The model corrected for possible distortions in luminosity resulting from non-economic sources like reflections on large bodies of water, which can distort satellite images.

FORBES: The Case for Keeping the Lights On

Southwest airlines stock tumbled after a Tuesday morning after Prudential Equity analyst Bob McAdoo downgraded the stock to "underweight" from "overweight, " citing problems with the airline's model that are not likely to be corrected soon.

FORBES: Southwest Stock Drops On Downgrade