Chirping Data 啁啾数据 参这里
一个外星人的星球相对于我们的地球保持静止是完全不可能的。您应记得人类正在随着一个绕着太阳旋转的自转着的星球疾驰，而太阳本身也在绕着我们的银河系中心转动。我们可假设我们的地球之外的朋友也有着同样的处境。
这里有一个有趣的结果，就是所有这些运动都将有信号从移动的源发出和/或在移动的星球上接收(all this motion will have on a signal emitted from a moving source and/or received on a moving planet.)。这就是多普勒效应。您无疑是对此非常熟悉的，就像您听到一辆汽车一边鸣笛一边从您身边驶过一般。声音的频率，或定调，会随着卡车的经过而不断变化。您可以出门去亲身体会一下。站在路边并倾听一个朋友鸣着笛从您身边驶过。您也可从一辆固定着的鸣笛的汽车旁飞奔而过，同样您也会听到音调的变化。这就是非常重要的相对速度。
我们正忙于进行几个长期项目，这些项目将提高SETI@home的能力与科学的输出率(power and scientific output)。我们在过去一年的大多数时间都用在了构建与发布建立在BOINC志愿者计算系统上的下一代的SETI@home软件。随着这些成果的逐渐完成，我们将把更多的精力花费到接下来的项目中去。
The antenna platform, 500 feet above the Arecibo dish. The Gregorian dome at the center and the needle-shaped antenna currently used by SETI are clearly visible.
Courtesy of the NAIC - Arecibo Observatory, an NSF facility.
The multi-beam receiver hanging between Arecibo's reflecting dish and the Gregorian dome at 8:30 am on April 21, 2004.
Courtesy of the NAIC - Arecibo Observatory, an NSF facility.
The multi-beam receiver arrives at the Gregorian dome on the morning of April 21.
Courtesy of the NAIC - Arecibo Observatory, an NSF facility.
The multi-beam receiver installed in its place inside the Gregorian dome.
Courtesy of the NAIC - Arecibo Observatory, an NSF facility.
Because Moore's law has been continually increasing the computing power of our volunteers, we developed a new SETI@home application with increased sensitivity. The original SETI@Home stepped coarsely through doppler drift rates. Because of this, there was a possibility of a Gaussian shaped or pulsed signal drifting out of a frequency bin during the duration of the analysis. These signals would be recovered later when the analysis is performed at lower frequency resolution. However, because more noise is included in the analysis performed at lower resolution, it decreases our sensitivity to such signals by a factor of two. Before now there wasn't enough computing power available to perform the full analysis at high resolution.
This new application has been released to the public. The BOINC core client automatically updated SETI@home to the new enhanced version once it was made available. Since there is more computing involved, users will notice a greatly increased turnaround time per work unit. Since BOINC credits by computation and not by workunit, this will not change the rate at which you receive credit. We also extended the return deadlines since clients will be crunching on workunits for longer periods of time.
发表于 2007-7-26 14:40:51
发表于 2007-7-27 11:35:48
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发表于 2007-7-27 17:01:08
