兰州门静脉系模型(广西开髓定位模型) (今日更新中)

WASHINGTON, Aug. 17 (Xinhua) -- Latest research shows that the Moon could be younger than previous estimates. The findings were published online Wednesday in the Nature journal.The prevailing theory of the Moon's origin is that it was created by a giant impact between a large planet-like object and the proto-Earth. The energy of this impact was sufficiently high that the Moon formed from melted material that was ejected into space. As the Moon cooled, this magma solidified into different mineral components. Analysis of lunar rock samples thought to have been derived from the original magma has given scientists a new estimate of the Moon's age.According to this theory for lunar formation, a rock type called ferroan anorthosite, or FAN, is the oldest of the Moon's crustal rocks, but scientists have had difficulty dating FAN samples. The research team used newly refined techniques to determine the age of a sample of FAN from the lunar rock that was brought back to Earth by the Apollo 16 mission in 1972.The team analyzed the isotopes of the elements lead and neodymium to place the FAN sample's age at 4.36 billion years. This figure is significantly younger than earlier estimates of the Moon's age that range as old as the age of the solar system at 4. 568 billion years. The new, younger age obtained for the oldest lunar crust is similar to ages obtained for the oldest terrestrial minerals -- zircons from western Australia -- suggesting that the oldest crusts on both Earth and Moon formed at approximately the same time, and that this time dates from shortly after the giant impact.This study is the first in which a single sample of FAN yielded consistent ages from multiple isotope dating techniques. This result strongly suggests that these ages pinpoint the time at which the sample crystallized."The extraordinarily young age of this lunar sample either means that the Moon solidified significantly later than previous estimates, or that we need to change our entire understanding of the Moon's geochemical history," Carnegie Institute of Science's geochemist and study author Richard Carlson said.

WASHINGTON, June 9 (Xinhua) -- Observations from NASA's Voyager spacecraft suggest the edge of our solar system may not be smooth, but filled with a turbulent sea of magnetic bubbles, the U.S. space agency said Thursday in a statement.While using a new computer model to analyze Voyager data, scientists found the sun's distant magnetic field is made up of bubbles approximately 100 million miles wide. The bubbles are created when magnetic field lines reorganize. The new model suggests the field lines are broken up into self-contained structures disconnected from the solar magnetic field. The findings are described Thursday in the Astrophysical Journal.Like Earth, our sun has a magnetic field with a north pole and a south pole. The field lines are stretched outward by the solar wind or a stream of charged particles emanating from the star that interacts with material expelled from others in our corner of the Milky Way galaxy.The Voyager spacecraft, more than nine billion miles away from Earth, are traveling in a boundary region. In that area, the solar wind and magnetic field are affected by material expelled from other stars in our corner of the Milky Way galaxy."The sun's magnetic field extends all the way to the edge of the solar system," said astronomer Merav Opher of Boston University. "Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit like a ballerina's skirt. Far, far away from the sun, where the Voyagers are, the folds of the skirt bunch up."Understanding the structure of the sun's magnetic field will allow scientists to explain how galactic cosmic rays enter our solar system and help define how the star interacts with the rest of the galaxy.So far, much of the evidence for the existence of the bubbles originates from an instrument aboard the spacecraft that measures energetic particles. Investigators are studying more information and hoping to find signatures of the bubbles in the Voyager magnetic field data."We are still trying to wrap our minds around the implications of the findings," said University of Maryland physicist Jim Drake, one of Opher's colleagues.Launched in 1977, the Voyager twin spacecraft have been on a 33- year journey. They are en route to reach the edge of interstellar space. NASA's Jet Propulsion Laboratory built the spacecraft and continues to operate them.

XICHANG, Sichuan, July 27 (Xinhua)-- China successfully launched an orbiter into space at 5:44 a.m. Beijing Time Wednesday, as a part of its indigenous satellite navigation and positioning network known as Beidou, or Compass system, sources with the launch center said.The orbiter,launched from the Xichang Satellite Launch Center in southwestern Sichuan Province, was boosted by a Long March-3A carrier rocket into a geostationary orbit.China started to build up its own satellite navigation system to break its dependence on the U.S. Global Positioning System (GPS) in 2000.A Long March-3A carrier rocket lifts off at the Xichang Satellite Launch Center in southwest China's Sichuan Province, July 27, 2011. China successfully launched into space a ninth orbiter for its independent satellite navigation and positioning network known as Beidou, or Compass System here early WednesdayBetween October 2000 and May 2003, the country set up a regional satellite navigation system after launching three Beidou geostationary satellites.The system was known as Beidou-1 and is said to have played an important role in the rescue efforts following the devastating earthquake in May 2008 in Wenchuan as it provided the only channel connecting the quake-hit area and the outside.The Beidou-1 system can not meet growing demand, so a better functional Beidou-2 regional and global navigation system will be set up, Qi Faren, former chief designer for Shenzhou spaceships said in an interview with Xinhua early this year.From April 2007 to April this year, China launched another eight orbiters to form its Beidou-2 system, which will eventually consist of 35 satellites.The network will provide satellite navigation, time and short message services for Asia-Pacific regions by 2012 and global services by 2020.

BEIJING, Aug. 14 (Xinhua) -- China's National Energy Administration (NEA) announced Sunday that the country's total electric power consumption rose 12.2 percent from a year earlier to 2.69 trillion kilowatt-hours (kwh) during the first seven months of this year.In July alone, power consumption was up 11.8 percent year-on-year to 434.9 billion kwh, according to the NEA.During the first seven months, power consumption in the country's primary industries rose 5.1 percent year-on-year to reach 59.1 billion kwh; power use in secondary industries totaled 2.0253 trillion kwh, up 11.9 percent; consumption in tertiary industries surged 15.5 percent to reach 285.3 billion kwh.Meanwhile, consumption by residents in both urban and rural areas rose 12 percent to 317.2 billion kwh.Power generated by China's newly-built power plants reached 41.23 million kilowatts during the January-July period, of which 7.69 million kilowatts was hydro-generated and 27.74 million was coal-fire generated.

来源：资阳报