Moon and established that the average thickness of the Moon's crust is about 40 km on the near side and 50 km on the far side.It was introduced that the resulting lunar mapping was the hard work of a dedicated research team led by Professor Chen Yong-qi, Emeritus Professor of the Department of Land Surveying and Geo-Informatics, who is also serving on the Expert Committee of China's Lunar Exploration Programme (ECCLEP), with the concerted efforts of team members Prof. Chen Wu, Prof. Ding Xiao-li, Prof. Baki Iz, Dr. Bruce King, and Dr. Wu Bo.According to Chen Yong-qi, the lunar mapping project started in 2006. The primary objective was to develop the methodologies and techniques for mapping the Moon surface, which is much more challenging than mapping the Earth's surface because of very few surveyed control points which are essential for accurate map making.Statistics showed that there were only fourteen lunar laser ranging retro reflectors (LRRR) and Apollo lunar surface experiment package (ALSEP) transmitter sites with accurately known coordinates available only on the near side of the Moon, installed by the U.S. Apollo and former Soviet Union Luna missions in the 1960s.Moreover, according to the team, the gravitational field of the Moon is not as well-known as that of Earth, which means the accuracy of the computed lunar satellite's position at any given time is lower than for Earth satellites, thus degrading the mapping accuracy and reliability.In addition, the team expressed that highly reflective lunar surface created significant problems for the automatic processing of images to develop 3D models using the technique of photogramemtry, which is a widely used and highly reliable technique for the creation of maps and 3D models on Earth.Furthermore, the team also revealed they had a plan to compare such data with other data sources in order to evaluate the performance of the ChangE mapping sensors. Since Chen Yong-qi is serving on the ECCLEP, the team has direct access to more recent data captured by the ChangE satellite.

ISLAMABAD, Sept. 11 (Xinhua) -- Chinese ambassador to Pakistan declared on Sunday that the Chinese government will provide an emergency humanitarian aid worth 30 million RMB (4.7 million U.S. dollars) to Pakistan to help its relief efforts.In light of the immense damages caused by the floods in some parts of Pakistan, Chinese Ambassador to Pakistan Liu Jian called on Pakistani Foreign Minister Hina Rabbani Khar on Sunday to express sympathy and solidarity of the Chinese people toward Pakistani people and declared that the Chinese government will provide the emergency humanitarian aid.Diplomats and staff of the Chinese Embassy in Islamabad have recently voluntarily donated 600,000 rupee (about 6860 U.S. dollars) to the people who hit by the floods. The Chinese ambassador handed over the donation to Pakistani side on Sept. 8.On Sept. 9, Chinese Foreign Minister Yang Jiechi sent a message to his Pakistani counterpart H.E. Hina Rabbani Khar, expressing his profound condolence to the victims and sincere sympathy to the affected people of the floods.The Chinese foreign minister said that China, as Pakistan's close friend, feels as much pain as Pakistan does and is ready to provide help to the best of its ability, in line with Pakistan's needs. He is convinced that the Pakistani people will definitely prevail over the natural disaster and rebuild their homes at an early date.

来源：资阳报