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WASHINGTON, Aug. 31 (Xinhua) -- Astronomers using NASA's Chandra X-ray Observatory discovered the first pair of supermassive black holes in a spiral galaxy similar to the Milky Way, NASA announced Wednesday.Approximately 160 million light years from Earth, the pair is the nearest known such phenomenon.The black holes are located near the center of the spiral galaxy NGC 3393. Separated by only 490 light years, the black holes are likely the remnant of a merger of two galaxies of unequal mass a billion or more years ago.Both of the supermassive black holes are heavily obscured by dust and gas, which makes them difficult to observe in optical light. Because X-rays are more energetic, they can penetrate this obscuring material. Chandra's X-ray spectra show clear signatures of a pair of supermassive black holes."If this galaxy weren't so close, we'd have no chance of separating the two black holes the way we have," said Pepi Fabbiano of the Harvard-Smithsonian Center for Astrophysics, who led the study that appeared Wednesday in on-line issue of the journal Nature. "Since this galaxy was right under our noses by cosmic standards, it makes us wonder how many of these black hole pairs we've been missing."Previous observations in X-rays and at other wavelengths indicated that a single supermassive black hole existed in the center of NGC 3393. However, a long look by Chandra allowed the researchers to detect and separate the dual black holes. Both black holes are actively growing and emitting X-rays as gas falls towards them and becomes hotter.When two equal-sized spiral galaxies merge, astronomers think it should result in the formation of a black hole pair and a galaxy with a disrupted appearance and intense star formation. A well-known example is the pair of supermassive black holes in NGC 6240, which is located about 330 million light years from Earth.However, NGC 3393 is a well-organized spiral galaxy, and its central bulge is dominated by old stars. These are unusual properties for a galaxy containing a pair of black holes.

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.

WASHINGTON, Sept. 15 (Xinhua) -- The rates of new lung cancer cases in the United States dropped among men in 35 states and among women in six states between 1999 and 2008, according to a report released Thursday by the Centers for Disease Control and Prevention (CDC).Among women, lung cancer incidence decreased nationwide between 2006 and 2008, after increasing steadily for decades.The decrease in lung cancer cases corresponds closely with smoking patterns across the nation, the report said. In the West, where smoking prevalence is lower among men and women than in other regions, lung cancer incidence is decreasing faster. Studies show declines in lung cancer rates can be seen as soon as five years after smoking rates decline.The report also noted that states that make greater investments in effective tobacco control strategies see larger reductions in smoking; and the longer they invest, the greater the savings in smoking -- related health care costs. Such strategies include higher tobacco prices, hard-hitting media campaigns, 100 percent smoke-free policies, and easily accessible quitting treatments and services for those who want to quit."Although lung cancer among men and women has decreased over the past few years," said CDC Director Thomas Frieden in a statement. "too many people continue to get sick and die from lung cancers, most of which are caused by smoking. The more we invest in proven tobacco control efforts, the fewer people will die from lung cancer."Lung cancer is the most commonly diagnosed cancer, and the leading cause of cancer death in the United States. Cigarette smoking and exposure to secondhand smoke cause most lung cancer deaths in the United States.

SYDNEY, Aug. 16 (Xinhua) -- People sitting in front of TV for hours on end could shorten their life expectancy by almost five years, according to an Australian study published on Tuesday by the British Journal of Sports Medicine.Researchers from the University of Queensland estimate that for every hour adults spend in front of TV, their life expectancy shortens by almost 22 minutes.Those who watched six hours a day lived 4.8 years less than those who don't watch TV.The study is the first in Australia to look into how TV habits affect longevity.The Australian researchers found that watching TV could have a similar negative impact on life expectancy to that of obesity, smoking and low physical activity."People don't realize how it all adds up," the study's lead author Dr. Lennert Veerman told the Australian Associated Press (AAP)."They should try not to watch too much TV and find alternative things to do, preferably things that are light activities," Veerman said.The study was based on data from the Australian Diabetes, Obesity and Lifestyle study and asked more than 11,000 people aged over 25 about their weekly TV viewing time.The study found that in 2008 Australian adults watched 9.8 billion hours of TV."These findings suggest that substantial loss of life may be associated with prolonged TV viewing time among Australian adults," the study said."TV viewing time may have adverse health consequences that rival those of lack of physical activity, obesity and smoking; every single hour of TV viewed may shorten life by as much as 22 minutes," it said."With further corroborative evidence, a public health case could be made that adults also need to limit the time spent watching TV."Australians are recommended to spend at least 30 minutes a day doing moderate-intensity physical activity to reduce an increased risk of developing cardiovascular disease.

BRUSSELS, May 31 (Xinhua) -- Baby bottles containing the substance Bisphenol A (BPA) would have to be pulled from the shelves across the European Union (EU) starting from Wednesday, in a "milestone" move to better protect the health of EU citizens, an official said Tuesday."Due to the fact that there are uncertainties concerning the effect of the exposure of infants to Bisphenol A, the commission deemed it both necessary and appropriate to take action," said John Dalli, EU Health and Consumer Policy Commissioner."The aim is to further reduce the exposure of the most vulnerable part of our population, i.e. infants," he said.The ban, adopted in an EU directive in late January, would prohibit baby bottles containing BPA from placing on the EU market and import into the 27-member EU from June 1.Previously, the bloc had already banned the manufacture of the controversial baby bottles on March 1, and the industry has been withdrawing such products voluntarily.BPA is an organic molecule that is used in the manufacture of polycarbonate plastics, which are used to manufacture plastic materials, such as baby bottles.Traces of BPA can be released from plastic containers into the food they carry if these containers are heated at high temperatures. They may lead to early sexual development of children and could cause cancer, according to health officials.China would also prohibit the manufacture of feeding bottles containing BPA from June 1, while imports and sales of bottles containing BPA would be banned starting from Sept. 1.