[Stuff deleted]

Would Mr. Hart please explain how one could get every nation on
earth and every corporation to agree that astronomers own the
night sky without `coercion'.   Remember that not every nation
follows the English common law.   In most countries, for most of
history, it was probably true that the rulers `owned' everything
not explicitly owned by individuals.   Even in North America,
where by the principle enunciated, the aboriginal inhabitants should
have owned everything, when new arrivals wanted to use land
and resources, they just took it over.  In case Mr. Hart hasn't noticed,
there is currently a brutal war going on in Bosnia about who owns what.
Of course, if some friendly super power were to give an international
astronomy organization some anti-satelite missiles and also agree
to defend it if attacked, such a proposal might work, but it
would hardly be non-coercive.

Some of us nutty environmentalists think it might make sense first
to try to mobilize public opinion against advertising in space
and also to use governmental actions (like taxing power, for example)
to discourage them.   This of course would be too coercive for
Mr. Hart.