re: Astronomy & matching seemingly indistguishable points of light
From a practical point of view, I don't think that this is a real concern. Why? Random snapshots of the sky I might take from my backyard won't provide any additional useful info to an astronomical database, since pretty well anything that's visible with the
naked eye would already have been photographed & catalogued by real astronomers (not to mention a huge amount of objects which are not visible).
However, huge collections of photos taken by astronomers (both professional & amature) do exist - and guess what? They're already tagged! Every object in the collection is catalogued and been assigned coordinates (though there are competing astronomical coordinate
systems - I remember that from the Jim Grey video in which he discussed Skyserver, among other things). So images can be grouped according to the coordinate metadata associated with each photo. So essentially, they'd just have to point this sucker at the Skyserver
library (with mods to allow it to use the coordinate info) & let it rip...
Would it be possible for future versions of Windows mobile (PDA, cellphone) be able to participate in this type of p2p collaboration (PNRP or PNM)? ie. in the 'desktop broadcast' scenario when showing a powerpoint presentation directly on other PC's, could
some participants be viewing the contenct on an iPaq? Would windows mobile be announcing & reading 'presence' status in a compatible way? People could use virtual earth mobile for locating each other when trying to meet up somewhere.