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15h
revised how did James Bradley discover light aberration?
added 49 characters in body
15h
revised how did James Bradley discover light aberration?
added 49 characters in body
1d
comment is there any theory or observational evidence that our universe is electrically neutral or not?
Thanks, you two. I met this several times. I really do not understand why.
2d
asked how did James Bradley discover light aberration?
Jul
21
reviewed Approve suggested edit on The RA and Dec of lunar poles
Jul
17
comment The RA and Dec of lunar poles
The north pole of the moon should point at some place near north ecliptic pole very roughly. The physical laws can not give me a precise value and region.
Jul
17
comment The RA and Dec of lunar poles
ļ¼ Envite Thanks, I saw this. I need a RA&Dec and a general region pjojected on the sky.
Jul
17
comment The RA and Dec of lunar poles
Yes. This helps. The rotation axis changes. However I am still not able to find a value which can specify the general position of its axis direction and the circle size draw on the sky.
Jul
16
comment The RA and Dec of lunar poles
do you know the exact RA and Dec which the moon points at?
Jul
16
comment The RA and Dec of lunar poles
en.wikipedia.org/wiki/Libration en.wikipedia.org/wiki/Poles_of_astronomical_bodies The main reason should be caused by the change of lunar pole which should be very small. But why is there not position of lunar poles in the second wiki link?
Jul
16
asked The RA and Dec of lunar poles
Jul
15
comment is there any theory or observational evidence that our universe is electrically neutral or not?
OK. I find a paper. arxiv.org/abs/1201.6585 This can partly answer my question.
Jul
15
asked is there any theory or observational evidence that our universe is electrically neutral or not?
Jul
3
revised what will be the exact position of the Thirty Meter Telescope
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Jul
3
asked what will be the exact position of the Thirty Meter Telescope
Jun
27
comment what is the farthest object we've been able to bounce signals off of to date?
Very useful wiki link. At least we have got the signal bounced off by asteroids between Mars and Jupiter. However it seems we are able to do it further, because we still have good resolution at that distance.
Jun
26
comment what is the farthest object we've been able to bounce signals off of to date?
So far, we are able to communicate with Voyagers. However that is not what I wanted. I mean direct reflection of laser or radio signal, which is totally different with communicating with Voyagers.
Jun
26
asked what is the farthest object we've been able to bounce signals off of to date?
May
30
answered What is the difference between LMC and SMC?
May
30
revised Why do we think that there is no two-solar-mass black hole?
deleted 8 characters in body