<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial, helvetica, sans-serif;font-size:12pt"><DIV>What about the effect of light from other stars?</DIV>
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<DIV>Regards,</DIV>
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<DIV>Dan<BR></DIV>
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<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: arial, helvetica, sans-serif"><FONT face=Tahoma size=2><B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> spike <spike66@att.net><BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> ExI chat list <extropy-chat@lists.extropy.org><BR><B><SPAN style="FONT-WEIGHT: bold">Sent:</SPAN></B> Tue, March 29, 2011 7:57:34 PM<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> [ExI] destiny's road: was RE: rebuilding a saturn v today<BR></FONT><BR>...On Behalf Of Mike Dougherty<BR>...<BR><BR>>...In "Destiny's Road" Larry Niven poses a nanotech solution of polishing<BR>the moon's surface to mirror-smooth finish to provide solar power at<BR>night... Mike<BR><BR><BR>Interesting thought experiment: imagine the moon to be a perfectly spherical<BR>polished mirror surface of 100 percent reflectivity in all wavelengths.<BR>What would it look like from here? I would be open to counterargument, but<BR>I
think it would appear as one very bright point of light caused by the<BR>reflection of sunlight. This point of light would have an apparent diameter<BR>of about 80 microradians and would provide a little less than 1% the light<BR>of the sun, nearly regardless of the phase of the moon. This point of light<BR>would be accompanied by a reflection of the earth, which would also look a<BR>lot like a bluish point of light, much dimmer than the other point of light.<BR><BR>I might be off by a factor of two on the big side. I need to ponder that<BR>harder.<BR><BR>Someone please think that through and see if you can get similar looking<BR>numbers. Or if you get different numbers, do explain your reasoning: I am<BR>open to suggestion on it. Mike what numbers did you get, and why?<BR><BR>Another thought experiment: imagine we can stop the nutation of the moon by<BR>some means and round out the orbit, so that it is perfectly
stationary from<BR>our point of view. Then imagine grinding a flat spot on the moon and polish<BR>that. What diameter does the flat spot need to be in order to reflect all<BR>the light down to earth? Think about that one carefully.<BR><BR>spike<BR><BR><BR><BR><BR><BR>_______________________________________________<BR>extropy-chat mailing list<BR><A href="mailto:extropy-chat@lists.extropy.org" ymailto="mailto:extropy-chat@lists.extropy.org">extropy-chat@lists.extropy.org</A><BR>http://lists.extropy.org/mailman/listinfo.cgi/extropy-chat<BR></DIV></DIV></div></body></html>