If we find vast amounts of gold in asteroid, the price of gold will fall to just above the marginal cost of recovering that gold as long as it's lower than its

If we find vast amounts of gold in asteroid, the price of gold will fall to just above the marginal cost of recovering that gold as long as it's lower than its current price -- this is some very basic economics. A good example to consider is aluminium. In early 1880s, the price of aluminium was around $10000 of today's dollars for kilogram -- actually the price of ounce made more sense, as you very rarely saw pieces of aluminium so large to weigh a kilogram back then. For example, the capstone for Washington Monument, weighing 9 kilograms, was the largest single piece of aluminium ever cast at that time. Then, in 1888, the modern process of aluminium was invented, and soon its price rapidly fell by orders of magnitude.