加载中…在太阳系边缘寻找变化迹象
(2012-08-09 13:17:41)
标签：
杂谈 |
分类： 科学与技术 |
http://photos.state.gov/libraries/amgov/3234/Week_1/08062012_pia13892-640_jpg_600.jpg
美国 “旅行者1号”探测器的最新数据显示，代表星际界未来变化的三个现象中的两个现象在过去7年中格外活跃。
根据美国国家航空航天局（NASA）的“旅行者1号”（Voyager 1）探测器获得的最新数据，代表将在星际界发生的变化的三个现象中的两个现象，在过去7年中比在任何时候都有更活跃的动态。
过去7年里，“旅行者1号”一直在探索太阳向自己周围散发出的电粒子泡外壳。在7月28日这一天之内，从“旅行者1号”的宇宙射线仪获得的数据表明，来自太阳系以外的高能宇宙射线的水平跃升了5％。在当天的后半天，源于太阳系内的低能粒子的水平下降了一半。然而，不出三天，粒子水平又恢复接近原状。
美国航天局在其网站上说，第三个关键的迹象是磁场的方向，科学家们正大力分析数据，看是否已经改变了方向。科学家们预计，当“旅行者1号”穿越到星际空间时，所有这三个迹象都将有所改变。对最新磁场数据的初步分析预计将在下个月出炉。
高能宇宙射线粒子的水平多年来一直在上升，但比现在要慢。最后的跃升—— 5％——在5月份用了一个星期。我们太阳系内的低能粒子的水平在过去两年里在慢慢下降。科学家们预计当“旅行者1号”最终穿越到星际空间时，低能粒子的水平将下降到接近为零。
位于加利福尼亚州帕萨迪纳（Pasadena）加州理工学院(California Institute of Technology)的“旅行者”项目科学家爱德华·斯通（Edward Stone)说：“这些升降比我们以前看到的更明显，但是我们对5月份的数据也曾这样说。数据在以我们始料未及的方式变化，但‘旅行者号’总是带来令我们惊讶的新发现。”
Read more: http://iipdigital.usembassy.gov/st/chinese/inbrief/2012/08/20120808134378.html#ixzz231VFoUy0
Searching for Signs of Change at Solar System's Edge
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NASA scientists say two of three key signs of changes expected to occur at the boundary of interstellar space have changed faster than at any other time in the last seven years, according to new data from NASA's Voyager 1 spacecraft.
Two of three key signs of change expected to occur at the boundary of interstellar space have changed faster than at any other time in the last seven years, according to new data from NASA's Voyager 1 spacecraft.
For the last seven years, Voyager 1 has been exploring the outer layer of the bubble of charged particles the sun blows around itself. In one day, on July 28, data from Voyager 1's cosmic ray instrument showed the level of high-energy cosmic rays originating from outside our solar system jumped by 5 percent. During the last half of that same day, the level of lower-energy particles originating from inside our solar system dropped by half. However, in three days, the levels had recovered to near their previous levels.
A third key sign, NASA said on its website, is the direction of the magnetic field, and scientists are eagerly analyzing the data to see whether that has changed direction. Scientists expect that all three of these signs will have changed when Voyager 1 has crossed into interstellar space. A preliminary analysis of the latest magnetic field data is expected to be available in the next month.
The levels of high-energy cosmic ray particles have been increasing for years, but more slowly than they are now. The last jump — of 5 percent — took one week in May. The levels of lower-energy particles from inside our solar system have been slowly decreasing for the last two years. Scientists expect that the lower-energy particles will drop close to zero when Voyager 1 finally crosses into interstellar space.
"The increase and the decrease are sharper than we've seen before, but that's also what we said about the May data," said Edward Stone, the Voyager project scientist based at the California Institute of Technology in Pasadena, California. "The data are changing in ways that we didn't expect, but Voyager has always surprised us with new discoveries."
Above, an artist's concept shows NASA's two Voyager spacecraft exploring a turbulent region of space known as the heliosheath, the outer shell of the bubble of charged particles around the sun.
Read more: http://iipdigital.usembassy.gov/st/english/inbrief/2012/08/20120805134170.html#ixzz231VHd91b
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