metal or ceramic foam

More information on the asteroid (3753 Cruithne) referred to in "They've already discovered one asteroid which follows a very peculiar orbit; one which basically horseshoes back and forth around the L-4 and L-5 points of the Earth-Sun system ... Mike Combs" has a 385 year period and is 3x6 km (and therefore probably 100 billion tons). That is enough mass for lots of different industries, solar power satellites, O'Neill Colonies, trips to Mars, etc. It is some times referred to as Earth's second Moon. More details can be found at http://aries.phys.yorku.ca/~wiegert/3753.html. Sincerely, Jay Huebner