NASA的旅行者1号探测器明年可能飞出太阳系
（来源：space.com）本人水平有限，有不通之处，还请大家指正
| Artist's concept of Voyager 1 and Voyager 2 at the edge of the solar system.
旅行者1号和2号在太阳系的边缘的美术概念图
CREDIT: NASA/JPL-Caltech
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[img][/img]
A venerable NASA spacecraft could pop out of our solar system into interstellar space as early as next year, a new study suggests.
一项新的研究表明，一个值得尊敬的NASA航天器最早将在明年飞出我们的太阳系进入星际空间。
The Voyager 1 probe, which is now about 11 billion miles (17.7 billion kilometers) from Earth, has entered an unexpected "transition zone" at the edge of the solar system, according to the study. This finding, along with observations by NASA's Cassini spacecraft, hints that Voyager may be about to go where no man-made object ever has — into the space between the stars — a few years earlier than previously thought.
根据这项研究，现在在离地球大约110亿英里(177亿公里)处的旅行者1号探测器已经进入了在太阳系的边缘
的一个出乎意料的“过渡区”。这一发现,加上NASA的卡西尼号飞船的观测，暗示我们旅行者号可能将要去到从没有人造物体去到过的地方——进入星际空间——这比人们预想的要早几年。
"Perhaps by the end of 2012, we will be out in the galaxy," said the study's lead author, Stamatios Krimigis, of Johns Hopkins University's Applied Physics Laboratory.
“在2012年年底，也许我们将进入银河系”，该研究的带头人，Johns Hopkins 大学应用物理实验室的Stamatios Krimigis说。
Where the solar wind turns a corner 在太阳风的拐弯处
Our sun's sphere of influence, composed of solar plasma and solar magnetic fields, is called the heliosphere. This gigantic structure is about three times wider than the orbit of Pluto. On the outskirts of the heliosphere lies the heliosheath, a turbulent region at the outer reaches of the solar system. 我们太阳的影响范围由太阳等离子体和太阳磁场组成，称为日球层。这个巨大的结构大约是冥王星轨道的三倍宽。在日球层的边界是太阳风鞘，这是一个在太阳系外围的紊流区。
At the edge of the heliosheath is the heliopause — the demarcation line between our cosmic neighborhood and interstellar space. 在太阳风鞘边缘是日球层顶——我们的邻近宇宙和星际空间的分界线。
Voyager 1, which launched in 1977, is currently plying the heliosheath, as is its twin, Voyager 2. Recently, Voyager 1 stumbled into a part of the heliosheath that scientists didn't know existed. 在1997年发射的旅行者1号和它的孪生兄弟旅行者2号，现在正在通过太阳风鞘。最近,旅行者1号磕磕绊绊地进入了太阳风鞘的一个部分——科学家们还不知道这个部分的存在。
[url=][/url] [img][/img] The Voyager 1 spacecraft.
CREDIT: NASA
In this region, the outward speed of the solar wind — the charged particles streaming from the sun — is essentially zero. Voyager 1's measurements show it dropping from about 130,000 mph (209,000 kph) in August 2007 down to zero by April 2010. And it hasn't picked up since. 在这个区域，太阳风——来自太阳的带电粒子流——向外的速度实质上是零。旅行者1号的测量表明，在2010年4月，它从2007年8月的大约130000英里/时(209000公里/时)跌至0，至今没有加快过。
It's not that the solar wind has ceased altogether out there; rather, it’s apparently being blown sideways by a powerful interstellar wind, researchers said. This find, first announced at a conference in December, is reported more fully in the new study and backed up with several more months' worth of data. 这并不是说太阳风在那里完全停止；相反，它显然是被强大的星际风吹到一边，研究人员说。这一发现，在12月举行的一次会议上第一次被宣布，在这项新的研究中得到更充分地报道，并且得到了这几个月更多的数据的支持。
The nature and extent of this "transition zone" should come as a surprise to many scientists, who had predicted a relatively sharp boundary between the heliosheath and interstellar space, researchers said. 研究人员说，这个“过渡区”的性质和范围应该会让许多科学家感到惊讶，应为他们之前预测太阳风鞘和星际空间之间会有一相对清晰的边界。
"It's at variance with all the theoretical models that anybody has come up with so far," Krimigis told SPACE.com. "Nobody predicted that we would go through this region of zero velocity, where essentially the solar wind would be sort of sloshing around and not doing anything." “这和目前为止任何人提出的理论模型都不一致”，Krimigis对SPACE.com说。“没有人预言我们会穿过这个（太阳风）速度为0的区域，在这里太阳风实际上游离在边缘而且起不了任何作用。”
Leaving the solar system 离开太阳系
Krimigis and his colleagues also wanted to figure out just how far Voyager 1 has to go before it reaches interstellar space. So they enlisted the aid of another NASA spacecraft, the Saturn-studying Cassini probe. Krimigis和他的同事们也想知道旅行者1号到达星际空间之前要走多远。所以他们找到了NASA的另一个航天器——研究土星的卡西尼号探测器的帮助。
The researchers looked at Cassini's measurements of energetic neutral atoms flowing out of the heliosheath. This information, combined with Voyager 1 observations of charged particles, gave them an idea of how wide the heliosheath is, and by extension where its edge — the heliopause — is located. 研究者查看了卡西尼对来自太阳风鞘的高能中性粒子流的测量数据。这些信息,结合旅行者1号对带电粒子的观测，让他们知道太阳风鞘有多宽，并进一步了解到太阳风鞘的边缘——日球层顶——的位置。
The team calculated that interstellar space likely begins about 11.3 billion miles (18.2 billion km) from Earth. So Voyager 1 appears to be almost there. Since the probe covers about 330 million miles (531 million km) every year, it could pop out of the solar system as early as next year — a surprise, since previous estimates had pegged the probe's exit at 2015 or so. 他的团队计算出星际空间好像是从距离地球113亿英里（182亿公里）处开始的。所以旅行者1号好像就在那里。因为探测器每年飞行大约33000万英里（53100公里），他最早可在明年飞出太阳系——这是一个惊喜，因为之前的估计认为探测器将在2015年左右飞出太阳系。
That's not a sure thing, however; the calculation has some uncertainty attached to it. In fact, the heliopause could lie anywhere from about 10 billion to 14 billion miles (16.1 to 22.5 billion km) from Earth, researchers said. 但是这不是一件确定的事,因为这项计算有一些不确定因素。据研究人员说，事实上，日球层顶可能位于离地球100亿到140亿英里(161亿公里到225亿公里)的任何地方。
"It could happen any time, but it may be several more years," said Ed Stone, Voyager project scientist at Caltech in Pasadena, Calif., who was not involved in the new study. “这随时都有可能发生，但可能要等多几年。”，加州帕萨迪纳的加州理工学院的旅行者计划科学家Ed Stone说。他并没有参与这项新的研究。
So researchers will doubtless be scrutinizing Voyager 1's data over the coming months and years, looking for any signs that the probe has officially crossed the heliopause. 因此研究人员将在未来几个月或几年仔细检查旅行者1号的数据，寻找任何表明探测器已正式穿过日球层顶的迹象。
"I think we'll know it when we cross it," Stone told SPACE.com. "The direction of the [magnetic] field will change when we get out there, and probably its strength as well." “我认为当我们穿过它时我们会知道的，”Stone对 SPACE.com说。“当我们飞出太阳系时，磁场的方向，或许连同强度也会改变。”
Another likely sign, Krimigis said, would be a sudden drop in the density of hot particles, which are common in the heliosheath, and higher readings of the colder particles thought to populate interstellar space. Krimigis说,另一个可能的迹象,会是热粒子密度的突然下降，这在太阳风鞘很普遍，并且大家认为在星际空间冷粒子读数较高。
Krimigis and his colleagues report their results tomorrow in the June 16 issue of the journal Nature. Krimigis和他的同事们明天将再6月16号的《自然》杂志上发表他们的研究成果。
The Voyagers' instruments are powered by radioisotope thermoelectric generators, which convert the heat emitted by plutonium's radioactive decay into electricity. The instruments should have enough juice left to keep taking measurements until at least 2020, researchers have said. 旅行者号航天器的仪器使用放射性核素热电发电机驱动，它把钚放射性衰变发出的热转化为电能。研究人员说过，这些仪器（have enough juice left ，juice什么意思？请高手指点一下）。
。。 Voyagers still truckin' 旅行者号继续前行
The main mission of both Voyager 1 and Voyager 2, which is currently about 9 billion miles (14.5 billion km) from Earth, was to study Jupiter, Saturn and their moons.
目前离地球大约90亿英里(145亿公里)的旅行者1号和2号的主要任务是研究木星、土星和他们的卫星。
During the 12 years of their initial planetary mission, the twin probes returned a great deal of data that changed scientists' understanding of our cosmic backyard, according to Stone. 在它们最初的行星任务的12年里，这对孪生探测器传回大量数据,改变了科学家对我们的宇宙的后院的理解，据Stone说。
"Time after time, our view of the solar system greatly expanded, as we saw the diversity of bodies in the solar system," he said. 他说：“一次又一次，随着我们认识到太阳系内物体的多样性，我们对太阳系的认识得到极大地拓展。”
But when that phase of the mission was over, the Voyagers just kept cruising and contributing. And now, nearly 34 years after their launch, the spacecraft are still delivering key information — this time from the solar system's edge. Just last week, for example, researchers analyzing Voyager data announced the surprising discovery of huge magnetic bubbles out in the heliosheath. 但当那个阶段的使命结束后，旅行者号还继续航行和贡献。而现在,在它们发射的近34年后，这艘飞船仍然在传送重要信息——这一次在太阳系边缘。举例来说,刚在上周，分析旅行者号的数据的研究人员公布了在太阳风鞘有巨大的磁场泡的惊人发现。
"Our motto [at first] was 'Saturn or bust,'" said Krimigis, who has worked on the Voyager mission for four decades. "That was the original objective, to go to Saturn. Everything else was gravy. And now, here we are." “我们的座右铭（起初）是“土星或失败,”,已为旅行者任务工作40年的Krimigis说。“原来的目标是去土星。其它任何事都是奢望。但现在，我们走到这里了。” | 
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