Why is Arch interested in space weather?
John Nelson of the RCA Corporation would call Arch with the information that a flare was in progress and radio communications across the North Atlantic were totally blocked. Arch would then check the market and find that, typically, the stock market was dropping sharply and that Gold was rising meaningfully during the geomagnetically disturbed period. Arch calculated the average percent change in the Dow Jones Industrial Average around onset of these worst storms and found much stronger than usual negative bias from 2 days before to 3 days after onset of such storms.
