Neville J Comments in teal From Neville Jones Mon Sep 10 01:37:29 2007 Paul, My replies in red -----Original Message----- From: paul_deema@xxxxxxxxxxx Sent: Sun, 9 Sep 2007 17:26:33 +0000 (GMT) Neville J Please allow me a dissenting view! Certainly. The suggestion that the Moon has nothing to reflect off is simply wrong. You can read a book by its light on Earth a quarter million miles away on a clear Full Moon night. It has an albeido of 7%! The fact that the Moon reflects light does not alter the fact that the Moon's (reflected) light has nothing to reflect off. The albedo has nothing to do with what I am saying. There are no clouds, no trees, no buildings, and there is no atmosphere. [OK -- no trees, buildings, atmosphere or clouds, but lots of rocks, big rocks and even bigger rocks ie terraine. Light reflects off all of these and albeido is certainly a relevant parameter.] Now if you were standing on it [by this I mean the Moon] and there were scratches and dust on your visor, however small and/or sparse, the glare would certainly shut down your irises. Utter nonsense. The Moon must be at least as far, if not farther, away from the Sun as we are. When was the last time your iris "shut down"?! [I think this comment is based on a false premise. Perhaps you read "shut down" as "close completely"? Let me rephrase -- "reduce aperature".] But apart from that, and I think you may have the expertise to evaluate this suggestion, you don't have to be looking at a bright object in order for your irises to close down -- it is only necessary that light can enter your eyes from an object at any angle. I speak from the perspective of someone who both wears spectacles and sands wood. Paul, you would simply have to do the same thing that you have to do here, either tilt your head back or use your hand as a blinker. [If you can't imagine this I'll draw you a picture, but that takes a significant amount of time so I hope your visualization process is working. You are standing on the Moon surrounded by reflecting objects. There is dust on your visor. There are minute scratches on your visor. Regardless of where you look or hold your hand, light is reflecting off these visor transparency deficiencies into your eyes. Everything inside your helmet -- including your face -- is reflecting this together with any direct incident light which also reflects off the transparency deficiencies and the inside of your visor into your eyes. The irises reduce their apature. If you can't imagine that then try imagining this. (I assume you wear spectacles? If not, then sunglasses would be even better). Take these vision enhancing optical devices and give them a light dusting, perhaps by holding them close to and downwind of the vacuum cleaner bag as you shake it to remove the fine particles. Carefully place them on your head and in full sunlight, look into a shadowed area -- an opaque fence between you and the Sun would be ideal. Now tell me if you can make out anything in the shadow and if not suggest a cause.] As the shuttle crew have (finally) confirmed, you can see stars in space, and those stars are "BRILLIANT."[Yes, compared to the blackness of space. But few of their photons reach your eye. If you irises have reduced their aperture, as influenced by local and incomparably greater photon density, you won't see them. Besides, as has been pointed out by Philip -- they were rather busy and checking that the stars were still in their accustomed places was not an issue.] [I note that you have not attempted to address my suggestion.] Neville. Paul D ____________________________________________________________________________________ Sick of deleting your inbox? Yahoo!7 Mail has free unlimited storage. http://au.docs.yahoo.com/mail/unlimitedstorage.html