2014年1月24日 星期五

Unexpected discoveries by GOCE spacecraft

http://phys.org/news/2013-12-earthquake-scars-earth-gravity.html]http://phys.org/news/2013-12-earthquake-scars-earth-gravity.html

http://www.uwants.com/viewthread.php?tid=16804120&page=1#pid213621370
http://www.discuss.com.hk/viewthread.php?tid=22741881&page=1#pid378300158

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kevin_hingwanyu
1 / 5 (2)Dec 04, 2013
the satellite's accelerometer and ion thruster also revealed that GOCE had 'felt' sound waves in space from the Japanese quake

Layperson's view. Is it possible that the sound waves 'felt' by the satellite's instruments and ion thruster (in space) were some sort of varying electric fields, where the earthquake compressed and stretched the crystals or quartz in rocks to generate the changing electric fields, e.g. piezoelectric effect.
careful analysis shows the effects of the 9.0 earthquake that struck east of Japan's Honshu Island on 11 March 2011 are clearly visible in GOCE's gravity data

I realise that today's instrumental sensitivity could be sufficient to measure gravitational waves with two or few (or one) GOCE spacecrafts.


Read more at: http://phys.org/news/2013-12-earthquake-scars-earth-gravity.html]http://phys.org/news/2013-12-earthquake-scars-earth-gravity.html#jCp

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kevin_hingwanyu
5 / 5 (1)Dec 05, 2013
If some instruments (theoretically) can detect very faint gravitational waves from distant galaxies where the sources with enormous amplitude were produced by some bizarre objects e.g. the distribution of mass collapsed/expanded suddenly for black holes or supernovae, then, on planetary scale the sudden redistribution of mass (earthquake) is sufficiently to generate although "weaker" gravitational waves but ultimately can be detected by nearby instruments or satellites. The logic is, 'gravitational waves' have no specialness, are just common natural phenomena, not discovered yet. (I think) It doesn't make sense why only blackholes supernovae can producing it but to exclude other objects or events. Or magnitude too weak not detectable.

A question is, does the wavelength, frequency or spectrum of gravitational waves matter? i.e. to detect radio, infrared or visible waves the instruments are very different, using an inappropriate instrument (high sensitivity though) will detect nothing!



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kevin_hingwanyu
5 / 5 (1)Dec 25, 2013
A conjecture, no answer yet(?). Assume two GOCE spacecrafts, their distances to the source of an earthquake were different, d1 and d2. Assume their sensitivity could distinguish the difference before / and after the earthquake. The questions are: at the instant when the earthquake occurs, are the two GOCE detect the change (e.g. after earthquake) of mass distribution at the **same time/instant** ? If not the same time, how long would it take for the information (e.g. the change of distribution of mass at the source of earthquake) to travel from d1 to d2 ? The time it would take to travel from d1 to d2, is this the speed of gravity or gravitational wave ?


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kevin_hingwanyu
not rated yetDec 26, 2013
@ Zephir_fan. Thx for your support. Science advances very fast. I update knowledge from Physorg, this forum, other sites and forums. Perhaps other peoples/users of this forum too. How one can know the others' mind/thinking (e.g. pretending . . . etc)?


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