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主题:[转载]牛顿的水桶1687-2011(一:绝对的转动) -- witten1
共:💬37 🌺175 新:
剩余磁场大概能到一亿分之一高斯?
地球附近的磁场强度大概零点几个高斯吧。
不过最后问题好像还是出在磁屏蔽系统。下面一段来自 Clifford Will 的 “Finally, results from Gravity Probe B”。
What ensued during the data analysis phase was worthy of a detective novel. The critical clue came from the calibration tests. Here, they took advantage of residual trapped magnetic flux on the gyroscope. (The designers used superconducting lead shielding to suppress stray fields before they cooled the niobium coated gyroscopes, but no shielding is ever perfect.) This flux adds a periodic modulation to the SQUID output, which the team used to figure out the phase and polhode angle of each rotor throughout the mission. This helped them to figure out that interactions between random patches of electrostatic potential fixed to the surface of each rotor, and similar patches on the inner surface of its spherical housing, were causing the extraneous torques. In principle, the rolling spacecraft should have suppressed these effects, but they were larger than expected. The patch interactions also accounted for the “jumps”: they occurred whenever a gyro’s slowly decreasing polhode period crossed an integer multiple of the spacecraft roll period. What looked like a jump of the spin direction was actually a spiraling path—known to navigators as a loxodrome. The team was able to account for all these effects in a parameterized model.
- 相关回复 上下关系8
🙂[转载]四:历时48年的“水桶”实验 37 witten1 字3413 2012-01-05 00:04:31
🙂看过新闻说到这几个水晶球。 1 az09 字157 2012-01-07 12:37:06
🙂他们是如何屏蔽地球和其他星球的磁力线对这个水晶镀铌陀螺的 97年的鱼 字51 2012-01-05 19:29:39
🙂超导磁屏蔽
🙂不太明白如何超导磁屏蔽,但觉得磁场不是那么容易屏蔽的. 97年的鱼 字243 2012-01-06 22:50:39
🙂[转载]三:爱因斯坦的“颠覆” 26 witten1 字1723 2012-01-05 00:03:32
🙂问个傻问题啊! tollerson 字167 2012-01-10 15:29:11
🙂整个地球看作一个水桶,呵呵 1 witten1 字0 2012-01-10 17:54:48