http://boinc.equn.com/einstein/gwaves/detection/index.htm
相关主题的"direct evidence"和"indirect evidence"怎么一样的？？

http://boinc.equn.com/einstein/gwaves/detection/next.html
Next Generation Detectors
下一代的探测器

Binary stars are the strongest and most predictable sources of gravitational waves. However, these waves can be hard to detect. Waves from binary stars are mostly low frequency waves; this makes their signals hard to separate from the earth’s gravitational field and vibrations in the earth. To avoid this problem, scientists are designing new experiments to detect gravitational waves in space.
双星是最强最可预测的引力波源。但是，它们发出的引力波很难以探测。它们发出的引力波大多数是低频率的，这就使这些引力波难以和地球引力场的震荡区分。为了避免这个问题，科学家正在设计新的实验来探测空间中的引力波。

The Laser Interferometer Space Antenna, LISA, is a detector that will fly in space. The equipment for LISA will go on three spacecraft. The spacecraft will orbit the sun as an equilateral triangle with sides of 5 million km. Each spacecraft will communicate with the other two, enabling LISA to detect both the strength and direction of gravitational waves. LISA is a joint European Space Agency and NASA project and should launch around 2014.
LISA（全称空间天线式激光干涉仪），是一个空间的探测器。LISA的仪器会被放在三艘航天器当中。这三艘航天器会围绕太阳运行，形成一个边长为五百万千米的正三角形。每个航天器会与其他的航天器通讯，令LISA可以同时探测引力波的方向和强度。LISA是欧洲空间机构和NASA的一个合作项目，将于2014年左右发射。


LISA (European Space Agency and NASA)
LISA（欧洲空间机构和NASA）
Artist's concept of the LISA mission.
艺术想象图
Image courtesy of NASA.
NASA惠赠

http://boinc.equn.com/einstein/gwaves/predict/waves.html
Gravitational Waves
引力波

To understand the need for gravitational waves in the General Theory of Relativity, we should go back to the previous question:
为了了解为什么在广义相对论中需要引力波，我们回到前面的问题：

What would happen if the sun suddenly disappeared?
如果太阳突然消失，将会发生什么事？


Image courtesy of NASA/JPL-Caltech.
NASA/JPL-Caltech惠赠
   
According to the General Theory of Relativity, the planets orbit the sun because they are taking the shortest path through the curved spacetime (recall the tennis ball).
根据广义相对论，行星之所以环绕太阳是因为它们沿弯曲时空的最短路线行走（回忆网球的例子）。

If the sun suddenly disappeared, the spacetime surrounding it would be changed. According to Einstein’s theory, the spacetime surrounding Mercury would be distorted before the spacetime surrounding Pluto, and Mercury would fly out of orbit first. These spacetime distortions travel as gravitational waves.
如果太阳突然消失，它周围的时空会发生改变。依据爱因斯坦的理论，在水星附近的时空会比在冥王星附近的时空先发生改变，所以谁星会先飞出轨道。这些时空的改变以引力波的形式传递。
  

Artist's drawing of gravitational waves
引力波的艺术想象画
Image courtesy of NASA/JPL-Caltech.  
NASA/JPL-Caltech惠赠
   
It may help to think of gravitational waves as the ripples that form when you throw a rock into a pond. When the rock hits the water, the water immediately surrounding the rock is disturbed and the disturbance spreads out from there. Similarly, a change in the mass or speed of a heavy object disturbs the surrounding spacetime and this effect spreads out as gravitational waves.
把引力波想象成投入池塘中的石头引起的水波可能会帮助理解。当石头投入水面时，在石头周围的水就立刻被扰动，并且扰动会从那里传播到其他地方。相似的，大质量物体的质量或者速度的突然改变会扰动周围的时空，然后这些扰动会用引力波的形式传播出去。

[ Last edited by fwjmath on 2005-11-13 at 10:42 ]

http://boinc.equn.com/einstein/gwaves/predict/space.html
Gravitational Waves and Space
引力波与空间

As they travel through space, gravitational waves cause spacetime to change. This means that the shape of an object pulsates as gravitational waves pass through it. Imagine a gravitational wave passing through a book – the book will be stretched and squeezed, stretched and squeezed, etc. At a given time, the distance between the front and back of the book will have increased and the distance between the top and bottom will have decreased.
当引力波在空间中传播的时候，它们会引起时空的变化。这就意味着物体的形状会由于引力波的通过而发生震荡。想象一束引力波通过一本书时候的情景：那本书会先被伸长，再被缩短，如此反复。在一个给定的时间内，书的厚度会增加，而书的高度会减少。

The strength of the gravitational wave determines how much an object will change in shape. This depends on the type and scale of the event that it came from. Only large-scale events make gravitational waves that we can detect.
引力波的强度决定了物体形变的程度。这取决于它来自什么类型和尺度的时间。只有大尺度的事件发出的引力波我们才能探测到。

To give you an idea of the scales involved, a wave from the collision of two black holes would change space by around 10 -18 meters per kilometer. In other words, a gravitational wave from the collision would change the height of the Empire State building by an amount smaller than 1/100 th the width of a proton. That is why gravitational waves are so difficult to detect!
举个例子，两个黑洞的碰撞产生的引力波可以让空间以大约10^-18米每千米的程度改变。换句话来说，两个黑洞的碰撞产生的引力波会使帝国大厦的高度改变一个质子宽度的百分之一。这就是为什么引力波的探测如此困难的原因。

Fortunately, scientists are now able to build instruments that can make such precise measurements.
幸运地，科学家现在可以建造进行如此精确的测量的仪器了。


A gravitational wave originating from colliding black holes would change the height of the Empire State building less than 1/1000 th the width of a proton! The width of a proton is a thousandth of the width of an atom, the width of an atom is a millionth of the width of a hair, and the width of a hair is a thousandth of one millimeter.
来自黑洞碰撞的引力波会使帝国大厦的高度改变一个质子宽度的百分之一。一个质子宽度是原子宽度的千分之一，原子宽度是一根头发宽度的百万分之一，一根头发宽度是一毫米的一千分之一。

回复第 74 楼：“但是，他最为人知的贡献是发现了重力学定理。”其中的“重力学”改为“引力学”。

回复第 76 楼，我看过官方网站了，官方网站上也是这样的......这，我也没办法.....

上面的四个页面均已转入，谢谢！

Einstein's Special Theory of Relativity

爱因斯坦的狭义相对论

In the late 1800’s, many scientists were comfortable with the existing description of the universe. In fact, many of them thought physics research was winding down and that all they had left to do was work out the details. The problem was that many of the “details” were observations or experimental results that couldn’t be explained by current theories. One such “detail” was that experiments always measured the speed of light as 3x10 8 m/s (186,000 mph).

19世纪末期，大多数科学家都认同于当时对于宇宙的描述。实际上，他们中大部分认为物理学的研究已经相当完善，所剩下的也只是将一些细枝末节了解清楚即可。但问题是许多所谓的细枝末节都是些不能用当时的理论给予解释的观测或实验结果。其中之一就是实验中对光速的测量结果总是在每秒30万公里（也就是时速18.6万英里）。

According to everyday experience, it seems that the speed of light should change depending on how fast you are moving. Imagine a car with a “For Sale” sign in the window going 55 mph.

按照我们的日常经验，光的速度应该是随观测者的移动速度而改变的。想像一辆在车窗上贴着“待售”标牌并以55英里的时速行驶的汽车。

A person standing still on the side of the road would see a car flying by and the sign would be a blur.

一个站在路边的人将看到一辆车飞驰而过，车窗上的标记模糊成一片。

A person driving next to the car at 55 mph could look out the window and copy down the phone number from the sign.

而一个在旁边同样以55英里时速行驶的车上的人就可以将头探出车窗并将标牌上的电话号码抄下来。

A person going down the road in the opposite direction at 55 mph would zoom by the car and probably not even know the sign was there.

但另一个以同样时速却往反方向行驶的人甚至连标牌都看不到。

The speed we see things moving at depends on the difference between how fast the other person is going and how fast we are going.

我们对于物体移动速度的观测结果是依赖于物体与我们自身移动速度的差值的。

The person standing still sees the car going at 55 mph.

静止站立的人看到的车速是每小时55英里。

55 mph (sign) – 0 mph (person) = 55 mph.

每小时55英里（标牌） - 每小时零英里（人） ＝ 每小时55英里。

The person in the car next to the sign sees the car going at 0 mph.

在同样速度的车上的人看到的车速是零。

55 mph (sign) – 55 mph (car) = 0 mph.

每小时55英里（标牌） - 每小时55英里（汽车） ＝ 每小时零英里

The person going the opposite way sees the car going at 110 mph.

往反方向行驶的车上的人看到的车速是每小时110英里

55 mph (sign) - -55 (car) = 110 mph.

每小时55英里（标牌） - （反方向）每小时55英里（车） ＝ 每小时110英里.

Because of this, scientists assumed that if you measure the speed of light in different directions, you should get different speeds since the earth is in orbit around the sun. In 1895 Albert Michelson and Edward Morley performed this experiment and surprisingly, saw no difference in the speed of light for different directions.

因此，科学家们认为，因为地球是在围绕太阳运行，如果我们沿不同方向测量光的速度，将得到不同的结果。1895年，阿尔伯特·迈克尔逊和爱德华·莫雷进行了这个实验，并且出乎意料地末能发现光在不同方向的传播速度有任何的差异。

Albert Einstein resolved this puzzle in 1905 by suggesting that unlike the speed of a car, the speed of light is the same no matter how fast the observer is moving. In other words, even if you ran very fast you would not be any closer to catching up with a light wave than someone standing still. The first principle of Einstein’s Special Theory of Relativity is that the speed of light is always the same regardless of the motion of the observer or the light source.

阿尔伯特·爱因斯坦在1905年解释了这个现象，他认为不同于车的速度，光的速度是恒定的，不会随观察者的移动而变化。换句话说，即使你跑得非常快，你也无法追上光。爱因斯坦的狭义相对论中第一条定律就是光速是恒定的，完全不依赖于观测者及光源的速度。

Einstein also realized that although people see things differently (for example the speed of the “For Sale” sign), the laws of physics have to be the same for all observers. Someone riding on a train should be able to do the same experiments and get the same results as someone sitting in a classroom. If this were not true, people would get conflicting answers about how nature behaves depending on their motion – but nature does what nature does, it can’t follow different predictions depending on who is observing it. Therefore, the second principle of Einstein’s Special Theory of Relativity is that the laws of physics do not depend on the motion of the observer as long as the observer is not speeding up or slowing down.

爱因斯坦也认识到虽然对于同一件事物，不同的人会有不同的看法（比如上面待售车速度的例子），但物理学的法则一定对于所有观测者都是相同的。做同样的实验，火车上的人和教室里的人一定会得到同样的结果。如果不一样，那人们对于自然界的解释将依赖于他们自己的行为，但自然界就是自然界，它不会因为有谁在观察它而表现出什么不同的行为。因此，爱因斯坦的狭义相对论中第二条定律就是物理学的法则并不依赖于观测者的运动，除非观测者的速度有变化。

Principles of the Special Theory of Relativity

狭义相对论的原理

The speed of light is always the same regardless of the motion of the observer or the light source.

光速是恒定的，完全不依赖于观测者及光源的速度。

The laws of physics do not depend on the motion of the observer as long as the observer is not speeding up or slowing down.

物理学的法则并不依赖于观测者的运动，除非观测者的速度有变化。

If these two principles are true, Einstein showed that motion must affect distance and time. Imagine two people watching a beam of light. If one person is standing still, the light will look to her like it is moving at a speed of 186,000 mph. If the other person is in a spaceship traveling 100,000 mph, he still sees the light moving at 186,000 mph. How can this be true? Only if space and time are not absolute.

如果这两条定律都是正确的，爱因斯坦认为运动将会对距离和时间产生影响。设想有两个人在观察一束光。对于静止站立的人，光速是每小时18.6万公里；对于在以10万英里时速飞行的太空船中的人来说，光速仍将是每小时18.6万英里。但是这又怎么可能呢？除非空间和时间都不是绝对的！

According to Einstein’s theory, an object in motion is shorter than when it is at rest. Similarly, a clock in motion ticks more slowly than a clock at rest. In fact, Einstein concluded that distance and time are more accurately described as one thing – spacetime.

按照爱因斯坦的理论，运动中的物体在比它静止时来得短。类似地，运动中的时钟跳得比静止的时钟更慢。实际上，爱因斯坦推断空间和时间可以精确得描述为一个整体 - 时空。

We don’t notice these strange effects on a day-to-day basis because things on earth move significantly slower than the speed of light, so the effects are tiny. As strange as these ideas sound, scientific evidence has continually supported Einstein’s theory.

之所以在日常生活中我们没有注意到这些奇怪的变化是因为地球上物体的移动速度都远远小于光速，因此这些效应显得非常的微弱。虽然这些想法听上去相当奇怪，但不断有新的科学证据被发现可以验证爱因斯坦的理论。

欢迎大家提修改意见～～

另外，我在想这里的spacetime（还有其它页面中的）要不要翻译成“四维空间”什么的？

http://boinc.equn.com/einstein/gwaves/predict/general.html

General Theory of Relativity

广义相对论

Over the next few years, Einstein continued to work out the details of the Special Theory of Relativity. As he did this, he began to wonder how Newton’s definition of gravity fit in with this theory.

在接下来的几年，爱因斯坦继续研究狭义相对论的细节。这时，他开始考虑怎样将牛顿的引力理论溶入到新理论中。

Einstein realized that a person falling to the earth does not feel the effect of gravity, just like astronauts in space. He also realized that a rocket increasing in speed at a constant rate would feel the same force of “gravity” as one sitting on the earth.

爱因斯坦认识到在地球上自由下落的人就像太空中的宇航员一样感觉不到地心引力的作用。他也认识到在恒定加速上升的火箭中，人将感受到和坐在地球上的人相同的引力作用。

Einstein’s General Theory of Relativity is based on this idea that objects on earth feel the same gravitational force as identical objects that are far from heavy objects and speeding up at a constant rate. Einstein realized that since these two forces are the same, the laws of physics have to hold in both cases. This required a change in the definition of gravity.

爱因斯坦的广义相对论的基本假定是地球上的物体感受到的地心引力和远离大质量物体、恒定加速的物体所感受到的力是完全相同的。爱因斯坦认识到既然两种力是相同的，物理学法则在两种情况下也都是适用的。这需要修改对于引力的定义。

Einstein showed that gravity is not the “force” Newton thought it was. He explained that objects are attracted to each other because heavy objects curve spacetime and other objects take the shortest path through this curved spacetime. Mathematically, Einstein found that spacetime is similar to a stretchy fabric, much like a trampoline.

爱因斯坦认为引力并不是牛顿所想的那样。他认为物体之所以会互相吸引是因为重的物体扭曲了时空，其它物体则选择了扭曲时空中的最短路径。爱因斯坦通过数学方法发现时空结构是弹性的，就像蹦床。

Curved Space Around a Massive Object

时空被大质量物体扭曲

Imagine a bowling ball in the middle of a trampoline. The weight of the ball makes the trampoline sink in the middle. A light object, like a tennis ball, on the edge of the trampoline will follow a curved path toward the bowling ball – like a planet orbiting the sun.

想像在蹦床中心放一个保龄球。球的重量将使蹦床中部下陷。而蹦床边缘的轻物体，比如网球，将沿着曲面移向保龄球 - 就像行星围绕着太阳运行。

The sinking of the trampoline represents how heavy objects curve spacetime. The path taken by the tennis ball illustrates an object taking the shortest path through curved spacetime. Newton thought gravity was a mysterious force acting between two objects, but Einstein explained that it is the curving of spacetime.

蹦床的下陷描绘了大质量物体如何扭曲时空。网球的移动路径说明了物体在扭曲时空沿最短路径移动。牛顿认为地心引力是两个物体间的神秘作用力，而爱因斯坦认为它反映的是时空的扭曲。

One prediction of this theory is that light should bend near heavy objects. Heavy objects should curve the spacetime surrounding them and everything, even light, should follow a curved path through spacetime.

广义相对论的预言之一是光线经过大质量物体时会弯曲。大质量物体会扭曲它们周围的时空，以至任何物质，即便是光，在穿越时空时也将按弯曲的路线行进。

In 1919, Sir Arthur Eddington tested this prediction during a solar eclipse by measuring starlight bending around the sun. His result exactly matched Einstein’s prediction. This was the first experimental confirmation of Einstein’s theory and made him immediately famous among scientists and the public.

1919年，阿瑟·艾丁顿通过在日全食时测量太阳边缘处的星光对这个预言进行了验证。他的结果完美地符合了爱因斯坦的预言。这也是对爱因斯坦理论的第一个实验上的证实，并使他在科学界和公众中迅速成名。

[ Last edited by Youth on 2005-11-13 at 23:22 ]

感谢 Youth 斑竹翻译，我这几天在寝室的时间少，基本上都在实验室里，不太方便转到网页中去，不好意思，可能要等几天我再转过去了。

好，以上两个页面都已经转入了，也已经上传了，另外把 http://boinc.equn.com/einstein/gwaves/predict/ 下面六个页面的导航栏都修改过了。

好像直接翻译成“时空”就行了吧~~~

http://boinc.equn.com/einstein/gwaves/detection/resonant.html

Resonant Mass Detectors

共振质量探测仪

Joseph Weber working on a resonant mass detector.
Image courtesy of AIP Emilio Segrè Visual Archives
约瑟夫·韦伯正在共振质量探测器前工作
图片由美国物理协会...提供

Joseph Weber built the first resonant mass detector in the late 1960s. Many similar detectors have been built, but they have not detected gravitational waves yet.
约瑟夫·韦伯在六十年代后期搭建了第一个共振质量探测仪。之后也有许多人搭建了类似的探测仪，但至今仍末成功探测到引力波。

Most resonant mass detectors are made of large, cylindrical aluminum bars. When a gravitational wave passes through the bar, it changes the distance between the two ends of the bar. The bar then absorbs energy from the wave and this makes it vibrate. Then, sensors around the bar detect the vibrations and turn them into electrical signals that researchers can analyze. The bars are often suspended in a vacuum and kept at low temperatures to reduce noise.

大多数共振质量探测仪是由巨大的圆柱形铝棒构成。当引力波经过铝棒时，铝棒的长度将有所改变。铝棒会从引力波中吸收能量并产生振动。铝棒周围的感应器将检测到这些振动并将它们转化为可供分析的电信号。铝棒一般放置在真空中，并保持极低的温度以抑止噪音。

Schematics of a gravitational wave bar detector:
Image courtesy of AURIGA Detector.
用铝棒探测引力波的示意图
图片由“御夫座”探测仪提供

The size of the vibrations depends on the strength of the gravitational wave. Therefore, scientists can figure out the strength of a wave that passed through by measuring the size of the vibration.

振动的幅度依赖于引力波的强度。因此，科学家们能够通过测量振动的幅度来得到引力波的强度。

Resonant mass detectors are less expensive to build than laser interferometer detectors. However, they are only sensitive to waves from specific sources and have lots of background noise. Most of the new gravitational wave detection projects are using laser interferometers instead of resonant mass detectors because they are more sensitive.

建造共振质量探测仪不像建造激光干涉计探测仪那么昂贵。但它们只对特定的有大量背景噪音的引力波源敏感。大多数引力波探测项目都是使用更为灵敏的激光干涉计探测仪而不是共振质量探测仪。

There are a number of resonant mass detectors in use, below are links to some of them.

目前仍有不少共振质量探测仪在使用中，下面是其中几个的主页。

EXPLORER (Switzerland)
NAUTILUS (Italy)
AURIGA (Italy)
miniGRAIL (Netherlands)

EXPLORER（探索者）（瑞士）
NAUTILUS（鹦鹉螺）（意大利）
AURIGA（御夫座）（意大利）
miniGRAIL（小圣杯）（荷兰）

http://boinc.equn.com/einstein/gwaves/detection/laser.html

Laser Interferometers

激光干涉计

A laser interferometer has two arms arranged in the shape of an “L.” Mirrors hang on test masses at each end of both arms, and there is a beam splitter is at the intersection of the two arms. Laser light enters the beam splitter, and the beam splitter sends half of the light down one arm and half down the other arm. The laser light bounces between the mirrors many times before recombining.

激光干涉计中有“L”型放置的两条臂。每条臂上均放置了一些透镜，在两臂交会的地方有一个分束器。激光进入分束器后，分束器将光分为两半后分别送往两臂。两束激光在重新会合前将在镜子间多次反射。

Schematic of a laser interferometer detector.
Image courtesy of LIGO-Caltech.

激光干涉计探测仪的示意图
图片由加州理工LIGO提供

When the two light beams recombine, they interfere and form a pattern that depends on the difference between the distances they traveled. Sensors measure the light pattern and turn it into electrical signals.

当两束光重遇后将发生干涉，并形成一个依赖于两条光路光程差的图样。感应器将对这个图样进行测量并转化为电信号。

Gravitational waves change the interference pattern, so researchers look for them by examining changes in the pattern over time. Scientists can then figure out which signals are from local disturbances and which are from gravitational waves by comparing data from interferometers in different parts of the world.

因为引力波会改变这个干涉图样，研究者们将通过检测图样的变化以搜寻引力波。科学家们还将比较分布在世界各地的干涉计的检测结果，以判别信号是真地来自引力波还是来自于本地的干扰。

Laser Interferometer Detectors

激光干涉计探测仪

LIGO (US)
GEO 600 (Germany)
TAMA (Japan)
VIRGO (Italy, France)
ACIGA (Australia)

LIGO（美国）
GEO 600（德国）
TAMA（日本）
VIRGO（意大利）
ACIGA（澳大利亚）

http://boinc.equn.com/einstein/gwaves/detection/index.htm

图片的说明

At the time of the discovery Russell Hulse (right) was a graduate student and Joseph Taylor (left) was his supervisor at the University of Massachusetts, Amherst.

在作出这次重要发现时，拉赛尔·赫尔斯（右）仍是马萨诸塞州州立大家的一名研究生，而小约塞夫·泰勒（左）是他的导师。

http://boinc.equn.com/einstein/ask/owen.html

关于本·欧文博士
   
Dr. Ben Owen is an Assistant Professor of Physics at Penn State University. Much of his research involves gravitational wave physics. He is hoping to test his predictions with LIGO data.

本·欧文博士是宾州州立大学的助理教授。他的研究领域主要为引力波。他希望能够用LIGO的数据对他的预测进行检验。

Dr. Owen received his Ph.D. from the California Institute of Technology where he worked under Dr. Kip Thorne, author of Black Holes and Time Warps: Einstein’s Outrageous Legacy. Dr. Owen won the Clauser Prize for the best thesis in his graduating class. Titled "Gravitational Waves from Compact Objects", his thesis predicted a new source of gravitational waves. This research has been discussed during several conferences and in over 100 articles.

本·欧文博士在加州理工获得博士学位，他那时的导师是Kip Thorne博士，后者是《黑洞和时间弯曲：爱因斯坦的遗产》一书的作者。Owen博士的研究生论文《来自高密物体的引力波》赢得了Clauser最佳论文奖，他在论文中预言了一种新的引力波源。这篇论文在多次会议和超过100篇的论文中被讨论。

Dr. Owen did research at the Albert Einstein Institute in Germany and at the University of Wisconsin-Milwaukee before joining the Institute for Gravitational Physics and Geometry and the Center for Gravitational Wave Physics at Penn State. Dr. Owen is a member of the LIGO Scientific Collaboration and does data analysis. He visits the LIGO sites in Hanford, WA and Livingston, LA regularly.

在进入宾州州立大学前，欧文博士曾在德国的阿尔伯特·爱因斯坦学院和威斯康星·密尔沃基大学做过研究。欧文博士是LIGO科学协作组的成员，担任数据分析的工作。他经常去拜访汉福和利文斯顿的LIGO观测站。



Institute for Gravitational Physics and Geometry and the Center for Gravitational Wave Physics
最后一段中的这个不知道怎么翻译...