[extropy-chat] Suicide the Green way

[spike]

________________________________________
From: extropy-chat-bounces at lists.extropy.org
[mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of Robert Bradbury
...

Offhand, does anyone know why boron doesn't reflect light?

No, but for a light sail boron would have no advantage over lithium, which
does reflect well in the lower frequencies.



  Or whether we can have hydrogen mirrors? 


We couldn't keep them cold enough to stay solid.  Even in deep space the
atoms would pick up enough energy from stray photons to sublime.  I think
that stuff is gone as soon as it hits about 14 kelvin.



 Why do we have to constrain ourselves to aluminum?  Robert


We can make the mirrors on the deck if we use aluminum.  If we take a large
inflatable surface, we could probably vapor deposit pure lithium onto it in
space, but I am not sure there is much weight advantage once one takes into
account the structural strength of aluminum.  Let me look this up tomorrow
Robert.  My reference material is at the office.  My intuition is that for
reflectivity and strength, aluminum packs a lotta bang for the buck in solar
sails.

spike